Hello! My home was originally equipped with two Tappan model CM 36-41 C three ton AC condensers (1975) on its two split systems, one serving the downstairs, the other upstairs. Both are combination gas fired furnace/AC systems.
12 years ago the downstairs unit condenser gave up the ghost and was replaced by a Rheem model RAKA-042JAZ 42,000 btu 10 SEER 3 1/2 ton R-22 condenser unit. The original inside natural gas heater and A coil unit was left intact and unmodified. This combination has worked perfectly for the past 12 years and continues to do so today.
Now the 37 year old Tappan CM 36-41 C condenser for my upstairs AC/heater has finally bitten the dust (grounded compressor) and needs to be replaced. I would like to do the same thing as before and replace with a 10 SEER Rheem R-22 unit but they now have only 13 SEER R-22 condenser units. My question for you experts is would it be ok to install a new 13 SEER R-22 3 or 3 1/2 ton Condenser leaving old upstairs A coil intact as before?