I have an old 6-ton commercial Carrier heat-pump AC system, 38AQ-40RR.
The evaporator coil just bit the dust. We're looking to replace it, but it's a major operation just to get to the air-handling unit itself due to its location above a ceiling grid. Since we're going in anway, we're thinking ot replacing the whole air-handler unit instead of just the coil. It uses R22.
* Can we replace just the inside unit with an r410a indoor air handler but still keep the same old rooftop unit?