RACA Journal June 2016 - Page 73

Responsible Refrigeration Barney Richardson Barney Richardson is the Director of South African Refrigeration and Air Conditioning Contractors Association (SARACCA) and sits on various other boards within the HVAC industry, including the South African Qualifications and Certifications Committee for Gas (SAQCC) Gas. Split air conditioning units By Barney Richardson We take a look at the problems that can be caused by the incorrect installation of split air conditioning units. A number of people have become aware of the poor quality of split air conditioning unit installations resulting in a number of problems. To name a few: • Failure of the compressor in the guarantee period, due to poor oil return or slugging of liquid. • Poor performance of the unit, due lack of refrigerant charge. • Leakage of refrigerant charge (due to a number of reasons which I try to highlight here). The loss of refrigerant from a split unit installation is a contributing factor to ozone depletion and global warming. This is the whole reason for the Montreal Protocol and the phase out of CFCs and HCFCs. If the response from your service mechanic is just to recharge the system every time there is a loss of gas, the possibility is that that person is not competent and is not registered with SAQCC Gas as an Authorised Refrigerant Gas Practitioner. All that is happening is that, by adding refrigerant, the system becomes over-charged for a while but the leak continues to lose gas and the problem continues. The user ends with having to put up with poor unit performance. There also could be other consequences of the poor operation of the unit which cannot be solved by an incompetent service mechanic. The other consideration is that some people may consider the loss of refrigerant a hazard, which may be true if the gas concentration in a confined space is high enough. A refrigerant like the commonly used R410a has the ability to displace oxygen; ASHRAE Standard 34-2010 has established a maximum refrigerant concentration limit of 11.8Kg /28.3m³ of occupied space volume. The volume of refrigerant charge in a split room air conditioning unit is not large and the gas leak usually is very slow and the gas www.hvacronline.co.za #ResponsibleRefrigeration dissipates quickly. Most of the common refrigerants are non-toxic and non-flammable. The classification of R410A in Standard 34 is class A1 and it has no ODP and it meets requirements of the Montreal Protocol. Some older installations may still be charged with R22 which will still be around for a number of years until unit installations are gradually replaced and updated. While R22 is cheaper than R410a it is morally not a good thing to be still using R22 to service the older systems where they should be removed and the refrigerant recovered in a safe and proper manner. VRV/VRF systems present a different problem because the indoor units are connected by a piping system with a large refrigerant charge. A VRF system is classified in ASHRAE Sta ndard 15 as a direct system and is classified as a high-probability system which could mean that a refrigerant leak could be directly into occupied space. The piping system and indoor units are in occupied areas. The air conditioned and non-air conditioned areas must be assessed with regard to the volume and potential leaks and safety for the occupants. This means a building may be made up of several rooms and the passages that connect these all together. A leak may exceed the recommended gas concentration levels. The answer to addressing the leaking of refrigerant gases into occupied spaces is in training of installers by the contractors and suppliers of air conditioning units in the correct and proper way to install split units and to connect piping so as to avoid and limit potential leaks. In many cases where multiple units are installed the piping is laid haphazardly and not properly secured and insulation damaged by the binding straps. This makes the job of finding a leak a nightmare for the service mechanic. The answer? Become competent, registered and take responsibility for the installation and issue a certificate of conformity. RACA RACA Journal I June 2016 71