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Printed in U.S.A.

           

440 04 4321 02 

 Aug. 2011

SERVICE AND TECHNICAL

SUPPORT MANUAL

TwoStage, ECM Blower Motor

35” Tall, High Efficiency Condensing Gas Furnace

(F/G)9MXT

Save this manual for future reference.

Safety Labeling and Signal Words

DANGER, WARNING, CAUTION, and NOTE

The signal words 

DANGER, WARNING

,

CAUTION

,

 

and

 NOTE 

are used to identify levels of

hazard seriousness. The signal word

 DANGER 

is

only used on product labels to signify an immediate
hazard. The signal words 

WARNING

CAUTION

,

and 

NOTE

 will be used on product labels and

throughout this manual and other manual that may
apply to the product.

DANGER

  Immediate hazards which will result in

severe personal injury or death.

WARNING

  Hazards or unsafe practices which

could result in severe personal injury or death.

CAUTION 

 Hazards or unsafe practices which

may result in minor personal injury or product or
property damage.

NOTE 

 Used to highlight suggestions which will

result in enhanced installation, reliability, or
operation.

!

WARNING

Signal Words in Manuals

The signal word 

CAUTION

 is used throughout

this manual in the following manner:

!

CAUTION

Signal Words on Product Labeling

Signal words are used in combination with
colors and/or pictures or product labels.

The signal word 

WARNING

 is used throughout

this manual in the following manner:

Safetyalert symbol

When you see this symbol on the unit and in
instructions or manuals, be alert to the
potential for personal injury.

TABLE OF CONTENTS

STARTUP, ADJUSTMENT, AND SAFETY CHECK

4

. . . . . . . . . . .

THERMOSTAT SETUP SWITCH

4

. . . . . . . . . . . . . . . . . . . . . . . . . . .

PRIME CONDENSATE TRAP WITH WATER

4

. . . . . . . . . . . . . . . . .

PURGE GAS LINES

4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ADJUSTMENTS

5

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ADJUST TEMPERATURE RISE

9

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

ADJUST BLOWER OFF DELAY (HEAT MODE)

9

. . . . . . . . . . . . . .

ADJUST COOLING AIRFLOW

9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ADJUST CONTINUOUS FAN AIRFLOW

10

. . . . . . . . . . . . . . . . . . . .

ADJUST THERMOSTAT HEAT ANTICIPATOR

10

. . . . . . . . . . . . . . .

CHECK SAFETY CONTROLS

10

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHECKLIST

10

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SERVICE AND MAINTENANCE PROCEDURES

12

. . . . . . . . . . . . .

ELECTRICAL CONTROLS AND WIRING

12

. . . . . . . . . . . . . . . . . . .

TROUBLESHOOTING

12

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CLEANING AND/OR REPLACING AIR FILTER

14

. . . . . . . . . . . . . .

BLOWER MOTOR AND WHEEL MAINTENANCE

14

. . . . . . . . . . . .

CLEANING BURNERS AND FLAME SENSOR

16

. . . . . . . . . . . . . . .

SERVICING HOT SURFACE IGNITER

17

. . . . . . . . . . . . . . . . . . . . . .

FLUSHING COLLECTOR BOX AND DRAINAGE SYSTEM

17

. . . .

CLEANING CONDENSATE DRAIN AND TRAP

18

. . . . . . . . . . . . . .

CLEANING HEAT EXCHANGERS

18

. . . . . . . . . . . . . . . . . . . . . . . . . .

SERVICE LABEL

20

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

WIRING DIAGRAM

21

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SEQUENCE OF OPERATION

24

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PARTS REPLACEMENT INFORMATION GUIDE

28

. . . . . . . . . . . . .

PRODUCT NOMENCLATURE

29

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MODELS

(F/G)9MXT0401410A
(F/G)9MXT0601714A
(F/G)9MXT0801716A

(F/G)9MXT1002116A

(F/G)9MXT1202422A

Use of the AHRI Certified TM Mark indicates a
manufacturer’s participation in the program.
For verification of certification for individual
products, go to www.ahridirectory.org .

Summary of Contents for F9MXT0401410A

Page 1: ...bination with colors and 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 alert to the potential for personal injury TABLE OF CONTENTS START UP ADJUSTMENT AND SAFETY CHECK 4 THERMOSTAT SETUP SWITCH 4 PRIME CONDENSATE TRAP WITH WATER 4 PURGE GAS LINE...

Page 2: ...death 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 is used to highlight suggestions which will result in enhanced installation reliability or operation WARNING PERSONAL INJURY AND OR PROPERTY DAMAGE HAZARD Failure to carefully read and follow this w...

