Before replacing the board, count the LED blinks — the error code tells you what actually failed. Sometimes it’s a $15 fuse, not a $140 board.
21M51U-843 – CONTROL BOARD (2-STAGE, PSC)
$337.70
White-Rodgers 21M51U-843 universal 2-stage furnace control board for PSC motors. Replaces hundreds of OEM boards. LED diagnostics built in.
Mon–Fri 10 am – 7 pm | Sat 10 am – 3 pm | In-Store Pickup Only
Description
If your furnace won’t ignite, shows error codes, or the blower won’t start, the control board controls all of it. The 21M51U-843 is a universal replacement for 2-stage gas furnaces using PSC (standard) blower motors. Replaces hundreds of OEM boards with built-in LED diagnostics.
Specs: 2-stage, PSC motor compatible, universal integrated furnace control, LED diagnostics, by White-Rodgers
Replaces: 1006225, 100869-03, 10207708, 10207712, 10207713, 1148167, 18381, 18384, 18M34, 20300001, 20300003, 21M51-495, 21M51U-843, 265903, 39M26, 43207001, 44957001, 449573, 46M99, 50A51-210, 50A51-211, 50A51-215, 50A51-225, 50A51-235, 50A51-242, 50A51-243, 50A51-405, 50A51-495, 50M51-242, 50M51-495, 50M61-120, 50M61-288, 50M61-289, 50M61-495, 50M61-843, 542767, 62798, 63W26, 83L93, 872670, CNT01308, CNT02184, CNT03077, CNT05122, CNT06424, CNT07566, CNT1308, CNT2184, CNT6424, D330934P01, D330937P01, D340021P01, D341418P01, D341418P02, D344301P01, KIT15943, KIT17858, PCB00114, PCB00115, PCB00116, PCBBF114, PCBBF115, PCBBF116, PCBBF120, PCBBF125, PCBBF149, PCBBF149S, R43207001, R44957-001, R44957001, S1-03101290000, S1-03101909000, S1-03102954000, S1-03103009000, S1-03109117000, S1-03109168000, S1-33102954000, S1-33103009000, S1-33109117000, S1-33109168000, TUD100R948J0, X13650839010, Y4151
Fits: Universal — most 2-stage PSC motor furnaces. Lennox: 18M34, 39M26, 46M99; and many other brands
Need help? See our Furnace Not Heating Guide.
In stock at Open To Public HVAC Parts in Dallas. We test parts at the counter before you buy. Call or text (214) 340-9421.
