Heat Pump Water Heater Troubleshooting (Troubleshooting Guide)

On this page

Quick answer
Confirm the symptom
Tools and prep
Step-by-step troubleshooting
Common causes table
Parts matching
When to call a pro
FAQ
Related guides

Quick answer

If your heat pump water heater isn't heating water, first check the power and thermostat settings. Ensure the unit is not in 'eco' mode and the temperature is set above 120°F. If the issue persists, inspect the heat pump components for errors or call a professional.

Confirm the symptom

Water not heating to desired temperature
Heat pump makes unusual noises
Unit displays error codes
Water heater not turning on at all
High electric bill with no clear reason

Tools and prep

Voltage tester
Screwdrivers (flathead and Phillips)
Thermometer
Owner's manual
Safety gloves and goggles
Flashlight
Plumber's tape
Shut off power at the circuit breaker
Shut off water supply if needed

Step-by-step troubleshooting

Check Power Supply
Do: Verify the circuit breaker is on and the unit is receiving power.
Observe: Unit powers on and displays normal status.
Means: Power is restored.
Next: If power is off, check wiring and reset the breaker.
Inspect Thermostat Settings
Do: Ensure the thermostat is set above 120°F and not in 'eco' mode.
Observe: Thermostat shows correct temperature and mode.
Means: Thermostat is properly configured.
Next: If settings are correct, move to the next step.
Check for Error Codes
Do: Look for any error codes on the digital display or LED indicators.
Observe: Error code is visible.
Means: Specific issue identified.
Next: Refer to the owner's manual for code meanings and solutions.
Inspect Heat Pump Components
Do: Visually check the heat pump for ice buildup, dirty coils, or damaged parts.
Observe: Clean coils and no ice buildup.
Means: Heat pump is functioning normally.
Next: If issues are found, clean or replace components as needed.
Test Water Temperature
Do: Use a thermometer to check the water temperature at the tap.
Observe: Water temperature matches the thermostat setting.
Means: Heating system is working correctly.
Next: If temperature is low, check the heating element or heat pump operation.
Reset the Unit
Do: Turn off the power for 1 minute, then restore it to reset the system.
Observe: Unit restarts and operates normally.
Means: Temporary fault resolved.
Next: If the issue returns, further diagnosis is needed.

Common causes

Cause	Likelihood	Difficulty	Part often needed
Incorrect thermostat settings Improper temperature or eco mode settings prevent full heating.	Common	Easy	None
Dirty or iced coils Reduced heat transfer efficiency lowers water temperature.	Common	Easy–Medium	Coil cleaner
Faulty heating element Backup electric element may fail if the heat pump isn't working.	Sometimes	Medium	Heating element
Power supply issues Tripped circuit breaker or wiring problems disrupt operation.	Sometimes	Easy	Circuit breaker
Error codes from internal sensors Sensor malfunctions can trigger shutdowns or incorrect operation.	Sometimes	Hard	Control board
Poor ventilation Inadequate airflow reduces heat pump efficiency.	Rare	Easy–Medium	Ventilation kit
Refrigerant leak Low refrigerant levels prevent proper heat transfer.	Rare	Hard	Refrigerant and repair kit

Parts matching

Common parts needed for heat pump water heater repairs include:

Coil cleaner for removing dirt and debris
Heating element for backup heating
Circuit breaker for power restoration
Control board for sensor and system management
Ventilation kit to improve airflow
Refrigerant and repair kit for leaks

Always refer to your owner's manual for part specifications and compatibility.

When to call a professional

Error codes persist after checking all settings and components
Refrigerant leaks or suspected refrigerant issues
Electrical issues beyond basic circuit breaker checks
Heat pump makes loud or unusual noises that don't resolve after inspection
Water temperature remains below 120°F despite troubleshooting
Unit repeatedly trips the circuit breaker
You're unsure about diagnosing or replacing complex parts like the control board

FAQ

Can I use my heat pump water heater in colder climates?

Yes, but efficiency may drop below 40°F. Ensure the unit is rated for your climate zone.

How often should I clean the coils?

Clean the coils every 6–12 months to maintain efficiency.

Why is my unit using more electricity than expected?

High usage may indicate a malfunctioning heat pump, incorrect settings, or a faulty backup element.

Is it normal for the heat pump to make noise?

Some noise is normal, but loud or unusual sounds may signal a problem.

Can I install a heat pump water heater myself?

Installation requires electrical and plumbing work. It's recommended to hire a licensed professional.