R22 Replacement

There are still a whole load of older Rheem systems, such as this 1991 vintage RAWB100 model out there going strong. With the end of R22 the choice is now do we retrofit or replace.

Retrofit

We have been using R417a refrigerant in Rheem systems since 1998 with great results. The result is a slight capacity drop compensated for by a reduction in electrical power. In essence the system uses less power but for longer. If your system is working perfectly well then this may be the right answer for you in the short term.

We can advise the exact gas charge for your system when you want to change to R417a but the general rule is to add 5% to the base system charge by weight but use the same weight of gas for the lines as you would have used for R22.

This results in a system that will behave as if slightly undercharged compared with its performance with R22 in cooling mode but will behave as iof slightly overcharged in heating compared with before. It is important not to overcharge your system as this will cause damage. Charging by 'feel' or superheat will often result in as much as 20% overcharge and this will cause liquid slugging in cooling and high pressure trips in heating. Always charge by weight and always charge as a liquid.

Replacement

We have a full range of brand new R410a models that you can use to replace your old R22 system. We recommend checking for previous burnouts if you intend to retain the same pipework or indoor coil. We also recommend checking that the pipes and indoor coil are compatible and also strength and pressure testing both before deciding upon retaining them. The Expansion valves should be replaced along with sight glasses and driers.

All refrigerant and oil should be recovered from the pipes and indoor unit before connecting the new outdoor unit. Check both for strong 'burnout' smells as this will mean that both indoor coil and pipes will need to be replaced and not reused. Check the state of the oil with the chart below. If the oil is clear or yellow then flush the pipes and coil with Pro-Flush, remove all residue before remaking the connections, triple evacuating and charging. If the oil is orange, brown or black then the pipes and coil will need to be replaced.

If you decide to replace the entire system then you will find that the differences between the old and new systems are less than you may think. R410a is a more efficient refrigerant and often the new system will be the same size or smaller than the existing one.