Hi
Hope someone can help!
My heating is timed to come on twice a day, and after 15 mins of start up
it sounds as though we have a steam train running through the house followed by a loud clicking form the boiler (Glow worm spacesaver).
this only hapens for about five-ten seconds and then everything seems to work fine although sometimes downstairs rads can take up to 20 mins to get warm.
This only seems to happen when starting from cold, if we sometimes use the boost for that little extra time there doesn't seem to be a problem.
Boiler thermostat has been checked and is working ok so i don't think it's a boiling problem, although it sounds like a kettle,looking through the spy hole at the actual time the burners are off.
Thanks