Boiler pressure too high?

My combi boilers pressure too high when I turn on more than 3 heating on how to fit the problem please?

Paul
January 2015

Exspansion vessel 100% turn hot tap on leave running then recharge vessel to 0,75 bar or what ever the sticker says.

I mopit
October 2013

I have a mighty therm with a new #90 expansion tank and aquastats. Boiler pressure still exceeds 32psi at 180 degrees. The fill valve was replaced about 8 yrs ago. Could it be the problem again?

Brian K
January 2013

I have a Wein McLain residential boiler. The pressure in the boiler is too high. The pressure pop off valve is venting hot water. What is wrong?

Mark
December 2010

Repair leak and bleed central heating system

Matt p
November 2010

how do i get the pressure to go down on my boiler plus i have got hot water but no heating, my boiler is a biasi combi..... please help, also it makes a noise and pours out of a pipe on the outside wall....

jayne
April 2010

safty valve not oprate
boiler not high pressure cut off

mangat
March 2010

Hi, what pressure should the red pressure tank be pumped up to..? anyone.?

steve
March 2010

Have check the air cylinder and set it at 1bar, I've disconnected the top up water vaule, drained the off the water and set the gauge back to 1.5bar but the pressure go'es back up to 2.5 to 3.5bar when the central heating is put back on

bill smith
April 2008

You can reduce pressure by twisting the red knob on the over pressure valve, this will vent through a pipe in an outside wall. You should establish the cause of the overpressure.

Does it only happen when the boiler is hot, and drop right down when all of the heating system is cold?. Suspect expansion vessel in need of recharge. Common problem.

Otherwise....

Does it stay high with the boiler cold?. Suspect filling loop leak from water main (disconnect filling loop to see if it drips) /cures problem.

or .. (worst of all):

leak between the sides of the secondary heat exchanger (turn off the cold water feed, open a hot tap, does the pressure gradually fall, with a dripping hot tap?).

c
December 2007

you can easily reduce the pressure by using an air bleed valve at the top of one of your radiators, use a cloth and a bowl as water could be very dirty or even black.

Bert
December 2007