White Rodgers 21M51U-843 Universal 2-Stage Furnace Control Kit

Overview

White Rodgers 21M51U-843 Universal Two-Stage HSI Integrated Furnace Control Kit
MFG# 21M51U-843 | REM# 3C502

This Universal Integrated 3-Speed (PSC) Blower Furnace Control Kit is designed to replace White Rodgers 50M51-242 and all 50M61-XXX two-stage HSI furnace control boards.

Engineered for professional HVAC service applications, this kit supports both 80V and 120V hot surface ignitors and is compatible with major furnace brands including Goodman, Amana, Coleman, Luxaire/York, Lennox, American Standard, and Trane.

Kit Includes:
• Integrated furnace control board
• 21D64-2 universal 120V nitride ignitor kit
• OEM cross-reference documentation

Key Performance

Features

• Two-stage HSI gas furnace control
• LED diagnostic light for fast troubleshooting
• Push-button fault code recall
• Adjustable heat fan-off delay
• Automatic second-stage delay (dip switch selectable)
• 120 VAC humidifier output
• 120 VAC electronic air cleaner output
• Compatible with PSC blower motors

Ideal For:

• Residential and light commercial gas furnace repair
• Natural Gas and LP/Propane heating systems
• HVAC service contractors
• Replacement of obsolete White Rodgers boards

This universal control kit reduces truck inventory by covering multiple OEM part numbers and provides enhanced diagnostic capability for faster system troubleshooting.

Product details

Part / SKU	21M51U-843

Package includes

Kit Includes:• Integrated furnace control board• 21D64-2 universal 120V nitride ignitor kit• OEM cross-reference documentation