Open or Closed System - Help

[opponent]

Hello people. My first post so please bear with me. Also i am new at DIY.

I noticed one of my radiators is cold at the top and warm at the bottom. After researching DIYnot.com i realised i need to bleed the system. But someone also told me i need to represurize the central heating afterwards.

How do i know if i have a open or closed system. I have a hot water cylinder in my airing cupbaord. And water tanks in my loft is it an open system.

Any help will be appreciated

 

[meldrew's_mate]

Generally an open vented system has two tanks in the loft, the smaller one being the heating header tank (feed & expansion).
A sealed system will have a gauge somewhere obvious (!), and only the large tank or no tanks in the loft.

With an open vented system you don't have to top-up the pressure after bleeding (only!) the air from the rads.

 

[bab]

Go ahead & blead rads while heating & hot water is turned off. Bleed valves at top of rad. some do think there at the bottom.