International Comfort Products F9MXT0401410A, F9MXT0601714A, F9MXT0801716A, F9MXT0802120A, F9MXT1002120A TECHNICAL MANUAL
...
SERVICE AND TECHNICAL
SUPPORT MANUAL
Two−Stage, 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.
Signal Words in Manuals
The signal word WARNING is used throughout
this manual in the following manner:
!
WARNING
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.
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 LINES 4......................................
ADJUSTMENTS 5.........................................
ADJUST TEMPERATURE RISE 10............................
ADJUST BLOWER OFF DELAY (HEAT MODE) 11..............
ADJUST COOLING AIRFLOW 11.............................
ADJUST CONTINUOUS FAN AIRFLOW 11....................
ADJUST THERMOSTAT HEAT ANTICIPATOR 11...............
CHECK SAFETY CONTROLS 12.............................
CHECKLIST 12.............................................
SERVICE AND MAINTENANCE PROCEDURES 13.............
ELECTRICAL CONTROLS AND WIRING 13...................
TROUBLESHOOTING 13....................................
CLEANING AND/OR REPLACING AIR FILTER 15..............
BLOWER MOTOR AND WHEEL MAINTENANCE 15............
CLEANING BURNERS AND FLAME SENSOR 17...............
SERVICING HOT SURFACE IGNITER 18......................
FLUSHING COLLECTOR BOX AND DRAINAGE SYSTEM 18....
CLEANING CONDENSATE DRAIN AND TRAP 19..............
CLEANING HEAT EXCHANGERS 19..........................
SERVICE LABEL 21.........................................
WIRING DIAGRAM 22.......................................
SEQUENCE OF OPERATION 25.............................
PARTS REPLACEMENT INFORMATION GUIDE 29.............
PRODUCT NOMENCLATURE 30.............................
MODELS
(F/G)9MXT0401410A
(F/G)9MXT0601714A
(F/G)9MXT0801716A
(F/G)9MXT0802120A
(F/G)9MXT1002120A
(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 .
Printed in U.S.A. 440 04 4321 04 July 2012
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service,
maintenance, or use can cause explosion, fire, electrical shock,
or other conditions which may cause death, personal injury, or
property damage. Consult a qualified installer, service agency,
or your distributor or branch for information or assistance. The
qualified installer or agency must use factory−authorized kits or
accessories when modifying this product. Refer to the individual
instructions packaged with the kits or accessories when
installing.
Follow all safety codes. Wear safety glasses, protective clothing,
and work gloves. Use quenching cloth for brazing operations.
Have fire extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions included in
literature and attached to the unit. Consult local building codes,
the current editions of the National Fuel Gas Code (NFCG)
NFPA 54/ANSI Z223.1, and the National Electrical Code (NEC)
NFPA 70.
In Canada refer to the current editions of the National standards
of Canada CAN/CSA−B149.1 and .2 Natural Gas and Propane
Installation Codes, and Canadian Electrical Code CSA C22.1.
Recognize safety information. This is the safety−alert symbol
. When you see this symbol on the unit and in instructions or
manuals, be alert to the potential for personal injury.
Understand these signal words; DANGER, WARNING, and
CAUTION. These words are used with the safety−alert symbol.
DANGER identifies the most serious hazards which will result in
severe personal injury or 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 warning could
result in equipment malfunction, property damage,
personal injury and/or death.
Installation or repairs made by unqualified persons could
result in equipment malfunction, property damage,
personal injury and/or death.
The information contained in this manual is intended for
use by a qualified service technician familiar with safety
procedures and equipped with proper tools and test
instruments.
Installation must conform with local building codes and
with the Natural Fuel Gas Code (NFCG) NFPA 54/ANSI
Z223.1, and National standards of Canada
CAN/CSA−B149.1 and .2 Natural Gas and Propane
Installation Codes.
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal
injury or death.
Before performing service or maintenance operations
on unit, always turn off main power switch to unit and
install lockout tag. Unit may have more than one power
switch.
!
WARNING
WARNING
CARBON MONOXIDE POISONING AND FIRE
HAZARD
Failure to follow safety warnings could result in personal
injury, death, and/or property damage.
This furnace is not designed for use in mobile homes,
trailers or recreational vehicles.
!
CAUTION
CUT HAZARD
Failure to follow this caution may result in damage
personal injury.
Sheet metal parts may have sharp edges or burrs. Use
care and wear appropriate protective clothing, safety
glasses and gloves when handling parts and servicing
furnaces.
2
Specifications are subject to change without notice.
