Boiler pressure gauge

T

Thirsty

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Someone was kind enough to respond to my earlier post; unfortunately the moderators removed the responses. Would very much appreciate if you could reply again - plumbers seem to be in precious short supply at present and I'm getting very, very cold.

I have a Combi-boiler; which, given the weather, has been running almost continuously for the last week.

I've just noticed that the pressure guage needle is between 3 and 4 (4 is the highest); it's normally around 1-2. Should I be concerned about this? When I switched it off the needle dropped back down to 3 immediately.

I understand it isn't good for the guage to be up this high, so the boiler is turned off now.
 
Re: Boiler pressure guage

I am not a plumber but that is way too high it should be between 1 and 2.

Have you fiddled with anything that made the pressure go up so high, turned off any valves in the system?
 
Re: Boiler pressure guage

Nope, other than the boiler running almost day & night for the last week; nothing has been done to it.
 
Re: Boiler pressure guage

It's either a filling valve letting by

a faulty gauge, (unlikely)

An expansion vessel that needs to be repressurised.

or an expansion vessel that is damaged and needs to be replaced.

Try venting a rad, catch water in bucket and drop pressure to 1.5 bar. Then watch it from there.

You will need a service person to have a look at this most likely.
 
Re: Boiler pressure guage

Thanks for that DavyJones - it was the 'letting by' bit I didn't understand?

How would I be able to check if the expansion vessel was damaged? is it located in the boiler itself?
 
Re: Boiler pressure guage

yes, in at the back. If the pressure jumps around a lot it may be worth looking at. A good serviceperson will check it when they do the boilers annual service.

did your pressure releif valve open at all? water spilling from pipe outside.
 
Re: Boiler pressure guage

Thanks DavyJones - finally got someone round last night.

It seems there isn't any pipe from the safety valve to the outside (not good); if it vented it would have just sprayed water inside the house.

Plumber reckoned though that some freezing had occured on the water pipes & this had caused the increase in pressure.

The pressure gauge is back to normal this morning (around 1.5) so given the general thaw today, I think his theory may be correct.

We'll see how it goes for a day or two.
thanks for your help.
 
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