1 new radiator not getting hot!

[Murdoch]

Pretty much as the title says - we had an extension built which has 6 radiators in it.

1 isn't fitted as its in the shower room which isn't fitted out

4 work really well

1 doesn't get very warm

So I've tried:

1. Bleeding the radiator in question - there is water in it.

2. Check the thermostatic valve - its free to move up and down

3. The other valve - I've wound it up and down a couple of times

4. I've just turned off all the other radiators in the extension (except the shower room as it's still not fitted out) - and very, very slowly the incoming pipe to the "cold radiator" gets warm - but only warm and the radiator doesn't get really get warm.

5. If I turn the utility radiator, which is in the adjacent room, it gets very hot very quickly, as do the other radiators in the extension.


Any ideas what to try next?

Thanks

 

[rpm]

http://www.ukplumbersforums.co.uk/central-heating-forum/87115-croppies-balancing-thread.html

 

[JCplumb]

I doubt balancing would work if the OP has turned off every other radiator and this one only gets a little warm.
There could be an airlock on the run to that rad, I'd try removing the rad and opening the valves into a bucket, any spluttering is the airlock.
Do you have a manifold based design? Do the rad feeds come from the floor or drop down from above? What size pipe is it? Is it a pressurised heatign system?

 

[Murdoch]

I doubt balancing would work if the OP has turned off every other radiator and this one only gets a little warm.
There could be an airlock on the run to that rad, I'd try removing the rad and opening the valves into a bucket, any spluttering is the airlock.
Do you have a manifold based design? Do the rad feeds come from the floor or drop down from above? What size pipe is it? Is it a pressurised heatign system?

Ok thanks, I'll try my best to answer your points!

1. I don't like meddling with water so I'll get a mate to take it off

2. Not a manifold system

3. Drop from above (all the extension pipework is above the ceiling on the ground floor) in essence there are 2 "branches" from the boiler (which is upstairs too) - 1 does most of the original house, and the 2nd which does all the extension and 1 radiator on the landing adjacent to the boiler

4. The pipe size at the boiler is 22mm and it drops to 19mm "somewhere" - that said the furthest rads away are working perfectly.

5. Yes - pressurised.


Thanks for your help!

 

[rpm]

I doubt balancing would work if the OP has turned off every other radiator and this one only gets a little warm.

Fair enough, was thinking after turning multiple valves on-off, up-down it will need doing at some point?

No.5 in post#1 baffles me though and doesn`t sound like air lock does it? (just asking).

 

[Murdoch]

Fair enough, was thinking after turning multiple valves on-off, up-down it will need doing at some point?

No.5 in post#1 baffles me though and doesn`t sound like air lock does it? (just asking).

Oops, poor terminology - No5 in post 1 means the utility radiator gets hot quickly, not the radiator in question - that is still cold!

 

[1Steven]

Turn off valves. If you can connect hose to half inch outlet, by removing air vent and using half inch male iron to copper sort bit of pipe. Put other end of hose in bucket turn on one valve let it run for a bit stop when the bubbles stop. Repeat other end, if you're rad has small air vent take rad off put hose on valves.

 

[Azzer1704]

Sounds like the flow to the rad is restricted, is it possible some dirt could have got in the pipework during installation and has gotten stuck in the valve? I'd start by checking the flow through each end using the methods explained above.
Failing that it could have been piped up incorrectly.
Hope you sort it

 

[townfanjon]

Has it got one way only TRV''s fitted on the flow ? ,

 

[Murdoch]

Has it got one way only TRV''s fitted on the flow ? ,

How can I check this? I have taken the thermostat part off to check the movement.