Problem
Boiler fires up on Central Heating Mode, Pump runs and system heats up.
Boiler reaches temperture and thermistor shuts boiler burner down.
Pump runs on, then..
Pump and boiler shut down. for no reason! (approx 45 seconds after boiler gas goes off)
Boiler gradually overheats as there is nowhere for the water to go.
Boiler pushes hot water and steam through Pressure Relief Valve.
Boiler cools down and once recharged to 1 Bar starts all over again.
The Boiler works fine on Hot Water Mode, and has done all summer
Its as if the boiler goes to sleep whilst trying to heat the system up, then starts to come back on and go through the same actions again.
Boiler was installed in 1999 and has been serviced annually
Any ideas out there please
Boiler fires up on Central Heating Mode, Pump runs and system heats up.
Boiler reaches temperture and thermistor shuts boiler burner down.
Pump runs on, then..
Pump and boiler shut down. for no reason! (approx 45 seconds after boiler gas goes off)
Boiler gradually overheats as there is nowhere for the water to go.
Boiler pushes hot water and steam through Pressure Relief Valve.
Boiler cools down and once recharged to 1 Bar starts all over again.
The Boiler works fine on Hot Water Mode, and has done all summer
Its as if the boiler goes to sleep whilst trying to heat the system up, then starts to come back on and go through the same actions again.
Boiler was installed in 1999 and has been serviced annually
Any ideas out there please