White Rodgers 21M51U-843, Wiring Diagram

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21M51U-843 Replaces:
18M3401 50M61-495
20300001 50M61-843
20300003 83L9301
21M51U-843 CNT03077
46M9901 CNT6424
50M51-242 D344301P01
50M51-495 PCBBF120S
50M61-120 PCBBF125
50M61-288 X13650839010
50M61-289
CROSS REFERENCE
21M51U-843 Kit
Includes:
• Module
• HotRod
Ignitor Kit
Model
Number Pre-Purge
Ignitor
Warm-Up Retries
Heat
Delay to
Fan ON
Heat Delay
to Fan OFF
Cool
Delay to
Fan ON
Cool
Delay to
Fan OFF
Automatic
Reset
Time
21M51U-843 15 17 2 45 90/120/150/180 5 60 60 minutes
?
PAGES
179–180
21M51U-843 UNIVERSAL INTEGRATED HSI
FURNACE CONTROL KIT
Replaces White-Rodgers 50M51-242 and 50M61-XXX's Two-Stage
HSI Systems with 80V or 120V Ignitors
FEATURES
• 120 VAC 3-speed PSC (Permanent Split Capacitor) circulator output, two-speed
inducer output, two-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.
SPECIFICATIONS
Electrical Rating:
Input Voltage. . . . . . . . . . . . . . . . . . . . 24 VAC, 60 Hz (Class II transformer required)
Nom. Input Current @ 24 VAC . . . . . . 530 mA + MV
Relay Load Ratings:
Gas Valve Relays . . . . . . . . . . . . . . . . 1.5 amps @ 24 VAC, 60 Hz
Inducer Relays . . . . . . . . . . . . . . . . . . 2.2 FLA – 3.5 LRA @ 120 VAC
Circulator Relays . . . . . . . . . . . . . . . . 14.5 FLA – 25.0 LRA @ 120 VAC
Humidifier Load . . . . . . . . . . . . . . . . . 1.0 amp max. @ 120 VAC
Electronic Air Cleaner Load . . . . . . . . 1.0 amp max. @ 120 VAC
Ignitor Relay . . . . . . . . . . . . . . . . . . . . 4.0 amps max. @ 132 VAC, 60 Hz
Flame Current Requirements:
Minimum current to insure flame detection
0.3 µa DC*
Maximum current for non-detection . . 0.1 µa DC*
Maximum allowable leakage resistance 100 M ohms
*Measured with a DC microameter in the flame probe lead
Operating Temperature Range. . . . . . -40
o
to 175
o
F (-40 to 80
o
C)
Humidity Range . . . . . . . . . . . . . . . . . 5% to 93% relative humidity (non-condensing)
Flame Failure Response Time . . . . . . 2.0 sec. max. @ 60Hz
TECHNICAL HELP
Wiring Diagram/Operation . . . . . . . . . . . . . . See pages 179–180
TWO-STAGE
INTEGRATED 3-SPEED (PSC)
HSI FURNACE CONTROL
UNIVERSAL
REPLACEMENT
www.white-rodgers.com 45
HEA
TING