Hi, Onec again i'm having trouble with my boiler. First i had heating but no hot water, anyway i called the usual guy out this time he thinks it was a circuit board fault. He has today changed two boards in the control panel. It was working when he left so thought it was ok, came to wash up turned hot water tap on and it ran cold, checked boiler and the orange light was not on and the boiled had failed to light. I switched it to central heating, waited 3/4 mins it sounded as if it had switched over to CH but again failed to light. The fan/grundfos pump are running. The slide switch to select timer,off, or constantly on doesn't seam to be working. He's coming back tomorrow, can you offer an advise on what he should be checking