How Big Air Compressor To Blow Out Sprinklers

How Big an Air Compressor Do You Need to Blow Out Sprinklers?

Protecting your sprinkler system from winter freeze damage is crucial. Blowing out your sprinkler lines with compressed air is a common and effective method, but choosing the right air compressor is key. Using the wrong size can be inefficient, ineffective, or even damaging. This guide helps you determine the appropriate air compressor size for your sprinkler system.

Understanding the Factors Affecting Compressor Size

Several factors determine the size of air compressor needed for effectively blowing out your sprinklers:

1. System Size:

• Small Systems: For smaller systems (under 1/2 inch mainline, fewer than 10 zones), a smaller, portable compressor might suffice. Think 2-5 gallon tank capacity with a CFM (Cubic Feet per Minute) rating around 3-5 CFM @ 90 PSI.
• Medium Systems: Medium-sized systems (1/2 inch to 1 inch mainline, multiple zones) require a more powerful compressor. A 6-20 gallon compressor with a CFM rating of 5-10 CFM @ 90 PSI is generally recommended.
• Large Systems: Large, complex sprinkler systems (over 1 inch mainline, numerous zones) demand a significant air compressor. Consider a larger capacity compressor (20+ gallons) with a high CFM rating (10+ CFM @ 90 PSI). You might even need a professional-grade compressor for these systems.

2. Pipe Diameter:

Larger diameter pipes require more air pressure and volume to effectively clear water. This translates to a need for a compressor with higher CFM.

3. Desired Speed:

A larger compressor will complete the job faster. While a smaller compressor might work, it will take significantly longer and potentially lead to incomplete blowouts.

4. Air Pressure:

Aim for a minimum of 90 PSI (pounds per square inch). Higher pressure ensures the water is forcefully expelled from the lines, preventing freezing. Your compressor should be able to maintain this pressure during operation.

Choosing the Right Compressor: A Practical Approach

Instead of focusing solely on tank size, prioritize CFM (Cubic Feet per Minute) at 90 PSI. This is the crucial metric. A larger tank is helpful for extended use, but a high CFM rating is essential for efficient water removal.

Here's a simplified approach:

• Small system (under 10 zones): Look for a compressor with 4-6 CFM @ 90 PSI.
• Medium system (10-20 zones): Aim for a compressor with 6-10 CFM @ 90 PSI.
• Large system (over 20 zones): You'll likely need a compressor with 10+ CFM @ 90 PSI.

Remember: Always consult a professional irrigation technician for advice tailored to your specific system. They can assess your system's size, complexity, and recommend the appropriate compressor size to ensure a thorough and damage-free winterization.

Safety First!

• Always disconnect the power to your sprinkler system before starting.
• Use appropriate safety gear, including eye protection.
• Never work alone.
• Ensure adequate ventilation when operating the air compressor.

By carefully considering these factors and choosing the right compressor size, you can efficiently protect your sprinkler system investment and avoid costly repairs due to winter freeze damage.