Climatemaster Geothermal: GSV/GSH

Re: Code 2 / High Pressure Fault (Heating)

Code 2 = High Pressure Fault

► There may be an optional High Water Temperature Switch (HWTS) or a High Water Pressure Switches (HWPS) wired in series with the refrigerant High Pressure Switch.

► When the high pressure switch circuit opens the compressor relay is de-energized immediately since the high pressure switch is in series with the compressor contactor coil.

CHECKOUT:

1. Check Indoor Airflow

• Set the thermostat to call for heat.
• Confirm that the indoor fan is operating and air is blowing out of the supply registers
  • No Airflow → Step 2. Check Blower Motor
  • Airflow → Step 3. Check Operating Conditions

2. Check Blower Motor

• These units use a standard PSC Indoor Blower Motor, controlled by a Fan Relay.
• Check for 230VAC between the Blue and Yellow wires feeding the motor on a call for "G".
  • 230V Power Present + No Blower Operation = Bad Blower Motor or Capacitor ⇒ Test the Capacitor
  • No Power ⇒ Check for 24VAC between BR and BRG at the control board on a call for "G".
    • No Power = Bad CXM Control Board
    • 24V Power + No 230V Power = Bad Blower Relay

3. Check Operating Conditions

• If the heat pump is in lockout, reset by removing 24VAC power to the control board.
• Unplug the 3-wire heater connector from the control board to temporarily prevent aux heater operation.
• Allow the unit to operate for at least 5 minutes.
  • If the unit kicks-off on Hi Pressure safety in the first 5 minutes = Bad Overcharge, Refrigerant Restriction or No Airflow
  • If the compressor never kicks on & the control locks-out on High Pressure ⇒ Suspect a Bad Pressure Switch
• 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.
• Calculate Subcooling.
  • High Pressure Gauge Temp - Liquid Line Temp = Sub-Cooling
• Check and record the Air Temperature Rise through the unit.
• Compare operating conditions to Unit Performance Chart.
  • High Subcooling + High Discharge Pressure + High Suction = Overcharged
  • High Subcooling + High Discharge Pressure + Low Suction = Bad Expansion Valve
  • Low Subcooling + High Discharge Pressure + High Air Temp = Low Indoor Airflow or Heat Transfer → Step 4. Check Air Filter & Indoor Coil

► Be sure to re-connect the 3-wire heater plug and HWG pump before closing the unit.

4. Check Air Filter & Indoor Coil

• A dirty air filter or indoor coil generally won't cause a Code 2 due to the nature of a V/S blower unless badly clogged.
• Remove the Air Filter and Check for a Dirty Indoor Coil
  • If the Indoor Coil is OK ⇒ Re-Check Temperature Rise with the filter removed.
    • No Change = Restricted Ductwork or Low Blower Speed → Step 5. Check Duct Static Pressure
    • Temperature Rise Becomes Normal = Clogged or Restrictive Air Filter ⇒ Replace Filter & Re-Check Pressures

5. Check Duct Static Pressure

• Check the return duct static pressure.
• Check the supply duct static pressure.
  • High Static = Above 0.5" w.c.
    • High Return Static + Low Supply Static = Restricted Return Ductwork
    • Low Return Static + High Supply Static = Restricted Supply Ductwork
  • Static Pressure Normal ⇒ Increase Blower Speed or Clean Blower Wheel