Vaillant Ecotec Combi will not repressurise

[sys4096]

Hi All, any tips or pointers gratefully received :

Woke up to no hot water yesterday, Vaillant Ecotec with F22 problem, showing 0.4 bar. I knew about re-pressurising the boiler via the two valves at the bottom, but they did not seem to work, when I've used them previously (rarely once or twice) there has been a big rush of water into the system with the corresponding pressure rise, this time no joy.

I reset the boiler leaving it off for 3 mins, with the valves open and I seemed to get to a pressure of .5 and hot water was back working when I closed the valves. I checked the valves are turning OK (manually with a screwdriver).

When I came home, pressue was at 0.9 all working, I tried opening the valves again, but no pressure increase. After leaving them open for 30 mins I rose from 0.9 to 1 bar. I then checked the water supply is actually flowing by disconnecting the braided pipe from the right hand valve and there is water at high pressure if I open the valve. So I reconnected the braided pipe and tried opening the valves again, still no joy. Reset the boiler completely a few times etc. I left it overnight all working.

This morning all was OK but checking the pressure was 2.6 bar - I double checked I had closed the valves and I had. So I then bled the highest radiator in the house, and I got a LOT of air out. Then checking the boiler pressure is down to 0.4 again immediately after bleeding. This did not cause an F22 error though so the boiler is working the heating and hot water, I tried resetting again, opening valves but no joy. I've left it running on 0.4 pressure and come to work. I wonder if it will be back to 1 bar this evening.

Any pointers please - boiler is about 4 years old and annually serviced. The only thing I can think of is maybe a problem with the left hand valve for re-filling, but they both turn ok with a screwdriver.

Cheers,
Paul.

 

[sys4096]

and i got home and its on 1.3 bar. Checking for air by bleeding all rads and none. Checking before putting the kids to bed and its hit 3.1 bar and flashing with the heating on. Let some water out down to 1.5, Going to keep an eye on it. Does anyone know if theres some sort of mechanism that will let out water if it hits max pressure over night?

I notice also the right hand water inlet filler valve if i disconnect the braided filling pipe constantly drips even when shut off fully.

 

[The831Bunny]

Sounds like you need to replace the flow isolation valve & filling tap, and the cold inlet valve & filling tap. If you are in a hard water area the valve seats can score and pass water with the valves in the off position, hence the system pressure slowly increases. This seems to happen on older ecoTECs, say 5-6 years old. Its a job for an engineer who's familiar with Vaillants. Get him to check the expansion vessel and burner door seal too while he's at it.