Flammable Refrigerants

Another point worth mentioning here is the apparent variation in the style of electric motor that is being used on many of the small 'energy optimised' LBP R600a Hermetic compressors. The usual single phase motors include: • RSIR Resistance start Induction Run } Winding resistance values different • CSIR Capacitor Start Induction Run • PSC Permanent Split Capacitor } Winding resistance values similar • CSR Capacitor Start Capacitor Run However, some manufacturers are using a Resistance Start Capacitor Run (RSCR) motor which would appear to be an RSIR motor fitted with a run capacitor (commonly 4.iF). No further information could be obtained on this motor style. Condensers for Hydrocarbon Systems The current materials used in the manufacture of condensers are totally compatible with the hydrocarbon range of refrigerants. The only significant factor to be considered when selecting a condenser for use in a HC system is the type of fan motor used. Avoid motors fitted with carbon brushes and commutators as they present a source of ignition. All types of condensers are suitable with the following being predominant in the self-contained market: • Bare pipe • Finned static • Finned induced draft Evaporators for Hydrocarbon Systems The discussion presented for condensers also applies to evaporators with one additional consideration. It is well known that current synthetic blends such as those in the '400' series are not suitable for use in flooded type evaporators as the individual components will tend to separate (or fractionate). This will also occur for the two hydrocarbon blends of isobutane/propane and propane/ethane. Only run single substance refrigerants in flooded type evaporators. RMD's for Hydrocarbon Systems There are no known compatibility issues for the entire range of refrigerant metering devices available today. The two most common are discussed below. Capillary Tube RMD The information contained in the table below was obtained from a software program called DanCap by Danfoss and is a free download from their website. An inside bore of 0.90mm was used as a baseline for the comparison. The system parameters used were 145W at - 23.3°C SET and 45°C SCT.

Refrigerant Calculated Inside Recommended Capillary Increase in Volume flow Diameter Length (m) Pressure Length Drop (kPa) rate (L/s) (mm) compared to 930 R12 R12 0.2833 0.90 1.54 1.0 1018 R134a 0.2500 0.90 1.96 534 1.27 R600a 0.2467 0.90 2.01 1737 1.30 R404A 0.1650 0.90 4.5 1288 2.92 R290 0.1583 0.90 4.9 1479 3.18 R22 0.1150 0.90 9.43 6.12 The information contained in the following table was obtained when the capacity was raised to 290W (doubled). Refrigerant Calculated Inside Recommend Capillary Increase in Volume Diameter ed Length (m) Pressure Length flow rate (mm) Drop (kPa) compared (L/s) to R12 R12 0.5583 0.90 0.40 930 1.0 R134a 0.4950 0.90 0.50 1018 1.25 R600a 0.4733 0.90 0.55 534 1.38 R404A 0.2950 0.90 1.42 1737 3.55 R290 0.2817 0.90 1.56 1288 3.90 R22 0.2283 0.90 2.36 1479 5.90 Note that 'DanCap' does not recommend the use of 0.90mm capillary tube for most of the refrigerants in this table. This size was maintained for comparative reasons only. After comparing the data from both tables it would appear that the length required for R600a is very close to the length already used for an R134a system of the same capacity however, the higher operating pressures of R290 require a much longer tube length. TX Valve RMD Australian and International Standards place a restriction on the maximum acceptable refrigerant charge in hydrocarbon systems. Manufacturers of self-contained refrigerated appliances are continually refining their system designs to enable them to operate with the smallest possible charge. It therefore stands to reason that TX valves and their associated liquid receivers will be avoided in the range of systems covered by this manual. However, if you are faced with the need to service a hydrocarbon system fitted with a TX valve, Danfoss produce a range of valves specifically for the hydrocarbon refrigerants R600a, R290 and R1270. Along with these, both Danfoss and Carel now produce the newer electronic expansion valves (EEV’s) that will operate on a wide range of refrigerants including R600a and R290.

Also note that the standard range of thermostatic expansion valves will provide satisfactory results in a hydrocarbon system provided the operating pressures and temperatures are similar to those of the synthetic refrigerant the valve was intended for. Normal superheat values and adjustment techniques should be maintained when adjustments are made. Ensure all faulty components are only replaced with components complying with the relevant Australian Standard/s and approved by the manufacturer. Ancillary Equipment for Hydrocarbon Systems LP and HP controls Existing controls are materially compatible however arcing between electrical contacts will present a hazard, depending upon the type. Manufacturers now produce adjustable pressure controls specifically for hydrocarbon systems. The pre-set, totally encapsulated versions are gaining in popularity on self-contained systems due to their arc-free operation. AS/NZS 60079 describes the requirements for electrical equipment installed in an explosive atmosphere and must be complied with when the refrigerant charge exceeds 2.5kg. Encapsulated Type Electro-Mechanical Type

Evaporator Pressure Regulating Valves Existing EPR valves are totally compatible however their use will probably not arise in the self-contained domestic or small commercial markets (except for automotive air conditioning systems). Crankcase Pressure Regulating Valves Existing CPR valves are totally compatible however their use will probably not arise in the self-contained domestic or small commercial markets. Filter Driers Existing liquid and suction line filter driers are totally compatible. Solid core 100% molecular sieve driers are recommended for use in systems using a POE or PAG oil while solid core 80% molecular sieve, 20% activated alumina desiccant mixes are preferred in systems using mineral or AB oils. This latter type of desiccant is also recommended for POE and PAG systems operating under stressful conditions (e.g.high condensing temps) and therefore require protection from acid formation. Suction filter driers having a 30% molecular sieve, 70% activated alumina desiccant mix should be fitted to the suction line immediately before the compressor to remove large quantities of acid that may have accumulated within a system. Note that desiccants containing activated alumina are not suitable for use on systems using POE and PAG oils that contain special additives as these additives will be removed. Keep in mind that filter driers will also remove the odourising (stenching) agent that is added to hydrocarbon refrigerants produced in Australia. Solenoid Valves Existing liquid, suction and 4 way solenoid valves are materially compatible with the hydrocarbon refrigerants. Observe any requirements for electrical equipment installed in an explosive atmosphere. Maintenance Procedures There are no special maintenance requirements that would make a hydrocarbon system stand out from any other normal synthetic system. A routine maintenance should be carried out at regular intervals. It should include: • Keeping the equipment clean • Maintaining clean condensers and evaporators • Checks on compressor oil level and cleanliness • Recording the current draw of electrical components • Checking electrical terminals for tightness and integrity • Ensuring refrigerant circuit integrity using suitable leak detection techniques

Types and properties of compressor lubricating oil Types All of the compressor lubricants used with CFC, HCFC and HFC refrigerants are compatible with HC refrigerants. • MO Mineral Oil A hydrocarbon based wax free oil used with • POE all CFC and HCFC refrigerants in the past. • AB Not suitable for use with the newer HFC refrigerants. • PAG Polyol Ester A synthetic oil developed for use with all HFC • PAO refrigerants but also compatible with all CFC and HCFC refrigerants. Less hygroscopic and higher chemical stability than PAG oils. Alkyl Benzene The first synthetic oil to be used in the industry. Created from aromatic hydrocarbons. It is compatible with mineral oil and has improved oil return. It should not be used with HFC's. Poly Alkyl Glycol The first synthetic oil developed for use with HFC's. Not compatible with copper and extremely hygroscopic. Popular in new auto A/C compressors using HFC refrigerant and ammonia systems. Not recommended for retrofits as it is not compatible with other lubricants. Poly Alpha Olefin A synthetic oil with the same structure as a mineral oil. Developed for use in systems working in extreme conditions and ultra-low temperature systems • AB+M A mixture of synthetic and mineral oils Viscosity Is a measure of the resistance of a fluid which is under 'shear' or 'extensional' stress (or in simple terms, a fluids thickness). All of the oil types mentioned above are available with various viscosity grades as demonstrated below.

Oil Type ISO Viscosity Common Example Grade Suniso 3GS Suniso 4GS MO 32 Suniso 5GS Mobil Arctic EAL 22 68 Mobil Arctic EAL 32 Mobil Arctic EAL 46 100 Mobil Arctic EAL 68 Mobil Arctic EAL 100 POE 22 Emkarate RL 170H Zerol 150 32 Mobil Zerice S46 Mobil Zerice S68 46 Mobil Zerice S100 ELF PAG 244 68 ELF PAG SP20 ELF PAG 488 100 Mobil Arctic SHC 224 Mobil Arctic SHC 226E 170 Mobil Arctic SHC 228 Mobil Arctic SHC 230 AB 32 Shell SD22-12 46 68 100 PAG 46 100 150 PAO 32 68 100 220 AB+M 32 Always refer to the manufacturers' recommendation when selecting a compressor lubricating oil for a system. If this information is not available use a lower viscosity oil in low to medium temperature systems (e.g. 32W) and a higher viscosity oil in compressors that run under severe (or very hot) conditions (e.g. 68 to 100W). Most manufacturers appear to be using a 32W POE oil in the hermetic compressor of small self-contained HC systems. Miscibility This topic was covered in the manual dealing with HC Safety but is re-produced here. Hydrocarbons mix well with all of the current compressor lubricants, especially mineral and POE as indicated in the following table: Lubricant Miscibility and Viscosity Mineral POE Fully soluble. Excessive solubility at high temperatures (use next higher viscosity grade to compensate). Solubility is generally excessive (may need to use a viscosity grade that is one level higher

