The Cleveland Controls DFS-301-112 is a dependable SPDT air flow switch engineered for reliable detection of air movement and combustion by-products in HVAC and combustion systems. Designed to operate on pressure rise, this switch provides a fixed trip point that makes installation and commissioning straightforward — no field calibration required.
How It Works
The DFS-301-112 senses differential air pressure through its 1/4″ barbed connections and actuates its SPDT output contact when pressure rises to the factory-set threshold. This makes it ideal for proving airflow in furnaces, air handlers, draft inducers, and combustion equipment before allowing ignition or continued operation — a critical safety interlock in modern HVAC systems.
Key Specifications
- Switch Type: SPDT (Single Pole, Double Throw)
- Operating Principle: Fixed, operates on pressure rise
- Set Point: .03″ ± .02″ w.c. (water column)
- Voltage Rating: 120–277Vac
- Port Connections: 1/4″ barbed fittings
- Maximum Inlet Pressure: 1/2 PSI
- Compatible Media: Air or combustion by-products that will not degrade silicone
Features & Benefits
- Factory-fixed set point eliminates field adjustment and reduces installation time
- Wide voltage range (120–277Vac) provides flexibility across commercial and residential applications
- 1/4″ barbed connections for easy tubing attachment and a secure, leak-free seal
- Silicone-compatible wetted materials ensure durability when exposed to combustion gases
- Low set-point sensitivity (.03″ w.c.) enables accurate detection of low-velocity airflow
- SPDT output allows both normally open and normally closed circuit configurations
Typical Applications
- Furnace and boiler airflow proving switches
- Draft inducer and combustion air proving
- Air handler and blower operation verification
- Safety interlocks requiring airflow confirmation before ignition
