Valliant boiler and dropping pressure

[opps]

Hi there

My client had two new ground floor rads fitted on the 23rd of December (new pipework etc). The Valliant boiler on the 3rd floor only serves the ground floor heating.

Since the rads were fitted the pressure on the boiler constantly drops to 0 bar.

On Tuesday the client called the plumber who topped up the system again, I overheard him saying something about a new pump being needed and that there were no leaks in the foundations (he didn't look though), I wasn't privy to the conversation but got the impression that he was not referring to the internal boiler pump.

Yesterday as I was working I noticed it getting colder, I topped the pressure up again.

The boiler is on the 3rd floor, I opened the filling loop, I could hear what sounded like air escaping and gurgling. Once the needle started to creep I shut the loop. After about 2 minutes the pressure was now at 2.5 bars. I went down stairs and bled one of the rads to reduce the pressure. I let the pressure drop to 1.5 bars. I left the boiler turned off for about 3 hours, on it's own the pressure had dropped to 0.75 bars,

Whilst I am not trying to malign the plumber in any way, what could be the possible causes?

The old rads were removed about 6 weeks ago. There were no problems until the new ones were fitted

 

[lightning]

Check prv pipe is not dripping out side

 

[Agile]

Although your description is not very clear it does sound as if the expansion vessel is not working correctly.

Boiler pressure should not rise by more than about 25% from cold to hot rads.

Why are you getting involved if you have not been employed to work on the heating?

Tony

 

[opps]

Hi Tony.

I ask because I am nosey and hope that a fuller understanding will help me if I directly experience any problems in the future.

I got involved becuase I needed the room to be warm in order to be able to work efficiently. And because I've got a girlie cold.

Aplogies for not being clear in the description.

The rads had recently become cold when i topped it up (with the boiler turned off). I over filled the system, i hadn't expected such a big time lag between shutting the filling loop and the needle moving.

Because I had over filled I decided to drop the pressure down via the bleed valve.

The pressure then continued to drop over the next 3 hours on its own.

The water in the system was cold when I turned the boiler back on. I didn't notice the needle moving as the water started to heat up. by the time the water had heated to 60 degrees the needle was still showing 0.75 bars.

Hope that is a tad clearer. Tnx