Heat Pump Underfloor Heating 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 heat pump thermostat settings and ensure the underfloor heating system is activated. Inspect for tripped circuit breakers or GFCI outlets. If the system still doesn't heat, test the floor sensors and call a professional if needed.

Confirm the symptom

Warm heat pump but cold floors
Underfloor heating not turning on
Thermostat shows heat demand but no floor warming
Uneven heating across the floor
Error codes on heat pump display related to underfloor heating

Tools and prep

Voltage tester
Screwdriver set
Thermal imaging camera (optional)
Owner's manual for heat pump and underfloor system
Safety gloves and goggles
Ensure power is off before inspecting electrical components

Step-by-step troubleshooting

Check Thermostat Settings
Do: Verify the thermostat is set to 'Heat' mode and the temperature is higher than the room temperature.
Observe: Thermostat displays correct settings and heat demand.
Means: Thermostat is functioning correctly.
Next: If thermostat is correct, proceed to next step.
Inspect Circuit Breaker
Do: Locate the electrical panel and check if the circuit breaker for the heat pump and underfloor heating is tripped.
Observe: Breaker is in 'On' position and not tripped.
Means: Electrical supply is stable.
Next: If breaker is fine, proceed to next step.
Test GFCI Outlets
Do: Check any GFCI outlets connected to the underfloor heating system for tripped status.
Observe: GFCI outlet buttons are not tripped and power is restored.
Means: Electrical safety devices are functioning.
Next: If GFCI is fine, proceed to next step.
Examine Floor Sensors
Do: Locate the floor temperature sensors and ensure they are not damaged or loose.
Observe: Sensors are securely connected and show consistent readings.
Means: Sensors are operational.
Next: If sensors are faulty, proceed to next step.
Check Heat Pump Mode
Do: Confirm the heat pump is set to 'Underfloor Heating' mode, not 'Air Heating' or 'Cooling'.
Observe: Heat pump display shows underfloor heating mode active.
Means: Heat pump is configured correctly.
Next: If mode is incorrect, adjust and monitor.
Inspect Floor Piping
Do: Visually check underfloor heating pipes for leaks, blockages, or airlocks.
Observe: Pipes are intact, no visible leaks, and water flows freely.
Means: Hydraulic system is functional.
Next: If issues are found, proceed to next step.
Reset the System
Do: Turn off the heat pump and underfloor heating system for 10 minutes, then restart.
Observe: System restarts and heating resumes.
Means: Temporary glitch was resolved.
Next: If no improvement, call a professional.

Common causes

Cause	Likelihood	Difficulty	Part often needed
Incorrect thermostat settings Thermostat not set to heat mode or incorrect temperature target.	Common	Easy	None
Tripped circuit breaker Overload or short circuit in the system.	Common	Easy	None
Faulty floor sensors Sensors may be damaged or disconnected.	Sometimes	Medium	Floor temperature sensors
Heat pump mode mismatch Heat pump set to air heating or cooling instead of underfloor heating.	Sometimes	Easy	None
Blocked or leaking pipes Debris or airlocks in the system or pipe damage.	Sometimes	Hard	Pipe repair kit or replacement
GFCI outlet tripped Electrical safety device activated due to moisture or fault.	Rare	Easy	None
System software error Firmware or control system malfunction.	Rare	Hard	Professional service

Parts matching

Common parts needed for heat pump underfloor heating repairs include:

Floor temperature sensors
Pipe repair kit
Thermostat replacement (if faulty)
GFCI outlet (if replacement needed)
Heat pump control module (rare cases)

Always refer to your system's manual to ensure part compatibility before purchasing.

When to call a professional

System does not heat after checking all basic settings and components
Persistent error codes on the heat pump display
Visible leaks or significant pipe damage
Thermostat is non-responsive or shows erratic behavior
Multiple system resets fail to resolve the issue
You are unsure about handling electrical components or hydraulic repairs

FAQ

Can I use a regular thermostat with a heat pump underfloor heating system?

No, a compatible thermostat designed for heat pump and underfloor heating systems is required to ensure proper control and safety.

Why is only part of my floor heating?

This may indicate a blockage in the piping, a faulty sensor in that area, or an issue with the zone valve controlling that section.

How often should I check my underfloor heating system?

Inspect the system at least once a year for leaks, sensor functionality, and thermostat calibration to maintain efficiency.

Is it normal for the floor to be very hot in some areas?

No, uneven heating usually indicates a blockage, airlock, or faulty sensor in the affected area.