The control panel was turned off. Had been off for 2 hours. It suddenly started buzzing loudly for about 5 minutes. We had a really heavy thunderstorm at the time but no power cut. Any ideas as to why this happened? Is it safe to turn on again? I don?t know if this is a silly question but the rain was so heavy running down the outside wall where the outlet thingy for the boiler is. Could water have got in there and affected anything?