Owner Manual

Refrigerant pressure operating too high or locking out on high limit
1. Unit running in cooling:
1.1. Too little water flow. Check loop pump including fuse on closed loop units or
check well pressure and water temperatures for open loop units.
1.2. Bad high limit switch. Replace limit switch.
1.3. Unit overcharged. Adjust refrigerant charge.
2. Unit running in heating:
2.1. Clogged air filter. Replace filter.
2.2. Dirty air coil. Clean air coil.
2.3. Bad high limit switch. Replace limit switch.
2.4. Unit overcharged. Adjust refrigerant charge.
2.5. Check blower module.
Refrigerant pressures operating too low or locking out low limit
1. Unit running in cooling:
1.1. Refrigerant leak. Find and repair leak.
1.2. Dirty air filter. Replace air filter.
1.3. Dirty air coil. Clean air coil.
1.4. Bad low pressure switch. Replace limit switch.
1.5. Check blower module.
2. Unit running in heating:
2.1. Refrigerant leak. Find and repair leak.
2.2. Too little water flow. Check loop pump including fuse on closed loop units or
check well pressure and water temperatures on open loop units.
2.3. Bad low pressure switch. Replace limit switch.
Freeze sensor tripping
1. Too little water flow. Check loop pump including fuse on closed loop units or check well
pressure on open loop units.
2. Bad freeze sensor. Replace sensor located on exiting refrigerant line of heat exchanger.
3. Closed loop unit WITH antifreeze but “ANTIFREEZE” tab on Dallas® board not
removed. Use a small pair of needle nose pliers to remove the tab. SEE PAGE 13,
SECTION 7.4 FOR MORE INFO REGARDING FREEZE PROTECTION.
Fan runs continuously when compressor is off
1. Thermostat set to “fan on”. Set thermostat to ‘fan auto”.
16.0 Wiring diagram
Page 30