Err
Tuya
General System Error / Firmware Fault
Thermostat shows generic 'Err' on the display and does not operate the HVAC system
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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
Corrupted firmware, Incomplete OTA update via Tuya cloud, Internal memory error, Unexpected reset loop on main MCU
How to Fix / Troubleshooting
Safety first: No high-voltage work is required unless you choose to replace the unit.
Steps to troubleshoot:
- Power-cycle the thermostat by turning off the breaker for 1–2 minutes, then turning it back on.
- Check the Tuya/Smart Life app for any available firmware updates and apply them if possible.
- Perform a factory reset from the thermostat menu (this will erase schedules and Wi-Fi settings).
- If the error appears after a failed update, try re-adding the thermostat to the app and repeating the update.
- If 'Err' persists and the thermostat cannot be controlled, the main control board is likely defective; replace the thermostat.
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Repair Difficulty
Medium
3/5
Required Part
Main Control PCB / Firmware (Tuya Smart Thermostat)
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