Boiler pressure problem

[Teasy]

My mother's boiler recently wasn't working so I took a look at it. Noticed there was no pressure. So I opened the valve and put the pressure up to 1.5 (which is where it should be according to the manual). Boiler was working fine, but then around 20 minutes later she noticed that all of a sudden the pressure dial now read 3. Is this just a faulty pressure dial? Or is there more to worry about here? Boiler is a Greenstar 30si combi mk iii.

 

[cross thread]

Get it serviced and they will recharge the expansion vessel at the same time

 

[Teasy]

Definitely will, just wanted to see if anyone thinks it's anything dangerous in the meantime? I've asked her to keep an eye on the pressure and keep me updated. Just worried because she's elderly.

 

[terryplumb]

It's not inherently dangerous. If you lower the pressure when system is cold to 1 bar ( you can do that by bleeding a radiator), what does pressure then rise to when heating is in use ??

 

[Teasy]

It's all over the place. Which is why I was just thinking it was a faulty dial. But I wanted to see what other people thought just in case. I don't mean it's moving a bit when the heating comes on. I mean it can go from 1 to 3 than 2 then 3 again. Cant be actual pressure, but just not sure if something else other than just the dial could be wrong. Know nothing about boilers and just trying to make sure that if it's left on overnight nothing can happen that could cause a major issue for my mother.

 

[terryplumb]

Your EV ( expansion vessel) probably needs attention. If pressure does happen to rise above 3 bar ,the PRV
( Pressure relief valve) Would open and expel some water out of the system to reduce pressure, via an open ended pipe routed to outside.
It's fine to continue to use the heating for a few days until an engineer can attend.

 

[Teasy]

Excellent, thanks

 

[Londoner2]

Did you close the valve AFTER repressure?

 

[Teasy]

Did you close the valve AFTER repressure?

Yeah, apparently there was a leak.. Plumber is scheduled to have a look. But it's a council property so nothing happens quickly ..