How can I solve the intermittent fault on my potterton profile 40e?

Here is a link to a Potterton 50e saga which may help you...

http://kaijaks.co.uk/blog/nick/2008/02/10/dodgy-old-boiler

It seems that electrolytic capacitors deteriorate and fail in a warm environment - and guess what? - boilers are a warm environment.

This chap fixes his boiler for just a few pence.

Tapping to get your's running suggests a bad connection or a poor solder joint - which amounts to the same thing.

Tap more gently and more selectively - it may get you to the root of the problem...

There's a pressure switch to sense that the fan is OK - if the fan or the switch is bad or the switch has a dodgy connection then the pilot flame will not light. If the case has a bad seal then the pressure switch may have trouble working.

Check out the link...

Good Luck...
February 2016