ClimateMaster Heat Pump: Cooling
Re: Code 4 / LT1 Fault
Code 4 = Low Water Coil Temperature (FP1 or LT1)
- LT1 FAULT SHOULD ONLY OCCUR IN THE HEATING MODE.
- AN LT1 FAULT IN COOLING MODE TYPICALLY INDICATES A BAD SENSOR.
- The LT1 sensor is located on the Water Coil side of the expansion valve at the compressor section.
- The LT1 thermistor temperature must be below the selected low temperature limit setting* for 30 continuous seconds during a compressor run cycle to be recognized as a LT1 fault.
- *JW3 Clipped = 10 deg. Unclipped = 30 deg.
- The LT1 input is bypassed for the initial 120 seconds of a compressor run cycle.
- LT1 is set at the factory for one try. Therefore, the control will go into lockout mode once the LT1 fault has occurred.
| Qty |
Possible Causes: |
|
Reversing Valve/Operating in HEAT mode |
| 1 |
Bad LT1 Sensor |
CHECKOUT:
1. Check JW3 Jumper
- The JW3 jumper on the control board should be clipped in all applications with ground well piping.
- Locate the JW3 jumper on the board and confirm that it is clipped.
- Not Clipped ⇒ Turn off power to the unit and clip the jumper.
2. Check Operating Conditions
- Turn the thermostat to the "Off" position and ensure that the compressor stops operating.
- Compressor Continues to Operate = Stuck Compressor Contactor
- Set the thermostat to call for heat and ensure that the unit is running at full capacity (Y1 & Y2 Energized).
- If the contactor is energized but the compressor is not operating ⇒ Check for a Stuck Compressor Contactor
- Unplug the 3-wire heater connector from the control board to prevent aux heater operation.
- Allow the unit to operate for at least 5 minutes.
- Check and record the HWG Inlet and Outlet Temperatures (if present).
- Cold HWG temperatures drastically affect operating conditions and can cause excessive unit operation.
- Make sure bottom heating element of water heater is operational and thermostat is set for approx. 120 deg.
- Unplug the HWG pump motor (if the HWG piping is hooked-up and active).
- Check and record the Water Pressure Drop through the geo-thermal unit.
- Check and record the Entering Water Temperature and the Leaving Water Temperature.
- Check and record Refrigerant Pressures.
- Check and record the Air Temperature Rise through the unit.
► Be sure to re-connect the 3-wire heater plug and HWG pump before closing the unit!
3. Compare to Unit Performance Chart
- Use Flow Sheet to convert pressure drop to GPM and then GPM per Ton.
- Compare actual conditions to Unit Performance Chart.