Air Compressor Troubleshooting and Quick Fix, pressure switches.
⚙️ Fixing & Maintaining Air Compressor Pressure Switches: A Practical Guide
Your air compressor’s pressure switch is the brain behind its operation—controlling when the motor starts and stops based on tank pressure. A faulty or misadjusted switch can lead to short cycling, pressure drops, or even system failure. Fortunately, maintaining and adjusting it is straightforward with the right approach.
🔍 What Is a Pressure Switch?
A pressure switch monitors the air pressure inside the tank and activates or deactivates the compressor motor accordingly. It’s typically mounted near the tank and wired to the motor and power supply.
We recommend Hubbell’s Furnas pressure switches, known for their durability and precision. You can explore their product line here.
🛠️ How to Fix and Maintain a Pressure Switch
1. Safety First
- Turn off the compressor and unplug it.
- Bleed off all air from the tank using the drain valve.
- Confirm zero pressure before proceeding.
2. Inspect the Switch
- Remove the switch cover (usually held by a single screw).
- Check for signs of corrosion, burnt contacts, or loose wires.
- Clean contacts gently with a fine emery cloth if needed.
- Tighten any loose terminals.
3. Test the Pressure Range
- Plug in the compressor and let it run.
- Observe the cut-in and cut-out pressures (when the motor starts and stops).
- Compare these to the manufacturer’s specs—usually printed on the switch label.
🔧 How to Adjust Pressure Settings
Most Furnas-style switches have two adjustment screws:
🔹 Main Pressure Adjustment (Cut-Out)
- This screw adjusts both cut-in and cut-out pressures simultaneously.
- Turn clockwise to increase pressure range.
- Turn counterclockwise to decrease.
🔹 Differential Adjustment (Cut-In)
- This screw adjusts the difference between cut-in and cut-out.
- Increasing differential means the compressor runs longer before restarting.
- Decreasing differential shortens the cycle.
✅ Step-by-Step:
- Locate the screws under the switch cover.
- Mark current settings (use a marker or take a photo).
- Turn the main screw slowly—¼ turn at a time.
- Test the system after each adjustment.
- Fine-tune the differential if needed to avoid short cycling.
🧼 Ongoing Maintenance Tips
- Check the switch monthly for dust, moisture, and wear.
- Replace damaged wires or terminals immediately.
- Keep the switch dry—use a moisture shield if operating in humid conditions.
- Replace the switch if it fails to respond to pressure changes.
🔗 Trusted Source: Hubbell Furnas
For reliable replacement switches and technical specs, visit Hubbell’s Furnas product page. Their switches are compatible with most industrial and commercial compressors and offer consistent performance under demanding conditions.
Need help choosing the right switch or troubleshooting a specific issue? Drop us a message or visit our Parts Store for expert support and fast shipping.