AB than normal to compensate). PAG Fully soluble. PAO Use normal viscosity grades. AB+M Solubility not consistent – depends upon conditions. Use normal viscosity grades. Soluble Soluble Use normal viscosity grades. Acid Formation All of the oils that have commonly been used as compressor lubricants are hygroscopic. This means they will readily absorb quantities of water from the atmosphere that are detrimental to the efficient operation of the system. Mineral Oil was considered to be highly hygroscopic but the newer synthetic POE is much higher while PAG is extreme. Inorganic acids are produced in all systems using CFC, HCFC and HFC refrigerants as they decompose due to heat however they do not activate until moisture is present. Water contained in the oil will accelerate the formation of these acids (hydrochloric and hydrofluoric) and also activate them. Organic acids such as acetic acid and formic acid are formed through a reaction with the oil and moisture. The hydrocarbon refrigerants do not possess any chlorine or fluorine so the formation of inorganic acids is not possible however the presence of organic acids due to reactions with the oil is still of concern. With this in mind it is imperative that new oil is obtained from an unopened container and any unused portion be discarded. This precaution applies to all types of refrigerant. Replacing Lubricating Oil in Compressors The procedure for replacing the lubricating oil in the sump of a compressor is virtually the same as for any other refrigerant with one exception. The HC refrigerants are extremely miscible with both mineral and POE oils. Care must therefore be taken with the old oil as it will retain a large quantity of the hydrocarbon refrigerant in solution. The following process is best performed while the compressor and oil are hot: • Isolate the electrical supply to the system • Remove the refrigerant charge from the system or isolate the compressor from the system if service valves have been provided • Draw a vacuum on the compressor and allow to sit for a short period • Charge the compressor with dry nitrogen and allow to sit

• Draw a second vacuum on the system • Bring the compressor to a positive pressure with dry nitrogen • Drain the old oil into a suitable graduated measuring container • Open a new container of oil and add the same quantity as was removed • Replace the liquid line filter drier • Draw the recommended vacuum on the compressor (or entire system as appropriate) Note that the Refrigerant Handling Code of Practice for self- contained low charge systems specifies a vacuum of 500 microns (or 67 Pascals) • Charge system with the recommended quantity of refrigerant. Discarding old oil Always remain mindful of the following points with regard to lubricating oils that have been removed from an operating system: • The oil will most probably contain a number of organic and possibly inorganic acids. Protection from eye and skin contact due to spillage or splashing can be maximised by wearing suitable PPE. Wash the areas of contact and any affected clothing immediately. • Oils removed from any system will continue to release adsorbed quantities of refrigerant to the atmosphere for a long period of time. This can be accelerated by increasing the temperature of the oil and/or evacuating the compressor before removing the oil. • Mineral and POE oils are extremely miscible with the hydrocarbon refrigerants. Any oil removed from a hydrocarbon system will therefore release a flammable gas for a long period of time (days to weeks). Prior to disposal at a waste depot, store the oil in a freely venting container in an outdoor location and isolated from any ignition sources. • Used oil should be returned to a waste oil depot however, operators at the depot must be informed of the possible dangers if you have placed the oil in a sealed container.

System Design Operating Conditions Current design operating practices used for the synthetic refrigerants will still apply to the hydrocarbon refrigerants. The following diagrams provide examples of the design parameters that may be applied to a fridge/freezer running on Isobutane and a high wall split system running on Propane. Each system is using a capillary RMD with suction line accumulators (standard practice on capillary systems) All pressures and temperatures are in kPa gauge and °C respectively. An allowance of 1K equivalent pressure drop has been applied to each major component in both systems. The Refrigerator system includes a liquid line filter drier and a liquid to suction heat exchanger (again, standard items). RMD P = 550kP SET = -23°C Storage = -18°C SCT = 45°C -40 510 Ambient = 25°C 38°C 0°C R600a Domestic Frost Free Refrigerator on Isobutane RMD P = 790kPa SET = 4°C Storage = 21°C SCT = 40°C 415 1298 Ambient = 25°C 35°C 14°C R290 High Wall Split A/C system on Propane

Section Summary • Comply with all relevant Australian Standards and fit replacement components that meet or exceed the original manufacturers’ specification. • Hermetic compressors specifically made for R600a are now available. They have a larger pumping capacity for the same cooling capacity (kW output) and non-arcing electrical relays. • The major modifications required involve the isolation of electrical components that generate sparks • Hydrocarbon systems will probably remain on small critically charged systems using a capillary tube RMD • Maintenance procedures should remain the same but with additional focus on leaks and electrical integrity. • All of the lubricating oils currently used for refrigeration and air conditioning systems are suitable for use with hydrocarbons. • Acid formation within the system is not as profuse as with the synthetic halogenated refrigerants however some acids will be introduced with the oil. Continue to use the same practices with regard to cleanliness and evacuation. • Hydrocarbon systems are designed with the same operating conditions as the synthetic systems we are familiar with.

Access Valves The following methods are suitable for obtaining access to the refrigerant in a hydrocarbon system. Schrader Valves These are usually fitted as an aftermarket item by a mechanic in order to gain access to the refrigerant. The Schrader core must be removed before the valve body is silver brazed into the process tube of the compressor. Once installed, the valve core opens when the valve stem is depressed. A valve core depressor is usually fitted into the hoses of a service manifold gauge set. Process Tube Discharge Line Suction Line For a superior seal, discard the cap supplied with the Schrader valve and fit a 1/4\"flare nut with 1/4\" copper bonnet. These can then be tightened with spanners. Bullet Piercing Valves Are typically supplied with spacers that allow fitment to 3/16\", 1/4\", 5/16\" and 3/8\" copper tube however, a larger 1/2\" and 5/8\" size is available. They are designed to clamp over the process tube and penetrate the tube when a sharp needle is screwed into the centre of the valve assembly.

The refrigerant handling Code of Practice states that their use is acceptable in gaining initial access to the refrigerant however, they must not be left on the system once the required repairs have been made (as they do not provide a good permanent seal). The hydrocarbon refrigerants are not governed by this requirement however, a leaking hydrocarbon system can be very dangerous. It is highly recommended that a superior access valve be fitted once the refrigerant has been removed from the system (i.e. Schrader valve), irrespective of whether a synthetic or hydrocarbon refrigerant has been used. Process Tube Adaptors These were originally designed to speed up the process of charging a small sealed system in the manufacturing industry. They are a small compression clamp device that slips over the open end of the process tube on a hermetic compressor. They are rated to a pressure of 700kPa so are not really suitable for pressure testing or for use on high pressure refrigerant systems. They are available in 3/16\", 1/4\", 5/16\" and 3/8\", but have mostly been replaced by piercing pliers. Piercing Pliers These are primarily used by the manufacturing industry for refrigerant charging and recovery purposes. They provide rapid access to the refrigerant circuit and are fitted with a 1/4\" flare connection for the direct connection of a service hose. When used in conjunction with a set of pinch-off pliers, a small self-contained system can be pressure tested, evacuated, charged & sealed off quickly & efficiently. Various Piercing Pliers Pinch-off Pliers

Service Gauge Manifold Sets The typical service manifold sets currently used for the synthetic range of refrigerants are totally compatible with the hydrocarbon refrigerants. Many digital manifold sets are already available with R600a and R290 pressure/temperature values pre-programmed. The use of short manifold hoses and the fitting of isolation valves such as ball valves (or similar) to the end of each hose is highly recommended for two reasons:  When attaching and more importantly, detaching hoses from a synthetic refrigerant system the Refrigerant Handling Code of Practice requires that you prevent release of any refrigerant to the atmosphere  Hydrocarbon systems typically require a 45% lower refrigerant charge by weight. The system charge will be very low when compared to synthetic refrigerant systems, particularly domestic refrigerators and freezers where the charge could be as low as 15 grams. Placing long hoses on one of these systems could conceivably empty the charge into the hose. Remember: Always open the ball valves and vent your hoses in a safe place as soon as you have removed them from the system. Do not leave a flammable gas locked in them.

Ventilation Requirements EN 378 Part 4 deals with the Operation, Maintenance, Repair and Recovery of refrigerating systems and heat pumps. Annex E of this standard provides the informative 'Guidelines for repairs of equipment using flammable refrigerants'. With regard to the ventilation of an area while repair work is being performed, it states: The following precautions should be taken before working on the refrigerant circuit: • obtain permit for hot work (if required) • ensure that no inflammable materials are stored in the work area and that no ignition sources are present anywhere in the work area • ensure that suitable fire extinguishing equipment is available • ensure that the work area is properly ventilated before working on the refrigerant circuit or before welding and soldering work • ensure that the leak detection equipment being used is non-sparking, adequately sealed or intrinsically safe (check with manufacturer for suitability of use with flammable gases) • ensure that all maintenance staff have been instructed NOTE: If the installation permits, it is recommended that the equipment is removed from its existing position to a controlled workshop environment where work can be conducted safely. Although the information above does not provide a specific flow rate, Always check that the volume of fresh air in the area in which you are about to work exceeds the practical limit of 8 g/m3 (8 grams of refrigerant per cubic metre of air) and provide mechanical air flow where possible. Section Summary • Bullet piercing valves are an acceptable tool for gaining initial access to the refrigerant but should always be removed • Schrader valves are superior to bullet valves but should have a properly tightened cap to limit unauthorised access and undue leakage • Piercing pliers will open the system quickly • Only pierce the process tube. Not the suction or discharge unless you intend to fit proper access valves to these areas prior to recharging the system. • Digital gauges now have P/T values for the common hydrocarbon refrigerants • Use short gauge hoses • Fit and use ball valves to the ends of each gauge hose • Safely vent any hydrocarbon gases from the gauge hoses once they have been removed from the system • Do not work on a hydrocarbon system unless the volume of air surrounding the work area exceeds the practical limit • Mechanical air flow around/through the work area should provide additional safety

