I've just been told that the heater exchange has "scaled" up and needs replacing. Quoted about £400 for parts and labour. Not sure if this includes vat, or not). Right now only the pilot light works - boiler does not "fire-up" for heating and/or for hot water purposes.

Peter, November 2006

You need the original manual to go through the fault checklist. That way it eliminates the problems one by one and usually points to the fault.

phil, November 2006

Just changed the heat exchanger (an hour ago!) in my 80 as it was leaking (due to overheating) fortunately I have an old 80e which I used for the spares. These boilers have been a pain for me over the years, especially the 80e which I replaced (I own two flats) A few years back I spoke to a boffin at potterton and was told the electronics were poorly designed causing premature failure (I think in the relays) on the boards! The one I've just fixed is now switching off and on every few seconds (thermistors/sensors I think) and the Hot water flow is not as powerful as it should be which I need to look at! The cold supply has pleanty of pressure - might possibly be a restriction in the cold feed ball o fix valve, but probably something else! Not sure what ..diaphram?

Phil, November 2006

it would probably still fire up if it was scale.would be noisey and overheat?
Check pump?
does the fan run?

simon, November 2006

worked for british gas for 16 years and only ever had to change 1 main heat exchanger, so i suspect that not to be the case.

BG MIKE, November 2006