Tuya
Open Heating Circuit or Failed Output Device
Thermostat shows 'heating' icon but electric underfloor heating remains cold
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Open circuit in heating mat/cable, Loose load terminal on thermostat, Failed triac/relay not actually switching power, Tripped floor heating safety device
How to Fix / Troubleshooting
Safety first: Turn off power to the heating circuit at the breaker before testing.
Steps to troubleshoot:
- Verify that the thermostat indicates a heating call (flame icon or similar).
- Remove the thermostat and check that the load wires are firmly connected to the output terminals.
- With power off, measure resistance of the heating mat/cable at the thermostat terminals; compare to manufacturer specs. Infinite resistance indicates an open circuit.
- If the heating element is open, the floor heating system must be repaired by a specialist.
- If the element is intact, test whether voltage appears at the thermostat output terminals when heating is called (use caution and proper meter). If not, the thermostat’s output device is faulty; replace the thermostat.
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Repair Difficulty
Professional Required
5/5
Required Part
Output Relay/Triac and Underfloor Heating Mat/Cable
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