vokera Compact HE sealed boiler losing pressure

26 May 2011
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United Kingdom
Any help would be gretfully received.

I have a 3 year old Vokera Compact HE, sealed boiler fitted in a first floor cupboard. For the past 6 months the boiler has been slowly losing pressure requiring it to be toped up every 5 or 6 weeks. However over the last few days the pressure has dropped to a level where the unit wont fire up, this is happening on a daily basis. When I fill to re-pressurise to 1.5 bar and turn the boiler on, the pressure increases to about 3 bar it then starts to lose pressure and will fall below .5 bar after about 3 hours. The system does not lose any pressure when it is not running. Having done what research I can it seems to be that the expansion vessel is the most likely problem either a faulty unit or it needing re-pressurised. I have attempted to find the shrader type valve for the expansion vessel to test for water or low pressure but I cant for the life of me locate it even with the service instruction book.

Does anyone have any experience of this model of boiler or this problem?


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Take a look at the top /rear of the boiler behind the flue turret and all will be revealed when you look down on the exp vessel. Getting a pump connection on it is another matter.
Thanks Gasman.

Found the valve and gave it a quick press, air came rushing out however there was also a small ammount of water spray. The system was off when I did this. Would this indicate that the boiler is ok and the leak is in the system?

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