Worcester Bosch Greenstar 24Ri Blue Flashing Light

A customer called me worried because the blue light was flashing on his Worcester Greenstar 24Ri and he was worried that it had developed a fault. When I arrived, he switched the controls on and the boiler's blue light began to flash straight away. Apparently, he had noticed the blue light flashing a few days ago but the heating and hot water seemed to be working as they should be. I thought that the the boiler would stop working if the blue light was flashing so thought this strange.

Fortunately, the gentleman had the manual to hand for me to consult. I looked at the fault finding pages where it gives a description of the different statuses and faults that may have occurred indicated by the blue light. The installation and servicing instructions can be downloaded from Worcster-Bosch which contain the fault finding on page 51.

As soon as I looked in the book I realised that the light was actually pulsing rather than flashing which is the indication that the boiler is in it's service mode for measuring the flue gases at the boiler's maximum rate. I removed the cover which allows access to the service mode switch, and expected to find the tool for the service mode selector switch still inserted. The tool was parked in it's clip where it should have been, and the switch when turned to the normal position was only a fraction away from the normal position.

A junior colleague had been to service the boiler just over a week prior, and had obviously failed to turn the service selector switch fully back. After resetting the switch to the normal position the boiler was working as it should be with the blue light on and not flashing.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.