If you have drained down you heater for the winter, when you recommission you may find water passing down a clear tubeconnected to a red connection at the top of the heater and going down through the floor outside the van.
This connection is a non return valve designed to let air in when you drain the system, but which may "jam" in the open position due to very hard water drying out as is the case here in Somerset.
The pump will then run often trying to keep up the pressure in the system.
Before tearing the whole system apart, try a few sharp blows in the "red block" with the handle of a screwdriver with the pump enabled i.e the system pressurised. Thismaywell do the trick
This connection is a non return valve designed to let air in when you drain the system, but which may "jam" in the open position due to very hard water drying out as is the case here in Somerset.
The pump will then run often trying to keep up the pressure in the system.
Before tearing the whole system apart, try a few sharp blows in the "red block" with the handle of a screwdriver with the pump enabled i.e the system pressurised. Thismaywell do the trick