SQUARE D 9013FH pressure switch 105-135 psi 1 port unloader

Pressure Switch 9013FH 105–135 psi

The Square D 9013FH pressure switch controls air compressors within a factory-set range of 105 to 135 psi. It features a 30 psi differential and a 1/4 in FNPS port with an integrated unloader valve. Rated for NEMA 1 enclosures, it handles up to 2 hp at 120 V single-phase, 3 hp at 240 V single-phase, 5 hp at 240 V three-phase and 1 hp at 480 V three-phase. The DPST contact form provides standard on/off action for compressor motor circuits.

Installation Notes

The switch mounts via its 1/4 in FNPS port directly onto the compressor tank or manifold using standard pipe thread sealant. Manual Auto/Off lever allows local override without rewiring. Wiring connects to the DPST terminals for line and motor leads; ensure supply voltage matches the motor nameplate and the switch horsepower rating for that voltage. Common issues include debris blocking the pressure port, incorrect unloader line routing causing continuous bleed, and overtightening the port which can crack the housing.

Sustained Load Behaviour

Under continuous cycling the 30 psi differential reduces short-cycling compared to narrower ranges, lowering motor heating and contact wear. The NEMA 1 rating limits use to clean, dry indoor environments; moisture or dust ingress can degrade contact reliability over time. Contacts are rated for the listed horsepower values at the specified voltages; operating beyond those limits accelerates contact erosion and may cause welding. The unloader valve vents head pressure on each off-cycle, easing restart torque on the motor during frequent starts.