Emerson 50M56U-843 INSTALLATION INSTRUCTIONS

50M56U-843 with Black Cover

CAUTION

!

Universal Integrated Single Stage

120V Hot Surface Ignition Control Kit

INSTALLATION INSTRUCTIONS

FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY
BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE
PERSONAL INJURY AND/OR PROPERTY DAMAGE.

PARTS INCLUDED

• 50M56-843 Integrated Furnace Control

• 21D64-2 HotRod Universal Ignitor Kit (120V)

• 3 - Main Harness Assemblies (A, B, M)

• 4 - Ignitor/Inducer Harness Assemblies
(C, D, E, H)

• 1 - Rollout Shunt Jumper

• 1 - Carrier Blower Motor Neutral Adapter (L)

• 4 - White 8.5” Long Wiring Extensions

• 4 - Plastic Mounting Standoffs (use without
control cover)

• 4 – 1” Sheet Metal Mounting Screws (use with
control cover)

• 3 – ½” Sheet Metal Mounting Screws (use with
mounting tabs)

• 2 - Wire Ties

• Installation Instructions

INSTALLER MUST READ

SPECIAL REPLACEMENT

INSTRUCTIONS FOUND ON

PAGE 2

DESCRIPTION

The 50M56U-843 is an aftermarket universal replacement
control kit for single stage furnace products with PSC blower
motors.

TWINNING: 50M56U-843 can be twinned. Both control
boards must be from the same manufacturer for proper
functionality.

SPECIFICATIONS

ELECTRICAL RATINGS:

Input Voltage: 25 VAC, 50/60 Hz
Max Input Current: 0.45 A @ 25 VAC
Relay Contact Ratings:

Gas Valve: 1.5 A 0.6 PF @ 30 VAC
Ignitor Relay: 1.2 A @ 120 VAC
Inducer Relay: 2.8 A @ 120 VAC
Circulator Relay: 10 FLA, 25 LRA @ 120 VAC
Humidifier Load: 1.0 A @ 24 or 120 VAC
Electronic Air Cleaner: 1.0 A @ 120 VAC

Flame Current Requirements:

Minimum current to ensure flame detection: 0.25 μA DC*
Maximum current for non-detection: 0.1 μA DC
Maximum allowable leakage resistance: 100 M ohms
* Measuring with a DC voltmeter (1VDC = 1 μA)
Flame Establishing Time: 0.8 seconds maximum
Flame Failure Response Time: 2.0 seconds maximum

OPERATING TEMPERATURE RANGE:

-40° to 176°F (-40° to 80°C)

HUMIDITY RANGE:

5 to 95% relative humidity (non-condensing)

AGENCY APPROVALS: CSA USA / Canada
GASES APPROVED: Natural, Manufactured, Mixed,

Liquid Petroleum, and LP Gas Air Mixtures.

Risk of Electric Shock.
Disconnect electric power
to system until installation
is complete. Do not use on
circuit exceeding specified
voltage. Higher voltage will
damage control and could
cause shock or fire hazard.

This control is not intended
for use in locations where
it may come in contact with
water.

May cause flame rollout.
Shut off main gas to heating
system until installation is
complete.

emerson.com/white-rodgers

PART NO. 37-7042002

Replaces 37-7042001

2005

SPECIAL REPLACEMENT INSTRUCTIONS

ROLLOUT SHUNT JUMPER REQUIRED ON ALL TRANE/

AMERICAN STANDARD FURNACES, AND ANY YORK
P3UR/PCLU MODELS

For proper operation you must install the included shunt
jumper on the circled 2-pin R/O “rollout” terminal.

The shunt jumper is packaged separately as an accessory
item in the kit. Failure to do so will disable furnace operation.

IGNITOR UPDATE Required on all 80V HSI systems. See Cross References shaded orange on outside of color box.

FLAME SENSOR KIT Required on RHEEM/RUUD Models (1994 and earlier)

If the control being replaced has 2 greens lights (no amber light), and a date code of 3294 or earlier, a Flame Sensor Kit,
RHEEM part number 62-24044-71 is required (not available through White-Rodgers).

HARNESS UPDATE Required on existing White-Rodgers

50M56U-843 Control with white cover

If a furnace has already been retrofitted with an original
White-Rodgers 50M56U-843 control (white cover) and is
being changed out to a new 50M56U-843 (black cover), it
is required to also update/replace the Main wire harness
adapter that plugs into the 12-pin connector since some
control pinouts are different.

