Medium
Viessmann boilers on Viessmann Vitopend 111

Your boiler is operating in a permanent manual control mode, likely because it has lost its connection to external thermostats or sensors.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

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

Control mode

DIY fix possible

Check your room thermostat has power and fresh batteriesEnsure the thermostat is within wireless range of the boilerAttempt to re-pair the thermostat with the receiver modulePress the reset button to clear the manual override

Find a Gas Safe engineer
Search the official register →

Related guides you might find useful

Boiler won't turn on — 9-step checklist

Work through these before the call-out.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →