CASE STUDIES
RV manufacturers required a compact, cost-effective solution to manage air conditioner systems without full HVAC complexity. The market lacked a UL-listed, AC-powered control box that could reliably handle compressor control, dual-speed fan operation, and freeze sensor input—while meeting the durability and compliance standards expected in mobile applications and supporting volumes over 100,000 units per year.
Steiner developed the Cool Only Control Box, a rugged, production-ready solution designed specifically for 120VAC RV air conditioner systems. Built with internal 12VDC control logic, the device seamlessly manages fan speed and compressor operation based on input signals. The unit is fully UL listed and is manufactured across multiple countries of origin to support diversified, scalable production.
Accepts inputs for Y (Compressor), GH (Fan High), and GL (Fan Low) to enable:
Integrated J-curve thermistor disables the compressor below 28°F, reactivating above 55°F, protecting against coil freezing in cold environments.
Fully UL listed, with UL 94-5V flame-rated plastics, safe field wiring compartments, and robust relay control design.
Includes reverse polarity protection and tolerance for 400VDC spikes, ensuring long-term reliability in volatile RV electrical systems.
Designed with high-throughput assembly in mind, including modular wiring, quick-connect terminals, and flexible harness options.
And cost-optimized manufacturing
Now deployed in high volume across multiple RV lines, the Cool Only Control Box has become a go-to component for manufacturers seeking dependable A/C system control. Its simplified signal interface, built-in safeguards, and global manufacturability reduce complexity and improve serviceability in the field — critical advantages for both OEMs and end users.
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