I have a baxi combi 80e also and have just had the problem sorted by BG today! They were brilliant. It was the PCB (circuit board). I paid a one off fee which you can see on their website (if you don't have homecare - which I didn't - I now do!). It only took 1/2 hour to sort out the problem. Now all working fine.
P
November 2008
you have air lock. there is valve under the boiler open slowly and let the air out. soon as the water comes out closed the valve.soon as the air out boiler start working.
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Try fixfault.com to fix home heating systems.