Question
My Sta-rite water pump is constantly running when my Rainbird ESP-ME controller has power to it even when the knob is turned to off. Then only way I can get the water pump to cut off after watering is to flip the circuit breaker supplying power. If I unplug the power cable going to the Rainbird display the water pump turns off. If I do not turn the pump off it builds up pressure and blows the pvc pipes off and spews water. I have 4 zones and only 4 zones are programmed. We had some lightning storms recently and had surge protectors pop. I don't know if that has anything to do with it. Please help

Answer
Hey Michael, so normally when a sprinkling system is hooked to a pump, the controller turns the pump on via a relay switch. In the back of the controller on the terminal board, you will either see a wire hooked to the PS (pump start) or MV (master valve) terminal. Your problem, is that either the controller is sending a 24 volt charge to the relay switch all the time, or the relay switch is stuck in the "on" position. If the controller is working properly, the charge is sent only when one of the valves is running. When the controller is not running a valve, the charge is not sent to the relay switch. Disconnect the wire from the terminal board (either the PS or MV terminal). Now with the controller in the "off" position, take a volt/ohm meter, and take a reading with the negative lead to the (C) common terminal, and the positive lead to the MV or PS terminal, and see if you are getting a reading of between 22 to 26 volts. If you are, then the controller is defective and needs to be replaced. If the only time you get a reading on the MV or PS terminal, is when you turn a zone on, then the controller is fine, and the relay switch is defective, and needs to be replaced. Good luck and have a great day.