I have a glow worm fuelsaver mk11 and when the room stat and cylinder stat are satisfied and the valves close down i get a banging noise, i also have a back boiler plumbed into the same system that we use as an alternative (not both at same time) and this works ok without any noise, can you help?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.