SQUARE D 9013FH Pressure Switch 135-175 PSI Unload

Compressor control switch

The Square D 9013FH pressure switch manages air-compressor motors by opening and closing contacts at factory-set cut-in and cut-out pressures of 135 and 175 psi. It carries a DPST contact form rated for single-phase motors 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. The 40 psi differential and 60 to 200 psi adjustable range suit typical workshop compressors. NEMA 1 enclosure rating indicates indoor use only.

Installation checks

Verify that the compressor tank port accepts a 1/4 in FNPS thread and that the unloader line matches the 1/4 in compression fitting on the switch. Confirm the motor voltage and phase match one of the listed horsepower ratings so the contacts are not overloaded. Ensure the wiring can accommodate a DPST switch action and that the mounting location meets the NEMA 1 indoor requirement. The switch uses standard action with no manual lever, so automatic pressure cycling is the only control method.

Build and daily use

The housing carries a NEMA 1 rating, meaning it is not sealed against water, oil spray or outdoor exposure. The single 1/4 in FNPS port threads directly into the tank fitting, while the integrated unloader port uses a 1/4 in compression connection for the bleed line. DPST contacts break both lines of the motor circuit for positive shut-off. Factory pressure settings of 135/175 psi are fixed unless the adjustment nuts are turned within the 60 to 200 psi range.