Hello,

I drained down a system today and replaced a few rads then when I re-filled only a few rads downstairs were heating up. Is it possible that sludge could have blocked the valves on the rads that aren't working? All the rads bled fine. If it is sludge what's the best course of action?

Thanks

are the rads that don't heat on the same drop down pipework ?

what was the condition of the water when you drained ?
is it an open vent or sealed system ?

need more info.

Hi,

The rads are on the same drop down pipe. A few work but a few don't. It is an open vent system.

Thanks

more likely airlocked in the pipework.

How do I over come airlocks, all the rads have been bled? There are no air vents anywhere on the system. The boiler only feeds the heating, the tank is on an immersion, there are 2 pumps but no port valves.

Thanks

if the boiler only feeds the heating you won't need a motorised valve unless the heatings zoned.
whats the 2 pumps for one for the heating whats the other ?

as for the cold rads and the info i have try shutting the hot rads off leaving cold rads on and let the water circulate.

let us know what happens ?