Our Boiler was fitted 2yrs 10mths ago and after being serviced at the end of October it developed the following symptoms: Would not ignite when switched on, made a few tinkling sounds, temp gauge started to go up, say to 40 then would drop quickly all the way down to 15 at which point a loud 'clunk' could be heard from inside the Cabinet, the Green pilot would come on and it fired up. This happened during the week after the service was done so I called back the Engineers (Father & son). Luckily enough it did it when they came so they saw first hand what was happening. As the Boiler is under warranty they said to call Baxi as they were not allowed to go 'into' the Boiler. Baxi have been out today and having opened it up and checked they could not find/or see any reason as to why it would be behaving this way. However what the Engineer did say he found (which would not be the problem) was that the "Expansion Vessel was flat and needed charging" and that it should be re-charged with every service. As I did not have a clue what he was on about I simply made a note of the comments and tonight told our Service Engineer who has responded with "He hasn't got a clue what he's talking about, he's given you a load of old toff" - Now why would the Baxi Engineer lie? he wasn't trying to flog me something. Anyone got any views on this please. Think I may need to change my Service Engineers next year!