Cold radiator

[Burnerman]

It probably is, Jenny but its always worth making sure. After all, you have removed some water from the system so that has to be replaced.
Ideally the small 4 galllon tank in the loft should have about 4" of water in it. The thing is, this water level doesn't alter if the system is working well so when the valve needs to open to let some fresh water in, often it doesn't due to lack of use.
At the end of the day, when you open both radiator valves, clean water should flow out. If it does then your radiator should heat up nicely.....if either of those valves proves stubborn then you've no chance.
John

 

[jennyjpk]

But it only flowed out from one side but it did get hot for about 10 mins then gradually cooled down...its all very confusing

 

[kevplumb]

yev got a blockage in the pipework

 

[Burnerman]

Water must flow from both valves, Jenny, and your header tank must have water in there.
Heated water cannot flow around your system unless both of these things happen. The rad got warm for a short time because the blockage moved....now its trapped again! Happens all the time - seriously!
John

 

[jennyjpk]

Ok so if we do the same again could it solve the problem??

 

[Burnerman]

It certainly could - if your luck is in, the black sludge will eventually work its way out.
With microbore pipes, the sludging issue is much more apparent than with the traditional 15mm pipes - the smaller these pipes are, the easier they are to block up.
Obviously, a power flush by someone who knows what they are doing is probably on the cards at the end of the day, but sad people like me have hose pipe connections that fix onto the radiator valves, and its possible to blast water into the system and dislodge the crap that way.
Your particular system does seem to be suffering from sludge, maybe due to a lack of inhibitor in the past.
John

 

[jennyjpk]

Thanks i will keep you informed but your advice has given us hope. Jenny