Vaillant pressure dial very high

slatepipe · Sep 10, 2019

hi there

just checking if there is anything else i can do before i get a plumber in to attend to my boiler. yesterday i noticed that the pressure gauge on the Vaillant boiler was off the scale, it was past the red (see pic 1). I checked around and was advised to bleed the radiators which I did last night (I bled 3 out of 5 in the flat) and this brought the pressure gauge down to pic 2, with the arrow pointing to 12 o'clock, but still quite high. Then when I had a shower and left for work this morning the gauge had gone up to the red again, pointing to about 3 o'clock.

Can anyone offer any advice on what the issue might be or what I can do before I call a plumber to come and help?

thanks

Harvest Fields · Sep 10, 2019

You need to make sure that the filling loop is closed and then let some pressure out of the system. (From a radiator).

RayW · Sep 10, 2019

The refill device may be passing water. With the isolator taps turned off disconnect the silver braided hose.

Harvest Fields · Sep 10, 2019

RayW said:
The refill device may be passing water. With the isolator taps turned off disconnect the silver braided hose.

Not sure that model has a braided hose

slatepipe · Sep 10, 2019

Harvest Fields said:
You need to make sure that the filling loop is closed and then let some pressure out of the system. (From a radiator).

hi - thanks for this. there is one lever underneath the boiler (almost directly under the dial) which i can open and close to add pressure into the system when it gets a bit low, which i have done in the past. is that what you mean by the filling loop? and then would i just bleed one radiator or all of them? i'm guessing one will be ok if they're all on a loop?

Harvest Fields · Sep 10, 2019

Yes, that is the filling loop and yes from 1 radiator. You need to remove some water. Until about 1.3 bar. If it then rises you need a engineer to visit.

slatepipe · Sep 10, 2019

Harvest Fields said:
Yes, that is the filling loop and yes from 1 radiator. You need to remove some water. Until about 1.3 bar. If it then rises you need a engineer to visit.

hi - thanks again. I'll check this again tonight and i'll make sure the filling loop lever is closed. But i'm fairly sure it was closed last night when i bled 3 radiators and then the needle only went down to 12 o'clock on the gauge after i bled the first one and it wouldn't go any further down after i bled the other two. so i'm thinking i might have to give the plumber a call?