440 04 4321 04
SERVICE AND TECHNICAL MANUAL Gas Furnace: (F/G)9MXT
START−UP CHECK SHEET
For PSC Models (F/G)9MXT
(This sheet is optional. Keep for future reference.)
Date of Start−Up:
Dealer Name:
Address:
City, State(Province), Zip or Postal Code:
Phone:
Owner Name:
Address:
City, State(Province), Zip or Postal Code:
Model Number:
Serial Number:
Setup Checks
Check the box when task is complete.
All Electrical Connections Tight?
Have hoses been relocated for furnace U/D/H application?
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 Return Air:
Temperature Rise (Supply − Return): High Heat
Low Heat
In Rise Range (see furnace rating plate)?
Static Pressure (Ducts) High Heat: Supply
Return
The Blower Speed Tap used for: High Heat
Low Heat
Optional Check: CO?
CO2?
Cooling Check
Condensate Drain Connected?
Condensate Drain Trapped?
Manual Gas Shut−off Upstream of 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:
OFF
ON
TT
OFF
DLY
1 2 3
Temperature of Supply Air:
Temperature of Return Air:
Temperature Difference:
Static Pressure (Ducts) Cooling: Supply
Return
The Blower Speed Tap used for: Cooling
Dealer Comments:
440 04 4321 04 3
Specifications subject to change without notice.
SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace: (F/G)9MXT
START−UP, ADJUSTMENT, AND SAFETY
CHECK
General
1. Furnace must have a 115-v power supply properly
connected and grounded.
NOTE: Proper polarity must be maintained for 115-v wiring.
Control status indicator light flashes code 10 and furnace does
not operate if polarity is incorrect or if the furnace is not
grounded.
Thermostat wire connections at terminals R, W/W1, G,
2.
and Y/Y2 must be made at 24-v terminal block on
furnace control.
3. Natural gas service pressure must not exceed 0.5 psig
(14-in. w.c., 350 Pa), but must be no less than 0.16 psig
(4.5-in. w.c., 1125 Pa).
4. Blower door must be in place to complete 115-v electrical
circuit and supply power to the furnace components.
!
CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution may result in intermittent unit
operation or performance dissatisfaction.
These furnaces are equipped with a manual reset limit
switch in burner assembly. This switch opens and shuts off
power to the gas valve if an overheat condition (flame
rollout) occurs in the burner assembly/enclosure. Correct
inadequate combustion-air supply, improper gas pressure
setting, improper burner or gas orifice positioning, or
improper venting condition before resetting switch. DO
NOT jumper this switch.
Before operating furnace, check flame rollout manual reset
switch for continuity. If necessary, press button to reset switch.
EAC-1 terminal is energized whenever blower operates. HUM
terminal is only energized when the the gas valve is energized
in heating.
Thermostat Setup Switch
This furnace can be installed with either a single−stage heating
or a two−stage heating thermostat. Setup switch SW−1 (TT) is
used to configure the furnace for single or two stage thermostat
operation. (See Figure 4)
For single−stage thermostats, connect 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 SW−1 (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 SW−1 (TT) to ON position before starting furnace. This
overrides built−in control process for selecting high and low
heat and allows the two−stage thermostat to select gas heating
modes. The W2 from thermostat must be connected to W2 on
control terminal block.
Prime Condensate Trap with Water
! WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow these warnings could result in personal injury
or death.
Failure to use a properly configured trap or NOT
water-priming trap before operating furnace may allow
positive pressure vent gases to enter the structure through
drain tube. Vent gases contain carbon monoxide which is
tasteless and odorless.
1. Remove upper and middle collector box drain plugs
opposite of the condensate trap. (See Figure 1)
2. Connect field-supplied 5/8-in. (16 mm) ID tube with
attached funnel (see Figure 1) to upper collector box
drain connection.
3. Pour one quart (liter) of water into funnel/tube. Water
should run through collector box, overfill condensate
trap, and flow into open field drain.
4. Remove funnel; replace collector box drain plug.
5. Connect field-supplied 5/8-in. (16 mm) ID tube to middle
collector box drain port.
6. Pour one quart (liter) of water into funnel/tube. Water
should run through collector box, overfill condensate
trap, and flow into open field drain.
7. Remove funnel and tube from collector box and replace
collector box drain plug.
Figure 1 Priming Condensate Drain
Representative drawing only, some models may vary in appearance.
L11F065
Purge Gas Lines
If not previously done, purge the lines after all connections
have been made and check for leaks.
4 440 04 4321 04
Specifications subject to change without notice.
SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace: (F/G)9MXT
! WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death, and/or property damage.
