Radiator Warms Up Then Goes Stone Cold

[soulbrother40]

Hi there. I don't know anything about radiators so I need help!

When I turn my heating on all 5 radiators in my flat heat up. After about half an hour 2 of them cool down and are stone cold. There are 2 radiators in the living room. The one under the window cools down. There other remains hot. The other affected radiator is in the kitchen. The dial at the side of the radiator is at the max on every one in the flat.

Does anyone know what's going on?

Thanks.

 

[Goldspoon]

I would suspect a TRV (thermostatic rad valve) is too sensitive so even tho on full is switching off flow. Take TRV off (they unscrew) to see if it helps.

 

[penfold46]

Hi there. I don't know anything about radiators so I need help!

When I turn my heating on all 5 radiators in my flat heat up. After about half an hour 2 of them cool down and are stone cold. There are 2 radiators in the living room. The one under the window cools down. There other remains hot. The other affected radiator is in the kitchen. The dial at the side of the radiator is at the max on every one in the flat.

Does anyone know what's going on?Thanks.

Details of your system will help, but try goldspoons advise first of all.

 

[mysteryman]

Looks to me as if the thermostatic radiator valves are doing their job admirably.

Have you noticed - it is high summer with outside temperatures in the twenties?

 

[soulbrother40]

Looks to me as if the thermostatic radiator valves are doing their job admirably.

Have you noticed - it is high summer with outside temperatures in the twenties?

Thanks for the replies.

How come it only happens on 2 out of 5 radiators? Can I keep them on full blast if I want, regardless of the temp outside?

 

[Alfredo]

No two TRVs turn off at exactly the same temp, they are a bit of a blunt instrument, and sensitive to draughts and other influences.

Having said all that it is possible the pins on the TRV valves are sticking, so unscrew and remove the thermostat heads and give the exposed pins a few sharp 'taps' with a small hammer, then work them up and down with something hard you can place on the pin, just to make sure they are moving freely. Don't hit them very hard as you might break them. Then refit the heads and see if it makes any difference. It might help, but it might not.

Alfredo