preasure too high on my combi boiler

[chrisrig]

i have a biasi garda 28s combi boiler. the preasure overflow was leaking so i replaced the preasure valve. the problem is that the preasure is actually too high, 3 bar plus, ive drained and refilled the system several times but doesnt fix it. is it a problem with the expansion tank? or could it be something else? please help!

[bloaterbum]

I don;t know about your boiler but mine operates at 1to 1.5 bar max Ihad this problem and it kept blowing my valve until someone pointed out a bladder affair which has to be pumpes up ,in there which compensates for the increase as it occurs mine is leblanc but check to see if a similar device is on yours

[carrust]

Does the pressure gauge go to zero when you drain it?If not it could be a faulty one.Are you making sure you turn-off the filler valve properly?

[carrust]

You could also try draining the system( via the bleed nipple on one of the radiators) until the pointer on the gauge falls to 1.5 bar.You must remember that the pressure valve is a SAFETY device ! They only leak when the pressure is too high ! Try putting a screwdriver on the filler valve & put your ear on the handle,if it is leaking you will hear the water passing through the valve...honestly

[jam79]

if you've set it to 1.5 bar and the filling point definately is shut then it will be your expansion vessel. it may just want recharging.

[Hard@it]

If you are in an ordinary house then 1bar should be more than suitable, but I think jam 79 is on the button get your vessel checked, it may need renewed or recharged as Jam79 says. You do not say how old your boiler is ! Hard@it