Schneider Electric (Barber Colman) THCR-4 Enthalpy Controller

The Schneider Electric (Barber Colman) THCR-4 Enthalpy Controller is a high-precision analog electronic sensor designed for economizer cooling control in commercial HVAC systems. This SPDT changeover control measures both dry bulb temperature and relative humidity to determine the total heat content of outdoor air, ensuring the system only utilizes free cooling when the outside air is more efficient than mechanical refrigeration. Operating on a 24V AC power supply, the THCR-4 features a broad operating temperature range of 40 to 150°F and handles 5 to 95% non-condensing relative humidity. For technicians performing retrofits, this unit serves as the direct replacement for HH57AC076, utilizing standard 3-wire leads for straightforward integration into existing rooftop units (RTU). Housed in a durable NEMA 1 enclosure, it provides reliable ambient air monitoring for airside economizer sequences, maximizing energy efficiency by optimizing outside air intake based on real-time enthalpy calculations.

• Universal Replacement: Specifically engineered as the direct functional equivalent for the HH57AC076, simplifying field repairs.
• Precise Enthalpy Sensing: Combines temperature and humidity data to prevent high-latent heat air from entering the building.
• Rugged Construction: NEMA 1 rated housing protects internal solid-state components in demanding mechanical environments.
• Simple Integration: Standard 3-wire lead configuration ensures compatibility with common 24V control circuits.

Common Questions

Can the THCR-4 be used to replace older HH57AC076 controllers?
Yes, the THCR-4 is the manufacturer-designated direct replacement for the HH57AC076 enthalpy control, maintaining the same form factor and electrical specifications.

What is the primary function of this enthalpy controller?
It evaluates the total heat (enthalpy) of the outdoor air to determine if it is suitable for "free cooling," switching the economizer dampers accordingly via its SPDT contact.

Does this unit require a separate power supply?
The THCR-4 operates on a standard 24V AC Class 2 circuit, which is typically supplied by the existing HVAC unit's control transformer.

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.