Santos Expansion Vessel

[gasned123]

Hi all,

I have a Santos unvented system, with a Viessman Vitoden 100 heat only.

The heating has its own external Exp. Vess, and the DHW has its own white slightly bigger Exp. Vess.

I live in central London with very hard water, about 400 parts, and when I have a shower and someone else opens another taps the pressure drop dramatically. I remember when I moved in 4 years ago, it wasnt like that...

So I can assume that the White santos Exp Vess either needs pumping or replacing. What tests can I run?

If I close the mains coming into the system, then open all taps, they stop after 5 min. Do I then get a foot pump and pump to 3.5bar?


any help would be great...

 

[Slugbabydotcom]

You need a plumber who is registered for unvented cylinders for this work.
Do not pressurise the vessel to 3.5 bar, thats more than mains pressure and much too high.
The fault probably lies elsewhere