publication

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

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

to 175

F (-40 to 80

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

HEATING