Is there a way to check or test if a Thermostatic Expansion Valve might be installed on an AC evaporator coil? Replacing an old 3 ton Compressor / Condenser unit with a newer higher efficiency R-22 SEER 14, 36,000 BTU condenser unit. It is not practical to replace the air handler at this particular time. The evaporator coil of this AC split system is built into metal ductwork above a natural gas heating furnace with forced air blower. It is not a proper AC air handler, just an inverted V evaporator coil & drain pan permanently installed into the up-flow air discharge ductwork. Due to expediency and exceedingly poor existing workmanship, there no way to gain access to the coil short of destroying and rebuilding much of that ductwork. Replacing all the homes existing ductwork is a project for another year.

There is no practical way to determine the size, model, installer, manufacturer or other features of that evap. coil, but it was very recently a fully functional part of a working 3 ton central AC split system. R-22 refrigerant has been recovered, system evacuated, purged and sealed with low pressure Nitrogen in preparation to swap that condenser out and change its location. For purposes of recharging the system with R-22 and estimating correct super-heat, is there a non-invasive way to guess if that evaporator is using a fixed orifice or a built-in Thermostatic Expansion Valve?..