Rad not working

[jaylord79]

hi all,

Got a problem hoping you can help with. I fitted a new radiator on and in the process had to drain the system and change the valves. So all went well and refilled the system and all bled rads and everything working. All except a downstairs rad which no has no heat at all. Even the pipe work feed and return has no heat in it. So could it be sludge in the system that has badly blocked this rad? If so what is the best remedy? Take it off and flush it out? The other thing worrying me is in the process of fitting the new rad valves one side (believe it's the return) yielded a bit and I'm concerned there is a bend in that pipe now. Will need to cut the floor out to get to see it but not sure if this would effect the downstairs rad. It is a gravity fed system header tank in loft, the boiler and the cylinder tank are both downstairs in the extension at the rear of house. There is also a pump on the pipe work so don't know exactly where this downstairs rad would be fed from. Any help would be greatly appreciated. Many thanks in advance

Jay

 

[JohnD]

turn all the others off. Does the cold one now heat up?

what sort of valves are on your radiators?

 

[jaylord79]

Hi JohnD yeah tried that and no joy. Mixture of valves the new one is TRV and another rad has TRV and the other five rads inc the one not working just have standard twist to open and close valves

 

[JohnD]

when you bleed this one, does water squirt out freely?

did it work prior to your drain and refill? Was there sludge in the radiator you took off?

 

[jaylord79]

Water does come out yes. Did work before and there was a bit of sludge on old one. Not sure if this helps but when I drained down and filled back up the rad now not working always had water coming out of the bleed valve, opened it when draining down to let air in and water just came out then when I refilled it didn't let any air out just water

 

[JohnD]

turn off the valves at both ends of the cold radiator. Open the bleed valve to verify that water does not now squirt out. Undo the nut holding one of the valves onto the radiator, let the radiator dribble out into a bowl until it is empty (open the bleed valve and it will run out faster). When empty undo the other valve and lift the radiator out of the way. Tilt it to tip the remaining water and sludge out, then turn it upside down.

Cautiously open one of the rad valves and let it squirt into a bucket. Then close it and run the other into a bucket. If one of them does not run, the pipe is blocked, probably with sludge but might be an air lock (though the bucket test will probably clear air). If blocked follow the pipe back and try to find where it is blocked. If you have black sludge, a magnet will stick to it through the copper pipe. A blockage is likely to be at an elbow or T-joint. Once you have cleared the blockage and water is flowing you can do a chemical clean. A DIY clean will not work if there is a blockage as the chemical cannot flow past the blockage.

Be aware that black sludge leaves a permanent stain on walls, floors and especially carpets.

 

[jaylord79]

Quick update just found someone had turned lock shield off!! But it has got heat to the rad, very bottom is stone cold still would this still be a block?

 

[jaylord79]

Thank you JohnD really helps and I think I'm going to do this tomorrow anyway. If this is now overkill I won't do it if there is now a better remedy? Thanks

 

[JohnD]

turn the others off. What happens now?

If the radiator is starting to get hot, you have not got a blockage. But you may need to balance.

If you have radiators that are cold in the middle they have a partial blockage.

 

[jaylord79]

It's now fully hot many thanks. The new one upstairs is now hot at the top and cool at the bottom but I guess that's now a balancing issue? Really appreciate your help, thank you