Underfloor Heating Thermostat Not Working
- How urgent
- Low risk
- Who fixes it
- An electrician
What's happening?
The thermostat is the control centre for your electric underfloor heating. It reads the floor temperature sensor and switches the heating on and off to maintain the set temperature. When the thermostat fails, the heating may not turn on at all, may run continuously, or may display error codes.
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What usually causes it?
- Failed floor temperature sensor (most common thermostat-related fault)
- Blown fuse in the spur supplying the thermostat
- Thermostat internal electronics failure
- Loose wiring connections behind the thermostat
- Incorrect thermostat settings or programming
- Incompatible replacement thermostat
Is it dangerous?
A faulty thermostat is not dangerous in itself. However, if the thermostat fails in a way that the heating stays on constantly, the floor could overheat. If the floor feels unusually hot, switch the heating off at the isolator and call an electrician.
Can I fix it myself?
Check the fuse in the spur feeding the thermostat. Try resetting the thermostat to factory settings using the manual. Check the programming and mode settings: many thermostats have holiday or frost-only modes that prevent normal operation. Replace the batteries if it is a wireless thermostat.
When should you call an electrician?
Call an electrician if the thermostat display is blank despite having power, if it shows a sensor error, if the heating runs constantly and will not turn off, or if you need a replacement thermostat installed.
What will the electrician actually do?
- Test the supply to the thermostat
- Measure the floor sensor resistance and compare to the manufacturer's specification
- Check thermostat output to confirm it is switching the heating
- Replace the floor sensor or thermostat as needed
- Program and commission the new thermostat
Who fixes this
What it usually costs
- Electrical Fault Finding Cost
- Priced on survey
Questions people ask
Why does my thermostat show a sensor error?
Can I replace the thermostat myself?
Will any thermostat work with my underfloor heating?
Sources & References
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