A25CN-4C Johnson Controls Temperature Control

Overview

The Johnson Controls A25CN-4C is an electromechanical warm air limit control designed to automatically shut down systems like fans, burners, and dampers when the sensed air temperature exceeds the user-defined setpoint. It features a visible adjustment knob and utilizes a rigid bi-metal rod and tube sensing mechanism. Designed for applications requiring high-limit safety enforcement, the device features a positive, trip-free manual reset mechanism that locks out the electrical circuit until manual intervention occurs after temperatures cool.

Features

• Manual Reset: Enforces safety lockout when temperature limits are breached, requiring manual resetting once the temperature drops 20°F (11°C) below the setpoint.
• SPDT Switching: Equipped with Single Pole Double Throw contacts, providing versatile wiring configurations for controlling safety loops and indicator systems.
• Robust Sensing: Employs a reliable bi-metal rod and tube design engineered for industrial duct environments.
• High Visibility: Features an external, highly visible setpoint knob for straightforward checking and local adjustment.

Specifications

• Temperature Range: -4°C to 101°C (25°F to 215°F)
• Relay/Switch Type: Snap-acting SPDT contacts in a dust-protected enclosure
• High Limit Dial Stop: 125°F (52°C)
• Sensing Element: Bi-metal rod and tube construction
• Enclosure Materials: 0.063-inch galvanized steel case with a 0.025-inch cold-rolled steel cover finished in gray baked enamel
• Electrical Ratings: 16 FLA / 96 LRA at 120 VAC; 9.2 FLA / 55.2 LRA at 208 VAC; 8 FLA / 48 LRA at 240 VAC; 16 A non-inductive; Pilot Duty 125 VA at 24 to 600 VAC
• Approvals: UL Listed, cUL Listed

Applications

• High-Limit Safety: Ideal for installation in supply air ducts or plenums to prevent dangerous overheating situations.
• Fan and Burner Shutdown: Commonly applied to stop ventilation fans, air conditioners, or commercial heating burners during a sudden temperature rise.
• Duct and Environmental Air Systems: Serves as a vital safety lockout switch across diverse commercial and industrial HVAC air handling setups.