Boiler pressure keeps going up

[BigAlexS]

Hi

It's been ten years since I had my Valiant combi boiler looked at, it had been working perfectly fine, but I thought now is the time to get it serviced... big mistake....

A young gentleman came around to look at it. The first thing he did was remove the vertical pipe cover, and bashed one of the the two taps below it (I turn these to increase the pressure), immediately water started leaking out of it. He fixed it and said it would be no problem.

Later I then noticed him turning up the pressure, I did say to him the pressure is fine, it only goes up when the boiler is on. He muttered something like... if that happens there must be something wrong...

Just before he was about to leave I pointed out to him the pressure was now in the red, I told him this was what I previously told him. So we bled the radiators and off he went on his merry way with my money.

So every now and then I notice I get a leak approx where he bashed the tap, I'm finding it difficult to find the leak. Another thing is that the water pressure keeps rising. Anyway so much for my "service"....

Another thing I notice is that the tap that got bashed goes round and round forever when turned (does not stop it seems). Is this normal, perhaps this is the problem?

Any ideas?

Thanks and appreciated...!

 

[NY_Rob]

Does the water pressure go back to normal once the boiler has been off for some period of time or does it climb even when the boiler is not firing?
What's your "normal" pressure?

Some photos would help too.....

 

[Sponsor]

 

[BigAlexS]

I'll double check but boiler pressure goes way down almost zero when it's off.
"Normal" pressure is around 10pm. High pressure is midnight to 2am.

Here it is at normal pressure:
https://imgur.com/a/0XSrv

Thanks.

 

[NY_Rob]

Take a look near your boiler... you should see an expansion tank (circled in red in photo).
If you rap it with the handle of a screwdriver it should sound/feel empty. If you get a "thud" instead- it could be waterlogged and may need replacement.

 

[BigAlexS]

Hi

It's actually a combi boiler:
https://imgur.com/a/na4Hy

Here is a picture of the pipes looking from the bottom to the top of the boiler, the tap in question is the one on the left.:
https://imgur.com/a/HypBn

 

[Jadnashua]

The heating loop should have an expansion tank on it that should help keep the heating loop pressure stable. Without one, or having one that has failed, when the boiler runs, the water in the closed loop expands, and the pressure rises radically. The bladder in the expansion tank allows a safe place for that expanding water to be temporarily stored, then as it cools and contracts, pushes back into the system. If the pressure rises too far, there is a safety valve that will open to relieve it...that may be where the water is coming from.

It's much better to upload your picture to the post rather than a link. As you're posting, there's an "Upload a File" button...please use that rather than a link.

 

[BigAlexS]

Hi

It's a combi boiler so it's all within the unit (see picture).
I did try to upload but it judges a file being 405Kb (which is quite small) as being too large without telling me what the limit is, so I gave up and used another site.
Regardless manged to find a way to embed... appreciated!

Tap in question is the one on the left.

Thanks.

 

[djdavenport]

Take a look near your boiler... you should see an expansion tank (circled in red in photo).
If you rap it with the handle of a screwdriver it should sound/feel empty. If you get a "thud" instead- it could be waterlogged and may need replacement

Such a clean installation. Almost looks like a schematic. Did have a question...The loop going off to the left? Indirect water heater? Can't see how it's tied in. Does it use closely spaced tees on the boiler supply like the other zones? Just curious.