Wiring the valves to the controller is the last link between the lawn and drip irrigation system and the electronic irrigation controller which will operate the irrigation systems automatically.

In previous blogs we have discussed at length the irrigation controller, how to program it, and some of its special features. We have also blogged about the valve manifold. Now, we must discuss connecting the two, which means wiring the valves to the controller.

Before the job even begins, Details Landscape Art, a designer and builder of fine residential gardens in Sonoma County, does its homework. We are thinking about wiring the valves to the controller ahead of time. We figure out the most convenient water source for the location of the valves, and the optimum location for the controller, hopefully near an existing source of electricity. We also want to ensure that there is a clear path between the valve manifold and the controller location to run the connecting wires. Sometimes we are able to run wire directly along the perimeter of the house and drill a hole through an exterior wall into the garage, which is our preferred placement of the controller. Sometimes we are able to go through an exterior vent, under the crawl space of the house, and up through a garage wall. Sometimes there is a concrete walkway or driveway, which is a barrier. If so, we look for a ‘chase’ or sleeve through which we can run the wire. If we are pouring the walkway or driveway we are sure to insert our own chase. If all else fails, and there is no chase and no other route from the valves to the indoor controller, we may install an outdoor Raindial HR6100 near the valves. If there is no electrical outlet to plug the outdoor outlet into, we need to have an electrician install one. We frequently have the electrician simply locate an inside outlet, pull it out from the interior wall, drill through to the outside, and ‘piggy back’ a new outlet for exterior use. We ask him to place a large bubble cover on the outlet to keep it watertight.

If there are four valves, we would buy 6-strand wire, which is a cable with six color-coded wires in it. If there are five valves, we would buy 7-strand wire. The extra strands are for the ‘common’ wire, and for a possible future additional valve. The wire is then run from the valves to the controller leaving a little slack on both ends.irrigation system controller

Each valve is equipped with a solenoid, a coil of insulated wire wound on a rod-shaped form, which has two wires that enable us to connect to the controller. One of the wires is a ‘common’ wire, and one wire is ‘hot’. We gather one wire from each valve (it doesn’t matter which one), and connect them all together along with the white wire from the 6-strand wire going to the controller. The white wire at the controller end is connected to the COM screw on the controller board. The first valve’s hot wire is connected to a colored wire from the 6-strand. If red is used, then the corresponding red end is wired to ‘1’ on the controller board. The second valve’s hot wire is connected to a second colored wire, and the corresponding color is connected to ‘@’ on the controller…and so on, until all the valves are wired. The wire connections on the valve end are secured using watertight wire nuts, and the whole wire assembly is taped together.

Wiring the valves to the controller is now complete, and the controller may be programmed.