Help! Valiant combi boiler pressure dropping…

[Christian70]

Hi,

I need advice, my Valiant combi boiler, which is about 8 years old, pressure keeps falling day by day. I have had the Expansion Vessel replaced and PRV replaced, anti-leak stuff put into the system. Nothing has helped! There’s no signs of water or leaks anywhere. There are no pipes under the ground for or embedded in the walls. I even got a leak locator guy out who couldn’t find anything either or anything wrong with the boiler.
I’m at my wits end with it! Please help!

 

[muggles]

Turn the boiler off, and redirect the condensate into a bucket, then repressurise the boiler. If the bucket fills up, your main heat exchanger has failed

 

[Christian70]

Thanks! I’ll have to get a plumber to that for me as I’m disabled.
I don’t if it would be the Heat Exchanger, wouldn’t that affect the hot water too?

 

[ianmcd]

yes good chance it is the main heat exchanger

 

[CBW]

Does the pressure increase at all, or just drop? Has it been isolated from the heating system?

 

[Christian70]

The pressure just drops. No, I don’t think my usual plumber isolated it from the heating.

 

[CBW]

No, I don’t think my usual plumber isolated it from the heating.

It might be a worthwhile exercise to rule out certain factors.