central heating noise

[denis]

I changed the pump today thinking that the continuous droning noise was the pump.

It has made a difference but not solved the problem entirely.

Before the pump change noise wasevident with the water on and the rads.

After the pump change water only is quiet, but the heating on and there's noise.

Is it the motorised valve? it appears to be making a noise almost continuously when the heating is on.

Any advice, it's driving me mad...thanks

 

[ChrisR]

Put a big stick's end on eg the pump, and the other end to your ear. Try different bits until you identify the source