How to Install an Irrigation Controller When There’s a Pump

When your irrigation system uses a pump, installing the controller is typically a little more involved. There are a number of steps you’ll need to follow to ensure that the controller can safely and reliably activate the pump.

1. Choose the Right Controller

Select an irrigation controller that has a built-in pump start relay.  A pump start relay is an electrical device that allows your irrigation timer to communicate with the pump. This device is imperative when you are using a pump to supply water to your irrigation system. Pumps are built to use normal household currents; the relay changes the irrigation timer to normal household voltage. 

2. Mount the Controller

Before working with any wiring, shut off the electrical supply to the pump and controller. Install the irrigation controller in a convenient, sheltered location. This can either be indoors or in a weatherproof outdoor enclosure. Make sure it’s close enough to run control wires to both the valves and the pump relay.

3. Install the Pump Start Relay

Mount the pump start relay near your pump’s power source, connecting the low voltage and high voltage wires. Low-voltage wires connect to the controller’s pump or master valve terminals. High-voltage wires connect to the pump’s motor circuit. Connect the low-voltage pump start relay wires to the controller. Oftentimes, the manufacturer’s wiring diagram with provide guidance. After that, you can wire your irrigation valves to the controller as you normally would.

4. Test the System

Restore power, then run a manual test of each zone. The controller should trigger the relay, the pump should start, and water should flow to the active zone. You can set your watering schedule according to your landscape’s needs. The controller will now automatically start the pump and run each zone at the programmed times.

As a reminder, a sprinkler timer with a pump start relay is only required if your irrigation system relies on a pump to draw water from a well or pond. A municipal water system already provides the necessary water pressure, so your controller can likely operate without one. Ponds and wells don’t have any inherent pressure, so a pump is needed to draw the water and pressurize the system.