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SERVICE AND TECHNICAL SUPPORT MANUAL

Gas Furnace: N9MSE

Specifications  subject to change without notice.

440 04 4402 03

13

SERVICE AND MAINTENANCE

PROCEDURES

Untrained personnel can perform basic maintenance functions

such as cleaning and replacing air filters. All other operations

must be performed by trained service personnel. A qualified

service person should inspect the furnace once a year.

FIRE, INJURY OR DEATH HAZARD

Failure to follow this warning could result in personal

injury, death and/or property damage.
The ability to properly perform maintenance on this

equipment requires certain knowledge, mechanical

skills, tools, and equipment. If you do not possess

these, do not attempt to perform any service and

maintenance on this equipment other than those

procedures recommended in the Owner’s Manual.

!

WARNING

ENVIRONMENTAL  HAZARD

Failure to follow this caution may result in

environmental pollution.
Remove and recycle all components or materials (i.e.

oil, refrigerant, control board, etc.) before unit final

disposal.

CAUTION

!

ELECTRICAL SHOCK, FIRE OR EXPLOSION

HAZARD

Failure to follow this warning could result in personal

injury or death, or property damage.
Before installing, modifying, or servicing system, main

electrical disconnect switch must be in the OFF

position and install a lockout tag.  There may be more

than one disconnect switch.  Lock out and tag switch

with a suitable warning label.  Verify proper operation

after servicing.

!

WARNING

ELECTRICAL OPERATION HAZARD

Failure to follow this caution may result in improper

furnace operation or failure of furnace.
Label all wires prior to disconnection when servicing

controls. Wiring errors can cause improper and

dangerous operation.

CAUTION

!

Figure 6

Multipoise Orientations

A93041

General

These instructions are written as if the furnace is installed in an

upflow application. An upflow furnace application is where the

blower is located below the combustion and controls section of

the furnace, and conditioned air is discharged upward. Since

this furnace can be installed in any of the 4 positions shown in

Figure 6

, you must revise your orientation to component

location accordingly.

Electrical Controls and Wiring
Pressure Switches

Each pressure switch is labeled with the reference location

(noted as “COLLECTOR BOX

LPS” or “HOUSING

HPS” ON

THE SWITCH). The nominal break point of each switch is

shown on the label below the reference location in inches of

water column, “W.C.” The maximum and minimum break point

of the switch is +/

 0.05 inches of water column from the

nominal break point of the switch. The maximum make point of

the switch is 0.10 inches of water above the maximum break

point of the switch

Example:

 Nominal break point on pressure switch is 0.68

in.

W.C. The minimum break point of the switch is 0.63

in. W.C.

The maximum break point of the switch is 0.73

in. W.C. The

maximum make point of the switch is 0.83

in. W.C.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.
There may be more than one electrical supply to the

furnace. Check accessories and cooling unit for additional

electrical supplies that must be shut off during furnace

servicing.  Lock out and tag switch with a suitable warning

label.

!

WARNING

The electrical ground and polarity for 115

V wiring must be

properly maintained. Refer to 

Figure 7

 for field wiring

information and to 

Figure 15

 for furnace wiring information.

NOTE

:  If the polarity is not correct, the STATUS LED on the

control will flash code 10 and prevent the furnace from heating.

The control system also requires an earth ground for proper
operation of the control and flame

sensing electrode.

The 24

V circuit contains an automotive

type, 3

amp. fuse

located on the control. (See 

Figure 4

) Any shorts of the 24

V

wiring during installation, service, or maintenance will cause

this fuse to blow. If fuse replacement is required, use ONLY a

3

amp. fuse. The control LED display will be off when fuse

needs to be replaced.

Troubleshooting

Refer to the service label. (See 

Figure 14

—Service Label)

The Troubleshooting Guide 

 Flow Chart (See 

Figure 16

) can

be a useful tool in isolating furnace operation problems.

Beginning with the word “Start,” answer each question and

follow the appropriate arrow to the next item.
The Guide 

 Flow Chart will help to identify the problem or

failed component. After replacing any component, verify correct

operation sequence.
Proper instrumentation is required to service electrical controls.

The control in this furnace is equipped with a Status Code LED

(Light

Emitting  Diode) to aid in installation, servicing, and

troubleshooting. Status codes can be viewed at the indicator in

blower door. The green furnace control LED is either ON

heartbeat, off or a code composed of 1 or 2 digits. The first digit

is the number of short flashes, the second digit is the number of

long flashes.

Summary of Contents for N9MSE0401712A

Page 1: ...or pictures or product labels The signal word WARNING is used throughout this manual in the following manner Safety alert symbol When you see this symbol on the unit and in instructions or manuals be...

Page 2: ...eath WARNING signifies hazards which could result in personal injury or death CAUTION is used to identify unsafe practices which may result in minor personal injury or product and property damage NOTE...

Page 3: ...am of Furnace Drip Leg Gas Valve turned ON Type of Gas Natural Propane Filter Type and Size Check in box the Blower OFF Delay Jumper Heating Position for Fan Time OFF Setting 1 and 2 2 and 3 3 and 4 5...

Page 4: ...is energized whenever blower operates HUM 24vac terminal is only energized the draft inducer is energized in heating Prime Condensate Trap with Water CARBON MONOXIDE POISONING HAZARD Failure to follo...

