Question
I have a rainbird time clock and the pump will not come on by the clock,it only comes on by an on and off switch. Why?

Answer
Hey Verne, I hope this helps. For a pump to run off a time clock, it must have a 24 volt relay (switch) hooked to the pump. Do you have a 24 volt relay ? It sounds like you have a 110volt or 220 volt pump, that is turned on by either a 110volt or 220 volt switch. If you have a 24 volt relay installed, you can run a common wire from the common terminal on your time clock, and a hot wire that will hook to either the pump start terminal or MV(master valve) terminal on the time clock. Check your controller and make sure it has a master valve or pump start terminal, not all time clocks have this feature. I would suggest getting an electrician to hook up a 24 volt relay, if you do not have one now. Good luck and have a great day.