I have a Vaillant Sine 18 which has worked flawlessly for more than 18 years. I was in hospital for a week and when I came home I had HW but no CH. When I flicked the programmer the main burner came on for 30 secs or so then went back to pilot.
I checked the flowswitch (diverter valve) at the back of the combi and it was really hot at the top and cold at the bottom. I have taken the valve out and removed the wax capsule (and a lot of gunge in the housing). I boiled up the wax capsule and the pin in the middle moves about 6 or 7 mm upwards.
Thinking that means it was actually working I rebuilt the flowswitch and refilled the system and lit the pilot.....
As soon as I take my finger off the green button the boiler starts the pump and I can hear water flowing through the system. Turning on a hot tap or switching to CH does not light the main burner !
Any suggestions ? I have tried pressing the red button to kill the pilot and I can hear a click after about 20 secs or so. Have also pressed the overheat black button but it is very soft and not convinced it is doing anything....
I checked the flowswitch (diverter valve) at the back of the combi and it was really hot at the top and cold at the bottom. I have taken the valve out and removed the wax capsule (and a lot of gunge in the housing). I boiled up the wax capsule and the pin in the middle moves about 6 or 7 mm upwards.
Thinking that means it was actually working I rebuilt the flowswitch and refilled the system and lit the pilot.....
As soon as I take my finger off the green button the boiler starts the pump and I can hear water flowing through the system. Turning on a hot tap or switching to CH does not light the main burner !
Any suggestions ? I have tried pressing the red button to kill the pilot and I can hear a click after about 20 secs or so. Have also pressed the overheat black button but it is very soft and not convinced it is doing anything....