Hi all.
Just to add to this (very old) subject.. I had a problem with the 24i not firing up. Ignition was going and sparking ok, but no flame. Having read the posts here, i ordered the two relays from Amazon and replaced this evening and now the boiler is working fine.
I've joined the forum specifically to say a huge thanks, i guess primarily to carpman & rjdesigns. Thought the boiler had died as I've had the heating system drained down, painting rads and moving pipes. Attempted to fire back up and nothing.
The relays solved the problem! Thank you !!!
A.