Cleveland Controls DFS-221 Air Flow Switch, SPDT, 120-277Vac, 1/4″ Barbed

Description

Cleveland Controls DFS-221 Air Flow Switch Overview

The Cleveland Controls DFS-221 is a precision-engineered SPDT (Single-Pole, Double-Throw) air flow switch designed to reliably detect air movement in HVAC, combustion, and ventilation systems. Fixed to operate on pressure rise at a setpoint of .05″ ± .02″ w.c. (water column), this switch provides accurate, repeatable performance for proving fan or blower operation before allowing downstream equipment to energize — a critical safety and efficiency function in modern air-handling systems.

Key Features

• SPDT switching action for flexible normally-open or normally-closed circuit configurations
• Fixed operate point: pressure rise at .05″ ± .02″ w.c. for consistent, factory-set performance
• Wide voltage compatibility: 120–277Vac for use across standard commercial and residential electrical systems
• 1/4″ barbed connections for quick, secure tubing attachment
• Maximum pressure rating: 1/2 PSI, suitable for low-pressure air and combustion by-product applications
• Compatible with air or combustion by-products that will not degrade silicone — safe for use in furnace, boiler, and burner proving applications

Specifications

• Model: DFS-221
• Switch Type: SPDT (Single-Pole, Double-Throw)
• Operation: Fixed, activates on pressure rise
• Setpoint: .05″ ± .02″ w.c.
• Voltage: 120–277Vac
• Connection Size: 1/4″ barbed
• Maximum Pressure: 1/2 PSI
• Media Compatibility: Air or combustion by-products that will not degrade silicone

Typical Applications

• Fan and blower proving in air handling units (AHUs)
• Combustion air proving for furnaces, boilers, and burners
• Draft inducer and induced-draft blower verification
• Safety interlock circuits requiring airflow confirmation before ignition
• Commercial and residential HVAC control systems

Why Choose the Cleveland Controls DFS-221?

Cleveland Controls has a long-standing reputation for dependable pressure and flow sensing devices used throughout the HVAC and combustion industries. The DFS-221’s factory-fixed setpoint eliminates field calibration, reducing installation time and the risk of improper adjustment. Its broad 120–277Vac operating range makes it a versatile drop-in solution for a wide variety of system voltages, while the 1/4″ barbed connections ensure a fast, leak-free hookup to standard sensing tubing.