What equipment will change when I convert from R-22 to R-410A? I don't want to get rid of my current heater as it's a hydro-thermal unit that uses free heated/recycled hot water. Can I get away with just replacing the A/C unit and orifice tube? Or will I need to change out the entire cabinet, heater core, and evaporator?


1 Answer 1


On the AC side everything really needs to be changed R22 uses mineral oil based lubricants. R410a uses ester oil lubricants. Getting all the residue out would cost a bunch and these can’t be mixed. The compressor will need to be changed and the TXV / orifice will need to be changed. You might be able to have the evaporator cleaned (indoor coil) if it is in good shape and the size will work. Most of the time the older outdoor coils are in rough shape and of older less energy efficient design. Cleaning and changing the parts are not cost effective. It would help to have the model because some units have adjacent coils and some the coils are interlinked for improved efficiency. I have only worked on a couple of old units but they just needed a recharge, I know some charge $100/LB for R22 but it can still be purchased if the system is working.

Just an update, another Stack exchange member posted there system had been upgraded and now is not working well from under sized lines and possibly contaminated oil. Just thought I would add this to help your decision.

  • I'm sorry my HVAC parts knowledge isn't that great, and that it's difficult for me to figure out what I'm actually trying to ask.. I know that I need to get a new outside AC unit. But what do I need to change inside my house? I don't know what you call the large cabinet that houses the heater core and evaporator, but will have to change that cabinet, the evaporator, and the type of heater I currently have just to upgrade to R410A? Or can I keep the cabinet the way it is and just change out the AC unit along with the refrigerant and oil?
    – CodeSeven
    Jun 6, 2016 at 1:58
  • This is where it gets hard without looking at the system. The evaporator cooling coil in the house if properly sized and cleaned may work with r410 but it is difficult to get all the mineral oil out of the system, changing the evaporator if separate from the heating side would be the safest along with the suction and pressure lines to the compressor and condensing coil outside. If the 2 coils are combined that makes it a tough call. And if the evaporator inside coil can be cleaned the system may not be the same tonnage (cooling capacity) due to the differences in R22 & r410. Air handler = box
    – Ed Beal
    Jun 6, 2016 at 3:34
  • Awesome, thank you! Yes, the HVAC evaporator is housed separate from the box that houses the heater core (hydro-thermal) and the blower motor. So if I want, I can have that box with the evaporator changed out without changing anything else.
    – CodeSeven
    Jun 6, 2016 at 4:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.