SQUARE D 9013FH Pressure Switch 135-175PSI 4Port Unload

Air Compressor Pressure Switch

The Square D 9013FH pressure switch controls air compressor motors across a 135 to 175 psi range with a 40 psi differential. It offers four ports with 1/4 inch FNPS threads and an integrated unloader valve. The DPST contact form handles single-phase loads up to 1.5 hp at 120 V and 2 hp at 240 V, plus three-phase ratings of 3 hp at 240 V and 1 hp at 480 V. NEMA 1 enclosure suits indoor installations.

Industrial Maintenance and Small Shop Use

This switch suits technicians maintaining existing compressor systems that require the 135 to 175 psi factory setting and unloader function. It is not for buyers who need adjustable cut-in and cut-out pressures outside the 60 to 200 psi range or a different port count. Builders requiring NEMA 4 or higher ingress protection should look at other enclosures. Applications demanding electronic pressure sensing instead of mechanical actuation are not a match.

Verify Compressor Compatibility

Confirm the compressor motor voltage and phase match the listed horsepower ratings before ordering. Ensure the existing plumbing uses 1/4 inch NPT connections to suit the four ports. Check that the 135 to 175 psi operating window matches the tank and system design limits. The unloader valve requires a compatible discharge line for proper operation.