My system is an approx 1990-91 Inter City Products Split System. ICP is now Interanational Comfort Products and Carrier purchased them a few years ago. The Evap coil is very rusty and needs replacement. Will a new 13 seer coil be compatible with the 10 seer older system and if it is compatible is there a "converter valve" needed to make it compatible?
Any new evaporator coil 13 SEER will work with an old 10 seer system as long as the piston (orifice) or TX valve is compatible with the refrigerant in your existing system. It will not provide you with the energy savings of a new and matched system however. You may want to consider replacing the entire system to ensure you get the energy savings and have a unit with Puron (r410a) in it as R-22 is on its way out. The coil will also likely be larger than the old one.