external expansion vessel on combi

[gizmolang]

Hi all i am going fit a external expansion vessel for a combi . The current one is split on hermann icon 23t so i am going to cap it and fit a 12 litre external expansion on the return . The question is will the boiler be ok in hot water or will it over presurise during dhw operation due to expansion being on heating circuit. Any help would be greatly excepted

 

[Ermintrude]

Are you gas safe registered?
If your not registered , leave boiler alone and fit it externally without touching the boiler. From your question I think you are DIY so don't even look at the boiler. Just pay and get it serviced annually!

 

[gizmolang]

Hi i am gassafe registered lang property services ltd gassafe 510073 . I am asking as i have never needed to fit external expansion on a combi before .

 

[gizmolang]

I have spoken to glowworm who confimed its ok to and that a smaller expansion can be used as the boiler only has a 6 litre.

 

[gizmolang]

I have spoken to glowworm who have confirmed it is ok to fit and that a smaller expansion can be fitted as the boiler only has 6 litre expansion. Better to fit external expansion ,of the wall job and flue parts obsolete.

 

[Killy Bing]

How many rads? How much pipework?
the original could have been undersized in the first place, hence why its gone pop

get yourself in the gsr forum by messeging redsaw or gas man

If its not leaking then leave it in.

it will be fine for the dhw opperation...

 

[nysk2008]

As above

 

[Dotty]

Never, ever, ever downsize an expansion vessel.

ALso build your post count up so we can get you in the private forum for this kind of schizzle.

 

[albatross]

Should be fine. I wouldn't waste time capping the old one, just leave it there.

 

[gizmolang]

Thanks for the replys it was only a few rads and the expansion had split down the seams so it needed capping off. 8 litre external expansion fitted and all is now working well .

 

[AssuredHeating]

Easy peazy!

 

[IDCHAPPY]

Never, ever, ever downsize an expansion vessel.

ALso build your post count up so we can get you in the private forum for this kind of schizzle.

This a 1000 times, i always fit a 12 litre as a minimum to a small domestic property if it's decent sized then i go for an 18... the cost difference is pennies really

 

[Andyswad]

Agreed fit a bigger one if in any doubt, the cost is not much more. I have fitted a few additional ones in my time, most manufacturer's will allow and most do state in boiler instructions that in certain exceptional cases it will be required.

 

[gassafe]

Surely a bigger one will last longer too, it would have an easier life than one thats is almost at its peak!

 

[kay-jay]

A bigger one may hiss.........