I have a 9-yr old SEER 10 Carrier heat pump. Due to freon leakage, about 6 months ago, the contractor hired by my home warranty company replaced the indoor air handler with a Payne PF4MN model which is designed for R410. The outdoor R22 unit was not replaced. The contractor charged the system with R22 at the time of installation (which we found out recently).
We are not under home warranty any more. When the temperature started to rise about a month ago, we found out that the air that came out of the AC is not cool. We had a couple contractors over to take a look and was told that it is because the outdoor unit is incompatible with the indoor unit. When we went back to the insurance company, we were told that when they replaced the air handler, they installed an expansion valve KSATX0601, provided by Carrier, which allows my 410A fan coil to work properly in an R22 system. Therefore, they claim it's not their problem. Is what they are saying true? What options do We have? Some contractors told me that we have to replace the entire system including the new air handler, and others say that They can install a new condenser while keeping the current air handler - Two models quoted are Payne PH15NB03000G and Carrier 25HCC530A003, both in the $ range - cheaper than replacing the entire heat pump. my question is Will these two condensers work with the Payne PF4MN air handler I have given that I currently have R22 in my current system? Will that create any problem in the future? I was told by one of the contractors that my current PF4M air handler is designed for a SEER 13 condenser. If I match it with a 15 SEER condenser, I won't be able to get the efficiency benefit. Is that true? I'll be grateful for your advice?