I have a Pro Boiler in a Bungalow that was built 3 years ago
We have had it serviced and recently because it would not fire the boier
the diaphram pump switch was thought to be faulty and replaced
The boiler worked fine until the front cover plate that is secured by two heavy metal clips at the bottom was
fixed.
unclipping any one of the clips and the boiler fired up and worked fine --snap clips and it stops
the fan worked fine