How to Fix Sprinkler System Freezing

Plug in the air compressor to the power outlet, and allow it to charge thoroughly.

Turn off the water at the master shut off valve with your hand or a wrench. This valve is often located in the basement, utility room or crawl space.

Open the hose bib or drain on the backflow preventer with your hand or a wrench to drain the system. If the backflow preventer is located inside, have a bucket handy to catch the water.

Unplug the air compressor and turn the pressure-regulating gauge to between 50 and 60 PSI. A higher PSI could blow out your system.

Connect the compressor hose to the blow-out adapter attached to the main shut off valve

Turn on each zone on your sprinkler control pad. Start with the zone at the highest elevation point. For example, select zone 10. Allow the sprinklers to run at zone 10 until the water turns into mist, and then finally nothing but air comes out. Shut the zone off on the controller.

Put on protective eyewear. The compressor can cause excessive pressure which could result in flying debris.

Turn on the compressor. The sprinkler heads in that zone should pop up. If they don't, slowly increase the PSI up to 80 until they do. Shut off the compressor.

Select the next zone and repeat the process of relieving excess water and blowing air from the compressor for each zone. Then rerun each zone a second time to make sure all the water and air is removed from the system.

Turn the sprinkler controller to the "Off" position.

Open all drains on the sprinkler system and leave them open all winter. Leave the ball valve or drain on the backflow preventer at a 45-degree angle.