Never purge a gas line into a combustion chamber. Never
test for gas leaks with an open flame. Use a commercially
available soap solution made specifically for the detection of
leaks to check all connections. A fire or explosion may result
causing property damage, personal injury or loss of life.
Adjustments
!
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death and/or property damage.
DO NOT bottom out gas valve regulator adjusting screw.
This can result in unregulated manifold pressure and
result in excess overfire and heat exchanger failures.
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in reduced furnace
life.
DO NOT redrill orifices. Improper drilling (burrs,
out−of−round holes, etc.) can cause excessive burner
noise and misdirection of burner flames. This can result in
flame impingement of heat exchangers, causing failures.
(See Figure 2)
Figure 2 Orifice Hole
For proper operation and long term reliability the furnace input
rate must be within +/−2 percent of input rate on furnace rating
plate, or as adjusted for altitude.
The gas input rate on rating plate is for installation at altitudes
up to 2000 ft. (610 M).
WARNING
!
CAUTION
BURNER
ORIFICE
A93059
NOTICE
The NATURAL GAS manifold pressure adjustments in Table 3
compensate for BOTH altitude AND gas heating value. DO
NOT apply an additional de−rate factor to the pressures shown
in Table 3.
The heating content of natural gas at altitude may already
provide for a reduction in capacity or altitude. Refer to Table 3.
No adjustments to the furnace may be necessary at altitude for
certain gas heating values.
Refer to the instructions provided in the factory-specified
LP/Propane conversion kit for instructions for setting gas
manifold pressures for LP/Propane applications.
In the USA, the input rating for altitudes above 2000 ft. (610 M)
must be reduced by 2 percent for each 1000 ft. (305 M) above
sea level refer to Table 1. The natural gas manifold pressures
in Table 3 adjust for BOTH altitude and natural gas heating
value.
In Canada, the input rating must be reduced by 5 percent for
altitudes of 2000 ft. to 4500 ft. (610 to 1372 M) above sea level.
The natural gas manifold pressures in Table 3 adjust for BOTH
altitude and natural gas heating value.
NOTE: For Canadian altitudes of 2000 to 4500 ft. (610 to 1372
M), use USA altitudes of 2001 to 3000 ft. (611 to 914 M) in
Table 3.
Table 1 Altitude Derate Multiplier for USA
ALTITUDE
FT. (M)
0–2000
(0−610)
2001–3000
(610−914)
3001–4000
(914−1219)
4001–5000
(1219−1524)
5001–6000
(1524−1829)
6001–7000
(1829−2134)
7001–8000
(2134−2438)
8001–9000
(2438−2743)
9001–10,000
(2743−3048)
* Derate multiplier factors are based on midpoint altitude for altitude range.
NOTE: For Canadian altitudes of 2000 to 4500 ft. (610 to
1372 M), use USA altitudes of 2001 to 3000 ft. (610 to 914
M)
To adjust manifold pressure to obtain the proper input rate, first,
determine if the furnace 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 Service and
Technical Manual to match the required orifice to the manifold
pressure to the heat content and specific gravity of the gas. to
do this:
1. Obtain average yearly gas heat value (at installed
altitude) from local gas supplier.
PERCENT
OF DERATE
0 1.00
4−6 0.95
6−8 0.93
8−10 0.91
10−12 0.89
12−14 0.87
14−16 0.85
16−18 0.83
18−20 0.81
DERATE MULTIPLIER
FACTOR*
440 04 4321 04 5
Specifications subject to change without notice.
SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace: (F/G)9MXT
2. Obtain average yearly gas specific gravity from local gas
supplier.
3. Find installation altitude in Table 3.
4. Find closest natural gas heat value and specific gravity in
Table 3. Follow 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.
5. Check and verify burner orifice size in furnace. NEVER
ASSUME ORIFICE SIZE. ALWAYS CHECK AND
VERIFY.
FIRE HAZARD
Failure to follow this warning could result in personal injury,
death, and/or property damage.
Re−install manifold pressure tap plug in gas valve to
prevent gas leak.
14. Apply pipe dope sparingly to end of inlet gas pipe plug
!
WARNING
and re−install in the gas valve.
Adjust Manifold Pressure
NOTICE
If orifice hole appears damaged or it is suspected to have been
redrilled, check orifice hole with a numbered drill bit of correct
size. Never redrill an orifice. A burr−free and squarely aligned
orifice hole is essential for proper flame characteristics.
6. Replace orifice with correct size, if required by Table 3.
Use only factory−supplied orifices. See EXAMPLE 1.
EXAMPLE 1:
0 - 2000 ft. (0 - 609.6M) altitude
Heating value = 1050 Btu/cu ft.
