resetting water pressure on a Vaillant boiler

Ros · 11 Feb 2006

After bleeding a radiator the pressure on my boiler dropped below 1 bar. I have located the two black taps at either end of the filling loop that I need to turn in order to increase the pressure but they won't turn.

I remember the last time a Vaillant service engineer called he said something about needing to do something else first (turn a valve??) otherwise the black taps are impossible to turn. I can't work out what to do and the manual doesn't help. I had a go but accidently turned the pressure release valve and now I have no pressure at all. It's a Saturday and I can't get hold of any plumbers and it's freezing. Can you help?

chrishutt · 11 Feb 2006

There's guidance on using filling loops in the sticky FAQ topic, but I can't see why there should be any problem turning the black levers. Do you realise that they may only turn in one direction? Perhaps you're trying to turn them the wrong way?

gowdon · 11 Feb 2006

The black taps either end of the chrome filling loop need to open before you can re pressurise your system

Ros · 11 Feb 2006

Thanks you're right, the black taps do turn and I can hear water flowing but there is no change to the air pressure. Any ideas?

chrishutt · 11 Feb 2006

Not air pressure - it's the system water pressure. You may have left the PRV open. Twist the knob again to make sure it's seating properly. Otherwise perhaps you need to wait a while longer before the pressure gauge shows any movement. It can take 20 seconds or more before any movement occurs.

Ros · 11 Feb 2006

Oops, that's what I meant! I now have a fully functioning boiler again, hooray. Thanks for your help and sorry for being a dunce. Ros

chrishutt · 11 Feb 2006

Glad to hear it worked. It might be worth checking that the PRV isn't leaking (they often do once operated after a long time) - check the discharge pipe where it ends outside. Any sign of drips?

Ros · 11 Feb 2006

Yes everything seems dry so i think it's not leaking. Cheers, R.

abbiecadabra · 5 May 2012

I am also having problems. I think I have identified the black levers that need to be turned at either end of the loop but they won't turn. I've tried both ways really hard but they won't budge. I tried loosening the screw and that didn't help. I don't want to snap them. Are they supposed to turn a lot? Am I doing something wrong?

Please help!

abbiecadabra · 5 May 2012

I did it! It was just super-tight. [/img]

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resetting water pressure on a Vaillant boiler

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