Central heating

[codswallop]

I have a Combiboiler fired central heating system,How do I stop the water from coming out of the overflow pipe please? Th pressure meter on the boiler should show 1.5 but it's up to 2.5 which is obviously why it overflows.I've tried letting water out of the system to ease the pressure but it just builds up again.Thanks!!!!.

[buildersmate]

Then fresh mains water is getting into the closed system. If you are sure that the valve on the system refill tube is not slightly open and letting fresh water in, it's going to be a heating technician job I'm afraid.

[codswallop]

Thanks buildersmate,I was able to close the valve a minute amount.Whether it will make any difference I've not had the chance to find out yet.As soon as I can release some of the pressure I'll check,let's hope it's not your second option!!!!

[gucciman]

3 main reasons

1 - filling loop not closed properly

2 - problem with expansion vessel

3 - problem with secondary heat exchanger

additionally, if the pressure relief valve pipe is continually discharging water then the prv must have opened up and then failed to close, you still need to find out why it opened in the first place.

you need a heating engineer .

[codswallop]

Thanks again to you all for your replies.
The amount that's coming out of the pipe is only drips and it's cold water I thought that it would be hot,does that signify anything?

[gucciman]

is that because you've oly tested the temperature of the water from the overflow pipe when the boiler wasn't running or are you saying the water is cold even when the boiler is blazing away?

[codswallop]

It's cold even when the central htg is on.