Need help wiring humidifier into 24VAC heat circuit.
My furnace is an old single stage heat pump. There's no control board or "HUM" leads to connect to. All I got is what's on the panel in the photo. My furnace is a Trane TWV030B140A1 blower with aux heat element.
Please correct me if I'm wrong on any of this. My understanding is that typically it should be wired to "W" (heat) and "C" (common) so water flows to humidifier only on a heat call.
My issue: I don't have a "C" wire.
So what do I do in this case? Is the "B" wire the return instead of "C"?
Here's what I've determined so far if this helps:
- "R" hot (measures ~28VAC. Should this be 24VAC?)
- "G" fan (measures 25.5VAC when blower on)
- "Y" compressor (measures 25.5VAC when compressor on)
- "W1" and "W2" tied together. Assuming this is aux heat tied to emergency heat since only single stage heater. Measures 25.5VAC when heat on. Should this be 24VAC?
- Manual says "O" is reversing valve
- Don't know what "B" is
Any help is appreciated!