Refrigerant Recovery Safe Fill Capacity for Cylinders This is the quantity of liquid refrigerant that can be safely added to a storage cylinder without causing undue stress on the cylinder. The SFC is determined using the following formula: SFC = WC x SFR Where: SFC = The Safe Fill Capacity in kilograms (kg's) WC = The Water Capacity of the cylinder being filled in kilograms (kg's) SFR = The Safe Fill Ratio for the refrigerant being added to the cylinder All cylinders are stamped with their respective water capacity. This is, as the name implies, the quantity of water that the cylinder can hold. Refrigerant cylinders are now fairly standardized with the following types being common: Type WC Usual Tare (kg) Weight (kg) N P 11kg 6.5 R 22kg 9.5 66kg 23 Ullage is a term used to describe the vacant space between the top of the liquid and the top of the cylinder. To prevent explosion, a cylinder should always have some ullage (empty space). The safe fill ratio is a number that is based on the density of the refrigerant but also includes a safety factor for the ullage. Typical Safe Fill Ratios are: R22 1.03 R134a 1.05 R404A 0.82 R290 0.42 R600a 0.49 R1270 0.44 Using the information in these two tables and applying the formula we find that: An 'N' type cylinder can be filled with 11kg x 0.49 = 5.4kg of R600a however, that same cylinder can only be filled with 11kg x 0.42 = 4.6kg of R290. The calculations above apply to cylinders holding new refrigerants. The formula changes slightly for second hand refrigerants. The Refrigerant Handling Code of Practice states that

the ullage volume must be increased by 20% when the cylinder is holding a recovered refrigerant. The formula above changes to: SFC = WC x SFR x 0.80 Where: 0.80 = the additional safety margin created by filling the cylinder to 80% of its normal safe capacity. Therefore, an 'N' type cylinder being used to store 'recovered' R600a can be filled to 11kg x 0.49 x 0.80 = 4.3kg instead of the 5.4kg calculated above. The following table lists the allowable mass for new and recovered quantities of the hydrocarbons commonly used in small self-contained systems. Refrigerant Cylinder Cylinder New Recovered Type Water Refrigerant Refrigerant Capacity Capacity Capacity N (kg) (kg) (kg) Fluxthere are P 11 5.4 4.3 occasions R 22 10.8 8.6 66 32.3 25.8 N 11 4.5 3.6 22 9.2 7.4 R290 P 66 27.7 22.1 R 4.3 Recovery units The recovery pumps currently used with the synthetic refrigerants are also materially compatible with the hydrocarbon refrigerant range if they are intrinsically safe. The procedure for their use remains the same. However, check the manufacturers’ specification before using your existing recovery unit on a hydrocarbon system as some are not recommended for use with hydrocarbon refrigerants.

Before using a recovery (or reclaim) unit with a flammable refrigerant, ensure that all sources of ignition (arcing from switches and motors etc.), have been isolated from the atmosphere. Perform regular equipment maintenances and check for any new sources of electrical sparking during these events. Note that the systems covered by this manual generally contain a charge of approximately 250 grams or less. With this in mind, the manufacturers of small self-contained hydrocarbon systems do not recommend the use of recovery pumps to remove the charge from their systems as the quantity of refrigerant within the system is very small. Venting This procedure involves the release of the refrigerant charge to atmosphere and is the preferred method of many manufacturers (particularly domestic appliances). The following outlines a typical procedure:  If the appliance is located outside the building: o Check for any sources of ignition o Isolate any electrical devices in close proximity o Isolate the appliance o Position a suitable fire extinguisher (dry powder or CO2) nearby o Open the access valve (or gauge manifold) o Allow the refrigerant to vent to the surrounding atmosphere  If the appliance is located within the building o Obtain a length of clear PVC tubing long enough to pass out through an open window or doorway and extend a further 3m o Connect one end to the service manifold o Connect a suitable dispersion manifold to the other end of the hose and locate approximately 1m from the ground – outside the building o Check for any sources of ignition and remove or isolate as necessary o Isolate the appliance o Position a suitable fire extinguisher (dry powder or CO2) nearby o o Open the gauge manifold o Allow the refrigerant to vent to the surrounding atmosphere Adopted from GTZ Proklima manual 3m 1m

The diagram above illustrates the recommended hose layout during the venting process with the following additional points to note: • Ensure the hose is made of a material that is compatible with hydrocarbon refrigerants • Maintain constant lookout of the location surrounding the venting point to ensure passing pedestrians/vehicles do not cause ignition or are placed in an otherwise unsafe situation • Do not vent in a location that will allow the vapour (which is heavier than air), to collect in a drain system or recessed pit. • On completion of the venting process, purge the hose of any remaining vapour (with nitrogen) • A flammable gas warning sign should be placed at the venting location if it is possible for untrained or unaware pedestrians to enter the site • The refrigerant flow rate should be kept low to ensure maximum dilution with air Inert Flushing Agent When replacing or repairing any component that has anything to do with the refrigerant, the charge should be removed and the system flushed with an inert gas. Oxygen Free Dry nitrogen (OFDN) is the only recommended gas for this purpose. It will not react with any of the components within the system, prevents the entry of air and moisture and most importantly, will not burn. Never use compressed air or oxygen as they become explosive when under pressure and in contact with oil. Flushing/Purging Procedure Almost all forms of mechanical service work on a small self-contained system operating on a hydrocarbon refrigerant will require soldering or brazing work of some description as they are usually a sealed hermetic system with a critical charge and all of the joints will be soldered or brazed. The following procedure should be carried out when preparing the appliance for hot work:

Nitrogen Flushing: • Obtain permit for hot work (as required) • Remove the refrigerant charge using an appropriate method • Charge the circuit with dry nitrogen to a suitable positive pressure (e.g. a pressure equivalent to 25°C for the refrigerant used - Take extra care with R600a systems) • Allow the system to stand for a short period (3 to 5 minutes) then release the nitrogen to atmosphere • Evacuate the system to a pressure of -70kPa • Charge the circuit with dry nitrogen to a pressure equivalent to 25°C • Allow the system to stand then release the nitrogen to atmosphere Continuous Nitrogen Purging: • Access the other side of the system (usually the high pressure side) using a suitable piercing tool • Allow the nitrogen to flow (at very low pressure) through the area being brazed • Carry out the brazing work Remember: The compressor oil will have adsorbed a large quantity of the refrigerant and may continue to release hydrocarbon vapours while you are brazing. Purging the system with nitrogen while you braze will: • Dilute the flammable vapour • Prevent the formation of carbon/scale inside the pipework Section Summary • A cylinder used to store recovered refrigerant may only filled to 80% if its' normal safe fill capacity • Existing recovery pumps are materially suitable for use with hydrocarbon refrigerants • Enclose any sources of spark (ignition) on your recovery unit • Manufacturers do not recommend the use of recovery pumps • Atmospheric venting is simple but must be done with care • Always use oxygen free dry nitrogen (OFDN) as a flushing agent • Always use the recommended flushing/purging procedure prior to opening up a circuit for replacement or repair work

Tube Joining Methods Purpose In this section you will learn about the various compression fittings suitable for joining pipework on hydrocarbon systems. It also revises the common tube joining methods used with the synthetic refrigerants and describes their respective suitability with hydrocarbon systems. Typical Tube Joining Methods Joints between tubing and the components of a system have historically been made using a silver brazing technique or through the use of brass flare nuts and unions. These nuts typically range in size from 1/4\" through to 7/8\" and were initially designed to be used in situations where a component may need to be removed a few times in its lifetime. They have become wide spread in their application today and it is this practice that has recently been attributed to the excessive and therefore unacceptable leakage rates occurring on most systems today. Leaks on a hydrocarbon refrigerant system are unacceptable so it stands to reason that the manufacturers of small self-contained systems have chosen to avoid the use of flare nuts and their associated fittings. Silver Brazed Joints Strong, leak-tight connections can easily be made in copper tube systems by brazing with silver solder, an alloy of silver (Ag), copper (Cu), and phosphorus (P). These silver solders melt at a temperature range of 640°C to 750°C and are suitable for use with all hydrocarbon refrigerants. The Australian National Plumbing Code stipulates a nominal silver content of 2% and these sticks are usually colour coded canary yellow. This silver content is not recommended for normal refrigeration and air conditioning

systems as it is easily overheated during application. This can result in separation of the constituents, poor adhesion and refrigerant leaks. The low level of silver also increases the joints susceptibility to fractures and cracks if stressed with vibrational movement. A silver content of 15% (Brown tip) is preferred within the industry for copper to copper joints because it retains a fair degree of ductility and is self-fluxing on copper. It is also suitable for brass and bronze but requires a flux. It will form a brittle iron-phosphide if used with ferrous metals. A minimum silver content of 45% (Blue tip) is required for joints between copper and ferrous metals (steel) or where extreme vibration occurs (requiring extreme ductility). A tube cleaning flux must be applied to all mating surfaces of the tubes prior to using this quality of silver solder. Suitable Flux Pastes The purpose of a brazing flux is to assist the formation of brazed joints by protecting the base metal and filler metal from oxidation, to remove surface oxides before heating and to reduce oxides during the welding process (i.e. to lower the surface tension promoting better flow of the filler metal). The current range of fluxes are compatible with hydrocarbon systems. A range is available from a number of manufacturers. • The 'Silfos' range of products specifies a flux they refer to as 'Handy Flux'. It is an all-purpose, low temperature flux for brazing both ferrous and non-ferrous metals and alloys. • The 'Saldflux\" range specifies a 'Brasflux' and a 'CopperFlux'. Both promote excellent capillary action. Note that fluxes are either acidic or alkaline in nature. Water has a pH of 7 but the fluxes mentioned here have a pH of 8. Avoid skin contact and wash immediately if contact occurs.

