Air compressors can be used to blow out a sprinkler system. This method of winterization uses compressed air to remove most of the water from your sprinkler lines. This can help prevent cracks and breaks during deep freezes, which can occur when water is left inside supply lines and sprinkler heads. You must use an air compressor with a rating of at least 80 cubic feet per minute for this process to work properly.
Turn off the main water line. The main line is usually located inside the house or business and has a ball valve. Turn the ball valve 90 degrees to shut off the water.
Locate the vacuum breaker. It's usually brass and located directly above the sprinkler manifold.
Remove the black cap on the bottom of the two threaded bleed valves that are located on the side of the vacuum breaker.
Screw the 1/4-inch compressor quick connect into the exposed bleed valve. Turn the connector clockwise until it's tight inside the bleed valve.
Push the end of the air compressor hose onto the other side of the quick connect piece.
Unscrew the solenoid on the first sprinkler valve within the manifold. The solenoid is black and shaped like a cylinder.
Turn on the air compressor and allow it to fill to maximum capacity.
Turn both of the two ball valve handles on the side of the vacuum breaker so that they are in the open position. If you haven't turned off your sprinklers before, your valves are already open.
Pull the trigger on the air compressor hose and hold it until the entire compressor is emptied. You will hear and see water being blown out of the sprinklers on the first zone.
Allow the compressor to recharge fully and tighten the solenoid on the first zone.
Unscrew the solenoid on the next zone and repeat the compressor discharge process.