www. refrigerationandaircon. co. za RACA Journal I June 2025 53
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GRANT LAIDLAW
Grant Laidlaw is currently the owner of the Air Conditioning and Refrigeration Academy( ACRA) in Edenvale. He holds a Bachelor of Business Administration and an associate degree in educational administration. He has a National Technical Diploma and completed an apprenticeship with Transnet. He has dual-trades status: refrigeration and electrical. He has been involved with SAIRAC for over two decades and served on the Johannesburg committee as chairman and was also president between 2015 and 2018. Currently he is the SAIRAC national treasurer.
WELCOME TO THE SOLUTIONS PAGE
By Grant Laidlaw
Many people ask for assistance in understanding theoretical and practical aspects of the industry. I will endeavour to enlighten. We are going back to basics as I have questions coming in that indicate that the basic understanding necessary to work in industry is not in place.
Stanley sent in the following: Mr Laidlaw, can you please explain the recovery of R290 and the ventin?
Hi Stanley. At the moment in South Africa, the highest percentage of equipment using hydrocarbon refrigerants would be the domestic and light commercial sectors. However, the impact of the Montreal Protocol and in particular the Kigali amendment will most certainly see an increase in the quantity and scope of equipment using hydrocarbon refrigerants. This is especially true of R290. In the overseas markets the use of R290 extends into and from the unitary air conditioning market right up to and including large capacity indirect industrial chillers.
Stanley, the release of natural refrigerants including R290 is virtually harmless to the global environment, but we must consider all our options. In addition, while venting is permissible, we have to consider the health and safety aspects. As you may be aware, when dealing with hydrocarbons( R290, R600a) flammability and / or asphyxiation are hazards which must be considered.
In the last issue we dealt with the venting of hydrocarbons and will now move on to recovery. Hydrocarbon refrigerant venting should only be carried out as an alternative to recovery if the charge size is smaller than 500g. We are now looking at quantities greater than 500g that should be recovered.
Conventional recovery procedures, as used for any other refrigerant, are for the most part applicable when dealing with hydrocarbon refrigerants. However, attention should be paid to certain aspects such as:
• The recovery machine used must be suitable for use with flammable refrigerants in general and not have any potential sources of ignition
• Hoses should be complete with leak-free disconnect couplings and be in good condition
• Before using the recovery machine, check that it is in satisfactory working order, has been properly maintained and that any associated electrical components are sealed to prevent ignition in the event of a refrigerant release. Consult the manufacturer if in doubt
• The recovery cylinder must be suitable for the refrigerant
used, specifically, in terms of the pressure rating and the compatibility with the refrigerant
• Ensure that the correct number of cylinders for holding the total system charge are available
• Ensure all cylinders to be used are designated for the recovered refrigerant and labelled for the refrigerant( i. e. special cylinders for the recovery of refrigerant). Cylinders shall be complete with pressure-relief valve and associated shut-off valves in good working order
• When connecting hoses between the refrigeration system, manifold gauges, recovery machine and recovery cylinder, ensure that the connections are secure and there are no potential sources of ignition nearby
• A fire extinguisher must be available
Purge the hoses, manifold and recovery machine prior to recovery to avoid the ingress of air.
Take care to minimise the emission of refrigerant but also make sure that there is always sufficient ventilation to dilute the release by using a fan to disperse any refrigerant.
Note: Enriched oxygen content in the surrounding workplace environment must be avoided( e. g. recovery in the immediate surrounding of brazing equipment). The minimum ignition energy can be greatly reduced at elevated oxygen levels or temperatures. The flammability limits are widened at elevated temperatures and elevated pressures.
PROCESS FOR THE RECOVERY OF REFRIGERANT
Tools required:
• Evacuated appropriate recovery cylinder with pressure relief and shut-off valves
• Recovery cylinder valve adapter
• Recovery unit for the use with flammable refrigerants
• Four-way valve manifold gauge set for the refrigerant in use with hoses
• Access valves / tool in order to access system
www. refrigerationandaircon. co. za RACA Journal I June 2025 53