replacing manifold help

[gingerbloke]

help needed urgently. i've got a combi boiler sealed system the rads are fed with 10mm micro bore from a manifold. the upstairs manifold which serve four rads started to leek and had to be replaced from a copper one to two plastic ones ever since then the rads upstairs won't get hot both the flow and return pipe are hot and so is one pipe feeding each rad off one of the manifolds the four pipes from the other manifold is cold.
please help what have i done wrong.

[sonray ltd]

wheres the cold manifold flow,return ?

[gingerbloke]

both manifolds are next to each other.

[justlead1]

Hi. 1. Turn off all rads at one end (wheel head) 2. turn off both ends on the one you want working. 3. remove plug at top of rad. (have cloth at ready)
4. screw in 1/2' doc run short hose from this into bucket and open one end of rad (make sure system is fully charged) allow say 2ltr of water to fill bucket, turn off and repeat with other end. You may well here air purging from rad during the process. 5. Remove Doc re-fit plug turn on valves check results. Good Luck

[tomplumb]

what just lead said! ^^^^^^^^^^^^