Tuya Overcurrent or Short in Heating Output Circuit

Thermostat causes breaker to trip when heating turns on, or thermostat itself becomes very hot

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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

Heating load exceeds thermostat rated current, Shorted heating cable or valve actuator, Miswired line/neutral on Tuya thermostat, Internal relay or triac short to ground

How to Fix / Troubleshooting

Safety first: Immediately turn off the breaker and do not reset it repeatedly. Risk of fire or electric shock.

Steps to troubleshoot:

  • Verify the power and load wiring against the Tuya wiring diagram; correct any miswiring (e.g., line and load swapped, neutral missing).
  • Check the nameplate current rating of the thermostat and compare with the connected heating load; if the load is higher, install an external contactor and let the thermostat control the contactor coil only.
  • Disconnect the heating load from the thermostat and reset the breaker. If it no longer trips, the fault is in the load or field wiring.
  • Insulation-test the heating cable or actuator wiring; repair or replace any shorted components.
  • If the breaker still trips with the load disconnected, the thermostat’s internal relay/triac is likely shorted; replace the thermostat.
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Repair Difficulty

Professional Required 5/5

Required Part

Output Relay/Triac and Load Wiring (Tuya Smart Thermostat)
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