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SERVICE AND TECHNICAL SUPPORT MANUAL

Gas Furnace: N9MSB

Specifications  subject to change without notice.

10

440 04 4413 00

Table 3 (CONT.)

Orifice Size and Manifold Pressure (in. w.c.) for Gas Input Rate 

 Single Stage

A11253B

S

A

G

L

A

R

U

T

A

N

F

O

Y

T

I

V

A

R

G

C

I

F

I

C

E

P

S

S

A

G

.

G

V

A

HEAT VALUE

0.58

0.60

0.62

0.64

AT ALTITUDE

Orifice

Manifold

Orifice

Manifold

Orifice

Manifold

Orifice

Manifold

(Btu/cu ft)

No.

Pressure

No.

Pressure

No.

Pressure

No.

Pressure

ALTITUDE

RANGE

ft (m)

SINGLE-STAGE FURNACE

(TABULATED DATA BASED ON 20,000 BTUH PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL)

650

42

3.4

42

3.5

42

3.6

42

3.7

7001

675

43

3.8

42

3.2

42

3.3

42

3.4

(2134)

700

43

3.5

43

3.7

43

3.8

42

3.2

725

44

3.8

43

3.4

43

3.5

43

3.6

750

44

3.5

44

3.7

44

3.8

43

3.4

8000

775

44

3.3

44

3.4

44

3.5

44

3.7

(2438)

800

44

3.1

44

3.2

44

3.3

44

3.4

825

44

2.9

44

3.0

44

3.1

44

3.2

625

42

3.4

42

3.5

42

3.6

42

3.7

8001

650

43

3.8

42

3.2

42

3.3

42

3.4

(2439)

675

43

3.5

43

3.6

43

3.7

42

3.2

700

44

3.7

43

3.4

43

3.5

43

3.6

725

44

3.5

44

3.6

44

3.7

44

3.8

9000

750

44

3.3

44

3.4

44

3.5

44

3.6

(2743)

775

44

3.0

44

3.2

44

3.3

44

3.4

9001

600

42

3.3

42

3.4

42

3.6

42

3.7

(2744)

625

43

3.7

42

3.2

42

3.3

42

3.4

650

43

3.5

43

3.6

43

3.7

43

3.8

675

44

3.7

44

3.8

43

3.4

43

3.5

10000

700

44

3.4

44

3.5

44

3.7

44

3.8

(3048)

725

44

3.2

44

3.3

44

3.4

44

3.5

* Orifice numbers shown in

BOLD

are factory-installed.

to

to

to

U.

S

.A.

On

ly

U.

S

.A.

On

ly

U.

S

.A.

On

ly

Adjust Temperature Rise

NOTE

:  Blower door must be installed when taking temperature

rise reading. 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 result in:

S

Overheating the heat exchangers or condensing

flue gases in heat exchanger areas not designed

for condensate.

S

Shortened furnace life.

S

Component damage.

Temperature rise must be within limits specified on furnace

rating plate. Recommended operation is at midpoint of rise

range or slightly above.

CAUTION

!

Jumper R to W to check gas-heat temperature rise. Do not

exceed temperature rise ranges specified on unit rating plate.
This furnace must operate within the temperature rise ranges

specified on the furnace rating plate. Determine the air

temperature as follows:

1. Place duct thermometers in return and supply ducts as

close to furnace as possible. Be sure thermometers do

not “see” heat exchangers so that radiant heat does not

affect thermometer readings. This is particularly

important with straight

run ducts.

2. When thermometer readings stabilize, subtract return

air

temperature from supply

air temperature to determine

temperature rise.

If the temperature rise is outside this range, check the

following:

1. Gas input rate.
2. Derate for altitude if applicable.
3. Return and supply ducts for excessive restrictions

causing static pressures greater than 0.50

in. w.c. (125

Pa)

4. Adjust temperature rise by adjusting blower speed.

S

Increase blower speed to reduce temperature rise.

S

Decrease blower speed to increase temperature rise.

ELECTRICAL OPERATION HAZARD

Failure to follow this warning could result in personal injury

or death.
Disconnect 115vac electrical power before changing speed

tap.

!

WARNING

Summary of Contents for N9MSB0401410C

Page 1: ...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 alert to the potential for pe...

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: ...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 furnace S...

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: ...e terminals 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 te...

Page 12: ...2 5 394 1030 1025 1030 1010 985 940 905 855 805 735 801716C SIDE BOTTOM Black 4 0 389 1650 1620 1640 1605 1555 1495 1425 1345 1255 1165 Yellow 3 5 381 1420 1425 1400 1370 1335 1290 1230 1170 1095 1015...

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: ...LED 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 v...

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: ...ck for proper operation 18 Install control door when complete Servicing Hot Surface Igniter The igniter does NOT require annual inspection Check igniter resistance before removal Refer to Figure 9 Fig...

Page 19: ...6 Connect condensate drain elbow or 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...

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 N9MSB Specifications subject to change without notice 440 04 4413 00 21 Figure 14 Service Label 338310 2 Rev F...

Page 22: ...SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace N9MSB Specifications subject to change without notice 22 440 04 4413 00 Figure 15 Wiring Diagram 339241 2 Rev A...

Page 23: ...quence 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 individual...

Page 24: ...onent 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 NEUTR...

Page 25: ...ds 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 the...

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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