Question
I have a 4our zone irrigation system run by a Rainbird programer.  Pump started to cycle so I replaced the pressure tank and it still cycled. I noticed free running water at first zone so i replaced the solenoid. Pump still cycles.  Please advise

Answer
Hey Kevin, normally if a system runs off a pump, it will have a relay (switch) that is wired to the controller. When the controller is scheduled to run a zone (valve) the controller also opens the relay to start the pump. Is your pump wired to the controller? To tell, look in back of the controller where the wires are hooked to the terminal strip. If you have a wire hooked to either a terminal marked PS or pump start, or MV or master valve, then the pump is probably wired to the controller. If it is, then check and see if the controller is sending out a signal all the time, by checking the voltage across the pump start terminal and the common terminal. If your getting 24 + or - volts, then the controller is causing the problem. The only time you should get a voltage reading across the pump start terminal, is when the controller has turned on a zone. If you're not getting a voltage reading on this terminal, but the pump is still turning on, then I would check the relay itself, it could be stuck on all the time. Good luck and let me know if I can be of anymore help. Thanks and have a great day.