Vokera Combi boiler fault

[marhan31]

We have a 4 year old Vokera Combi boiler. The system overflow runs most of the time (steady but slow). The boiler pressure does not drop, and in fact the system pressure slowly rises over a day or two. I have disconnected the filling loop. So we can discount the filling valve. Anyone got an idea of how the system is loosing water and the pressure is going up?

[RAYMAN]

go to keyword or quick start.

type in  vokera combi boiler faultfinder   look for question&anwers

hope it helps.

[speedyme]

check expansion vessel pre-charge pressure.this must be done with boiler water pressure at zero.

[boilerman 2]

Possable fault with expansion tanks unless you know how to test them advise that you call in your local corgi engineer.

[tecman]

sounds to me like you have two problems now

depending on the model of the boiler

domestic heat exchanger needs replacing as this is the only way to pass water to the heating side of the boiler

probably now the auto pressure relief valove will need replacing

find a corgi registered gas fitter better safe than bodged

[kipperochkid]

Check the pressure compensation tank in the boiler. The large, red, circular thing behind the furnace, It has a valve on it like a tyre valve. It works like the bellows in an aneroid barometer, only twenty times bigger. If it is full of water it will cause problems. It's there to take the expansion on heating and return it on cooling.

[cee]

if you are getting water running all the time, it can only be comming from the domestic h/w side of the system, as you say that you have turned off the loop.try turning off the cold water inlet and if it stop running you have the source of the problem, to cure it , does the boiler have a hydraulic diverter valve, if so check the diaphragm

[marhan31]

Thanks to all who posted a suggestion.

I have fixed the problem now. It was a very small internal leak on the domestic hot water heat exchanger unit.

I bought one myself for �65.00+VAT and fitted it last week. It took less than a hour to finish the job. All is working fine now.