The White Rodgers 21M51U-843 is a universal two-stage Hot Surface Ignition (HSI) integrated furnace control kit designed for furnaces equipped with 3-speed Permanent Split Capacitor (PSC) blower motors. This advanced kit serves as a direct replacement for a wide range of OEM control boards, including 50M51-242 and all 50M61-XXX series, making it a convenient and versatile solution for HVAC professionals.Key Features:

• Universal Compatibility: Replaces a broad range of OEM control boards for simplified inventory and service.
• Integrated Control Functions: Manages ignition, blower operation, and system diagnostics within a single compact module.
• 3-Speed PSC Blower Control: Supports efficient airflow management for enhanced system performance.
• Advanced Diagnostics: Tri-color LED indicators and push-button access offer quick fault identification and historical error data.
• Comprehensive Kit: Includes ignition control module, universal 120V nitride ignitor (21D64-2), installation instructions, and OEM cross-reference guide.

Technical Specifications:

• Ignition Type: Intermittent Hot Surface Pilot
• Stages: Two-stage operation
• Voltage Outputs:
  • 120 VAC ignitor
  • 120 VAC two-speed inducer
  • 120 VAC humidifier
  • 120 VAC electronic air cleaner
  • 120 VAC 3-speed PSC circulator
• Gas Valve Output: 2-stage
• Fuse Protection: 3 Amp
• Operating Temperature Range: -40°F to 175°F
• Humidity Range: 5% to 93% RH (non-condensing)
• Dimensions: 8" H x 5-1/4" W x 1-1/4" D

Additional Features:

• Dipswitch-selectable heat fan off delay and automatic second stage delay
• Fan on delay for cooling applications
• Pressure switch monitoring inputs
• Flame current test points for diagnostics
• Flash microprocessor with non-volatile memory
• Terminal connections: YLO, Y, W1, W2, R, G, C, TWIN

This integrated control kit is the ideal upgrade or replacement part for two-stage furnaces using PSC blower motors, delivering reliability, advanced diagnostics, and installation ease.Available now at Beenimax.