How to Winterize a Hunter Sprinkler System

A Hunter irrigation system includes underground sprinklers that pop up to water your lawn after the zone valve that controls them is activated either manually or by a connected timer. As winter approaches, the entire system requires drainage to prevent damage. If temperatures drop below freezing, residual water left in the pipelines, sprinklers and valves freezes and expands causing breaks in the system. Winterize your system inside and out to protect your investment.

Air compressor

Male air compressor fitting

Air compressor fitting adapter

Locate the main water shutoff valves inside your home and turn them off by laying the ball valve lever perpendicular to the main water line.

Locate the main drain valve, which is close to or on the main line shutoff valve, and place a bucket beneath it. Twist the valve open and allow the water to drain into the bucket completely. Leave the empty bucket beneath the open drain valve for the duration of winter.

Activate the compressor and allow it to pressurize to approximately 40 to 80 pounds of pressure, not to exceed 80 pounds.

Locate the pressure vacuum breaker on the exterior of the house. Insert a flat-head screwdriver into the screws of the miniature ball valves, which jut out of the side of the valve, and twist them open so that the groove of the screw lies parallel with the miniature ball valve. Water drains from the valves. Lay the levers of the breaker's larger ball valves parallel to the pipe to open them. Unscrew the drain cap at the bottom elbow of the breaker and allow the water to drain. After drainage stops, move the levers of the larger ball valves perpendicular to the pipe to close them.

Twist the air hose fitting and connected adapter onto the hose bib or outlet drain, located between the irrigation system and the breaker.

Locate the Hunter zone valve housing boxes in the ground. Lift the lids, and turn the solenoid of the first zone valve counterclockwise to open it.

Open the compressor valve gradually. Air shoots through the sprinkler heads of the first zone sprinklers. First, water shoots out, followed by an airy mist. Allow the compressor to operate for two minutes and then shut it off. As the compressor recharges, twist the first zone valve solenoid clockwise to close it and open the second zone valve solenoid. Repeat the blowout process for all zones at least twice.

Unhook the compressor hose from the hose bib and twist both the miniature ball valves and larger ball valves of the breaker to a 45-degree angle. Open all zone valve solenoids and the system end valve inside the zone valve box to prevent future pressurization.

Twist the dial of the Hunter controller to the "Off" position to shut it down for winter.

Wrap exposed outside lines in towels for extra insulation.

Avoid standing over or near pipes, sprinkler or valves during the winterization process. Wear safety goggles.