Hi, This protherm boiler type 80 EC was working OK. I shut it down for about 1 month to carry out some work on the house.
now it only runs with the covers removed. If I remove the front cover, under that is a metal plate that fits over the burner unit.The boiler works with this cover removed but as soon as you fit this panel the gas supply shuts off. There is a pressure switch at the top of the chamber which has a tube going to the flue. This pressue switch appears to be the problem
Overriding this switch brings the boiler back on. Any suggestions on what might be causing this problem?. Many thanks John.
Check the flue isn't blocked by something daft like a bird's nest before you go changing the switch - it's an air pressure switch that uses a diaphragm to sense that the fan is running. It's also worth checking that the sense tubes are not split or blocked, and that the venturis (the bits where the sense tubes enters the fan) aren't blocked or damaged.