I have a Ideal boiler combi, and the lcd display is blank and there is a on/off switch at the side of it and another box with a green and red light and when you switch on the green and red light flash and goes out and nothing is displaying on the lcd is it the boiler or the thermostat switch at the side of the boiler

trevor mercer, August 2009

sounds like you have an isar, the fault could be caused by just about anything as they are not very reliable in my experience. sounds like the main pcb or user control pcb may be at fault, but get a qualified engineer to have a look.

Ian, August 2009