Cleveland Controls NS2-1239-00 Pressure Switch

The Cleveland Controls NS2-1239-00 is an industrial-grade air flow pressure sensing switch specifically designed to monitor positive, negative, or differential air pressure in HVAC systems. This fixed set point pressure switch is factory-calibrated at .70" w.c. (inches water column), ensuring high accuracy for critical safety applications such as proving fan flow or detecting filter blockage. Built with a glass-filled polycarbonate housing and a silicone diaphragm, the NS2 series provides long-term stability and contaminant-free performance in demanding environments. This SPST (Single Pole Single Throw) pressure switch is essential for residential and light commercial furnace operations, preventing system cycles if proper airflow is not detected. The integrated mounting bracket and color-coded high/low pressure ports streamline installation for field technicians. With its snap-acting switch mechanism and 90-degree male quick-connect terminals, the NS2-1239-00 is a reliable HVAC replacement part for maintaining furnace safety and efficiency.

• Factory-Calibrated Precision: Fixed .70" w.c. set point eliminates field adjustment errors and ensures consistent pressure monitoring.
• Engineered Durability: Features a robust glass-filled polycarbonate body capable of withstanding temperatures from -40°F to 180°F.
• Versatile Sensing: Designed to sense differential air pressure, positive pressure, or vacuum air flow across heat exchangers and coils.
• Easy Integration: Includes an integral mounting bracket and universal 1/4 inch quick-connect terminals for fast wiring.
• System Protection: Actively prevents overheating or "conking" by locking out cycles if the induction blower fails to meet the specified pressure.

What happens if the pressure does not reach .70" w.c.?
The SPST switch contacts will remain open, preventing the ignition sequence or cooling cycle from starting. This is a critical safety feature to ensure there is adequate draft or airflow before operation.

Can this switch be mounted in any orientation?
While the NS2 series is highly stable, it is best practice to mount the diaphragm vertically. If a custom mounting angle is required, ensure the sample line connections are not directed upward to prevent moisture accumulation.

What tubing size is compatible with the ports?
The color-coded ports are designed to accept standard 3/16 inch or 1/4 inch ID flexible tubing, which are the industry standards for HVAC pressure sensing lines.

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.