Cleveland Controls DFS-231-121 Switch

The Cleveland Controls DFS-231-121 is a fixed-setpoint diaphragm differential pressure switch engineered for precision performance in HVAC pressure monitoring and combustion air applications. This SPDT air flow switch is factory-calibrated to actuate on a pressure rise at 0.05" ± .02" w.c., providing a reliable safety interlock for systems requiring strict static pressure thresholds. Designed for versatility, the unit supports line voltage ranges from 120V to 277VAC and features dual 1/4" barbed connections for simplified field installation on positive pressure or vacuum sides of the blower housing. The silicone-based diaphragm is compatible with air and combustion byproducts, ensuring long-term stability in demanding environmental control systems. With a maximum pressure rating of 0.5 psi, this differential air pressure switch is the industry standard for verifying fan proof of flow and preventing unsafe operating conditions in commercial boilers and air handlers.

• Fixed Setpoint Reliability: Factory-set at 0.05" w.c. to eliminate field calibration errors and reduce commissioning time.
• Enhanced Compatibility: The SPDT switch logic allows for flexible wiring as normally open or normally closed to suit various control logic requirements.
• Industrial Build Quality: Features a rugged housing and a silicone diaphragm that resists degradation from typical combustion byproducts.
• Universal Voltage Support: Operates seamlessly across 120, 240, and 277VAC circuits, making it an essential HVAC replacement part for diverse mechanical rooms.

How do I plumb the 1/4" barbed connections for vacuum sensing?
For vacuum or negative pressure sensing, connect the tubing to the low-pressure port. For differential pressure monitoring across a filter or coil, utilize both barbs to measure the drop accurately.

Can this switch be mounted in any orientation?
For optimal accuracy at the 0.05" w.c. setpoint, the diaphragm should be mounted in a vertical plane. Mounting the DFS-231-121 horizontally may shift the actuation point due to the weight of the internal components.

Is the DFS-231-121 suitable for high-limit safety circuits?
Yes, this fixed-range pressure switch is frequently used as a safety limit switch to ensure proper drafting or airflow before ignition sequences are initiated.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.