In my new house I have just had a new combi boiler fitted. On the pressure guage it goes from just under 1 bar to almost 2.5. It currently is just on the minimum - and there's no problems - is there any benefits/downfalls if it were to go higher. We have complete new copper piping and a boiler fed shower.
Thanks
See my thread of a couple of days back with subject: Gloworm 30ci Combi pressure where I asked a similar question.
The FAQ I was referred to was very useful.
Geoff Lane
The pressure will change as the water in the radiators heats and cools. When the heating is off and all radiators have cooled down, the pressure will be lowest. When the heating is going at full pelt with radiators at max temperature, the pressure will be highest. The fill pressure needs to be set so that these two extremes are both within the design limits of the system. For a 1 or 2 story house, typical cold fill pressure would be 1 bar, and it might go up to 2 bar when hot. If you have a 3 story or more house, then it's also important to take into account the vertical distance between lowest and highest parts of the radiator plumbing in the house, and where in that height the pressure guage is.
Thankyou and apologies for posting so soon after your post. I really should check more threads. You wouldn't think I've been using usennet for over 12 years :) Thanks to Andrew aswell. All questions answered.
Only fill it until highest radiator if full of water, Less pressure =3D Longer life.
On Mine I had aproblem a few years back. The UFH people advised running at just 1.0 bar so I had it just above.... Then after a while the HW started cycling hot and cold. Boiler eng. Advised taking it closer to 1.5 to 2 Bar as the boiler wasn't happy at lower than 1.0 bar which is was dropping to when the pump started up.
System was originally pressure tested to 4 bar before filling so I'm happy running a bit more than suggested.
HTH Pete
Strangely my Gloworm 30ci 5 years old) with 8 rads in a chalet bumgalow shows .9 bar when cold and only rises to just over 1 bar when heating on even if the boiler stat is set quite high.
Geoff Lane
That means you have a pressure vessel which is much larger than the rest of your system actually needs, but that doesn't matter in the least.
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