Display shows 'Hi' or maximum temperature and thermostat may shut down or refuse to heat

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.

Possible Causes

Thermostat installed in very hot location, Internal sensor shorted, Sensor placed directly above heating outlet or in direct sun, Shorted NTC leads on Tuya PCB

How to Fix / Troubleshooting

Safety first: Turn off power before moving or opening the thermostat.

Steps to troubleshoot:

Check installation location: avoid direct sunlight, above radiators, or near hot air vents.
Relocate the thermostat to an interior wall away from heat sources if needed.
Inspect the sensor area for shorts or damaged components; clean and visually check for solder bridges.
Measure sensor resistance; if it is near 0Ω, the sensor is shorted and must be replaced.
After correcting the cause, restore power and verify that the temperature reading is realistic and 'Hi' is cleared.

Repair Difficulty

Medium 3/5

Required Part

Internal NTC Temperature Sensor (Tuya Thermostat)

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