2 rads dead cold

[manorpurl]

Dear ll, I have 2 rads in my house that are not getting cold at all. They will get warm if i turn off the other rads in the house. They only get warm despite the flow pipe (lockshield valve i believe) is piping hot. I should expect same temp in the rad as the flow pipe. Both valves are fully open as well.
Also, these rads seem to be on the circuit of the pipe where the extension was done.
Any ideas folks?

 

[Plumbstar Tom]

sounds like sludge and a clean needed

Take them off and flush them out

 

[manorpurl]

That is what i thought, but when i bleed, the water which comes out is not black color. Do you think it is some heavy sludge sitting at the bottom.

 

[Plumbstar Tom]

likely or corrision, how old are the rads?

 

[manorpurl]

likely or corrision, how old are the rads?

The rads are around 15 years old, single panel single convector.

 

[Plumbstar Tom]

maybe new ones but first bang it into your garden and flush through