Page 3: ...Furnace Drip Leg Gas Valve turned ON Type of Gas Natural Propane Filter Type and Size Shade in Heating Fan Time OFF Setting and Thermostat Type setting ON OFF 1 2 3 TT OFF DLY Calculated Input BTU Rate See Checks and Adjustments Section Heating Check Measured Line Pressure During High Heat Measured Manifold Pressure High Heat Low Heat Temperature of Supply Air High Heat Low Heat Temperature of Ret...

Page 4: ... thermostat W to W W1 at furnace control terminal block See Figure 7 For single stage thermostats the control will operate for 12 minutes on low heat then switch to high heat if heat call remains Setup switch TT must be in the factory shipped OFF position See Figure 7 and Figure 15 for setup switch information If a two stage heating thermostat is to be used move setup switch TT to ON position befo...

Page 5: ... heat value and specific gravity lines to point of intersection to find orifice size and low and high heat manifold pressure settings for proper operation f Check and verify burner orifice size in furnace NEVER ASSUME ORIFICE SIZE ALWAYS CHECK AND VERIFY Table 1 Altitude Derate Multiplier for U S A ALTITUDE FT M PERCENT OF DERATE DERATE MULTIPLIER FACTOR 0 2000 0 610 0 1 00 2001 3000 610 914 4 6 0...

Page 6: ...o increase input rate NOTE DO NOT set high heat manifold pressure less than 3 2 in w c or more than 3 8 in w c for natural gas If manifold pressure is outside this range change main burner orifices to obtain manifold pressure in this range c When correct input is obtained replace caps that conceal gas valve regulator adjustment screws Main burner flame should be clear blue almost transparent See F...

Page 7: ...3 8 1 6 42 3 2 1 4 850 44 3 8 1 6 43 3 5 1 5 43 3 6 1 5 43 3 7 1 6 875 44 3 6 1 5 44 3 7 1 6 43 3 4 1 4 43 3 5 1 5 4000 900 44 3 4 1 4 44 3 5 1 5 44 3 7 1 5 44 3 8 1 6 1219 925 44 3 2 1 4 44 3 4 1 4 44 3 5 1 5 44 3 6 1 5 950 45 3 7 1 6 44 3 2 1 3 44 3 3 1 4 44 3 4 1 4 750 42 3 3 1 4 42 3 4 1 4 42 3 5 1 5 42 3 6 1 5 4001 775 43 3 7 1 6 43 3 8 1 6 42 3 3 1 4 42 3 4 1 4 1220 800 43 3 5 1 5 43 3 6 1 5...

Page 8: ... 1 6 9000 750 44 3 3 1 4 44 3 4 1 4 44 3 5 1 5 44 3 6 1 5 2743 775 45 3 7 1 6 44 3 2 1 3 44 3 3 1 4 44 3 4 1 4 9001 600 42 3 3 1 4 42 3 4 1 5 42 3 6 1 5 42 3 7 1 6 2744 625 43 3 7 1 6 42 3 2 1 3 42 3 3 1 4 42 3 4 1 4 650 43 3 5 1 5 43 3 6 1 5 43 3 7 1 6 43 3 8 1 6 675 44 3 7 1 6 44 3 8 1 6 43 3 4 1 4 43 3 5 1 5 10000 700 44 3 4 1 4 44 3 5 1 5 44 3 7 1 5 44 3 8 1 6 3048 725 44 3 2 1 3 44 3 3 1 4 44...

Page 9: ...pply ducts for excessive restrictions causing static pressures greater than 0 50 in w c d Adjust temperature rise by adjusting blower speed e Increase blower speed to reduce temperature rise f Decrease blower speed to increase temperature rise ELECTRICAL OPERATION HAZARD Failure to follow this warning could result in personal injury or death Disconnect 115V electrical power before changing speed t...

Page 10: ...otor if furnace overheats By using this method to check limit control it can be established that limit is functioning properly and will operate if there is a restricted return air supply or motor failure If limit control does not function during this test cause must be determined and corrected a Run furnace for at least 5 minutes b Gradually block off return air with a piece of cardboard or sheet ...

Page 11: ... 375 120 30 60 150 49 73 147 367 Table 6 AIR DELIVERY CFM with filter INPUT BTUH RETURN AIR SUPPLY SPEED EXTERNAL STATIC PRESSURE in w c 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 40 000 SIDE BOTTOM 5 Gry 1120 1080 1030 980 925 875 820 760 690 630 4 Yel 880 845 810 780 740 710 680 640 615 570 3 Blu 695 665 620 575 535 495 455 420 370 280 2 Org 640 595 540 495 460 420 370 310 260 230 1 Red 570 525 475 4...

Page 12: ...n to component location accordingly Figure 6 Multipoise Orientations A93041 Electrical Controls and Wiring 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 swi...

Page 13: ...urnace control component test allows all components to run for a short time except the gas valve and humidifier terminal HUM are not energized The EAC 1 terminal is energized when the blower is energized The HUM terminal is energized when the inducer is energized This feature helps diagnose a system problem in case of a component failure The component test feature will not operate if any thermosta...

