my boiler doesn't fire up on very cold mornings i have to reset it then switch it back on and it fires up first time,this always seems to happen when outside temperature drops,dont have problem with it any other time,
it may be the ignition leads shorting out if they are getting damp with condisation,or if your using LPG/bottle gas it may be a pressure prob,finally it's not unheard of the pressure switch connected to the fan no working due to blockage where pipe joins the fan,cold air is more dence and switch doesn't know fan's working.
simon carter
December 2012
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