Cold radiator

[sparkyspike]

This is what I have done:

I took a radiator off the wall to replaster the room. It was in 8mm microbore. I extended the pipes so I could run them under the floor, rather than clipped along the skirting, by cutting them with a pipe cutter and using two compression fittings. After having nearly been scalded I put the radiator back on the wall, tightened up the two end fittings and opened the valves. I let the air out of the bleed valve until water came out. All the other rads are hot. This one is cold. But the flow pipe is hot right up to the rad.

So what have I done wrong? I suspect that I may have crossed over the flow and return pipes when I reconnected. But would this be a problem? Of the two rad valves, one can be opened by hand and the other has a cap which is removed and is opened with a spanner. It is this one which is hottest. Should I have it the other way round, or is there some other problem? Any replies appreciated!

 

[chr15]

This is what I have done:

I took a radiator off the wall to replaster the room. It was in 8mm microbore. I extended the pipes so I could run them under the floor, rather than clipped along the skirting, by cutting them with a pipe cutter and using two compression fittings. After having nearly been scalded I put the radiator back on the wall, tightened up the two end fittings and opened the valves. I let the air out of the bleed valve until water came out. All the other rads are hot. This one is cold. But the flow pipe is hot right up to the rad.

So what have I done wrong? I suspect that I may have crossed over the flow and return pipes when I reconnected. But would this be a problem? Of the two rad valves, one can be opened by hand and the other has a cap which is removed and is opened with a spanner. It is this one which is hottest. Should I have it the other way round, or is there some other problem? Any replies appreciated!

The pipe configuration shouldnt be a problem,sounds like you probably have an airlock. Close the valves on all the rads that are working and you will probably find this one will then get hot.

 

[sparkyspike]

I've done this for half an hour and it's still cold. But if I open the bleed valve and let water out into a bucket, the inlet valve gets hot and the top of the rad gets very slightly warm. Does this give you any clues? How about if I kept on running water out of the bleed valve; could this help. I've already filled half a bucket and haven't got air.

So I'm now thinking, if there is an airlock on the return pipe, that would explain why I can get hot water to the inlet pipe only by opening the bleed valve and letting water through. So if this is the case, how can I get the air out? It's probably at the low point under the floor.

 

[stumpynut]

Try closing both valves, disconnect them from the rad and open both into a bucket to flush the air out and to make sure both valves are opening properly.

 

[bobski1976]

how far is the radiator from the actual boiler it might just e that its needing balanced. if im correct in thinking you have a trv and lock shield. in stead of two lockshields. what you need to try and do is close the return a little. there are givin to you opened in a full position if your lockshiled has a nut on top of it you should take this off and behind it there is an allen key fitting close this a fully then open it up half way.

if this works your in. however to get the right heat you will need to play with it a little to get it just right.

think about it like this the vavles at either side r like taps you dont want to have both taps open fully as one will be returning the water as fast as the other one is feeding it what you want is for your radiator to fill and drain away slowly or slower. hope this works for you.

 

[bobski1976]

if you want to operate your system corectlly then the position of the vavles does matter. there are some trvs on the market that can be switched to let them act as the inlet or outlet. you have already identified the feed pipe going to the radiator as this is the one heating up first well thats your feed if your loackshield valve is on there then by closing it wont help you much as you need the hot water to feed in to the radiator faster in theory lol than the water flowing out does this make sence.

if your trv is in the worng postion. the best sugestion i can give is get rid of it and just fit two lock shield at both ends and open the flow fully and the return half way