Mars M43944 Low Pressure Switch 15/35 Psi

Product Description

The MARS M43944 is a low pressure switch rated at 15/35 PSI, designed to open on a fall in system pressure. This type of pressure control monitors refrigerant or fluid pressure within a system and interrupts a circuit when pressure drops to the cut-out threshold, protecting compressors and equipment from operating under unsafe low-pressure conditions. HVAC technicians install this switch as part of refrigeration and air conditioning systems where low-side pressure monitoring is required. Its open-on-fall action means the switch contact opens as pressure decreases to the set point, providing a direct safety cutout signal to the control circuit.

This low pressure switch is suited for residential and light commercial refrigeration and air conditioning applications. It is typically installed on the low-pressure side of a refrigerant circuit, wired into the compressor control loop or safety chain. Technicians use this switch when replacing a failed OEM pressure control or when adding low-pressure protection to a system. The 15 PSI cut-out and 35 PSI cut-in settings make it appropriate for common refrigerant applications where those pressure thresholds match system operating parameters.

Key Features

• Opens on pressure fall, protecting equipment from low-pressure operation
• Cut-out at 15 PSI, cut-in at 35 PSI
• Designed for low-side refrigerant pressure monitoring
• Interrupts control circuit to prevent compressor damage under low-pressure conditions
• Compact switch form factor suitable for standard refrigeration control wiring

Compatibility

Designed as an OEM-style replacement low pressure switch for residential and light commercial air conditioning and refrigeration systems requiring 15/35 PSI open-on-fall pressure control.

Installation Notes

Installation should be performed by a licensed HVAC technician or refrigeration mechanic. De-energize the system and recover refrigerant per EPA Section 608 requirements before disconnecting any refrigerant-side fittings. Verify that the system refrigerant and operating pressure range are compatible with the 15/35 PSI switch settings before installing. Follow all applicable mechanical and electrical codes, including NEC guidelines for low-voltage control circuit wiring.

Technical Specifications

• Switch Type: Low Pressure, Open on Fall
• Cut-Out Pressure: 15 psi
• Cut-In Pressure: 35 psi
• UPC: 685744439448

Standard Information

• Brand: MARS
• Manufacturer Part Number: M43944