I have a wall mounted boiler.(potterton neataheat electronic),which was installed about 15 years ago.It has been a great performer in the past,but recently it has decided not to start.I know it is not the fan,as it has been tested,and is working.When i turn the boiler on,i hear the normal click,but nothing activates.Can you help in the diagnosis?.

John H in Woking Surrey., March 2006

poss air pressure switch.up top side of fan.can be tested with multimeter i think wires most likley white, grey ,and yellow all 240 volts.tubes to this may be split or blocked.could poss suck on possitive tube should hear click of switch and then boiler will ignite

paul, March 2006