White Control Harness

Removed

A New A

B New B

F

K New M

Black Control Harness

Replacement

None, plug factory harness

into 50M56U-843

HARNESS SELECTION TABLE AND DESCRIPTIONS

Most furnaces are serviced by simply installing the new 50M56U-843 control board and included 120V ignitor.

Some furnaces will require the use of an adapter harness for the main system wiring and/or the ignitor/inducer wiring. Use
table on page 3 to determine which wire harness(es) in this kit are needed.

If the equipment brand or control P/N does not appear in the
table, no harness is required. Plug OEM wiring directly onto
50M56U-843 and proceed with installation and checkout.

2

CARRIER/ICP BRANDS

MAIN HARNESS/OTHER

HK42FZ004 HK42FZ007 HK42FZ008 HK42FZ009 HK42FZ011 HK42FZ016

MAIN HARNESS

194300330001 50A55-250 50A50-285

H
A

MAIN HARNESS

R
N

1012-83-9336AHSC1 1012-83-9337A 1012933D 1012-933D 41F-5

50T35-730 50T35-730-1 50T35-743 B1809906 B1809906S B1809908

B1809908S B18099-13 B1809913S CNT04664 CNT4664

E
S
S

MAIN HARNESS

10207701 10207702 102077-02 10207703 102077-03 10207704

S
E

L

E

102077-04 10207706 102077-06 102077-09 10207710 102077-10

10207714 102077-14 10207715 10207718 10207719 102077-19

20394001 50A50-207 50A50-288 50A50-298 50A55-288 50A55-288-05

50M56-281 50M56-291 50T55-288 PCB00117 PCBBF117 PCBBF117S

PCBBF134 PCBBF135 PCBBF135S PCBBF136 PCBBF138 PCBBF138S

PCBBF140 PCBBF140S RF000129

C

T

MAIN HARNESS

I

O

ICM280

L

IGNITOR/INDUCER HARNESS

M

FEDDERS & WHITE-RODGERS

None

IGNITOR/INDUCER HARNESS

GOODMAN/AMANA BRANDS (9-pin main connector)

A

IGNITOR/INDUCER HARNESS

GOODMAN/AMANA BRANDS (12-pin main connector)

None

IGNITOR/INDUCER HARNESS

ICM

A

IGNITOR/INDUCER HARNESS

None

E

C

E

C

N

MAIN HARNESS

T
A
B

L

1012-83-9559B 1012955A 1012-955A 624557 6245570 624564

6245640 624591 624591-A 624591-B 624591-C 624591-D

624628 624628-0 6246310 624631-0 624631A 624631-A

624631B 624631-B 624690 624742 624844 710128A

902378 902696 903106 904840 920915

B

E

MAIN HARNESS

1012-925A 1012-925B 1012-925C 62-22694-01 62-22694-02 62-22694-03

62-22694-11 62-22694-12 62-22694-82 62-22694-83 62-22694-91 62-22737-06

62-22737-07 62-22737-08 62-22737-10 62-22737-87 62-22737-88 62-24044-01

62-24044-81 62-24044-91 62-24045-01 62-24046-01 62-24084-01 62-24084-02

62-24084-71 62-24084-82 62-24084-91 62-24084-92 62-24268-01 62-24268-02

62-24268-03 695-200

NOTE: All other controls install without a harness

B

NORDYNE BRANDS

IGNITOR/INDUCER HARNESS

RHEEM/RUUD BRANDS

IGNITOR/INDUCER HARNESS

D

H

3

A

Furnace

Ground

MAIN HARNESS ADAPTERS A, B, & M

Goodman/Amana Brands, ICM (50T35 variants)

Furnace

9-pin

Furnace

Flame Sense

B

Furnace

9-pin

Furnace 24V

Transformer

Control Board

12-pin

Nordyne Brands, Rheem/Ruud Brands

Control Board
Flame Sensor

Control Board

12-pin

4

M

Furnace

2-pin, 3-pin

Furnace 24V

Transformer

Furnace

9-pin

Furnace 24V

Transformer

Carrier/ICPBrands

Control Board

4-pin

Control Board

12-pin