Doing some Pentair heat pump troubleshooting?
These error code explanations will give you some guidance for resolving the most common Pentair pool heater problems:
Pentair Heat Pump Error Codes
Need help troubleshooting or repairing your pool heater?
NOTE: Any troubleshooting that involves electrical work, or opening the heat pump, should be done by a professional
Pentair heat pump error code HIGH WATER TEMP
HIGH WATER TEMP
What it means: temperature sensor detecting water above 107 degrees
How to fix it:
- Measure water temperature with a thermometer to rule out a faulty temperature sensor
- Hire professional pool heat pump repair tech to inspect control board, thermistor, and unit
Pentair heat pump error code LOW WATER TEMP
LOW WATER TEMP
What it means: temperature sensor detecting water below 40 degrees
How to fix it:
- See HIGH WATER TEMP troubleshooting steps
Pentair heat pump error code LOW WATER FLOW
LOW WATER FLOW
What it means: the unit’s low-pressure switch senses that water flow is open or low
How to fix it:
- Check that pool pump is sending water to heater
- Ensure that pool pump is receiving enough water
- Check that your pool system’s multiport valves are on the correct settings
- Have pool heater repair tech check for bad pressure switch (or check it yourself)
Pentair heat pump error code REMOTE POOL/SPA
REMOTE POOL/SPA
What it means: remote inputs of Pool AND Spa are being triggered
How to fix it:
- Avoid triggering inputs at the same time
Pentair heat pump error code WATER THERM SHORT
WATER THERM SHORT
What it means: water thermistor circuit is shorted
How to fix it:
- Replace water thermistor
Pentair heat pump error code WATER THERM OPEN
WATER THERM OPEN
What it means: water thermistor circuit is open/receiving constant power
How to fix it:
- Seek pool heater repair tech to troubleshoot the water thermistor
Pentair heat pump error code SUCTION TH SHORT
SUCTION TH SHORT
What it means: defrost thermistor circuit is shorted
How to fix it:
- Replace defrost thermistor
Pentair heat pump error code SUCTION TH OPEN
SUCTION TH OPEN
What it means: defrost thermistor is open; power is being interrupted
How to fix it:
- Seek pool heater repair tech to troubleshoot the defrost thermistor
Pentair heat pump error code BROWNOUT
BROWNOUT
What it means: the 24 VAC supply voltage to the heat pump circuit board is low
WARNING: Any troubleshooting that involves electrical work is dangerous, and should be performed by a professional pool heater repair tech.
How to fix it:
- Check that transformer supply voltage is within 208 – 260 volts
- Check that transformer output is between 24 – 28 volts
- Replace transformer is voltage is below those ranges
- Check that heat pump supply voltage is between 208 -260 volts
Pentair heat pump error code HIGH REFRIG
HIGH REFRIG
What it means: refrigerant system’s high-pressure switch is open
How to fix it:
- Ensure that pool pump is sending water to your pool heater
- Check for any blockage in baskets and filters that are affecting water flow
- Have pool heater tech inspect higher-pressure switch
Pentair heat pump error code LOW REFRIG
LOW REFRIG
What it means: refrigerant system’s low-pressure switch is open
Causes & Fixes:
- The unit may have a refrigerant leak. Seek professional heat pump repair
- Outside temperatures are too low to operate
- Have pool heater tech check if the switch needs to be replaced
Pentair heat pump error code FIVE ALARMS
FIVE ALARMS
What it means: 5 faults have occurred within the heat pump’s last cycle
How to fix it:
- Turn unit off and on to remove warning
- Check for additional error codes that are listed in this post
- Try DIY pool heater troubleshooting