Page 5: ...ce has the correct orifice installed At higher altitudes or different gas heat contents it may be necessary to change the factory orifice to a different orifice Tables have been provided in the furnac...

Page 6: ...rewdriver counterclockwise out to decrease input rate or clockwise in to increase input rate NOTICE DO NOT set low heat manifold pressure less than 2 8 in w c 697 Pa or more than 3 8 in w c 947 Pa for...

Page 7: ...24 VAC CONNECTIONS P2 HOT SURFACE IGNITOR HSI INDUCER MOTOR IND CONNECTOR 115 VAC L1 LINE VOLTAGE CONNECTION SPARE1 COM BLUE 115 VAC L2 NEUTRAL CONNECTIONS 24 V THERMOSTAT TERMINALS HUMIDIFIER TERMINA...

Page 8: ...300 21 171 343 857 62 58 116 290 22 164 327 818 64 56 112 281 23 157 313 783 66 54 109 273 24 150 300 750 68 53 106 265 25 144 288 720 70 51 103 257 26 138 277 692 72 50 100 250 27 133 267 667 74 48 9...

Page 9: ...42 3 4 42 3 5 42 3 6 3001 800 43 3 8 42 3 2 42 3 3 42 3 4 915 825 43 3 6 43 3 7 43 3 8 42 3 2 850 44 3 8 43 3 5 43 3 6 43 3 7 875 44 3 6 44 3 7 43 3 4 43 3 5 4000 900 44 3 4 44 3 5 44 3 7 44 3 8 1219...

Page 10: ...ding Leaving blower door off will result in incorrect temperature measurements due to possible changes in duct static pressure and airflow FURNACE DAMAGE HAZARD Failure to follow this caution may resu...

Page 11: ...minals R and W The thermostat anticipator should NOT be in the circuit while measuring current 1 Remove thermostat from sub base or from wall 2 Connect an amp meter across the R and W sub base termina...

Page 12: ...85 750 715 665 605 0802120 BOTTOM or TWO SIDES 3 4 Black 2360 2250 2160 2065 1970 1880 1785 1685 1580 1455 Yellow 2100 2030 1960 1885 1805 1720 1635 1545 1440 1305 Orange 1840 1810 1765 1725 1665 1590...

Page 13: ...nominal break point of each switch is shown on the label below the reference location in inches of water column W C The maximum and minimum break point of the switch is 0 05 inches of water column fro...

Page 14: ...D 6 A component test sequence will follow 7 Reinstall the Main Control door Component Self Test NOTE The furnace control component test allows all components to run for a short time except the gas val...

Page 15: ...rvice as necessary 4 Inspect burner compartment before each heating season for rust corrosion soot or excessive dust If necessary have furnace and burner serviced by a qualified service agency 5 Inspe...

Page 16: ...t on blower wheel remove wheel from the blower housing and wash it with an appropriate degreaser To remove wheel a Mark blower wheel location on shaft before disassembly to ensure proper reassembly b...

Page 17: ...old or damaging the mounting to the burner assembly ELECTRICAL SHOCK AND FIRE HAZARD Failure to follow this warning could result in personal injury death and or property damage Turn off the gas and el...

Page 18: ...ontrol door when complete Servicing Hot Surface Igniter The igniter does NOT require annual inspection Check igniter resistance before removal Refer to Figure 9 Figure 10 and Figure 11 1 Turn off gas...

Page 19: ...r drain extension elbow to the condensate trap 7 Connect the leads of the condensate heat pad if used 8 Connect external drain piping to the condensate drain elbow or drain extension pipe 9 Turn gas o...

Page 20: ...ratures may be 32_ F 0_ C or lower freeze protection measures must be taken to prevent property or product damage CAUTION Since the furnace uses a condensing heat exchanger some water will accumulate...

Page 21: ...SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace N9MSE Specifications subject to change without notice 440 04 4402 03 21 Figure 14 Service Label 338310 2 Rev F...

Page 22: ...SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace N9MSE Specifications subject to change without notice 22 440 04 4402 03 Figure 15 Wiring Diagram 339241 2 Rev A...

Page 23: ...nce Gas valve and humidifier will not be turned on Inducer motor will start and remain on until the end of the blower test then off The following components are on for 10 15 seconds each individually...

Page 24: ...nt test Does the igniter glow orange white by the end of the 15 second warm up period Unplug igniter harness from control and repeat component test Check for 115V between connector P2 HSI and NEUTRAL...

Page 25: ...econds after the gas valve GV is energized Simultaneously the electronic air cleaner terminal EAC is energized and remains energized as long as the blower motor BLWM is energized f Heat Off Delay When...

Page 26: ...ctor box Condensate trap Condensate trap elbow Gaskets WARNING FIRE EXPLOSION ELECTRICAL SHOCK AND CARBON MONOXIDE POISONING HAZARD Failure to follow this warning could result in dangerous operation p...

Page 27: ...ble Speed X ECM S Single stage T Two stage FEATURE B Base AFUE Efficiency E Extra AFUE Efficiency C Communicating D Dual Certified 2 pipe or 1 pipe R 2 pipe only S Single stage T Two stage N Standard...

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