Lennox 11G27 Enthalpy Sensor

The Lennox 11G27 Enthalpy Sensor is a critical component for optimizing demand control ventilation (DCV) and economizer performance in Lennox commercial HVAC systems. This solid-state sensor monitors both sensible and latent heat to determine the energy content of outside air, allowing the controller to modulate economizer dampers for maximum efficiency. Designed for precise integration with Lennox rooftop units (RTU), the 11G27 ensures that "free cooling" is only utilized when ambient enthalpy is lower than the return air enthalpy/setpoint, preventing unnecessary cooling load and humidity spikes. It features a robust enthalpy sensing element that provides linear output, facilitating accurate communication with the A55 Integrated Modular Controller (IMC) or older Prodigy control systems. Field technicians will find the 11G27 essential for maintaining ASHRAE 90.1 compliance and ensuring consistent indoor air quality through effective enthalpy-based economizer control.

• Precise Economizer Control: Enables accurate free cooling transitions by measuring both temperature and humidity.
• Direct OEM Replacement: Guaranteed fitment for Lennox 11G27 and Honeywell C7400 series applications.
• Enhanced System Efficiency: Reduces compressor runtime by maximizing the use of outdoor air during favorable conditions.
• Robust Solid-State Design: Built to withstand the harsh environments of RTU intake sections.
• Standardized Integration: Seamlessly interfaces with existing enthalpy control logic on Lennox commercial platforms.

How do I test the Lennox 11G27 Enthalpy Sensor during a PM?
Technicians should verify the DC voltage output relative to current outdoor enthalpy levels. Compare the sensor's reading against a calibrated hygrometer to ensure the controller is receiving accurate data for damper modulation.

Can the 11G27 be used for differential enthalpy sensing?
Yes, in many Lennox configurations, two 11G27 sensors can be used—one for outdoor air and one for return air—to provide differential enthalpy control, which is the most efficient method for economizer operation.

What are the symptoms of a failed enthalpy sensor?
Common signs include the economizer dampers remaining closed when outdoor conditions are ideal or dampers staying wide open during high-humidity periods, leading to increased indoor humidity and cooling costs.

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.