Hi have a boiler mate 2000, problem is that the hot tap runs hot for 20 seconds than goes cold. Hve cheched the pump, have 240 volts on pump when tap is hot volts drop to 50 when the hot water goes cool. After it goes cool it stayes cool. Have tried the sensors and PCB. Gled tech think plate could be scaled up, but flow rate out of tap is constant, does not start fast then dies off. have put perm 240 v to pump live and water stays hot. could I have had a faulty newPCB?? or what else could it be??