Do I need expansion vessels?

[chriso]

Hi

Looking at getting a Worcester Bosch 4000 24kw system boiler and a 210L Ideal tank. A friend showed us their system and they had two expansion vessels, one for the hot water tank and one for the central heating. Thought I'd have a look into the technical side before speaking with plumber, just so I understand it.
Any thoughts?
Or just stop asking strangers on the internet and go straight to plumber?

Thanks

 

[ShaunCorbs]

How many radiators have you got ?

 

[chriso]

How many radiators have you got ?

11 or 12 (depends on what we keep) plus two towel

 

[ShaunCorbs]

I would add an extra 12l expansion

 

[king of pipes]

It's probably best to add another 10- 12 litre one it will take up the expansion across the system better . Kop

 

[chriso]

So do I need an expansion vessel (potentially) just for the cyclinder, or one for the central heating too?
I think the Worcester Bosch 4000 has some kind of expansion vessel built in too?

 

[ShaunCorbs]

That’s for the central heating

 

[king of pipes]

Potentially you need a extra one for the heating and one for the unvented cylinder, a system boiler has a expansion vessel built in but often that's not enough if you have more than 7-8 radiators which you have examples below. Kop