Schneider Electric (Barber Colman) TK-8124 Pneumatic Bulb Thermostat, Proportional Two Pipe, Reverse Acting

The Schneider Electric (Barber Colman) TK-8124 is a professional-grade pneumatic bulb thermostat engineered for precise proportional temperature control in commercial and industrial HVAC applications. Featuring a reverse-acting control response, this thermostat is ideal for systems requiring an increase in output signal as temperature falls — commonly used in heating applications and two-pipe pneumatic control systems.

The TK-8124 uses an averaging bulb sensor to capture a representative temperature reading across a broad surface or fluid medium, making it well-suited for duct averaging, pipe sensing, and hydronic system monitoring. Its 1/8″ NPT air connections ensure straightforward integration into standard pneumatic control piping.

Key Features

• Proportional two-pipe pneumatic control for accurate, stable temperature regulation
• Reverse-acting operation — output signal increases as temperature decreases
• Wide dial range: -20°F to 240°F for versatile application coverage
• Averaging bulb sensor: 3/32″ diameter x 8′ length for broad-area temperature sensing
• 1/8″ NPT air connections for easy pneumatic system integration
• Designed for commercial and industrial HVAC pneumatic control systems
• Barber Colman heritage — trusted legacy brand now under Schneider Electric

Specifications

• SKU: TK-8124
• Brand: Schneider Electric (Barber Colman)
• Control Type: Proportional, Two Pipe, Pneumatic
• Action: Reverse Acting
• Dial Range: -20°F to 240°F
• Bulb Type: Averaging
• Bulb Dimensions: 3/32″ diameter x 8′ length
• Air Connection Size: 1/8″ NPT

Typical Applications

• Commercial building pneumatic HVAC control systems
• Duct air temperature averaging
• Hydronic heating pipe temperature sensing
• Two-pipe pneumatic heating and cooling systems
• Industrial process temperature control