Compressor Starts Then Immediately Stalls
Why Your Compressor Starts... and Then Quits
It’s one of the most annoying compressor problems: the unit powers up, starts running, and then shuts right back down. Whether you’re using a reciprocating compressor, a portable rotary screw, or a stationary rotary screw, this issue usually comes down to power, load, or airflow problems. Let’s walk through what to check based on your compressor type.
If You Have a Reciprocating or Portable Rotary Screw Compressor
When these types of compressors stall out seconds after startup, it’s usually something electrical or mechanical: things you can troubleshoot quickly without pulling the manual.
Start Here:
- Breaker or Wiring Issues – A weak power supply or loose wiring may allow the motor to start, but not stay running.
- Motor Overload – Overheating or an old capacitor could trip the motor off right after startup.
- Check Valve Malfunction – If the check valve is stuck, built-up air pressure may prevent the unit from running properly.
- Belt Slippage or Seized Pump – The motor may start but can't overcome mechanical resistance from the drive system.
Quick Fixes:
- Verify tight electrical connections and solid voltage at the source.
- Let the motor cool and press the reset button (if equipped).
- Inspect and clean the check valve and replace if needed.
- Inspect belts and manually rotate the flywheel to check for pump lock-up.
If You Have a Stationary Rotary Screw Compressor
On rotary screw compressors with electronic controllers, stalling after startup is often a sign that something is stopping the motor from staying engaged under load.
What to Check:
- Controller Alarms – Look for alarms related to phase loss, overloads, or motor temperature.
- Incorrect Rotation – Especially after installation or maintenance, check that motor rotation is correct. Reverse rotation can trigger auto shutdowns.
- Low Voltage or Phase Imbalance – These can cause the drive or starter to drop the motor as a protective measure.
- Inlet Valve or Load Solenoid Sticking – A jammed valve may prevent the unit from loading properly and cause it to stall.
What You Can Do:
- Review the last few fault codes on the controller.
- Verify incoming power with a multimeter and check all three phases.
- Check for correct rotation and rewire if needed.
- Inspect the load/unload solenoid and the inlet valve for sticking or failure.