Compression Type Tube connectors There are occasions where a brazed joint cannot be performed. For example: • There is a risk of heat damage to the surrounding structure or equipment • The pipe or tube materials do not braze or solder easily • There is a risk of galvanic action resulting in corrosion • There is a need to join copper or steel pipe to PVC pipe Traditional methods used to overcome this problem have incorporated the use of flare nuts or brass couplings/unions. In order to overcome this problem and avoid the use of flare nuts a growing number of appliance manufacturers are employing the use of compression fittings. They provide a seal that is claimed to be as good as a brazed joint and quicker to complete. They are manufactured by the 'American Lokring Corporation' and are available for a large range of materials in a large range of sizes and styles. The brass connectors are designed for joining Copper to Copper, Copper to Steel and Steel to Steel. The aluminium connectors are designed for joining Aluminium to Aluminium, Aluminium to Copper and Aluminium to Steel. Applying Compression Type Connectors

This procedure can be difficult to begin with however, once you are familiar with the technique, a neat, leak free joint can be obtained quickly. • Ensure the tube ends are clean and free of any impurities • Apply a thin film of 'LokPrep' to the tube ends • Insert both tube ends into the connector until they meet the centre stop • Rotate the connector to smear the LokPrep around the outer surface of the tubes • Open the specially designed assembly tool and seat the connector within its jaws • Ensure that the tubes are fully seated in the connector and the connector is seated squarely in the jaws of the assembly tool • Operate the ratchet handle until the LokRings are completely compressed and meet at the centre. • The circuit can be pressurised or evacuated immediately

Ratchet Assembly Tool with replaceable jaws Section Summary • Flare nuts are not suitable for the joining of pipework on small self-contained and split hydrocarbon and R32 systems • Silver brazing is preferred by all manufacturers • Avoid 2% solder sticks • Use 15% and 45% silver content as applicable • Use flux on copper to brass if using 15% sticks • Always use flux with 45% sticks • Lokring compression fittings are being used by many hydrocarbon appliance manufacturers today

Pressure Testing and Leak Detection Occasions Requiring Pressure Testing An effective method for checking the gross sealing integrity of every joint and pipe run in a refrigerant circuit is to add a high pressure inert gas to the system and allow it to stand for a period of time. As a matter of good practice, this should be done on all systems, irrespective of the refrigerant type, on the following occasions:  On completion of a new system build (installation) prior to the evacuation stage.  After a leak has been repaired  Once a component has been replaced Part 1 of the Refrigerant Handling Code of Practice states that a fluorocarbon substance may be added as a trace gas to assist in locating leaks. Note that the maximum quantity is 10% by volume and only applies to manufacturers. Gases suitable for Pressure Testing The only inert gas recommended for pressure testing of a refrigeration or air conditioning system is Oxygen Free Dry Nitrogen (OFDN). BOC Australia and A-Gas list this product as 'High Purity' Nitrogen. It has a water vapour content of less than 10ppm and a minimum purity of 99.999%. It is available in D, E and G size cylinders. Do not use compressed air or oxygen as the lubricating oil may become explosive under pressure with O2. These two substances will also permit the creation of a flammable mixture within the system where hydrocarbon refrigerants have or are, being used. Recommended Testing Pressures Always check the manufacturers' recommendations first. If this is not available then AS 1677 Part 2, Table 3.1 states that the Minimum test pressure for the high side of an air cooled condensing unit is equivalent to a temperature of 59°C. The low side of all systems is equivalent to a temperature of 43°C. For the common range of hydrocarbon refrigerants, the minimum test pressures will therefore be: Refrigerant Refrigerant Trade Names High Side Low No. (kPa) Side Isobutane Minus 10/Care 10 Isobutane + Propane R600a Minus 30/Care 30 730 470 Propane Minus 40/Care 40 1450 1000 Propane + Ethane R290 Minus 50/Care 50 1980 1400 2230 1580 However, Clause 3.3 of the same standard states that: Self-contained systems containing not more than... 1 kg of Group A3 refrigerant where the low pressure side cannot be isolated from the high pressure side, the test pressure of the whole

system may be the maximum operating pressure of the low pressure side... It is therefore sufficient to use the test pressure stated for the low side (see table above) for the range of self-contained capillary tube appliances that fall within the scope of this manual. Suitable Leak Detection Methods The following leak detection methods are provided in the Refrigerant Handling Code of Practice and are acceptable for hydrocarbon refrigerant systems: • liquid submersion testing (where appropriate) • fluorescent leak detection • vacuum degradation test (gross leaks only) • electronic leak testing • positive pressure holding test / pressure drop off test (Nitrogen) • Liquid leak detection (soapy bubbles) Liquid submersion generally entails the pressurization of a part of the system followed by immersion in a tank of water. This would not normally be practical for a self-contained appliance. UV and Fluorescent additives are generally compatible with the hydrocarbon refrigerants however many manufacturers do not warrant its use. Check with the manufacturer before adding to a system. Vacuum degradation entails the evacuation of a system to the recommended level then leaving it to stand for a period of time. This method is only suitable for the detection of large leaks as the test pressure is only equivalent to 100kPa. Many electronic leak detectors will work with hydrocarbon refrigerants as they are often designed to trigger when anything other than air is drawn into the sensor tube. Some brands have now produced electronic detectors specifically for the hydrocarbon refrigerants.

Note that some types of electronic detector use a heated element in the sensor tip. If you intend to use your current detector, check with the manufacturer to determine whether it is suitable for use with hydrocarbon refrigerants and also test it before you start relying on it. Pressure testing the system with dry nitrogen to the minimum recommended test pressure then waiting to see if the pressure falls is limited in its dependability by the time period taken to observe any pressure drop and the effect of ambient temperature changes on the system. Although soapy water solution can be used, a number of liquid leak detection products that provide superior 'clinging' properties are now available. Apply the solution to all joins and connections once the system is at the recommended test pressure to readily and reliably detect and pinpoint any leakage points. This method is recommended as being the final 'best practice' method for all situations (regardless of refrigerant type).

Section Summary • Pressure testing of a system should be conducted when a system is constructed or when a component is replaced. • Dry or 'high purity' nitrogen should be used for pressure testing refrigeration and air conditioning systems. • Always use the manufacturers' recommended test pressure values • A pressure equivalent to 43°C for the refrigerant being used in the system should be used as the minimum test pressure on all self-contained capillary systems with a charge of less than 1kg when the manufacturers' recommendations are not available. • Liquid bubble detectors provide the best result when testing for leaks in a system or component. • Some electronic leak detectors may provide a source of ignition if they employ a heated sensor tip operating at with a surface temperature above the ignition temperature of the hydrocarbon refrigerants. • Always use electronic leak detectors that have been approved for use with hydrocarbon refrigerants. Evacuation Vacuum Pumps The current range of vacuum pumps used for synthetic refrigerant systems are materially suitable for use with hydrocarbon refrigerant systems as long as they are intrinsically safe. However, check the manufacturers’ specification before using your existing pump on a hydrocarbon system as some vacuums are not recommended for use with hydrocarbon refrigerants. All potential sources of ignition from the vacuum pump motor and/or switching mechanism must be isolated (shielded), prior to using on hydrocarbon systems as the drive motor creates a considerable inductive load on the electrical circuit which leads to arcing cross switch contacts. Avoid using pumps fitted with a universal type motor as these are fitted with a commutator and carbon brushes that arc continuously. Perform regular equipment

maintenances and check for any new sources of electrical sparking during these events. Considering the maximum allowable charge for small self-contained appliances, the maximum internal volume for these systems will be somewhere around 3.5 litres. A single or double stage pump with a capacity of approximately 30 to 40 Litres per minute should be sufficient. Note that 2 stage rotary pumps are preferred in the industry. Also note that the use of an oversized pump may cause any free water in the system to freeze thereby preventing its removal. Vacuum Measuring devices The current range of meters used to measure a vacuum is suitable for use with hydrocarbon refrigerant systems. These devices should always be fitted to a part of the system that is not directly connected to the vacuum pump however, this is often not possible with small self- contained appliances as the system is usually supplied with only with one access point. In this instance, ensure the meter is connected somewhere between the service manifold and the system access fitting, isolate the vacuum pump from the system and allow it to sit for a short period. This will give a more reliable system pressure reading. Avoid fitting the meter directly to the vacuum pump as the reading will be lower than has actually been achieved in the system. The practice of using the compound gauge on the service gauge manifold set to determine the depth of vacuum achieved by a pump is not acceptable for any type of system. The Refrigerant Handling Code of Practice states that: Absolute vacuums must be measured using accurate measuring equipment selected for the specific application. Always use a vacuum measuring device manufactured specifically for the trade and ensure that it is maintained regularly.

