Recent content by adp240

probably ok however you may find it difficulty to drain the pipe without vent from the boiler. I would not do that.

The expansion vessel may have lost all its pressure and may need to be recharged. More likely though is that the diaphragm in the expansion vessel may have a puncture. This would be why it took so long for you to top up the system when the pressure was lost. If this is the case, the expansion...

likely the leaking is in the water-to-water heating exchanger. when hot water is running, water leaks from primary flow to DHW and the pressure drops to 0.5 Bar. Once hot water tap is closed, the boiler will be filled via the leaking hole to main cold water pressure.