I recently had a power cut and when the power came back on the boiler was completely dead. No display, no noise, nothing. I have checked the 3amp fuse and thats ok and have also checked a small fuse on the pcb that seems ok too. Any ideas??

George, June 2012

I have a Glow Worm 30CXi and it was dead when be bought the house. We were quoted £300 to replace the printed circuit board.
Being an electronic engineer, I wasn't about to pay that without looking at it first, so this is what I found:

Symptom - Dead, no display and a faint ticking sound when the power is turned on or takes a long time to power up from cold. Fuse F100 is intact.

The switch mode power supply (adjacent to the fuse) is not starting up. This is caused by a faulty electrolytic capacitor C805 situated at the bottom of the PCB near to the fuse. This is a 47uF at 50v. Be sure to obtain a 105 degree type, not a cheaper 85 degree as this will provide a much longer service life.

A suitable type is available from RS components (www.rswww.com) part number 520-1567 priced £1.50 for a pack of 5!

It may also be worth replacing C813 100uf at 25v on the power supply secondary at the same time. This is situated at the bottom of the PCB to the left of the small transformer.

A suitable type is 519-4150 from RS priced at £1.00 per pack of 5.

Remember to isolate the boiler mains supply before touching the PCB as it is very, very live!!!

Hopefully this will save people some money :0)

J. Haywood, May 2016

I had the same problem on my 30CXi boiler when I back to home this morning. I have checked the fuse on the wall socket (rated 3A) and it looks fine. May I ask how to open the PCB and check the fuse ther?

Jungle, February 2015

if you are getting power to the boiler PCB & the boiler is dead chances are the PCB is defective

manwithnoname, June 2012