York Heat Pumps: YHM
Re: Reversing Valve not Energizing - Cooling
The reversing valve powers through a 2-wire plug on the Heat Pump Control Board.
► There have been reported incidents where the 2-wire plug does not make good contact and causes the unit to run in heating mode when calling for cooling.
| Qty |
Possible Causes: |
| 1 |
Loose Plug |
|
Mis-Wired Low Voltage |
|
Mis-Configured Thermostat |
|
Bad Stat Wire |
CHECKOUT:
1. Check Low Voltage
- Set the thermostat to call for Cooling.
- At the outdoor unit, check for 24VAC between "O" and "C".
- No Power --> Step 2. Check Thermostat
- When the unit starts, check the suction line temperature.
2. Check Thermostat
- Re-Apply Power to the unit (if turned off from previous step).
- Compressor and Condenser Fan start and run normally --> Step 3. Check Refrigerant Pressures
- Compressor Does Not Try to Start = Control in Lockout, Bad Control Board or Bad Contactor
- Check for 24VAC between each "Pressure Switch" terminal and "C" on the defrost board.
- Power on one side but not the other = Open Hi or Lo Pressure Switch
- Power on both sides = Pressure Safeties OK --> Reset control by disconnecting "R" and "Y" from the board then re-check.
3. Check Thermostat Wire