Medium Warning
A0:0 on Viessmann Vitodens 300-W

Your boiler has lost communication with its remote control or thermostat, meaning it cannot receive temperature instructions.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Without remote control

What causes this fault?

This fault occurs when the boiler's main control board loses its electronic connection with the external room thermostat or wireless receiver. The most common reason is simply that the thermostat batteries have died or the wireless signal is being blocked by a new physical obstruction. In some cases, it can be caused by a hardware failure within the receiver unit itself or a wiring problem between the components.

DIY fix possible

Check batteries in your wireless room thermostat or remote controlEnsure the wireless receiver plugged into the boiler is powered onRestart your home internet router if your heating uses a smart app control

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Related fault codes

A0:1View →A0:2View →CFView →

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