Radiator cold on bottom - are the valves the wrong way round?

[Brookr]

We had new rads put in a few years ago and one of them has always been cold on the bottom and warm on the top. I remember the plumber asking his mate to check for something in his van when they came to install this rad, and when he said no he mumbled something that they'll have to just do with 'that' - whatever 'that' was. Anyway, the thermostat valve is on the right (whereas it's on the left for all other rads) - so I wonder if that could be related?

The pipe coming out of the wall on the left is hot, and pass the valve that part of the radiator is hot too. However on the right hand side the pipe going into the wall and the rad area the other side of the valve (which is the thermostat one) is cool. I've tried turning the knobs on both valves but it doesn't seem to make a difference (although turning the valve on the left can turn the rad off completely). It seems to me that the thermostat valve which is on the right, should actually be on the left?

It's never really bothered me before but as we had an exceptionally cold winter, I hope we can get it fixed this year.

Any ideas what's going on? (New rads and new pipes - so I don't think it's sludge.)

[welshlibranr]

you probably need to just bleed the radiators, then they should be fine, there is probably air in the line!............get yourself a rad bleeding key!....

[Brookr]

Hi Welshlibranr - I have bled the radiators to no avail :-(

[welshlibranr]

Oh!..................think you need a heating engineer then!..............

[jomifl]

It sounds as if the flow is just too slow, If it is warm at the top it doesn't need bleeding.
It doesn't matter which way the water flows or which side the valves are although if the thermostatic valve is on the outlet side it should be fitted the correct way around. If the other thermo. valves are on the supply side then they should all be fitted the opposite way around to your suspect one. It could be that the thermostat part hasn't been fitted to the valve part properly. ( not screwed on far enough or cross threaded)They just unscrew from the valve. When this is done the valve should become closed so if you push down on the part that is actuated by the thermostat part water should flow. If this doesnt work. post again

[AlBags]

Increase the flow with the lockshield valve (on your left)
If no increase and more even heat distribution, you need to look at other causes. Likely could be the fact that the TRV fitted is not suitable to be used on the outlet side of the rad. Some are though, so check the TRV model and suitability for fitting to cold outlet.
Failing the above, the system 'may' need balancing to even out the flow between radiators. This involves throttling back radiators (with the lockshileld valves) nearest the pump first, then progressively opening a little more on rads moving away from the pump.

[Brookr]

jomifl - I undid the right hand side valve and took the thermostat valve off, then pressed on the pin but there was no change.

AlBags - the TRV valve's are these:

Right:
http://img560.imageshack.us/i/radr1.jpg/
http://img845.imageshack.us/i/radr2.jpg/

Left:
http://img838.imageshack.us/i/radl1.jpg/
http://img14.imageshack.us/i/radl2.jpg/

[AlBags]

Hi
Westherm Four is reversible (so should be ok on outlet or inlet)
Check flow then!
You might want to be sure pipework is not damaged anywhere, as I see you are using pushfit and flex pipework.
Will look by tomorrow.
Al.

[Hopkirk]

I thought cold at the bottom, warm at the top suggested sludge at the bottom, but that's unlikely with new radiators.

I suspect though that a heating engineer would elect to flush the system out.

[jomifl]

It seems that you may have a blockage or airlock. Try closing the shut off valves on all the other rads, set the the rad thermostat to maximum, and open the lockshied valve (after removing the cap)and make sure that the circulating pump is on highest setting. this may may shift the airloc/blockage.

[LCDMAN]

I agree with Hopkirk, sludge! When you had the new rads fitted, did you have the system flushed through first ?

[jomifl]

The sludge in radiators is usually produced in the radiator itself, so it is unlikely to be a problem in new radiators.

[AlBags]

Everyone around here has radiator sludge on the brain.
Loads of money been spent unnecessarily by hundreds of householders on unnecessary powerflushing. It is very often not required. It's a great money-spinner though.
After looking at/working on loads of systems over the years, I have only seen two pretty badly sludged up enough to block rads.
Usually it is a TRV/pump/balance/pipe or air problem.

[The Builder]

Got to agree with Al there:o)

[AlBags]

(or 'stitched-in' microbore with air lock at connections or manifold)

(Thanks mate)