Trane Heat Pump

[Cardlime8]

I checked a Trane Air handler unit and found out that only one out of three heating element energized when unit is in heat mode or emergency mode. This unit has only one high limit temperature switch and all heating elements are connected to it. This unit doesn’t have a sequencer but it has some type of relay that looks like the heat pump defrost control relay.
The Air Handler manufacture is Trane. Mode # BWV036A100E1 and the Serial # B06351302, I checked online and could not get any information on the unit.

Would someone please help me advise what to *
Thanks,

[aircooledtx]

Well, is it calling for *
You have amp meter, what is amp draw of heat *
Might want to check wiring AT air handler to see if both strip wires are connected.

[Cardlime8]

Yes! The system is calling for heat. I switched it back and forth from emergency and heat mode and nothing happened.
One strip is drawing 20 amps and the other two nothing.
At the air handler there is three wires connected between W1 and W2, two black and one white. but at the t-stat the black wire is not connected.

[aircooledtx]

**"Cardlime8"-*! The system is calling for heat. I switched it back and forth from emergency and heat mode and nothing happened.
One strip is drawing 20 amps and the other two nothing.
At the air handler there is three wires connected between W1 and W2, two black and one white. but at the t-stat the black wire is not connected.*/-*
black is usually heat strips/BUT check to ground before connecting all blacks at AH.
Heat should be at 85 / to insure all strips are called for at t-stat