This is tricky, because I last saw this movie on TV in about 1965. The central character, 'Mr Pastry', played by Richard Hearne, was a popular knockabout comic, still busy at that time, and I, as a child, welcomed any appearance by him on the television. He looked like a little old man with fluffy white hair and moustache, and a dark suit and hat.
As far as I know this was Mr Pastry's only feature film. The title refers to the huge boilers that are used to heat an office building, and Mr Pastry is the caretaker, who has looked after them all his working life. Trouble arises when the system is to be modernised, and oil heaters installed, meaning that the big old boilers will be scrapped, along with their loving caretaker.
I'm sure this film is full of slapstick and chases, but the only scene that remains in my mind is poor old Mr Pastry saying his good-byes to his boilers. They have names (one, I'm sure, is Bessie), and I think I remember the whole thing as being quite touching.
I also remember that it all turns out okay in the end. I hope this film is still intact somewhere, and someone sees fit to give it a TV airing one afternoon. It's a comedy about a changing world, and in 1965, it was shown at peak time in the evening, which just goes to show how the world continues to change.