Worcester 240 combi problem

[lanie]

Hi,
I'm new here & I wondered if anyone could help me with my combi boiler.
It's been switching itself off quite frequently (once a week or so) for some time now, but recently the pressure gauge has gone up & it's starting to leak (slow drip) from the 'overflow' tap underneath. It used to stay at between 0.5 & 1.5 bar, but it's gone up to 3-3.5 bar. I wonder whether it's the increased pressure that's started the leak.
Can anybody give me any clues as to how to lower the pressure, and whether the overheat switch, leak & pressure are all related?

Thanks in advance for any help.
Lanie x

 

[MANDATE]

To lower the pressure all you need to do is to bleed a radiator, as the volume of water goes down, the air side of the expansion vessel increases and the pressure reduces. That's the easy bit.
Basically your boiler has a 'hot water' side and a 'heating' side. The 'heating' side is where the pressure is determined by you. You do this with the filling loop using mains water pressure and you stop when it reaches say 0.5 bar. If for whatever reason the pressure should reach 3.5 bar then the pressure relief valve will open.
Now on the 'hot water' side you have cold water at mains pressure entering the boiler, being heated and coming out at mains pressure.
If the pressure is rising it means that water is still getting across from mains supply to the 'heating' side. It could be that the filling loop has been left connected and is water is leaking across or you have a leak within the boiler where it is seeping across and increasing the pressure.
That's how I understand it.

 

[keyplayer]

Galvanised is having a similar problem in his current post. I think you have to check your filling loop valve as a starter. Is it totally off? Is it knackered? The ones with the coloured plastic handles are in my opinion rubbish - they say off, but invariably aren't.