Hi i wonder if anyone can help me. I have a Trianco Eurostar oil boiler i think its quite old, i did have it serviced 6 months ago when i moved in the heating engineer said it was in good working order. The flue pipe that comes out of the top is about 4" in diameter and goes into a 6" pipe the gap between the two seems to be packed with a kind of cement compound and a lump has fallen out. could anyone tell me if this is flue jointing compound and is it just a case of filling in the hole from where the piece fell out and is it safe to use the boiler before this is done.
thanks