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Climatemaster - Code 2 / High Pressure Fault - Heating

Article ID: 247
Last updated: 08 Feb, 2023

Climatemaster Geothermal: Heating 

Re: Code 2 / High Pressure Fault

Code 2 = High Pressure Fault

When the high pressure switch opens due to high refrigerant pressures the compressor relay is de-energized immediately since the high pressure switch is in series with the compressor contactor coil.


Qty Possible Causes:
1 Refrigerant OverCharge
Bad Expansion Valve
Bad Blower Motor / Capacitor
Bad CFM Board
1 Low Indoor Airflow
Refrigerant Restriction
Bad Pressure Switch


CHECKOUT:

1. Check Indoor Airflow


2. Check Blower Motor

  • These units use with a Variable Speed Indoor Blower.
  • Confirm that 240VAC is being supplied to the motor.
  • Confirm that 24VAC is present between "C" and "G", "Y1" or "Y2".
    • No 24VAC power = No signal from thermostat
    • 240V Power Present + 24V Power Present + No Blower Operation = Bad Blower Motor or Bad CFM Board

3. Check Operating Conditions

  • If the heat pump is in lockout, reset by removing 24VAC power to the control board.
  • Ensure that the unit is running at full capacity (Y1 & Y2 Energized).
  • 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 GaugeTemp - 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 Dicsh Pressure + High Suction = Overcharged
    • High Subcooling + High Disch Pressure + Low Suction = Bad Expansion Valve
    • Low Subcooling + High Disch 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 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 Air Filter Replace Filter & Re-Check Pressures

5. Check Duct Static Pressure

  • High duct static generally won't cause a Code 2 due to the nature of a V/S blower unless badly restricted.
  • 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

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Article ID: 247
Last updated: 08 Feb, 2023
Revision: 20
Views: 2414
Comments: 0
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