One radiator doesn't heat . .

[badbaz]

One radiator in my system doesn't heat up properly. It is warmish at the thermostat end and stone cold everywhere else. It's only about 7 years old, is there a way to determine if it's blocked at all? I can bleed it and water flows out. The return/pipe valve isn't closed. What's the best procedure to locate the fault?

 

[Puddle]

Well would think,thermostatic valve is stuck in closed position ,open head fully and tap valve body with hammer to try to free,do not hit hard,you are just trying to get vibration to free rubber washer,if you hit to hard may loosen joints and they will require re tightening
If you have had turned off for a long while,the valve may have to be removed to free off,however if you have to remove ,best to replace as not expensive and old valve may stick again

IMHO