Medium
5 pulses on Worcester Bosch 35 RSF

Your boiler is accidentally stuck in a technician's test mode, meaning it is set to run at its highest power rather than responding to your thermostat.

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

Check service mode switch is in max position

DIY fix possible

Locate the control panel on the front of the boiler.Look for a small switch or dial labeled with a flame or 'Service' icon.Ensure the switch is moved out of the 'Max' or 'Test' position and set back to its normal operating position.

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