expansion vessel pressure

[GeorgeS]

hi guys,
what is the recommended pressure in the expansion vessel of a sealed system? is it to be check when the system is hot or cold? mine reads 0.4bar...
also, I read somewhere in one of Chris's posts that we need to add water to the system every year or so. How do you do that in a sealed system?
Thanks for you advice.

G.

 

[oilman]

The pressure is equal to the static pressure of the system, ie 34 feet =1 bar so if your top rad is 12 feet up, then 0.4 will do. Then again, some boilers have pressure switches which means the pressure has to be higher, but you haven't told us anything about your boiler or system have you? We are not mind readers.

 

[chrishutt]

See the entry on this in the sticky reference topic near top of topic list.

 

[GeorgeS]

thanks guys, the boiler is a potterton suprima50 and the upstairs rads are under 12feet up from the boiler. However some hot pipes go right up to the attic, which would be around 14feet from the boiler. Is there any recommended pressure in the vessel for this type of systems?
Thanks in advance
G.

 

[chrishutt]

The normal pressure setting of 1.0 Bar approx will do fine.