There is a very strong argument that the vast majority of air conditioning equipment still running on R22 is old and therefore should be replaced. With R22 banned from use in all new equipment back in 2004, it is fair to assume most equipment is more than 10 years old. With the advances of new equipment to work better and much more efficiently, you would think by now, the vast majority of R22 equipment would have been replaced.
The Merits of R438A
R438A is equally suited to replace R22 in split AC, package units, Variable Flow (VRF) systems, water chillers, close control data centre cooling as well as refrigeration applications. In split systems with hermetic compressors, no oil drain and a capillary tube, only a very simple refrigerant change is possible where the existing oil can be used. ISCEON® MO99 is therefore the best solution as minimal changes are required to effect the conversion.
It is recommended the elastomeric seals, such as the valve cores and caps, are changed to prevent leaks but any Teflon or nylon rings do not need to be changed. Where expansion valves are fitted they may need a slight adjustment and fitting a new filter dryer is good practice.
As with all conversions, it is recommended to read and follow the manufacturer’s conversion guidelines, have the pressure tables to hand or at least a refrigerant comparator or a mobile phone. More importantly, before starting, make sure the AC unit is working properly and record the operating conditions prior to conversion, so they may be compared post conversion.
Use of R438A in the UK
BT have converted some of their datacentres from R22 to ISCEON® MO99 where close control AC systems protect critical servers and data rooms. The initial trial took place at their West London site on a 17 year old 74kW system before the other 10 systems were also converted. It was important that changes in cooling performance and efficiency were kept to a minimum and this was achieved as the contractor, Temperature Control Ltd, used a simple tried and tested conversion procedure that they have used for the last 5-7 years.
Other applications such as Variable Flow AC systems have also been converted to ISCEON MO99. Typical operating conditions of ISCEON MO99 can be seen compared to R22 in table 1, which are very close to R22 on important parameters.