Recommended Depth of Vacuum The air within a hydrocarbon system must be removed using a vacuum pump to ensure that:  An explosive mix does not exist within the system  Any moisture is removed to prevent the: o Formation of detrimental acids in the system o Intermittent blockage of the metering device due to ice formation The depth of vacuum for a small, low charge self-contained appliance is stated in Part 1 of the Refrigerant Handling Code of Practice: The system must be evacuated to less than 67 Pa absolute (500 microns of mercury) if the system manufacturer has not supplied instructions with the system for evacuation. Note that the required vacuum for all other types of refrigeration and air conditioning systems is lower than the value stated here. Once this pressure is reached, the vacuum should be tested as follows: After the system has been evacuated the vacuum pump should be isolated from the system. As a guide, with constant ambient conditions, the vacuum should not rise more than 13 Pa (100 microns of mercury) in one hour. A greater rate of rise may indicate a leak or the presence of moisture

Section Summary • A small 40 L/m, 2 stage vacuum pump should be sufficient for evacuating the majority of self-contained hydrocarbon charged appliances • Always avoid the use of an oversized vacuum pump • Always use a vacuum measuring device manufactured specifically for the trade and ensure that it is maintained regularly. • The system must be evacuated to less than 67 Pa absolute (500 microns) • The vacuum should not rise more than 13 Pa (100 microns) in one hour • Always use a vacuum pump designed for use with hydrocarbon refrigerants. Charging Sources of Ignition Survey the area surrounding the appliance for any actual or potential sources of ignition. These were covered in detail in the hydrocarbon safety manual and should be reviewed at your convenience. Notify any relevant personnel of your intent to charge the system with a flammable refrigerant and place a suitable fire extinguisher within easy but safe reach. Charging Methods The method selected when charging the system will depend upon whether the system charge has been specified by the manufacturer or not. Specified Charge Most of the critical charge appliances in the market today are fitted with a label indicating the type of refrigerant used together with the required mass.Refrigerant charging cylinders were developed a number of years ago specifically for the critical charge domestic/small commercial market.

Digital scales are produced with a wide variance in capacity, accuracy and resolution. Capacity: Tends to vary from 50kgs to 100kgs Accuracy: From ± 0.5% up to 2% Resolution: Commonly 10grams but can be down to 5g or 2g Some of the small domestic hydrocarbon refrigerant appliances (e.g. bar fridges, wine coolers etc.) have a total charge of 14 grams ± 2g. These extremely low charge quantities combined with the even smaller deviations make it essential that the set of scales used to weigh-in the system charge have good accuracy (0.5% - 1.0%) and more importantly, low resolution (2g). Using the Scales: 1. Turn on the scales and set resolution to lowest available value 2. Place refrigerant cylinder on scale platform and wait for the refrigerant motion to cease 3. Fit gauge manifold hose to cylinder and to system access port 4. Purge hoses 5. Open bottle to fill center gauge hose 6. Zero the readout and note required system charge 7. Open gauge manifold allowing refrigerant into system 8. Close gauge manifold when required mass is obtained on readout It is important to avoid any disturbance of the gauge hoses during the charging process for small charge systems as the movement will cause the scales to read false values (with the likely outcome being a quickly overcharged system). Unknown Charge Mass First rule... Contact the manufacturer. If this is not possible then the situation comes more difficult and requires the use of a few more instruments and a number of 'rules of thumb'. Many small, critically charged systems operate within the following performance boundaries:  5K to 7K of liquid sub-cooling prior to the capillary tube  10K to 15K of suction line superheating prior to the compressor Using these values together with the expected suction and discharge pressures, it is possible to achieve a charge that is very close to the manufacturers' specification. The following diagram provides an example of where to take readings and what to expect.

Liquid or Vapour Charging The rules governing synthetic refrigerants apply to hydrocarbon refrigerants as well. If the refrigerant is a single substance (e.g. Isobutane or propane) then it can be vapour charged or liquid charged. If on the other hand, it's a blend of two or more refrigerants, then it must be liquid charged only. Note that the range of hydrocarbon refrigerants can be purchased in 300 gram disposable canisters. These are a convenient choice when typical small commercial charge masses tend to range between 70 and 100 grams. Be aware that these canisters may not be fitted with inductor tubes. Always check when using as they may need to be inverted during the charging process.

Section Summary • Survey the area for sources of ignition prior to charging a system with a hydrocarbon refrigerant • Take care of any possible threats before proceeding • Inform relevant personnel • Place a fire extinguisher nearby • Most systems will be fitted with a label indicating gas type and charge weight • Will need electronic scales with a very low resolution (2g) when charging small domestic appliances • Use rules of thumb for liquid subcooling and suction superheating when the charge weight is not indicated - after checking with the manufacturer How will the new F-gas regulation affect the choice of refrigerant for heat pump air conditioners? e new F-gas regulation affect the choice of refrigerant for heat pump Heat pump air conditioning systems are impacted by the new F-gas regulation, the gradual phase down of HFC’s quantities on the market will push the industry to use lower GWP refrigerants. Since 2017 the price of HFC’s has started to rise significantly, especially for those gases with high Global Warming Potential (GWP). Note: In the new F-gas regulation, the use of HFC’s with GWP greater than 750 will be prohibited from 2025 for mono split-system room air conditioners containing less than 3 kg of refrigerant. What is the refrigerant of choice as a replacement for R-410A and R22 heat pump air conditioners? R-410A and R22 alternatives must provide an acceptable compromise in terms of GWP, human safety, energy efficiency, and system cost. After several years of research and evaluation, most air conditioner manufacturers are switching from R-410A and R22 to R-32 (Difluoromethane HFC32) refrigerant which has a lower Global Warming Potential (GWP), is better for the environment and delivers greater energy efficiency. However this gas is mildly flammable (A2L safety class) and does require some redesign change. These changes will be seen in our new range of R32 residential and light commercial heat pump air conditioning systems. The benefits of HFC R-32 are:- - Zero Ozone Depletion - 1/3 GWP of HFC 410A (GWP675 v GWP2088) - Superior energy efficiency to R22 - High refrigeration capacity and thermal conductivity - Low pressure drop - Single component refrigerant easy to handle and recover - Low toxicity - Readily available Downsides to HFC R-32 Flammable / Turns to Mustard Gas when it is subject to a flame / Higher pressures R32 is classified as A2L “lower flammability” according to the International Standard for Refrigerant Designation: - - Safety Classification: ISO 817:2014 - REACH Registration number: 01-2119471312-47

International Standard ISO 817:2014 segregates the flammability class of refrigerants into 4 categories: - - (Class 1) no flame propagation non flammable - (Class 2L) lower flammability mildly flammable - (Class 2) flammable (Class 2) flammable - (Class 3) higher flammability highly flammable Refrigerants are divided into two groups according to toxicity: - - (Class A) signifies refrigerants for which toxicity has not been identified at concentrations less than or equal to 400 ppm - (Class B) signifies refrigerants for which there is evidence of toxicity at concentrations below 400 ppm How easy is R-32 to ignite? For a gas mixture to ignite, 3 specific conditions must be met simultaneously. 1) The concentration of the flammable gas must lie between the Lower and Upper Flammability Limit (LFL and UFL) for the particular gas. For R-32 this is between 14% volume and 29% volume (300 grams/m3 and 620 grams/m3 respectively). It should be noted that a 14% concentration of any foreign gas in air is the accepted oxygen deprivation safety limit. 2) The second requirement is that the flammable gas mixture must have a velocity lower than 3 to 4 times its laminar burning velocity for R-32 this is 6.7 cm/second. In the case of a wall mounted split system, because R-32 is heavier than air any leaked refrigerant leaving the unit will exceed 4 times its burning velocity due to gravity within 40 cm. Furthermore, measurements and computational fluid dynamic modelling has shown that even a rapid R-32 leak of 1000 grams in one minute will not present a flammable mixture outside of the wall unit due to dilution and the falling velocity of the refrigerant. 3) The third requirement for ignition to take place is an ignition source of sufficient energy. Unlike common flammable gases such as propane, R-32 cannot be ignited by the usual static electricity we experience. Tests by independent laboratories in Japan and America1 have demonstrated that sparks from light switches or contactors in residential appliances do not have sufficient energy to ignite R32. Therefore, the most likely source of ignition in a residential application is an open flame such as a candle, combustion heater or gas cook top. Therefore, if an accidental release of R32 refrigerant occurs from a cylinder or piping, the velocity will be too high to ignite near the release point and the concentration will be too low where the velocity becomes low enough. So, ignition of R-32 is difficult even if it is attempted intentionally. Even if all 3 criteria are met simultaneously, other characteristics such as quenching distance can limit propagation should ignition occur. For example, if ignition occurred inside a large commercial circuit breaker, the flame will not propagate outside the circuit breaker enclosure unless the enclosure has openings bigger that the quenching distance 5-6 mm for R-32. Flammability range LF UFLby Volume % in air 0% 14 % 29 % 100% Lower Flammability Limit (LFL) : the minimum concentration of the refrigerant tha t is capable of propagating a flame Unsafe range Upper Flammability Limit (UFL) : the maximum concentration of the refrigerant that is capable of propagating a flame

