id always change the dhw & ch thermistors first
whether they are in calibration or not
works 99 times out of 100
eveything on this boiler is controlled via the thermistors
very cheap parts to replace
approx £10 each
manwithnoname
March 2011
depends what you mean by fire up is pump,fan running can you hear it sparking ?
brian
March 2011
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.