Emerson 21M51U-843 Universal Integrated Furnace Control Kit with Three Speed Circulator Three-speed PSC (Permanent Split Capacitor) circulator output, two-speed inducer output, two-stage gas valve output Furnace status LED - tri-color (green, red and amber) Pushbutton fault history retrieval Heat fan off delay (dipswitch selectable), fan on delay for cooling, and auto second-stage delay Includes 21D64-2 Silicon Nitride ignitor kit and module