Mars mars-43306 Condenser Fan Cycling Switch Spst

Product Description

The MARS mars-43306 is an auto-reset condenser fan cycling switch designed to control condenser fan motor operation based on refrigerant pressure. Wired as a single-pole, single-throw (SPST) configuration, it closes on a rise in pressure, energizing the condenser fan when system head pressure climbs to the set point and de-energizing it as pressure drops. The switch resets automatically, eliminating the need for manual intervention after a pressure event. Licensed HVAC technicians install this switch as part of standard condenser fan cycling control strategies on air-cooled refrigeration and air conditioning equipment.

This switch is suited for use in commercial refrigeration systems, rooftop units, and air-cooled condensing units where head pressure management is critical to system efficiency and compressor protection. It is typically installed in the high-side refrigerant circuit and operates within a pressure range of 250 to 350 psi. Applications include both new installations and field replacement of failed or out-of-calibration cycling controls in low-ambient or head-pressure control systems.

Key Features

• Auto-reset operation eliminates manual reset after pressure normalization
• SPST close-on-rise configuration energizes condenser fan on rising head pressure
• Pressure operating range of 250 to 350 psi for high-side circuit control
• Supports head pressure control strategies in air-cooled refrigeration and AC systems
• OEM-style replacement design for field service and new installations

Compatibility

Designed as an OEM-style replacement condenser fan cycling switch for air-cooled refrigeration and commercial air conditioning condensing units requiring a high-side SPST close-on-rise pressure control in the 250 to 350 psi operating range.

Installation Notes

Installation should be performed by a licensed HVAC or refrigeration technician holding the appropriate EPA Section 608 certification. Recover or isolate refrigerant and relieve system pressure before removing or installing any pressure-actuated control. Follow NEC requirements for low-voltage control wiring connections to the switch terminals. Verify that the replacement switch pressure range matches the system design before returning the unit to service.