Just been to a customer for an electrical issue, they asked if I knew any thing about boiler, I don't so I was hoping one of you guys could assist... They say that the red light occassionally flashes, they reset the boiler everything ok for a couple of days then red light flashing again... What causes the red light to flash anyway? 1. low water pressure? 2. poor gas supply? 3. Faulty PCB, bad connections? 4. A safety issue? ????