Hi John, Contactor is in the back next to the inverters and logic. If you follow the wires from the emergency stop they go to it. Worth taking big connections off and removing top of contactor to clean as they do have a habit of sticking for no apparent reason. Pump motor current offset is slightly more worrying though but may be water ingress in logic or pump inverter. Point a little fan heater at back panel for a few hours and cross your fingers! :-)