Multihead G central heating pump

[Steve838]

Hi,

my boiler and central heating system seems to be running fine. Plenty hot water and heating. However, every few hours there is a loud hissing/vibrating noise coming from the pump on the water tank, it sounds like a build up of pressure.
I have turned the boiler off and on and it stops for a while.
I have been told the pump might just need bleed but really not sure.
Any suggestions?

 

[ianmcd]

Turn everything off then with a large screwdriver 1/4 turn of the large silver screw on the pump till all the air stops and water comes out then tighten back up, do not take the screw out, and that is a Grundfoss pump re badged for BG and they called it a multihead but a multihead is a different thing

 

[Steve838]

I will give it a try, I appreciate the advice.