How To Install A Start Relay Box


Read your manual for installation, operation, and safety information. This guide neither supplements nor replaces the Owner’s Manual.

How to Install a Lawn Sprinkler Pump Start Relay Box
The pump start relay box is needed to control the pump so that you can turn the pump on and off at will. The relay box is often connected to a device that can be programmed for automatic sprinkler system operation.

Cost (0-5 scale): 2
Difficulty (0-5 scale): 2

Items Needed:
• Pump
• Wire
• Start relay box
• Wire strippers
• Screwdriver
• Hammer
• Wire nuts

Step One – Mount the Pump Start Relay Box
Find a location to mount the pump start relay box after turning the power off at the breaker box. Mount the pump start relay box out of direct sunlight, at least 12 feet away from the sprinkler controller. Attach the mounting clips to the back of the pump start relay box with the provided screws. Remove the cover of the pump start relay box. Remove the appropriate knockout plugs with a screwdriver and hammer. Attach the pump start relay box to the wall with mounting screws.

Step Two – Make the Wiring Connections
Strip the power, pump and timer wires with wire strippers. Leave 3/8 inch of exposed bare wire on each wire. Run the wires into the pump start relay box. Use wire nuts for each of the following connections:
Connect the L1 pump wire to the L1 output wire.
Connect the L1 power wire to the L1 input wire.
Connect the L2 pump wire to the L2 output wire.
Connect the L2 power wire to the L2 input wire.
Connect the remaining wire from the pump to the remaining wire from the relay box.
Connect the black wire to the 24-volt wire outside the box.
Connect the white wire to the 24-volt wire inside the box.
Check the wiring against the manual that came with the pump start relay box to make sure all wires are attached correctly.

Step Three – Complete Wiring and Test System
Re-attach the cover to the box. Tighten the screws snugly - avoid breaking them. Connect one controller wire to the pump terminal and the other wire to the common terminal. Turn the power back on before turning on the water and the sprinkler system should operate as programmed.