Worcester 9.24 Electronic combi - pressure vessel dripping

[Emjay111]

Hi folks,

Could do with some advice about our 15 year old Worcester 9.24 Electronic combi.

For several months now, we've been losing pressure (as indicated by the dial on the front). Usually it drops overnight or during the day when the boiler is not in use.

We've been topping it up using the filling loop, but clearly there must be something wrong.

I ran the heating with the front cover off yesterday, and I noticed that after a few minutes of operation, water droplets start to seep out from around the pressure vessel seam (just above the giant jubilee clip that holds the vessel in place).

I've also noticed that when the boiler is running, the pressure does increase dramatically from 1.5 bar to close to 3 bar (sometimes over). At this stage water starts to drip out of the pressure relief pipe outside.

I've tried re-pressurizing the vessel with a footpump as per instructions found elsewhere on this forum, but the problem remains the same.

I'm pretty adept at most things, so if I had the right info, I'm pretty sure I can sort this one out.

Any help gratefully received !

Thanks,

Marcus

 

[Agile]

I dont think that you have followed the instructions correctly or noted signs of a failed EXV.

Please do it again carefully according to the FAQ.

Tony

 

[The Baker]

and I noticed that after a few minutes of operation, water droplets start to seep out from around the pressure vessel seam (just above the giant jubilee clip that holds the vessel in place).


Symptoms do point towards pressure vessel failure and probable PRV damage.

Change both while its being done


Tim

 

[Emjay111]

Hi !

Many thanks for the replies.

I definately followed the instructions properly, as I have the original installation manual here. It says pump 0.5 bar of air into the pressure vessel, then top up with water till the meter reads 1.5 bar.

The water seepage doesn't occur into the system is under considerable pressure (close to 3 bar).

Three things of note that worry me:

1) Why does the system pressure build up to over 3 bar, when the pressure vessel is obviously leaking water ?

2) Why doesn't the pressure relief valve kick in, and vent properly when the system pressure exceeds 3 bar (a few slow drips of water is hardly going to make a difference to the overall system pressure)?

3) Even assuming a faulty PRV, the system pressure shouldn't get so high should it - or is this some side effect of a duff pressure vessel ?

I'm happy to replace the pressure vessel and PRV as they look relatively straight forward. I'm wondering whether there is in fact another more severe fault lurking around the corner !

To be honest, I think the demise of our system has been caused by running the whole system at too great a pressure for many years. When we moved in (this is before we had any manuals - we had to get them later), there was a red marker pointing to about 2.2 bar. We assumed that this was the pressure level that the system should be maintained at, and topped it up accordingly.

For years, it's been running at around 2 bar without any trouble. I would say that even with the heating running flat out though, the system pressure never really crept up much above 2.2 - 2.5 bar. Perhaps we've damaged something else.

Anyway, I'll order the parts as mentioned, and let you know how it goes.

Thanks again for the input - much appreciated.

Have a Happy Xmas.

Marcus

 

[gasandoilman]

because the presure vessel is not presurising
change it

 

[Soggy_weetabix]

Very easy on this model of Worcester.

I hope you repressurised with an 'open end' on the CHS. If not, your efforts have been fruitless.

The ev replace is a 30 minute job for a RGI, not much longer for a diyer.

PRV can be done in 15 mins, or repaired by a boiler engineer.

David

 

[Emjay111]

I hope you repressurised with an 'open end' on the CHS.

Err - nope ! Must have missed this bit in the manual.

I take it you mean leave a bleed valve open on a rad somewhere ?

Thanks again,

Marcus

 

[bob110]

Good morning all. I'm new here and i've just joined as the messages going back and forward very much apply to me and our old 9-24 electronic. We have many of the same problems. Pressure gauge runs between 0.4 to just over 2-1. This is a fairly new problem and I reduce the pressure by letting some water out of a rad. The down side to this is that in the morning the pressure is very low so I have to top up the water again. Vicious circle. I understand the need to pressurise the PV but the bit i don't understand is the link (or difference) between pressuring by adding water or by adding air. I know there is an air top-up valve on the PV but i'm guessing adding air or water are doing different things. As there is only one gauge to read I can't work out the difference of one over the other. I have noticed that at 2-0 BAR I now get a couple of leak drips from the PV seam just above the big circular clamp but this stops when I let some water out of a rad. Any info would be gratefully recieved. I have a new PRV to fit but see no point as the system doesn't get to operating pressure (3 BAR). Would be happy to change the PV if that is what is needed, or do I simply need to repressurise with air and water and not simply with water. Best regards, Bob.

 

[45yearsagasman]

Just read another 4 year old post before I got to yours
Its better to start your own post and not reply to old ones.

 

[bob110]

Thanks Pete. I'm not too good at this forum type thing yet. Understand what you say and thanks for the guidance. Best regards, Bob.

 

[Agile]

You are also not very good at reading the instruction to see the FAQs on this site BEFORE posting as they will answer most of the simple questions that people have!

Your boiler is very old and it may well have failed ! If the instructions were written properly then that would be identified during the process. But I dont think that they are!

Tony