worcester 24siII 'self pressurising' ...???

[Colinscat]

Hello my problem is basically what you see in the subject title.
I have a Worcester 24siII combi boiler which seems to be over pressurising itself.I have relieved the pressure three times in a couple of days. It's going up to approx 3.5 bar (whether that is significant) The filler loop valve is firmly shut.I am monitoring as i write this and after relieving the pressure down to 1 bar it has gone to 2 bar in a matter of a couple of hours. Neither heating or hot water has been asked for so its 'cold'. i cannot hear any water running through the system and as ive said the filler loop valve is firmly shut.
About a month ago a tiler shut one of the valves that supply the hot water (underneath the boiler) temporarily so he could disconnect the sink in the bathroom but he opened it again afterwards - Not sure if that is significant either. but other that that no one has tampered with it. Any advice is welcome as i am not a plumber. Thanks for looking.

 

[petertheplumber12]

It is the expansion vessel that needs checking, it may be blocked, it may have a diaphragm leak, or it may need re-pressurising.

 

[Agile]

If the boiler is cold then any increase in pressure can only result from cold supply water leaking into the system water.

Turn off the cold supply for a number of hours and the pressure should remain constant.

If that happens then a boiler component is failed!

That may need a boiler engineer to identify.

Tony

 

[petertheplumber12]

Sorry having re read the post since the boiler is cold when it happens you have a boiler fault that needs to investigated by a GSR engineer. Sorry it is going to cost some money to sort it out. go to this site for one:-

http://www.gassaferegister.co.uk/registersearch/findbusiness.aspx?type=advanced

 

[Colinscat]

Thanks for the help lads ...i'll get an engineer in

 

[petertheplumber12]

Good Luck and try and get one that doesn't do a call out charge.

 

[hi1]

I may be missing the obvious here but i thought the filling loop had done its job then it should be disconnected, i know they aren't and neither is mine, but if the provision to do so is there then disconnect the filler pipe and that should eliminate mains water pressure as the culprit. Just because a valves turned off doesn't mean its working.

 

[petertheplumber12]

I may be missing the obvious here but i thought the filling loop had done its job then it should be disconnected, i know they aren't and neither is mine, but if the provision to do so is there then disconnect the filler pipe and that should eliminate mains water pressure as the culprit. Just because a valves turned off doesn't mean its working.

Your right it may be filling loop not shutting off.