Copeland Comfort Control (White Rodgers) 21D28-6 Control System

The Copeland Comfort Control (White Rodgers) 21D28-6 Control System is a professional-grade solution for managing evaporative cooling systems with precision. As a direct replacement for the legacy 21D28-3, this integrated kit includes the 1F51-619 thermostat and the 8A18Z-2 control box, ensuring seamless field integration. Engineered for multi-voltage versatility, the unit features an integral transformer compatible with 120 VAC or 240 VAC primary inputs, stepping down to 24 VAC for reliable low-voltage control. The system utilizes separate fan and pump relays, allowing the pump to engage approximately 60 seconds before the fan to fully saturate the cooler pads, preventing dry-air delivery. Designed for heavy-duty service, the relay panel is removable to simplify field wiring within the weather-resistant plastic enclosure. Whether you are performing a 21D28-3 retrofit or a new HVAC installation, this control system provides distinct Hi-Lo fan speed selection and a 55°F to 95°F temperature range for optimal performance.

• Universal Voltage Compatibility: Supports both 120V and 240V systems, reducing inventory requirements for service vans.
• Pre-Wet Cycle Logic: Automated 60-second pump lead-time ensures pads are wetted before the 2-speed fan initiates.
• Contractor-Friendly Housing: Durable, rain-proof plastic case meets code for outdoor mounting with a removable relay board for easier terminal access.
• Precise Load Handling: Rated for combined relay loads up to 16.0 A at 120 VAC, handling high-amperage motors without external contactors.

Common Questions

Is the 21D28-6 compatible with older 21D28-3 wiring?
Yes, the 21D28-6 is the designated direct replacement. While the internal components are updated, the terminal logic remains consistent for standard evaporative cooler control upgrades.

What thermostat is included in this kit?
This system comes paired with the 1F51-619 non-programmable thermostat, which provides Off-Cool-Vent switching and Hi-Lo fan speed control.

Can I use this for both 120V and 240V coolers?
The 8A18Z-2 control box features an integral transformer that allows for line voltage flexibility. Always verify your motor's full load amps (FLA) against the 12.0 A (120V) or 6.0 A (240V) fan relay ratings.

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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.