The pressure on my Vaillant boiler is about 0.8 when hot. How can i increase it? I noticed another person has asked the same question, to which you replied 'turn the key on the underside of the boiler', i have tried this but nothing happened.

Drew, March 2005

i found the two valvesunder the right hand front.two boxes which needed a flathead srew driver I turned the left hand one clockwise and then the right hand one clockwise till I heard it fill and when I got to 1 plus I turned the valves to close again and hey presto it worked.easy peasy

tony, November 2013

turning the far right hand key has filled my boiler up very quickly. I did not need to touch the one to the left of it at all.

My key has broke so I used a flat ended screw driver .

If you need to reduce the pressue you have to open the valve on a radiator and empty some water out that way, this will show on the boiler pressure.

Shell, March 2011

hi,
i turn clock wise but now its above 2.
how can i reduce it now.

noor, January 2011

Just to add to this, on mine, only the left hand key needed turning before it started to fill so if anyone is doing this, I would try that first.

Also, if you cannot see a key, both controls can be turned using a flat blade screwdriver. You are looking for two identical brass coloured flat screwheads a short distance up inside two little brass box shaped pieces of metal. These are on the right hand side of the boiler as you look at it, towards the front.

Matt, November 2008

I've turned all the valves in different combinations and there is no sound of water filling or any movement in the pressure (still at 0). Help!

Helpme., October 2008

Yes this works turn both 1 quarter turn anticlockwise,hear the water filling and the bar pressure will read 1 or just over turn both off and enjoy a good bath.

Kyle Robertson, December 2007

depending on the age of your boiler if you have the new tubomax then underneathe there are two points which you maust turn look under neath where the key is turn this clock wise until the key is at 3 0clock remove the key and looking under neath to th right of you, you will se another slot exactly the same insert the key do the sam e again now the boiler will fill up once it is about 1.5 bar turn off both
from

phil homer corg installer, September 2005

there are two slots for the key..... they both must be open for the boiler to fill! it will be about 3" away to the left or right of where the key is now. if you can look up into the key hole because the key only fits one way!

Dom., March 2005