when my boiler switches on to heat water in both heating and or domestic mode the green light changes to flashing red and remains like this for approx 30 seconds whereupon it resets itself and starts to produce hot water. the unit shows a fault code of 03 which i understand refers to a flu/fan problem. i have an extended warranty on this unit, and have previously had an engineer out to allegedly repair it, he replaced the ignition unit, and to honest this didn't make much difference to the problem, all i am after is a bit of knowledge so i can question the next attempt to repair this unit should i feel that the correct procedure is not being carried out
many thanks for any info

gordon, December 2009

quote: and to be honest it didnt make much difference - it wouldn't (in my opinion) ignition box does not tend to give that kind of fault, ignition box fault will never really red light, it will fire on demand for couple secs then switch off for couple secs then repeat repeat repeat on off on off on off resulting in just barely warm rads and water.

if its spitting out flue/fan fault and seems to be struggling at first ignition? assumed from your description once it resets it works ie hot water?
id be looking along fan, motor struggling to spin from dead start? fan spinning but hoses or venturi blocked or deterioating? air pressure switch?

if i attended i would of charged for a hr/visit and spent that time trying to work out but more importantly prove why its behaving that way. caution- some tend to throw parts at it and are guessing at your expense. a circuit problem is hard to diagnose cos they can throw up fault codes pointing you to something when it can be a piece of circuitry which we cant in general check as we're not electronics experts but most will try and rule other things out first.

best of luck, hope all goes well

ste, December 2009