Install Instructions

ManualsBrandsWhite Rodgers ManualsHeating SuppliesCarrier Single Stage HSI Furnace Control Kit

The 50M56U-751 kit is a Single Stage HSI Integrated Furnace

Control kit for Carrier. This kit replaces the following Carrier

controls:

Carrier White-Rodgers

HK42FZ004 HK42FZ009 HK42FZ016 50M56-751

HK42FZ007 HK42FZ011 HK42FZ034

HK42FZ008 HK42FZ013 325878-751*

*Universal replacement for all Carrier controls.

The control employs a microprocessor to continually monitor,

analyze, and control the proper operation of the gas burner,

inducer, and fan.

Twinning: The control board in this Kit CANNOT be twinned

with any of the Carrier circuit boards.

50M56U-751

Carrier Single Stage

HSI Integrated Furnace Control Kit

INSTALLATION INSTRUCTIONS

DESCRIPTION

Installation should be done by a qualiﬁed heating and air

conditioning contractor or licensed electrician.

If in doubt about whether your wiring is millivolt, line, or low

voltage, have it inspected by a qualiﬁed heating and air

conditioning contractor or licensed electrician.

Do not exceed the speciﬁcation ratings.

All wiring must conform to local and national electrical codes

and ordinances.

This control is a precision instrument, and should be handled

carefully. Rough handling or distorting components could

cause the control to malfunction.

Following installation or replacement, follow manufacturer’s

recommended installation/service instructions to ensure

proper operation.

PRECAUTIONS

Do not short out terminals on gas valve or primary

control. Short or incorrect wiring may damage the

thermostat.

CAUTION

Failure to comply with the following warnings could result

in personal injury or property damage.

FIRE HAZARD

• Donotexceedthespeciedvoltage.

• Replaceexistingcontrolwithexactmodeland

dash number.

• Protectthecontrolfromdirectcontactwithwater

(dripping, spraying, rain, etc.).

• Ifthecontrolhasbeenindirectcontactwith

water, replace the control.

• Labelallwiresbeforedisconnectionwhen

servicing controls. Wiring errors can cause

improper and dangerous operation.

• Routeandsecurewiringawayfromame.

SHOCK HAZARD

• Disconnectelectricpowerbeforeservicing.

• Ensureproperearthgroundingofappliance.

• Ensureproperconnectionoflineneutralandline

hot wires.

EXPLOSION HAZARD

• Shutoffmaingastoapplianceuntilinstallation

is complete.

WARNING

FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY BEFORE

INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL

INJURY AND/OR PROPERTY DAMAGE.

PART NO. 37-7513B

Replaces 37-7513A

1421

www.white-rodgers.com

www.emersonclimate.com

50M56-751

The kit contains:

1 – 50M56-751 ignition control board

1 – Set of interconnect harnesses

1 – Manual

1 – Bag of accessories

Summary of content (8 pages)

PAGE 1
50M56U-751 Carrier Single Stage HSI Integrated Furnace 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. DESCRIPTION The 50M56U-751 kit is a Single Stage HSI Integrated Furnace Control kit for Carrier.
PAGE 2
SPECIFICATIONS ELECTRICAL RATINGS [@ 77°F (25°C)]: Input Voltage: 25 VAC 50/60 Hz Max. Input Current @ 25 VAC: 0.45 amp Relay Load Ratings: Valve Relay: 1.5 amp @ 25 VAC 50/60 Hz 0.6 pf Ignitor Relay: 6.0 amp @ 120 VAC 50/60 Hz (resistive) Inducer Relay: 2.2 FLA–3.5 LRA @ 120 VAC Circulator Relay: 14.5 FLA–25.
PAGE 3
INSTALLATION INSTALLER MUST READ FOR PROPER INSTALLATION • Before removing existing control board, tag wires to assure proper connection to new board. • Wiring harness adaptors are included in this kit. Wiring harness adaptors will be used when replacing existing control as indicated below. The remaining harnesses can be discarded. • IMPORTANT: For low speed continuous fan speed operation, one of the unused parked motor taps must be connected to the low heat speed terminal.
PAGE 4
WIRING DIAGRAM TYPICAL SYSTEM WIRING DIAGRAM HOT (LINE) NEUTRAL (LINE) 120 VAC 24 VAC CLASS II TRANSFORMER TH 24 VAC TR 50M56 COOL LO HEAT HI HEAT LINE - H XFMR - H EAC - H HUM - H PARK PARK IND-N* IND IGN IGN-N* Optional HUMIDIFIER 120 V [4-Pin Connector] IGNITOR Y Y W W G G R R FLAME SENSOR PROBE FS HLO MV LO TH PSO Not Used TR HLI GND MV COM PSI Not Used Not Used GAS VALVE [12-Pin Connector] IGN IND N IGN N 4-Pin Connector OPTIONAL 24 V HUM HIGH LIMIT (N. C.) AUX.
PAGE 5
WIRING DIAGRAM TYPICAL SYSTEM WIRING TABLE 50M56 TERMINAL TERMINAL TYPE SYSTEM COMPONENT CONNECTION low voltage thermostat W terminal (or equivalent) low voltage thermostat G terminal (or equivalent) low voltage thermostat R terminal (or equivalent) W G R Y Terminal block with low voltage thermostat Y terminal (or equivalent) (2nd wire from Y terminal goes to 24 VAC HOT side of compressor contactor coil) 24 VAC COMMON side of compressor contactor coil captive screws C HLO (Pin 1) MV LO (Pin 2) TH (P
PAGE 6
OPERATION Check-Out and Self Test The 50M56U-751 is equipped with a self test routine used during the control’s installation. The self test checks the functionality of the control, Inducer, Ignitor, and blower to verify they are in proper working order. To initiate self test sequence, ensure thermostat is turned OFF or thermostat wires are disconnected. To enter self test: ● Turn on power and manually close blower door switch. ● Wait for 5 seconds. ● Slowly double click select button within 3 seconds.
PAGE 7
OPERATION SYSTEM LOCKOUT AND DIAGNOSTIC FEATURES SYSTEM LOCKOUT FEATURES When system lockout occurs, the gas valve is de-energized, the circulator blower is energized at heat speed, and, if flame is sensed, the inducer blower is energized. The diagnostic indicator light will flash or glow continuously to indicate system status. (System lockout will never override the precautionary features.) To reset the control after system lockout, do one of the following: 1.
PAGE 8
TROUBLESHOOTING Red LED Flash Error/Condition Comments/Troubleshooting 1 External lockout (exceeded retries) Failure to sense flame is often caused by carbon deposits on the flame sensor, a disconnected or shorted flame sensor lead or a poorly grounded furnace. Carbon deposits can be cleaned with emery cloth. Verify sensor is not contacting the burner and is located in a good position to sense flame. Check sensor lead for shorting and verify furnace is grounded properly.