Gurgling in or near an upstairs rad.

[Allex]

I have a rad in an upstairs bedroom which gurgles loudly when the heating starts. Its a bit variable and can go on a bit. The rad does get hot. An extension was added from the pipes adjacent to this rad to feed a rad in the room below although I'm not sure that is the problem.

I have bled the rad and it does release a bit of air when I do and it is the only rad in the system which collects air.

Do I have some air sitting in or near to this rad? Advice appreciated.

 

[gman76]

I had this issue with the first rad on the system, gurgled like mad & probably gained a quarter of its size in air over the course of a year. Solved by reducing the pump speed by one click. I think over pumping can induce air through the F&E pipe.
Maybe worth a try, mine functions silently now with no noticeable reduction in efficiency across the system & minimal air issues.