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

Check the power supply and thermostat settings first. If the unit isn't heating, ensure the heat pump is operational and the water temperature is set correctly.

Confirm the symptom

Water not heating to desired temperature
Unit making unusual noises
High energy bills despite normal usage
Water tank feels cold on top
Error codes displayed on control panel

Tools and prep

Voltage tester
Screwdrivers (flathead and Phillips)
Thermometer for water testing
Owner's manual
Safety gloves and goggles
Flashlight

Step-by-step troubleshooting

Check Power Supply
Do: Verify the circuit breaker hasn't tripped and the unit is receiving power.
Observe: Power indicator light is on.
Means: Power is active; move to next step.
Next: Check Thermostat Settings
Check Thermostat Settings
Do: Ensure the thermostat is set to a temperature above the current water temperature.
Observe: Thermostat displays correct temperature setting.
Means: Settings are correct; proceed to next step.
Next: Inspect Heat Pump Operation
Inspect Heat Pump Operation
Do: Listen for the heat pump to activate and check for airflow from the vents.
Observe: Heat pump is running and producing airflow.
Means: Heat pump is functioning; continue troubleshooting.
Next: Test Water Temperature
Test Water Temperature
Do: Use a thermometer to measure the water temperature at a hot water tap.
Observe: Water temperature is below the thermostat setting.
Means: Heating issue likely; check for error codes.
Next: Check for Error Codes
Check for Error Codes
Do: Refer to the owner's manual to interpret any displayed error codes.
Observe: Error code is identified.
Means: Follow manual instructions for error resolution.
Next: Contact a Professional
Contact a Professional
Do: Schedule a service call with a licensed HVAC technician.
Observe: Professional diagnosis and repair.
Means: Issue resolved by expert.
Next: Complete

Common causes

Cause	Likelihood	Difficulty	Part often needed
Incorrect Thermostat Settings Thermostat set too low prevents proper heating.	Common	Easy	None
Faulty Heat Pump Compressor or fan motor failure disrupts heat transfer.	Sometimes	Hard	Heat pump assembly
Dirty Air Filter Clogged filters restrict airflow, reducing efficiency.	Common	Easy	Air filter
Low Refrigerant Leakage reduces the system's ability to transfer heat.	Sometimes	Medium	Refrigerant charge
Malfunctioning Temperature Sensor Faulty sensor provides incorrect temperature readings.	Sometimes	Medium	Temperature sensor
Clogged Drain Pan Standing water in the drain pan can trigger shutdowns.	Common	Easy	Drain pan or pump
Electrical Issues Tripped breakers or faulty wiring disrupt power.	Common	Medium	Electrical components

Parts matching

Match your issue to the correct part for replacement:

Air filter – for restricted airflow and reduced efficiency
Temperature sensor – for incorrect temperature readings
Heat pump assembly – for non-functioning heat pump
Drain pan or pump – for clogged drain issues
Refrigerant charge – for low refrigerant levels
Electrical components – for power-related problems

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

When to call a professional

Error codes persist after basic troubleshooting
Heat pump makes loud or unusual noises
Water temperature remains below desired level despite correct settings
Refrigerant leaks are suspected
Electrical issues beyond simple breaker checks
System performance declines significantly over time

FAQ

How often should I replace the air filter?

Replace or clean the air filter every 3–6 months, depending on usage and environment.

Can I reset my heat pump water heater?

Yes, locate the reset button on the unit and press it. If it trips again, contact a professional.

Why is my water heater using more energy than usual?

Possible causes include dirty filters, incorrect thermostat settings, or a malfunctioning heat pump.

What temperature should I set my heat pump water heater?

Set the temperature between 120–140°F (49–60°C) for optimal efficiency and safety.

How long does a heat pump water heater last?

With proper maintenance, a heat pump water heater can last 10–15 years.