How to Blow Out Sprinklers

In areas where the frost level extends to your sprinkler pipes, blowing out sprinklers prevents water from freezing in your pipes and rupturing them. A mistake in blowing out sprinklers may result in sprinkler heads shooting like self-propelled rockets, busted up pipes or air compressor oil entering your drinking water. Read on to learn how to blow out sprinklers.

Instructions

1. Shut off the water supply to your sprinkler system and open the drain on the supply line. After the supply line drains, close the drain.

2. Get an air compressor with the right amount of cubic feet per minute. Most home sprinkler systems need at least a 50 cubic feet per minute air compressors. Professional use 125 cubic feet per minute for pipes up to 3 inches in diameter and an air compressor with 250 cubic feet per minute for anything larger.

3. Remove the back flow preventer located after the irrigation shut off valve and connect the air compressor to the back flow preventer rise. Make sure the air doesn't pass through the pump or the back flow preventer or damage may occur.

4. Open the last valve or the valve at the highest elevation. Close the rest of the valves.

5. Turn on the air compressor and monitor the temperature and the pressure. If the air gets too hot it melts the pipes. Don't let the pressure exceed 50 PSI. Stop every two or three minutes and allow the air compressor to cool before continuing.

6. Run the air compressor until only air exits the valve. Turn the air compressor off, close the valve and open the next valve in line.

7. Repeat Steps 5 and 6 for each valve. You may need to cycle through the entire system again starting with Step 4 before you turn off the air compressor and put the back flow preventer back in place.

Tips & Warnings

• Rent an air compressor rather than buying one.

• Make sure you turn your sprinkler system off at the controller when you finish blowing out sprinklers.

• Always have one valve open when you blow out the sprinkler system.