Linda - My Professional advice with this problem is simple - Get British gas out to it or ask Potterton if they will look at it. 1 reason only - safety. ANYBODY who advised you to do anything with this boiler is firstly incompetant, and secondly a danger to the gas industry. Has your Powermax been serviced? i.e all fibre gaskets replaced for graphite ones? The Baffles inside have they been replaced? This Boiler has specific reading that must be achieved when worked on and if not then the boiler is deemed as AT RISK, if the seals are allowing CO PPM then it is Immediately dangerous. If British Gas come out then they will fit all the seals on the job and advise if the baffles need remedial work. but for £164 to fix the fault and confirm safe operation its a small price to pay. Just ask the Family in Oxford if having these boilers safety checked is a good idea....... Too late they are alreasy dead.
Pay for an annual contract and get it serviced too if you want that piece of mind. Please dont accept any problem solving tips or how to DIY on any gas appliance especially these. ANY QUALFIED PERSON ON HERE TELLING JOE PUBLIC HOW TO FIX A GAS APPLIANCE NEEDS A REALITY CHECK. (Ian - give Linda all your personal details so if she does work on it, it wont be too difficult for the HSE to track you down, and if you are registered get you off the gas SAFE register
Paul
May 2010