Boiler pressure

[jswagger]

I have an Ideal Mini C24 Combi boiler and a lot of the time the boiler has too much pressure.

It started when we turned the heating back on about six weeks ago, I noticed that the pressure was a bit low so topped the system up with water to about 1 bar when cold . When the heating was on the pressure would rise to over 3 bar and water would come out of an overflow type pipe outside.
Whenever the pressure got above 3 bar I would drain off water from the system to get the pressure down to 2.0 bar quickly. Only problem was the pressure would go back up over time even when the heating was off though faster when the heating was on, although eventually the oproblem went away after about a week with the pressure being 1 bar cold and 1.5 – 2 bar hot.

About three weeks ago I had to drain the system down to take a radiator off and the same problem came back only this time it’s still happening. Only difference this time was I added central heating treatment. I’ve bled all the rads (never any air coming out) but I’m concerned that I’ve drained off so much water over time to get the pressure down that there will be little water left in the system.

I have read the FAQs on boiler pressure but was wondering if they apply as over time the problem seems to get a lot better/go away? The hot water doesn't appear to be as hot as before so could it be the heat exchanger may me broken

Apologies for the long post but anyone have any idea,

Thanks.

 

[apl]

does the pressure go up quickly if so sounds like your expansion vessel.

 

[jswagger]

It goes up but over a number of hours, eg overnight.

 

[apl]

is the filling loop turned completely off also make sure the valves are not passing.

 

[jswagger]

Filling loop is closed, what valves are you refering to?

Thanks again

 

[apl]

THE VALVES ON THE FILLING LOOP,TAKE THE LOOP OFF THE VALVES AND MAKE SURE THEIR NOT PASSING.

 

[jswagger]

THE VALVES ON THE FILLING LOOP,TAKE THE LOOP OFF THE VALVES AND MAKE SURE THEIR NOT PASSING.

Sorry thpought you meant somewhere else. I've taken the filling loop off and there is no water passing so the valves seem to be ok.

 

[spacethegas]

check the expansion vessel is charged correctly.

http://www.diynot.com/forums/viewtopic.php?p=251090#251090

 

[jswagger]

Thanks for all your help,

I recharged the expansion vessel and now everything seems to be ok.

Out of interest the the boiler pressure when cold is 1 bar and 1.75 - 2 bar when hot, is this ok?

Thanks again.

 

[spacethegas]

thats fine.