Expansion Vessel Size

[Chris2018]

I had a boiler fitted over 3 yrs ago. It is a commercial boiler - 100kw. The installer fitted an expansion vessel which is about 20 litres.

We have about 33 double rad and 2 single rads on the system. Someone mentioned to me that the expansion vessel is way too samll as we constantly have to rpressurise the boiler.

Any thoughts on this?

 

[Best]

Yes, has to be way too small.

 

[SimonG]

Be keen to bottom out where the waters coming from.

Then need to size a new vessel.

 

[ShaunCorbs]

Around 1l per rad rough quick guide so just for the rads 35l needed so I would put a 50l in

 

[Chris2018]

Thanks all for this. I will get this rectified.

 

[chris watkins]

Whats the head of water above above the vessel Chris ?