by BriJo »
Thu Jan 08, 2009 5:19 pm
Thank you for responding.
It is a Glow Worm Ultimate, I think system boiler (has a water cylinder pump and diverter valve.) I am not able to get it to make the noise when the system is up and running and at room temperature, during the day. However, It seems to be happening when heating up first thing in the morning and after about 1/2 an hour the pipes above the boiler start making the noise.