I have a PTAC unit in the room above my garage (Amana PTH123A35AC) that I’m trying to connect a thermostat (Honeywell 50018270-001) to. These are my current connections:
| PTAC | Thermostat |
|---|---|
| B | B |
| C | C |
| GL | G |
| R | R |
| W2 | W |
| Y/W1 | Y |
| GH | Unused |
| Unused | O |
| Unused | Rc |
The only thing that’s not working is the cool setting. Heat and the fan are working fine. I have tried connecting R to Rc and B to O, but neither worked. I’m fairly certain I have something incorrectly wired here, but I’m just not sure which connection.
PTAC Serial Number Decoded:
- PTH: Standard Heat Pump PTHP
- 12: 12,000 BTU/h, 60Hz
- 3: 230/208V, 60Hz, 1 Phase
- A: First Design Series
- 35: 3.5 kW (230/208V)
- AC: Standard Model
Does anyone have any ideas as to why the cool setting isn’t working?
Update for anyone who finds this post.
I think this was the wrong thermostat for this type of AC. I went out and got an Ecobee to attach to the unit and it’s working great! I did have to call Ecobee to find that I had to change the O/B setting from its default but it’s working like a charm now!