I've got an Ideal FF250 conventional boiler which, only a few months after it's last service, has started playing up.
It often 'forgets' to fire up and can only be coaxed into action with a sharp bang with a flat hand (discovered in desperation after trying every other option open to the novice user).
Seems ok for a while then wont start again until bashed. Any advice short of 'call an engineer' gratefully recieved! Thanks. Richard

richard, December 2008

I had the same problem, the micro switch on the air pressure switch had bad contacts, thumping the boiler makes the contacts inside the switch make long enough to ignite boiler, when boiler switches off you have to repeat the thumping, replacing the air pressure switch cured the fault.

coppershelmet, May 2012

i am having the same problem. apparently its the air pressure switch and a gas valve for which i have been quoted £230 so i am looking elsewhere

Di, November 2009

Fixed! Was a combination of both answers - loose connection to the air pressure switch.

Many thanks

R

Richard, December 2008

Thanks very much for the advice, on looking at the circuit diagram it seems that the t/stat LED is constantly on - I'm not sure whether it should be or not. I assumed that the LED was an indicator of mains power but am wrong. Perhaps the constantly lit LED points to a thermostat cut-out problem?
Will also check the air pressure switch connection.

richard, December 2008

You are half way to fixing it - if vibration can make the fault go away all you have to do is to get the lower cover off and gently tap around with something non-conductive to discover exactly which piece needs to be tapped to make it work. Here's a diagram

http://i30.photobucket.com/albums/c321/ChrisPlumber/Ideal-Classic-FF-pcb.gif

People often suspect dry joints on boiler circuit boards and if you have the confidence to take the PCB out, inspect it and resolder any dodgy joints you may save yourself some £££ but it may also be a mechanical part that needs your magic tap or any of the connectors or switches. Start with gentle tapping. Use a wooden spoon as a tapper. Take care not to electrocute yourself.

Peccavi, December 2008