Page 14: ... 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 Inspect the vent pipe vent system before each heating season for water leakage sagging pipes or broken fittings Have vent pipes vent system serviced by a qualified service agency 6 Inspect any accessories attached...

Page 15: ... balance will be affected 7 If greasy residue is present 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 Loosen setscrew holding blower wheel on motor shaft NOTE Mark blower mounting arms and blower housing so each arm is positioned at the same hole ...

Page 16: ...mage Turn off the gas and electrical supplies to the furnace and install lockout tag before performing any maintenance or service Follow the operating instructions on the label attached to the furnace WARNING Refer to Figure 9 1 Disconnect power at external disconnect fuse or circuit breaker 2 Turn off gas at external shut off or gas meter 3 Remove control door and set aside 4 Turn electric switch...

Page 17: ...e 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 and electrical supplies to furnace 2 Remove control door 3 Disconnect igniter wire connection 4 Check igniter resistance Igniter resistance is affected by temperature Only check resistance when the igniter is at room tempera...

Page 18: ...ach the relief hose to the relief port on the condensate trap and collector box 5 Secure tubing to prevent any sags or traps in the tubing 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 drain extension pipe 9 Turn gas on at electric switch on gas...

Page 19: ...amage If the furnace is installed in an unconditioned space where the ambient temperatures 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 in the unit as a result of the heat transfer process Therefore once it has been operated it cannot be turned off and ...

Page 20: ...SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace F G 9MXT Specifications subject to change without notice 440 04 4321 02 20 Figure 14 Service Label 338313 2E ...

Page 21: ...SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace F G 9MXT Specifications subject to change without notice 21 440 04 4321 02 Figure 15 Wiring Diagram 338313 2 Rev E ...

Page 22: ...be turned on Inducer motor will start in HIGH speed and remain on HIGH until the end of the blower test then shift to LOW speed for 7 to 15 seconds the following components are on for 10 15 seconds each individually hot surface igniter blower speeds LO HEAT HI HEAT COOL Was there a previous status code Go to section below for the flashed status code Does the control respond to W W1 W2 Y1 Y Y2 and ...

Page 23: ...K check burner carryover and flame sensor location Clean flame sensor with fine steel wool and recheck current Nominal current is 4 0 to 6 0 A DC Is current near typical value Replace electrode Will main burners ignite and stay on Replace furnace control Fixed YES YES NO NO Replace furnace control Check for continuity in the harness and igniter Replace defective component Reconnect the R thermosta...

Page 24: ...utes after ignition If HPS doesn t close after 2 minutes from LPS closing GV is turned off and heat off delay is completed Then a new cycle will begin if a call for heat remains b Igniter Warm Up At the end of the prepurge period the Hot Surface Igniter HSI is energized for a 17 second igniter warm up period c Trial for Ignition Sequence When the igniter warm up period is completed the main gas va...

Page 25: ... and Y1 or R to G and Y1 and Y2circuits are opened The outdoor unit stops and the furnace blower BLWM and electronic air cleaner terminal EAC 1 AMP will remain energized for an additional 90 seconds Jumper Y1 to DHUM to reduce the cooling off delay to 5 seconds See Figure 4 17 Dehumidify Mode See Figure 17 Figure 22 for humidity sensing thermostat connections The dehumidification output H on the h...

Page 26: ...and Y Y2 and G circuits are energized the furnace control CPU will switch to or turn on the blower motor BLWM at COOL speed and begin a high heat cycle The blower motor BLWM will remain on until the end of the prepurge period then shut off for 24 seconds then come back on at HI HEAT speed When the W W1 input signal disappears the furnace control begins a normal inducer post purge period and the bl...

Page 27: ...re 2 Outdoor Air Temperature Sensor must be attached in all dual fuel application 3 Refer to ICP thermostat Installation Instructions for additional information and setup procedure 4 When using a Humidity Sensing Thermostat set DEHUMIDIFY OPTIONS to H DE ENRGZD FOR DEHUM 5 Optional connection for Two Stage If wire is connected SW1 1 TT on furnace control should be set to ON position to allow ICP T...

Page 28: ...e when used Inducer motor capacitor when used Collector 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 personal injury death or property damage Improper installation adjustment alteration service maintenance or use can cause carbon monoxide poisoning ex...

Page 29: ...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 L Low Nox FEATURE 040 40 000 BTU hr 060 60 000 BTU hr 080 80 000 BTU hr 100 100 000 BTU hr 120 120 000 BTU hr INPUT HEAT 14 14 3 16 17 17 1 2 21 21 24 24 1 2 CABINET WIDTH 10 1000 CFM max 14 1400 CFM max 16 1600 CFM max 20 2000 CFM...

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