21M51U-843 White Rodgers Furnace Board Control Kit for 50M61-** 18M3401 83L9301


Product Description

White Rodgers Furnace Board Part number 21M51U-843.  

This is Brand New, Unused, In the Package.

  This is a Universal Two-Stage HSI Integrated 3 Speed Speed (PSC) Circulator Furnace Control Kit.



  • 120 VAC 3-speed PSC (Permanent Split Capacitor) circulator output, two-speed
  •  inducer output, 2-stage gas valve output.
  •   Pushbutton fault history retrieval.
  •   Furnace status LED  tri-color (green, red and amber).
  •   Heat fan off delay (dipswitch selectable), fan on delay for cooling.
  •   Auto second stage delay (dipswitch selectable).
  •   120 VAC humidifier output/120 VAC electronic air cleaner output.



  • 1F78-144 White Rodgers Wall Thermostat 24V Millivolt Battery Non Programmable
  •  120 VAC Ignitor Output
  •   120 VAC Two-Speed Inducer Output
  •   120 VAC Humidifier Output
  •   120 VAC Electronic Air Cleaner Output
  •   120 VAC 3-Speed PSC Circulator Output
  •   2-Stage Gas Valve Output
  •   Fuse Protection 3 Amp
  •   Furnace Status LED  Tri-Color (Green, Red and Amber)
  •   Heat Fan OFF Delay (Dipswitch Selectable)
  •   Fan ON Delay for Cooling  Auto Second Stage Delay (Dipswitch Selectable Mode)
  •   Historical Fault Retrieval by Pushbutton
  •   YLO, Y, W1, W2, R, G, C, TWIN Terminals
  •   Pressure Switch Inputs and Monitoring
  •   Flash Microprocessor with Non-Volatile Memory
  •   Flame Current Measurement Points  

Replaces: White-Rodgers 50M51-242 and 50M61-XXX's Two-Stage HSI Systems with 80V or 120V Ignitors.

18M3401, 20300001, 20300003, 50M51-242, 50M61-120, 50M61-288 , 50M61-289, 50M61-480, 50M61-495, 50M61-843 , 83L9301, CNT03077 , X13650839010

Product Reviews

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  • 5
    Trane XL80 Control Board

    Posted by Unknown on 15th Jul 2017

    Received the board the next morning! Took the tech about 20 mins to install. Works great!

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