Hi my name isXXXXX could be the programmer but I would rule out the motorised valve first as this is more likely to fail than the LP722. the valve has 2 circuits one is only live when the thermostat calls for heat, this runs the motorised valve. the other circuit is always live and operates a micro switch that runs the boiler.
hi Brian. I have taken the lp722 off the wall, turned down the thermostat, switched off the boiler and put the fuse in and it still blows the ring main. What do you think I should try next?
Hi I need you please, to go to the motorised valve and disconnect it from the wiring box just make sure you make a note of what colour wire goes where as I think this is your problem
How does your controller connect to the ring main breaker. Is it via a switched fused spur. if it is you will need to disconnect this and see if it trips. it sounds like you have a short in the wiring to the controller. Or from the ring main to the switched fused spur.
Hi no problem. Turn off the power at the main breaker and disconnect the wires leading to the controller from behind the fuse socket. it should only be live neutral earth.