having replaced the three way valve and renewing the water pump and both isolation valves, my system worked, for a fortnight.
It is again refusing to power-up despite the manual fire-up procedure being followed...
Turnining the three way manually has no effect.
Running the hot tap does spark up the pilot light.
It is a Potterton 40F.
When I press the pilot light trigger button, I can hear the boiler go 'Whhooo'- is it haunted? LOL!
The boiler front face gets hot to the touch. Could it be an internal stat problem?
The system is well bled too.
All help gratefully accepted.
Johnna