Basic Radiator Question

[SteveRobert5a]

I have a downstairs rad that has a 23 year old TRV and it's barely heating up. I bled it, and removed the TRV head and it still just gets a bit warm. It seems to be warm over all the rad, not just at the bottom. The rest of the system heats up fine with the other rads getting hot. It's sealed system with one of those tank thingies that you have to pressurise - pressure is set to 1 bar. I'm guessing it's sludged up, but maybe it could be the TRV valve, or something else. What's the protocol for figuring it out, before calling a professional?

 

[Last Plumber]

Have you checked whether or not the pin is stuck?

 

[SteveRobert5a]

Have you checked whether or not the pin is stuck?

Yep- have prodded it up and down. The other valve I've closed and then reopened fully again. After a further bleed and more waggling, the radiator is getting warmer but nothing like as hot as the other rads, when last year it would get really hot.

 

[Last Plumber]

It sounds like low flow rate but the cause can be many things.

Try turning all the other rads off to see if it gets hot.