31E High
Your boiler is having trouble 'talking' to your smart thermostat or external heater controls, meaning it may not receive instructions to turn on or off.
Technical description: OpenTherm (OT) communication error
Typical repair cost: £80-180 (including labour)
DIY fix possible
Check that your smart thermostat or wall controller is powered on and has working batteries.Ensure the thermostat bridge or hub is plugged in and connected to your Wi-Fi.Try restarting your boiler at the main isolation switch to reset the connection.
Protect yourself from future repair bills
A boiler cover plan would cover faults like 31E — no call-out fees, no surprises.
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Parts commonly replaced
- OpenTherm Interface Cable
- Thermostat Receiver
- Main Printed Circuit Board (PCB)
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