R410A Condenser with R22 Coil

New R410A condenser on an older system with an 18-year-old R22 coil at today’s inspection. I’m thinking that these are not meant to be paired together.

Yes/no, for those in the know?



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I have seen this a few times. The HVAC guy I use says it could work if modifications (orifices, I believe?) have been made.
I always note the incompatibility and refer it to a licensed HVAC contractor for review or repair.

This will work just fine.

Hopefully The tech cleaned the coil and line set prior to soldering in the new condenser.
Other than knowing the charge of R410A refrigerant in the condenser will not be adequate for the R22 coil and be ready to add more, the system should function properly.

Anything can be made to work for a little while lol… Some older air handlers will say they are rated for both, some say R-22 only. 410 runs at a higher pressure than R-22 so you have an older unit that may or may not have built to take a higher pressure. Also the lines sets have to prepared correctly or replaced so there are a lot of things that could wrong.

I always thought the Energy Code mandated a matching SEER rating, even you could modify the refrigerant. Is this not the case?

Thanks, guys.

I needed to turn the report around last night so I went with this

Not sure who thought it was a wise decision to stick with an 18-year-old coil.

Feel free to critique.

Pretty much exactly what I say and how I feel about Iit

I need to check but I think one of the times I came across this there were actual permits pulled for the changeout ( which happens like 25-30% of the time up here)

Started out in HVAC … Seen it done with mixed freon’s in the past.

OR where both were pulled out, new orifices, expansion devices, etc AND then both systems were recharged with 1 type newer freon.

Chucks comment was spot on.

The only thing is… The evap coil may not be rated to take the pressure of 410. Even if they made it work, its not a matched system so it will never work as designed. Its just a scab of a system, installed by a scab of a contractor.

I didn’t realize you could mix the different refrigerants :shock:

Didn’t mix … Removed both, retrofit, install one.

Chuck- From a design standpoint, the R 22 unit coil has a different design pressure than the R410a replacement.

R22 coils are made from copper which are more likely to leak refrigerant than the R410a coil.

Your particular unit is a heat pump and because of the reversed refrigeration process where high pressure is exposed to the evaporator coil (which does not happen in an air conditioner) you have a greater chance of coil failure.

The coil sticker has a design pressure of 350 psi. R410a runs well over 100 psi higher than this.

The ultimate decision should be made by the equipment manufacturer of the new part of the unit.