Vailent Eco pressure vessel

[kingjohn]

I know the pressure vessel needs pumping up, but how often?

The boiler was serviced in October and it was pumped up to 1.5 bar. When I checked it yesterday it was 0.6 bar.

Does that mean it is time to replace? Is it a diy job for someone who is fairly capable?

 

[John D v2.0]

Are you sure your checking the pressure vessel?
The normal pressure guage is displaying the pressure in the heating system. You can fill it using the filing loop which should be a short metal hose with 2 taps.
If it is the EV you're checking, you wouldn't be now wondering how to top it up.

The heating system may need topping up every year, but any more than every few months and there must be a leak that needs attention.

 

[kingjohn]

I used a tyre pressure gauge on the schroder valve with the pressure gauge display just above its bottom reading. It is three months, almost to the day, since the system was recharged

 

[terryplumb]

Not normal for the EV to need re pressurising after a few months. What made you want to check the EV pressure ? Are you having some issue with boiler that made you do this ??

 

[John D v2.0]

Oh yes sounds like an issue there, either replace or cap it off and fit an external one on the return of you have space

 

[kingjohn]

'Not normal for the EV to need re pressurising after a few months. What made you want to check the EV pressure ? Are you having some issue with boiler that made you do this ??'

The pressure in the system had been falling when I had the boiler serviced. No water was found in the EV. The engineer told me the EV should be pressurised to 1.5 bar with no water pressure. The system was then pressurised to about 2/3 on the pressure gauge. Over the next three months it has slowly fallen until the pointer was just above the base, which is when I took the EV reading of 0.6 bar.

I have pumped the EV up to 1.5 bar and repressurised the system, but realise that it is just giving me a breathing space and is not a cure for the problem.

One other problem reared its ugly head. For a couple of days before I repressurised the system the boiler made the most distressing grinding noise on start up. This has now stopped.

 

[terryplumb]

Clearly you have a fault somewhere .time to call in an engineer to diagnose what's going on.

 

[John D v2.0]

I presume the guy who topped it up drained the boiler and left the tap open when he was pressurising the vessel? Otherwise you can pump it up to any pressure you like but there won't be much more air in if it's mostly full of water.

Secondly 1.5 bar is too high unless youre topping your system up to 1.6 bar+ for some reason.

Basically open a drain off below boiler level.
Allow water to drain until it stops
leave the drain open and repressurise the vessel to around 0.2 bar below the fill pressure of your system (usually 1 bar for a 2 storey)
close the dust cap and the drain off
refill/inhibit/bleed as appropriate
Wait and see if the pressure goes.

If it still drops after that it must be a problem with the EV - the EV pressure should always appear to be the same as the system pressure once you've filled it though. The above procedure ensures that the EV is mostly air and a little water at a cold situation.

 

[muggles]

Does that mean it is time to replace? Is it a diy job for someone who is fairly capable?

Needs more diagnosis, but it's not a DIY job anyway as you shouldn't be removing the cover of the boiler unless you're Gas Safe Registered, and it shouldn't be operated again until the 26.9 checks have been carried out by a GSR Engineer.

 

[kingjohn]

Problem solved. Traced it to a leaking diverter valve. Won' buy Sunvic again.