All flammable refrigerants must be handled with precautions and in accordance with local regulations, In accordance with operation and installation manuals and safety standards. Manufacturers’ refrigerant charge limits must always be complied with when installing and servicing equipment Are they specific safety requirements to install heat pump air conditioners with A2L refrigerants It is mandatory to comply with safety requirements from local building safety codes with regard to the installation and operation of heat pump air conditioning equipment containing A2L mildly flammable refrigerants for human comfort in buildings and design, installation and maintenance must comply with safety requirements from EN378: 2016. All refrigerant gasses classified in ISO 817 can initiate some form of adverse health effect if the concentration is high enough, therefore it is technically incorrect to claim any classified refrigerant as “non-toxic”. However, compared to all other common refrigerants, R-32 requires the highest concentration level to cause any adverse health effect. International Standard ISO 817 defines 2 toxicity classes for refrigerants:- - (Class A) Lower Chronic Toxicity - (Class B) Higher Chronic Toxicity R32 is categorized as Class A. Class A refrigerants are called non-toxic and Class B are called toxic. Compared to all other Class A (Lower Toxicity) refrigerants such as R-22, R-410A, R-134a, R-290 (Propane) and R-600a (Isobutane), R-32 has the highest (safest) Acute Toxicity Exposure Limit (ATEL) of 220,000 ppm. R-32 has the highest ATEL of the 99 refrigerants designated in Table 5 of ISO 817. What is produced when R-32 decomposes? As is the case with all fluorinated refrigerants, R-32 will decompose and produce toxic by-products such as hydrogen fluoride (mustard gas) and carbon dioxide when burnt. The likelihood of R-32 being present within its flammable range and then being ignited is extremely rare. The most probable (but still extremely unlikely) cause of R-32 thermal decomposition would be a leak into an enclosed space that has an open flame source such as an electric or gas heater close to floor level. In this scenario, with a wall mounted split system mounted directly above the heater, testing has demonstrated that production of hydrogen fluoride from leaked R-32 is no more than the hydrogen fluoride produced by non-flammable refrigerants such R410A. Further, laboratory measurements of decomposition products from contact with a hot surface rather than a high temperature flame demonstrated that a 5% R-32 in air mixture exposed to a red hot wire produced significantly less hydrogen fluoride (less than 5ppm) than an equivalent mixture of R-22 (more than 70ppm of hydrogen fluoride). Analysis of R-32 exposed to a variable temperature heater revealed that hydrogen fluoride (mustard gas) started to be produced when the temperature was in the range of 570°C to 590°C. Note that R-410A, R-407C, R-404A, R-134A, R-22 and other commonly used non-flammable refrigerants also start to decompose at around the same temperature at which R-32 starts to decompose. Hydrogen fluoride has a very foul odour. It would be expected that if an R-32, R-22 or R-410A leak occurred in a room with a combustion source the smell would alert occupants to leave the room before they are exposed to dangerous levels of hydrogen fluoride. As HCFC and HFC refrigerants have been used in air conditioners for close to 50 years without major concern about the toxic by-products of combustion, any risk associated with the decomposition of R-32 can be managed in the same manner as existing fluorinated refrigerants. Can we retrofit an R-410A and R22 heat pump air conditioners with a lower GWP refrigerant? For now, all R-410A alternatives are mildly flammable (A2L safety class) and cannot be used to retrofit existing equipment designed to operate with non-flammable R-410A refrigerant. Retrofitting R-410A systems with mildly flammable refrigerants should not be attempted to avoid damaged to equipment and potential

damage to property and or possible injury to humans or animals. There have been many units successfully converted to natural refrigerants. The same applies with R22. Will it be possible to service heat pump air conditioners using R-410A and R22 in the future? In the new F-gas regulation there are no restrictions on the use of R-410A refrigerant for servicing refrigeration or air conditioning equipment. The new regulation introduces a gradual phase down of HFC’s quantities (in tons of C02 equivalent) with 21% of the reference level still available after 2030 to service equipment. Therefore, it should be possible to service heat pump air conditioners with R-410A for the foreseeable future but not R22 units. R22 units will all be replaced with low GWP refrigerants. I have heard about possible taxes on HFC’s, can you tell me more? Several governments, e.g., Denmark, Norway and Spain have introduced taxes on HFC’s. Some schemes tax all sales of refrigerant, others only tax refrigerant used for the servicing of equipment. The level of tax is typically related to the GWP of the refrigerant (for example; 20 € per ton of CO2 equivalent in Spain). The French government is also evaluating the implementation of a tax on HFC refrigerants from 2019. With uncertainties on refrigerant prices, we should anticipate that the quantity of refrigerant in a unit and the GWP of the refrigerant are becoming significant market drivers for customers who will operate heat pump air conditioners for the next 15/20 years. How do you expect HFC prices to change in the future? With the gradual reduction of HFC quotas in tons of CO2 equivalent (see F-gas regulation) refrigerant suppliers have to lower the overall GWP of all refrigerants they place on the market while delivering the same quantities of refrigerant (the market demand in tons of refrigerant is supposed constant). To achieve this target, refrigerant suppliers have increased the price of refrigerants with high GWP’s to push customers to use alternative gases with lower GWP’s. Between 2016 and 2018 prices of refrigerant used for heat pump air conditioners increased by approximately 500% What are the alternatives to R-410A and R22 for new equipment? There are multiple solutions to replace R-410A and R22. Medium GWP HFCs (GWP 300 - 750), R-32 and R32/HFO blends (R-452B or R-454B) are potential candidates to replace R-410A. All are mildly flammable (A2L safety class). All these substances are subject to the HFC phase down of the F-gas regulation, therefore they are considered as transitional refrigerants. Hydrocarbons, such as propane, have very low GWP’s (GWP < 10) but are highly flammable (A3 safety class). As such, they could be acceptable for all outdoor systems with limited refrigerant charge. HFO refrigerants such as R-1234zd Class A1 with nearly zero GWP are long term solutions but they will require the development of new compressor technologies. Caution: retrofitting R-410A systems with mildly flammable refrigerants should not be attempted to avoid damaged to equipment and potential damage to property and or possible injury to humans or animals. I have heard about constraints for importers of HVAC equipment made outside Europe According to the new F-gas regulation importers of HVAC equipment made outside the EU shall ensure that the refrigerant contained in the equipment is covered by F-gas quotas. In practical terms importers of equipment shall purchase from a refrigerant producer or importer in Europe an authorization to use its quotas. The cost of the authorization will represent a non-negligible asset for the importer and will have an impact on the price of the equipment. In addition every year the importer shall request an accredited auditor to reconcile the quantity of refrigerant allowed by the authorization with the actual quantity placed on the market in products. In conclusion since 2017 it is complex and more costly to import HVAC equipment into the EU.

Can we use CO2 as refrigerant for heat pump air conditioners? Although CO2 (R-744) is a very effective refrigerant for commercial refrigeration, it is not suitable for heat pump air conditioning applications because of its low efficiency. However, CO2 can be a good solution for high temperature heat pumps such as those intended for domestic hot water production. HCFC refrigerant HCFC stands for hydrochlorofluorocarbons. HCFC’s like R-22 refrigerant are substances depleting the ozone layer. HCFC’s are being phased out under the Montreal Protocol. In Europe since the 2000’s HCFC refrigerants are prohibited in new equipment and their production banned since 2010. HFC refrigerant HFC stands for hydrofluorocarbons. They belong to the family of fluorinated gases. HFC’s have been developed by the industry to replace substances depleting the ozone layer. HFC’s are mainly used as refrigerant for refrigeration & air conditioning equipment, aerosols sprays and insulation foams. HFC’s are non-toxic and have zero ozone depletion potential. All HFC’s are potent greenhouse gases. R-32, R-32/HFO blends and R-134a/HFO blends are lower GWP alternatives to R-410A & R-134a however they still fall into the basket of fluorinated gases controlled by the F-gas regulation and therefore seen as transitional refrigerants HFO HFO stands for hydrofluoroolefin. It’s the latest generation of synthetic refrigerants. Pure HFO’s have zero impact on the ozone layer (ODP) and nearly zero global warming potential (GWP). HFO’s are non-toxic; however in certain conditions most of them are mildly flammable when mixed with air. HFO R-1234yf has been designed as a substitute of HFC R-134a for the car industry. HFO refrigerants developed for the HVAC industry are R-1234zd, R-1234ze(E) and R-1233zd(E) with nearly zero GWP, pure HFO’s are not subject to the measures of the F-gas regulation and are therefore long term refrigerant solutions. HFC/HFO blend refrigerant HFCs can be mixed with HFOs to offer lower GWP alternatives with close thermodynamic properties to existing HFC refrigerants. R32/HFO blends designed as an alternative to R-410A, e.g.: R-452B, R-454B are mildly flammable while R-134a/blends, e.g. R-450A, R-513A, are non-flammable. It is important to note that all HFC/HFO blends are on a regulatory point of view HFCs. All HFC/HFO blends fall into the basket of fluorinated gases controlled by the F-gas regulation and are therefore seen as transitional refrigerants. EN 378 standard The European technical standard EN378 relates to safety and environmental requirements in the design, manufacture, construction, installation, operation, maintenance, repair and disposal of refrigerating systems and appliances including heat pumps. It consists of four parts: Part 1: Basic requirements, definitions, classification and selection criteria Part 2: Design, construction, testing, marking and documentation Part 3: Installation site and personal protection Part 4: Operation, maintenance, repair and recovery The last edition EN378: 2016 includes the new 2L safety classes Refrigerant safety class EN378 technical standard sets refrigerant safety classes depending on their flammability and toxicity. Substances with lower toxicity are classified from A1 non-flammable to A3 highly flammable while substances with higher toxicity are classified from B1 non-flammable to B3 highly flammable. In 2006 new A2L & B2L classes were introduced for mildly flammable refrigerants with a burning velocity < 10cm/second.

