Climatemaster- Code 4 / LT1 Fault- Cooling

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.

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.