4-Zone Heat and Cool Pump Control Panel with LCD Display, Single or Multi-Stage

Aprilaire® 6404 Zoned Comfort Control Panel – Technical Product Information

The Aprilaire® 6404 Zoned Comfort Control Panel is a professional-grade zoning system designed for precise climate management in single or multi-stage heating, cooling, and heat pump applications. Engineered for flexibility, this control panel supports 2 to 4 zones and integrates seamlessly into both residential and light commercial HVAC systems. The advanced logic circuitry and intuitive LED display streamline setup, diagnostics, and operation. The unit is designed to optimize airflow balance, enhance energy efficiency, and support multiple methods of system pressure management, including Aprilaire’s exclusive Controlled Pressure Relief™ system, standard bypass damper configuration, or oversized ductwork design.

Technical Specifications

• Manufacturer: Aprilaire®
• Model Number: 6404
• Product Type: Zoned Comfort Control Panel (Expandable)
• Voltage Rating: 20–30 VAC
• Maximum Current Draw: 3 A
• Compatible Systems: Universal single-stage, multi-stage, and heat pump systems
• Number of Zones Supported: 2–4 (expandable to 12 with additional modules)
• Stages of Operation: 2-Stage Heat / 2-Stage Cool
• Control Interface: LED display indicators for zone status, system mode, and diagnostics
• Dimensions: 14.72" H x 8.85" W x 1.86" D (373.9 mm x 224.8 mm x 47.2 mm)
• Mounting Type: Wall or panel mount
• Operating Temperature Range: 32°F to 120°F (0°C to 49°C)
• Pressure Relief Options:
  • Controlled Pressure Relief™ (no bypass damper required)
  • Traditional bypass damper with plenum temperature control
  • Oversized duct method
• Humidity/Dehumidification Control: Optional when integrated with compatible thermostats
• Communication Protocol: Compatible with Aprilaire thermostats and control modules
• Enclosure: Metal housing with integrated wire routing channels
• Indicators: Individual LED zone indicators for system monitoring and service verification
• Certifications: UL Listed, FCC Compliant
• Warranty: Limited manufacturer warranty per Aprilaire® standard terms

Design and Performance Features

• Supports multiple system types including gas, electric, and heat pump configurations
• Expandable architecture accommodates up to 12 total zones with additional panels
• Advanced control logic balances zone demands for consistent temperature regulation
• LED indicators provide real-time visual feedback for quick troubleshooting and diagnostics
• Compatible with Aprilaire Controlled Pressure Relief™ for bypass-free operation
• Integrates with existing thermostats for flexible installation and retrofit scenarios
• Engineered for professional installation with clear terminal labeling and structured wiring layout
• Provides efficient airflow management to minimize energy waste and improve comfort balance
• Durable enclosure ensures long-term reliability in demanding HVAC environments

Professional Summary

The Aprilaire® 6404 Zoned Comfort Control Panel provides HVAC professionals with a robust, flexible zoning solution for multi-zone heating and cooling systems. Designed for precision control, system protection, and simplified installation, the 6404 supports up to four zones with the ability to expand for larger applications. Its compatibility with various system configurations and multiple pressure relief methods allows contractors to tailor installations for performance and efficiency. Backed by Aprilaire’s engineering standards and compliance with industry certifications, this panel delivers reliable control and operational integrity for professional-grade zoning systems.