Safety classes of main refrigerants HIGHER TOXICICITY LOWER TOXICITY NON FLAMMABLE Class Refrigerants Class Refrigerants A1 B1 Seldom used MILDLY FLAMMABLE R-22, R-407C, R-410A, R-134a, (NEW) A2L R-450A, R-513A, R-744 B2L R-717 (ammonia)...etc. (burning velocity < 10cm/s) (CO2)...etc. FLAMMABLE R-32, R-452B, R-454B HIGHLY FLAMMABLE HFO R-1234yf & R1234ze...etc. A2 R-152A...etc. B2 Seldom used B3 No refrigerants A3 R-290 (propane) R-600a (isobutane)...etc. Refrigerant GWP GWP stands for Global Warming Potential. It is a relative index to quantify the amount of heat trapped in the atmosphere by a greenhouse gas. By definition the GWP of carbon dioxide (CO2) is equal to 1. Example: - R- 134a with GWP 1430 means that 1kg of R-134a has the same impact on global warming as 1430kg of CO2. GWP values are calculated over a period of 100 years and are updated by the Intergovernmental Panel on Climate Change (IPCC) on a regular basis. Thus GWP values may slightly differ in the different publications. Refrigerants can be classified in 3 main categories 1) Legacy refrigerants with high GWP >750 2) Transitional refrigerants with medium GWP 750 to 300 3) Long term refrigerants with very low GWP < 150 GWP VALUES OF MAIN REFRIGERANTS Refrigerant Type GWP GWP category R-404A HFC 3920 high > 750 R-410A HFC 2088 High > 750 R-134a HFC 1430 High > 750 R-407C HFC 1774 High > 750 R-452B HFC 698 High > 750 R-32 HFC 675 Medium 750-300 R-513A HFC 631 Medium 750-300 R-450A HFC 604 Medium 750-300 R-454B HFC 466 Medium 750-300 R-1234zd HFO 4.5 (<1) Very Low < 150 R-1234ze(E) HFO 7 (<1) Very Low < 150 R-1234yf HFO 4 (<1) Very Low < 150 R-1233zd(E) HFO 4.5 (1) Very Low < 150 R-717 (NH3) Natural 0 Very Low < 150 R-744 (CO2) Natural 1 Very Low < 150 R-290 (propane) Natural 3 Very Low < 150 Notes: GWP values based on International Panel Climate Change (IPCC) 4th Assessment Report and 2014 F- gas regulation. For HFOs values indicated into bracket are based on IPCC 5th Assessment Report The first European regulation on fluorinated gases (F-gas) was adopted in 2006 to reduce the emission of

fluorinated gases with high global warming potential and thus to protect the environment. Since 1st January 2015 the new F-gas regulation N° 517/2014 is applicable in all EU member states. The new F-gas regulation introduces three key measures: a) A phase down mechanism with a freeze of HFC quantities placed on the market in 2015 followed by a gradual reduction down to 21% in 2030. To implement the phase down, the European Commission allocates yearly quotas to refrigerant producers and importers for selling refrigerants on the market. To neutralize the GWP value of each gas, quotas are expressed in tons of CO2 equivalent (the mass of refrigerant multiplied by the GWP value) HFC phase down (tons of CO2 equivalent) Year 2015 2016 2018 2021 2024 2027 2030 31% 24% 21% Quantity 100% 93% 63% 45% Note: 2015 base line = average quantity sold in 2009-2019

Maximum allowable charge size for R-32 Mmax (kg) Height Factor (m) 0.6 1.0 1.8 2.2 Area Floor Mounted Window Wall Mounted Ceiling Mounted (m2) Mmax (kg) Mmax (kg) Mmax (kg) Mmax (kg) 3.77 9 1.03 1.71 3.09 4.35 1.19 1.98 3.56 12 4.67 13.8 1.27 2.12 3.82 4.87 5.33 15 1.33 2.21 3.98 5.76 18 1.45 2.42 4.36 6.16 21 1.57 2.62 4.71 6.53 24 1.68 2.80 5.04 6.88 27 1.78 2.97 5.34 7.22 30 1.88 3.13 5.63 7.54 33 1.97 3.28 5.91 7.85 36 2.06 3.43 6.17 8.15 39 2.14 3.57 6.42 8.43 42 2.22 3.70 6.66 8.71 45 2.30 3.83 6.90 8.98 48 2.37 3.96 7.12 9.24 51 2.45 4.08 7.34 9.49 54 2.52 4.20 7.56 9.74 57 2.59 4.31 7.76 9.98 60 2.66 4.43 7.97 10.21 63 2.72 4.53 8.16 10.44 66 2.78 4.64 8.35 10.66 69 2.85 4.75 8.54 10.88 72 2.91 4.85 8.73 11.10 75 2.97 4.95 8.91 11.31 78 3.03 5.05 9.08 11.52 81 3.09 5.14 9.26 11.72 84 3.14 5.24 9.42 11.92 87 3.20 5.33 9.59 11.97 90 3.25 5.42 9.76 90.7 3.26 5.44 9.79 Indicates values for largest SDI RAV-GP1401AT-E with maximum charge to 75m

Minimum floor area for R-32 Amin (m2) Height Factor (m) 0.6 1.0 1.8 2.2 Charge (kg) Floor Mounted Window Wall Mounted Ceiling Mounted Minimum Floor Minimum Floor Minimum Floor Minimum Floor < 1.8 1.8 Area (m2) Area (m2) Area (m2) Area (m2) 1.9 2.0 27.6 No Volume Restriction 2.1 2.1 30.7 2.3 2.2 34.0 9.9 3.1 2.5 2.3 37.5 2.8 2.4 41.2 11.1 3.4 3.1 2.5 45.0 3.3 2.6 49.0 12.3 3.8 3.6 2.7 53.2 4.0 2.8 57.5 13.5 4.2 4.3 2.9 62.0 4.6 3.0 66.7 14.8 4.6 5.0 3.1 71.6 5.3 3.2 76.6 16.2 5.0 5.7 3.3 81.8 6.1 3.4 87.2 17.6 5.4 6.5 3.5 92.7 6.9 3.6 98.4 19.1 5.9 7.3 3.7 104.3 7.8 3.8 110.3 20.7 6.4 8.2 3.9 116.5 8.7 4.0 122.9 22.3 6.9 9.1 4.1 129.4 9.6 4.2 136.2 24.0 7.4 10.1 4.3 143.1 10.6 4.4 150.1 25.8 8.0 11.2 4.5 157.4 11.7 4.6 164.8 27.6 8.5 12.3 172.3 12.8 4.675 180.1 29.4 9.1 13.4 13.8 4.7 186.0 31.4 9.7 4.8 14.0 4.9 188.0 33.4 10.3 14.6 5.0 196.1 15.2 204.3 35.4 10.9 15.8 212.8 37.5 11.6 39.7 12.3 41.9 12.9 44.2 13.7 46.6 14.4 49.0 15.1 51.5 15.9 54.0 16.7 56.7 17.5 59.3 18.3 62.0 19.1 64.8 20.0 67.0 20.7 67.7 20.9 70.6 21.8 73.6 22.7 76.6 23.6

Safety The Refrigeration Trade is considered by some to be the most dangerous trade. Surely a bomb squad technician or perhaps law enforcement officials or high steel workers face greater perils than a mere refrigeration mechanic. However the reasoning behind this assumption is understandable. An HVAC/R mechanic must deal with high voltage electricity and work from ladders and spend time on construction sites where all manner of dangerous situations arise. He deals with high pressure gases, operating machinery with spinning pulleys and belts, welding gases and hot pipes. He spends time on roofs and working with cranes and heavy suspended objects. If all of this isn't enough, he also spends much time wearing out his knees and back lifting heavy objects and kneeling in front of electrical control cabinets to troubleshoot live components or replacing a compressor, fan motor or some awkwardly placed component. Why do we do it? Why is a cop a cop? Why does a high steel worker romp about on skinny beams hundreds of feet up? The short answer is that it can be a well paying career. The real answer is that we find it extremely interesting. You have to be cut out for the job. It is possible to do anything if you have enough interest but the vast majority of technicians who end up staying in the trade find that they were born for the work. And that does not mean that everything is a bed of roses for the \"right type\" of person. It means you have to be capable of taking the good with the bad but believe that the interesting parts outweigh the miserable parts. If you are the type of person who finds he has an interest in mechanics and thermodynamics then you should also be the type of person that is always thinking ahead about consequences and choices while doing your job. Ninety-nine percent of staying safe in this trade or perhaps any job is thinking ahead and creating safety as you go. For example, it is less likely that you will set off a fire with your welding torch if you use a protective shield over nearby flammable surfaces. If a fire does develop it will likely be much less of a problem if you were following normal safety procedures and had a fire extinguisher standing by within immediate grasp.

