EMERSON 21M51U-843 Universal Two Stage Furnace Control Owner’s Manual

Bel-Aire
ElectronicAirCleaners.com
Purchase Here!
u Universal

21M51U-843 Universal Two Stage Furnace Control

Universal
Two-Stage Furnace Control for PSC Blower Motors
21M51U-843
Simplifies stocking, installation and ensures peak system performance

Universal Replacement Kit

Replaces most White-Rodgers 50A51, 50M51, and 50M61 two-stage HSI controls with 80V or 120V ignitor.
Kit Includes:

• Ignition control 50M51-843
• HotRod Universal Ignitor Kit 21D64-2
• Trane ignitor mounting bracket
• Installation instructions and cross references ™

Easy Installation
Cover allows flexibility during mounting Added dipswitches to trial for ignition and blower delays Additional blower motor wire extensions

Now replaces
50A51 applications

Universal Two-Stage Furnace Control for PSC Blower Motors

FEATURES:

• 120 VAC ignitor output
• 120 VAC two-speed inducer output
• 120 VAC humidifier output
• 120 VAC electronic air cleaner output
• 2-stage gas valve output
• 120 VAC 3-speed PSC blower motor output
• Fuse protection–3 amp
• Tri-Color LED and status codes
• Selectable W2 delay when used with Single Stage thermostat
• Selectable Trial for ignition timing
• Pushbutton fault recall
• YLO, Y, W1, W2, R, G, C, O, Twin terminals
• Flame current test pads
• Cover for additional mounting options
• Blower motor wire extensions

SPECIFICATIONS:

Electrical Ratings [@ 77°F (25°C)] Input Voltage: 120 VAC, 60 Hz
(Class II transformer required)
Max. Input Current @ 24 VAC 800mA + MV
Flame Current Requirements
Minimum current to ensure flame detection: 0.3 μA DC*

• Measuring with a DC voltmeter (1 VDC = 1μa)
  Operating Temperature Range
  -40° to 176°F (-40 to 80°C)
  Humidity Range
  5% to 95% relative humidity (non-condensing)
  Gases Approved
  Natural, Manufactured, Mixed, Liquid Petroleum, and LP Gas Air mixtures are all approved for use
  Dimensions
  BOARD: 4.82″ W x 8″ H x 1.25″ D
  COVER: 5.12″ W x 9.13″ H x 1.45″ D
  Agency Approval
  CSA
  1 Year Limited Warranty

TIMING SPECIFICATIONS

(All times are in seconds unless noted otherwise)

• Denotes factory default

CROSS REFERENCE

Amana/Goodman
10207708
10207712
10207713
20300001
20300003
50A51-215
50A51-225
50A51-235
50M61-288
50M61-289
PCB00114
PCB00115
PCB00116
PCBBF114
PCBBF114S
PCBBF115
PCBBF115S
PCBBF116
PCBBF116S
PCBBF120S
PCBBF125
Armstrong
43207001
44957001
50A51-210
50A51-211
R43207001
R44957001
Johnstone
L39-373
L39-376
L42-300
L42-301
L42-302
Lennox Industries
100869-03
18M3401
39M26
46M9901
50M61-120
63W26
83L9301
Y4151
Trane/
American Standard
1006225
1148167
21M51-495
50A51- 405
50A51- 495
50M51-495
50M61-495
CNT01308
CNT02184
CNT03077
CNT05122
CNT06424
CNT07566
CNT1308
CNT2184
CNT6424
D330934P01
D330937P01
D340021P01
D341418P01
D341418P02
D344301P01
KIT15943
K IT17858
X13650839010
White-Rodgers
21M51U-843
50M61-843
York International
18381
18384
265903
449573
50A51-242
50A51-243
50M51-242
542767
67298
872670
S1-03101290000
S1-03101909000
S1-03102954000
S1-03103009000
S1-03109117000
S1-03109168000
S1-33102954000
S1-33103009000
S1-33109117000
S1-33109168000

THE WHITE-RODGERS MOBILE APP:
Answers at your fingertips, with your smartphone or tablet.
Latest cross reference
  Installation instructions
Spec sheets
Product selection

https://DELIVR.COM/2DCTG-QR

©2022 Emerson Electric Co.
White-Rodgers and Emerson are trademarks of Emerson Electric Co.
All rights reserved
Customer Service or Technical Help: 888-725-9797
Emerson.com/White-Rodgers
R-4838-1 (2/22)

Read User Manual Online (PDF format)

Read User Manual Online (PDF format)  >>

Download This Manual (PDF format)

Download this manual  >>