Varem Expansion vessel

27 Jun 2012
Reaction score
United Kingdom
We have an unvented warm water system which is about 12 years old now.
I have not had the system serviced until last year when we did not have any water because it was simply leaking out through the pressure relief valve.

A heating engineer came round and pointed out that there was no pressure in the expansion vessel and the water pressure was simply pushing the warm water through the pressure relief.
This was an easy fix.
I was instructed to regularly check the pressure and open the pressure valves.

We have always had a small dribble from the relief pipe ever since.
A couple of weeks ago I noticed that there was water on the outside of the expansion vessel.
I checked the air valve and it was wet. When I depressed it some water was spurting out.
I reinflated / repressurized the system but there is a constant small water leak at the top where the air valve is placed.
When I repressurized the vesel I noticed some bubbling into the warm water cylinder and later in the pipes.

It is not very easily accessible as it is quite high in an airing cupboard.

The Expansion vessel does not have any rust on the outside.
The PN is Varem R1018228.
It is an 18l vessel.

My questions are now:
Why is there a water leak from what is normally an air valve?
Is the bladder in the vessel ruptured?
Sponsored Links
Yes this would normally indicate that the bladder inside is ruptured and you would need a new vessel
Sponsored Links
Thank you for the answers.

Can I replace this expansion vessel with a different size or is there a set formula for vessel to hot water tank?
depends on the capacity of the cylinder, but if the original is the varem and its 18ltrs then an 18ltr i would stick with, has to be potable water vessel though. ;)

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local