The most dangerous time for an HVAC mechanic is his or hers first years on the job. That's because everything is new and exciting and it's hard not to be overwhelmed by the vast assortment of amazing things to learn. A proper apprenticeship is the only way to learn how to do things the safe way. How else can you learn about the hidden dangers and tricks unless it is through the supervision of someone with experience. The first time you are standing on a roof assisting with the placement of a heavy roof top unit onto it's curb you will be thinking about the control system and where the T- Stat will be placed and anticipating all the wonders you are about to be exposed to. You may not be thinking about the large amount of momentum that a heavy unit has as it slowly moves while slung from the crane. If you happen to be standing in- between the unit and the edge of the roof you may not realize that if it swings in your direction it will sweep you off the roof like you weighed nothing at all. Any stabilizing you were considering doing for the unit can just as easily be done without placing your body in a position of danger. It's those types of things that turn out to be the most dangerous. The subtle things hiding in plain view in combination with a lack of experience. Never stop thinking ahead about safety. Attempting to manipulate a live electrical connection can sometimes save a lot of grief. This is certainly not a perfect world and there are an infinite number of improperly labeled or unlabeled circuits on electrical panels. Sometimes you can not shut down a whole panel and it becomes very tempting to work on a live circuit rather than spend an unknown amount of time tracing the disconnect switch or circuit breaker. Sooner or later you will face that dilemma. Remember to try to measure the amount of grief your loved ones will have if you are killed or injured compared to the amount of aggravation you would apparently be avoiding. If that logic doesn't do it for you then try to look at it this way; you can legitimately charge for the time it takes to trace a circuit and properly label it. It's the same pay for marching as it is for fighting. So why not take the time to do things the right way. Work safely and create a safer environment for the next guy at the same time. That is a far superior attitude than jumping from pillar to post trying to get things done in a hurry to please your

boss or please yourself. It is up to you to make your own rules and decide what is safe, what is not, and where you draw the line. It is smarter to do that before you are looking up from a hospital bed or blankly staring out from a coffin. If you need no convincing and wish to do things safely then you only need to keep that mind set and keep an eye out for the myriad of little things that are all waiting to get you. Each time you learn of some danger file it away in your head and never forget it. When learning the refrigeration trade there are lots of mistakes that can be made and lots of mistakes one can get away with. Safety is not always that forgiving. There are some mistakes that you just may not live through. You must learn right from the outset to anticipate dangers and avoid them. There has probably never been a refrigeration book written that does not mention that oil must never be placed on the threads of an oxygen fitting nor must oxygen ever be used to pressure test a piping system that contains oil. Still we read about the unknowing who do either of those things and blind or kill themselves with their own unintentional bomb. If it was possible to list ten thousand dangerous circumstances it would certainly not cover all possibilities. However the short list below, in no particular order, may be helpful as it exposes several dangers and also includes some recommendations. Safety Tips  Wear safety boots with steel shanks, steel toes and di-electric soles.  Wear knee pads when kneeling on concrete for extended periods.  Wear hard hats when appropriate.  Wear safety harness and safety rope when working on heights.  Carry safety equipment like fire extinguishers and maintain them.  Keep ladders in good repair.  Secure ladders on roof racks properly.

 Always tie off extension ladders.  Do not wear jewelry when troubleshooting electrical equipment.  Do not wear long ties or loose hanging clothing near pulleys and belts.  Shut off power before working on electrical components when possible.  Lock off and tag electrical switches when working on line voltage wiring.  Wear protective clothing when welding pipes because you will graze into hot pipes sooner or later.  Wear safety glasses when welding, drilling, grinding or any other time debris may threaten your eyes.  Wear safety glasses and gloves when working with refrigerants.  Acquire a proper fuse puller. No other tool removes cartridge fuses as safely.  Don't carry things up a ladder when you can haul them up with a rope.  Keep proper slope on extension ladders.  Don't stand between the roof edge and a suspended crane load.  Don't place parts of your body in jeopardy when a tool can be used instead.  Get in the habit of standing aside and looking away from electrical control panels when throwing disconnect switches and breakers.  When possible, don't have any part of your body other than your di-electric safety boot soles touching electrical grounds when working on live electrical components.  Don't troubleshoot electrical equipment in the rain.  Don't pop out electrical knock outs with your finger, use a tool. If your finger

slips it can rip your finger nail clean off. .  Find out what type of refrigerant is leaking before allowing any type of open flame in the area. Some of the new refrigerants have flammable components.  Use the proper tool for the job. A wrench is not a hammer, a knife is not a wire stripper.  Don't lay an acetylene tank on it's side while brazing.  Don't lay down a torch that you just used until you test it for a smouldering flame by cracking the fuel knob.  You are responsible for the danger from hot pipes that you create while brazing. Wet rag them before walking away. Don't subject other's to extreme burns by walking away from hot pipes.  Leave the area and make others do the same if you create phosgene while welding.  Don't assume power is dead just because a switch is off.  Discharge capacitors with a 20 KiloOhm 2 Watt resistor before handling them.  When hooking up an electrical device tie in the ground first so that if electricity suddenly appears it has somewhere to go other than through you. Tie in Neutral second and Lines last.  Don't assume a low voltage control circuit can only have low voltage present. Mistakes are made, always check for actual voltage with a test meter.  Never oil oxygen fittings.  Never pressurize a refrigeration system with oxygen.  Do not exceed manufacturers maximum pressure ratings on pressure vessels.

 Do not remove or leave safety controls bypassed. You must not put other's in danger.  Test a voltage meter on a live source before relying on it's read out of a supposed dead circuit.  Lock off and tag a remote disconnect switch that could put you in danger while working downstream of it.  Never allow a compressor to run with the DSV front seated.  Close off your welding tank before walking away from it.  Close panels on live electrical control sections before walking away from them. There is another ominous type of danger. That is the danger that comes with complacency. As you get used to working under what can be dangerous circumstances it eventually becomes common place and you may lower your guard a little bit. At the opposite end of the scale from a novice apprentice is the seasoned veteran. He is set in his ways and knows many things. He has lots of short cuts and over the years has learned to compromise safety in the name of expediency. Sooner or later that will catch up with him. Don't let that happen to you. Work safe, keep aware of the dangers around you, don't become complacent about safety. Enjoy a long healthy life.

Appendix. A. Glossary of useful terms. 1. Acute Effect. A toxic effect which occurs immediately or, after a short exposure. 2. ADG Code. Australian Code for the Transport of Dangerous Goods by Road and Rail. As a code, it provides a basis for State Governments to provide legislation for packaging, marking, transport and storage of dangerous goods. 3. Asphyxiant. A substance which, as a gas or vapour, can cause suffocation due to a lack of oxygen. 4. Auto Ignition Temperature. The lowest temperature at which a flammable gas or vapour in an air mixture will ignite from its own heat source without needing a spark or flame. 5. Chronic Toxicity. A toxic effect which is demonstrated after repeated or prolonged exposure which need not occur immediately after cessation of exposure. 6. Competent Person. Defined by the Commission as a person suitably qualified (by qualification, experience and/or experience) to carry out the kind of work for which the person is required or engaged to perform the required task (to comply with the Standard/Code). 7. Cylinder. A container, which is designed to be refilled, with a capacity of more than 100mL and less than 500 litres (i.e. not a bulk container which are greater than 500 litres) for packing Class 2 goods. 8. Dangerous Goods Class. The Dangerous Goods class is a number assigned to a group of dangerous goods which exhibit a single or most significant risk by certain criteria. Occupiers are expected to know the difference between dangerous goods and hazardous substances, which are classified according to different criteria Dangerous goods have immediate effects and are explosive, flammable, corrosive, chemically reactive, highly combustible, acutely toxic, radioactive or infectious, that may affect life, health, property or the environment. Hazardous substances are classified only on the basis of immediate or long term health effects. Dangerous goods and hazardous substances are covered by separate regulations, standards and codes, each focusing on controlling the different risks described above. Since many hazardous substances are also classified as dangerous goods, both sets of requirements will apply in these cases.

9. Earth. To reduce the potential of an item to that of the ground, normally by direct connection with a conductive cable or strap. It reduces the risk of static electricity discharges. 10. Exemption Limit. Is the maximum quantity of a dangerous substance for which no placarding is required. It depends on the dangerous goods class and packaging group. The greater the hazard, the lower the Exemption Limit. 11. Exposure Standards. Exposure standards detail levels of airborne concentrations of substances which, according to current knowledge, does not impair the health, or cause discomfort to the workers. Exposure standards are generally expressed as a time weighted average (TWA) concentration of a substance over an eight hour working shift, and applied to an eight hour day, for a five day week over an entire working lifetime. TWA permit exclusions above the limit provided that they are compensated by equivalent excursions below the limit during the workday. 12. Flammability Limits. The concentration range of a flammable vapour in air at which a flame can be propagated or an explosion will occur, with an ignition source. There is always an upper limit (UFL or UEL) above which the mixture is too rich and will not burn and a lower limit (LFL or LEL) below which the mixture is too lean and will not burn. The wider the gap between the flammability limits, the more violent the explosion of a cloud of vapour when it reaches a source of ignition. The terms flammability limits and explosive limits mean the same thing. 13. Flammable Liquid. Any substance that will ignite when in a liquid form is considered to be a class 3 substance. Note that the vapour form of that substance may not necessarily be flammable. Gasoline (or petrol) is an example of a flammable liquid. 14. Flammable Vapour. Any substance that will ignite when in a vapour form is considered to be a class 2.1 substance. Note that the liquid form of that substance will not necessarily flammable. The hydrocarbons are all flammable vapours but are not flammable liquids. 15. Flashpoint. The flashpoint is the lowest temperature at atmospheric pressure ( 101.3 kPa) at which a liquid gives off so much combustible vapour at the liquid surface that this vapour, when mixed intimately with air, can be ignited by a flame or spark. The lower the flashpoint value the higher the risk of ignition and fire. 16. Hazardous Atmosphere. A hazardous atmosphere is one in which: There is not a safe oxygen level for breathing; or Concentrations of hazardous gases, vapours, mists, fumes and dusts are at or above relevant exposure standards: or