Upgrading existing R410A air conditioners to R32 units in a large apartment building?
My building has dozens of R410A air conditioners that are approaching EOL. When they die they have to be replaced with R32 units. An important issue is whether the new units need new piping or not.
Most manufacturers specify:
R410A pipe minimum thickness: ~0.61 mm
R32 pipe minimum thickness: ~0.71 mm
The reason? R32 has slightly higher pressure and is flammabile (A2L class) so it requires a higher-rated copper pipe.
Advice I have found says no, you cannot directly replace R410A with R32 in an existing system; R32 is not a "drop-in" replacement, and doing so is unsafe, inefficient, and likely violates regulations and warranties because R32 is mildly flammable (A2L) and systems must be specifically designed and rated for it. While R32 is a component of R410A, using it alone in an R410A unit can damage components, increase wear, void warranties, and poses fire risks, requiring complete system replacement with R32-rated equipment for safe transition.
A lot of people say you can reuse the existing R410A piping and all will be fine for a while, and you'll save a lot of money and hassle which is priority #1 for many. However what they don't say is apparently that the pipes will then be prone to leak more quickly, and R32 coolant is mildly flammable. You also risk acid buildup, clogging, or compressor failure. Much of this is understandably of concern to residents in a large, tall multi story residential building.
ChatGPT says that if you decide to reuse the old piping, you should go through an extensive multi stage process the clean the old piping first.
https://chatgpt.com/s/t_69141e0bfe088191b594b5e89c6e53e0
In practice installers with the cheapest quotes get accepted, resuse the old piping and do none of that, leaving theproblems for someone else to deal with in future. Pipe coverings on the cheap new units are also not UV resistant so quickly disintgrate on the roof, where many of the units are.
My building needs a process that ensures safe long term outcomes, but whatever they are that process seems like it's going to involve an after installation inspection and cost $$$, which will greatly infuriate many.
It also seems like we should be arranging a close inspection and review of existing R32 units that have already been installed to ensure their long term safety. I suspect that in those cases the EC may have previously signed off on a high level plan for their installation. For the EC to potentially come back now and say an owner has to do something expensive like reinstall the piping for example, is going to go down like a lead balloon and I'm unsure if the existing building rules would permit such a thing. The standard speil you inevitably get is why are you making such a big deal about this? Everything's fine, just let it go and she'll be right and that is difficult to counter when you're not expert in this stuff at all.
Has anybody out there already dealt with and/or addressed issues like these?