Radiator not heating - kinked or blocked?

[pixie]

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I have a radiator that doesn't work properly, it's upstairs, furthest away from the boiler (Vaillant Combi 831). When the heating system is on and the effected radiator is turned on fully, it is warm on the bottom left hand side of the radiator (and the flexible plastic pipe attached to the valve there).

The thermostatic value is on the right hand side of the radiator. I thought the thermostatic value side of the radiator was where the hot water came in, but the flexible plastic pipe leading in to the valve from out the wall there doesn't get hot at all.

All the radiator have been bled. I have tried turning all the other radiators off and fully opening the valve on the left hand side of the affected radiator (with thermostat value on right set to fully open/hot). When I do this the radiator and pipe on the left no longer get warm at all. From what I read, I was expecting it to still be warm, if not the radiator to heat up throughout.

If I turn the one of the other (or all other) radiators back on, the bottom left of the radiator and the pipe heat up again.

I think it might be a kinked pipe (no idea where it would be, under floorboards?), or if it's clogged I could try flushing the radiator, just not sure which option to try first.

 

[Rickster123]

Unscrew the thermostatic radiator valve head and give the little pin a few taps. Sounds like its stuck shut.

 

[pixie]

Unscrew the thermostatic radiator valve head and give the little pin a few taps. Sounds like its stuck shut.

Recently had them replaced, have double checked to be sure, seems to moving fine though, not stuck.

 

[Rickster123]

Then the only thing you can do is isolate both ends of the rad, remove it, open each valve into a bucket or bowl to check there's flow from each. You can then refit rad and vent it.

 

[pixie]

Then the only thing you can do is isolate both ends of the rad, remove it, open each valve into a bucket or bowl to check there's flow from each. You can then refit rad and vent it.

Thanks, will try that before lifting any floorboards etc! Do I have to drain the radiator first? How long would you check the flow for on each side?

 

[Rickster123]

Thanks, will try that before lifting any floorboards etc! Do I have to drain the radiator first? How long would you check the flow for on each side?

Drain the water in the rad into ice cream tubs and into a bucket and get the rad outside out the way. Check the valves for a couple of seconds. Make sure you know how to repressurise your boiler tho before you do any of this or you'll end up in the cacka.

 

[pixie]

Drain the water in the rad into ice cream tubs and into a bucket and get the rad outside out the way. Check the valves for a couple of seconds. Make sure you know how to repressurise your boiler tho before you do any of this or you'll end up in the cacka.

Thanks, I can re-pressurize, will give it go this weekend!

 

[Rickster123]

Thanks, I can re-pressurize, will give it go this weekend!

Failing that get a plumber in and for the price of a half decent Chinese takeaway you'll have a working radiator again. Good luck!

 

[gassafe]

Then the only thing you can do is isolate both ends of the rad, remove it, open each valve into a bucket or bowl to check there's flow from each. You can then refit rad and vent it.

I normally do the same test but without draining the rad & taking it off the wall. I remove the air vent & fit an mic onto a hose into a bucket, open up the flow & it should flow nicely into the bucket & then try the on the trv valve! If the pipe is blocked or kinked you will get no flow or very little!!

 

[pixie]

Drain the water in the rad into ice cream tubs and into a bucket and get the rad outside out the way. Check the valves for a couple of seconds. Make sure you know how to repressurise your boiler tho before you do any of this or you'll end up in the cacka.

I couldn't get the valve untightened on the thermostat side, but I unscrewed the plastic feed pipe. On the bathroom radiator (that is cold) the water didn't really flow so much as drip out, a constant drip drip drip every second or so. On the landing radiator (which also stays cold) the water came out the pipe as more of a flow. The water out of both pipes was a bit murky, browny coloured but not very dark. There were a few little black flecks/sediment out of the landing radiator :/

EDIT: I opened the valves on both sides and now both radiators are not ice cold (as they were previously!) The valve that the thermostat is attached to is hot, and the radiator is warm on bottom corner next to this. They're slightly warm all over, warmest being at the top (but in no way hot, more like when radiators are cooling down a while after being turned off or just starting to heat up, if that makes sense!)