I have a residential job where the customer (large apartment owner, various locations) bought a new 1.5 ton air handler/heat pump with back up electrical heat from a local supplier 9 months ago.
I was getting ready to check out the low voltage wiring (there is no electrical ladder wiring diagram in the instructions, but there is one on the front panel) and noticed that the air handler has only three terminals, R, G, and I think a W.
I called the supplier about help on wiring the air handler correctly to communicate with the heat pump and after I gave them the model # (RHSL-HM1817AA) of the unit, they said someone sold the building owner the wrong air handler.
I have been trying to swap out for another air handler and I'm about to give up and just have the owner buy another air handler, but I think there is a chance I can make this air handler work, maybe with the correct DPDT relay and a new heat pump thermostat to kick on the back up heat. What do you guy's think?