radiators not getting warm

[ianclark100]

I have just moved the piping for 2 radiators in my home and now the radiators will not get warm unless I turn off the other radiators in the house.

The pipes were running over of the carpet and through holes drilled in the wall which looked a mess. I have re-piped so the pipes now run under the floorboards to make it look much tidier.

I cut the pipes coming down from upstairs where the boiler is and fitted 2 service/isolation valves so I could move the radiators whilst the heating was still operable. I have used soldered fittings to join all the pipes. Once I had moved the piped I connected the new piping to the service/isolation valves and opened them but no heat arrived at the radiators. I have checked that the the water can get through to each radiator OK by disconnecting the radiator and loosening the service valve to make water spray out of each of the pipes. I can't understand why I still have no heat. Could there be a lump of solder loose in the pipes blocking a valve somewhere or could the service valves restrict the flow of water enough to be causing me a problem? I know the diameter is reduced in the middle of the valves.

I don't want to have to strip it all out again so any tips would be gratefully recieved.

 

[bathjobby]

You don't say that you have bled the rads !

 

[sime10]

They get warm when the others are turned off may mean that they have been bled?

 

[bathjobby]

True, but maybe not. Maybe's have never been the best basis for fault finding.

 

[sime10]

It maybe air but you have said you have put isolating valves on these could well be restricting the flow and return to the radiators.

 

[ianclark100]

I bled the radiators after reconnecting the valves. The pipes don't get warm at all.

I'm not sure about removing the isolating valves unless there is a strong thought that they are the root cause of the problem.

 

[bathjobby]

When you turn the other rads off do these 2 get very hot or just warm. If not very hot, then where are they the hottest, top middle or bottom ? I assume its not a combi boiler ?

 

[gavinda]

isolation valves can be very restricive... not really much work to remove them is it?

 

[ianclark100]

bathjobby - We do have a combi boiler. The radiators do get hot when the other ones are switched off. Thay heat up evenly as I would expect.

gavinda - When I cut the pipes there was a lot of water that came out. Much more than I had expected even though I had turned all the other radiators in the house off and drained the pressure from the combi. I have a plasterer coming round next week to ski the walls and I'll have to remove the radiators again. It is so much easier with the isolating valves.

I guess I could remove the valves again once the plasterer has finished. I was just reluctant to unless it was felt that they were the most likely cause.

 

[kevplumb]

if you must have valves use full bore ones
yerv bugger ed up the balance by introducing a flow restriction

 

[ianclark100]

Thanks guys.

From the sounds of it the service valves are probably my problem. I'll remove them and solder a straight join in once the plasterer has been and sorted out the walls. I should have no need to ever remove the rads again after that - touch wood. I just hope when I set it all back the rads get hot as usual again.

 

[gavinda]

just isolate at the rad valves and put a bag over them to protect form the plasterer. just ask him not to kick those bags out of the way

 

[JohnD]

you can get full-bore isolating valves, though they are not so elegant.

 

[ianclark100]

Thanks,

I did have a look and didn't like the look of any I found. It's fine. I'll take them out. It was conveineit to have them in place whilst I was finishing up the pipework and having the rooms plastered but once that is done I'll not need them any more.


Ian