Specific gravity = 0.62
Therefore: Orifice No. 44
(Furnace is shipped with No. 44 orifices. In this example, all
main burner orifices are the correct size and do not need to be
changed to obtain proper input rate.)
Manifold pressure: 3.4-in. w.c. (847 Pa) for high heat, 1.4-in.
w.c. (349 Pa) for low heat
NOTE: To convert gas manifold Table pressures to Pascals,
multiply the in.w.c. value by 249.1 Pa/in. w.c. (1 in. wc. = 249.1
Pa).
Check Inlet Gas Pressure
The inlet gas pressure must be checked with the furnace
operating in maximum heat. This is necessary to make sure the
inlet gas pressure does not fall below the minimum pressure of
4.5 in. w.c.
1. Make sure the gas supply is turned off to the furnace and
at the electric switch on the gas valve.
2. Remove the 1/8 in. NPT plug from the inlet pressure tap
on the gas valve.
3. Connect a manometer to the inlet pressure tap on gas
valve.
4. Turn on furnace power supply.
5. Turn gas supply manual shutoff valve to ON position.
6. Turn furnace gas valve switch to ON position.
7. Jumper the R to W/W1 and W2 thermostat connections
at the furnace control board.
8. When main burners ignite, confirm inlet gas pressure is
between 4.5 in. w.c. (1125 Pa) and 13.6 in. w.c. (3388
Pa).
9. Remove jumper across thermostat connections to
terminate call for heat. Wait until the blower off delay is
completed.
10. Turn furnace gas valve electric switch to OFF position.
11. Turn gas supply manual shutoff valve to OFF position.
12. Turn off furnace power supply.
13. Remove manometer from the inlet pressure tap of the
gas valve.
1. Adjust manifold pressure to obtain low fire input rate.
(See Figure 3)
a. Turn gas valve ON/OFF switch to OFF.
b. Remove manifold pressure tap plug from gas valve.
c. Connect a water column manometer or similar device
to manifold pressure tap.
d. Turn gas valve ON/OFF switch to ON.
e. Move setup switch SW−1 (TT) on furnace control to
ON position to lock furnace in low−heat operation.
(See Figure 4 and Figure 15)
f. Manually close blower door switch.
g. Jumper R and W/W1 thermostat connections on
control to start furnace. (See Figure 4)
h. Remove regulator adjustment cap from low heat gas
valve pressure regulator (See Figure 3) and turn
low−heat adjusting screw (3/16 or smaller flat−tipped
screwdriver) counterclockwise (out) to decrease input
rate or clockwise (in) to increase input rate.
NOTICE
DO NOT set low−heat manifold pressure less than 1.3−in. w.c.
(324 Pa) or more than 1.7−in. w.c. (423 Pa) for natural gas. If
required manifold pressure is outside this range, change main
burner orifices.
Figure 3
1/2” NPT Inlet
1/8” NPT Inlet
Pressure Tap
i. Install low−heat regulator adjustment cap.
j. Move setup switch SW−1 (TT) to off position after
completing low−heat adjustment.
Redundant Automatic Gas Control
Valve (2−Stage)
ON/OFF Switch
Regulator Seal Cap
Regulator Adjustment
Regulator Seal Cap under Cap
1/8” NPT Manifold
Pressure Tap
1/2” NPT Outlet
A11152
6 440 04 4321 04
Specifications subject to change without notice.
SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace: (F/G)9MXT
k. Leave manometer or similar device connected and
proceed to Step 2.
2. Adjust manifold pressure to obtain high fire input rate.
(See Figure 3)
a. Jumper R to W/W1 and W2 thermostat connections
on furnace control. This keeps furnace locked in
high−heat operation.
b. Remove regulator adjustment cap from high−heat
gas valve pressure regulator (See Figure 3) and turn
high heat adjusting screw (3/16−in. or smaller
flat−tipped screwdriver) counterclockwise (out) to
decrease input rate or clockwise (in) to increase input
rate.
NOTICE
DO NOT set high−heat manifold pressure less than 3.2−in. w.c.
(797 Pa) or more than 3.8 in. w.c. (947 Pa) for natural gas. If
required 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 Figure 13)
d. Reinstall manifold pressure tap plug to gas valve.
e. Remove jumpers R to W/W1 and R to W2.
3. Verify natural gas input rate by clocking meter.
NOTE: Contact your HVAC distributor or gas supplier for metric
gas meter Tables, if required.
a. Turn off all other gas appliances and pilots served by
the meter.
b. Move setup switch SW−1 (TT) to ON position. This
keeps furnace locked in low−heat operation when
only W/W1 is energized.
c. Jumper R to W/W1.
d. Run furnace for 3 minutes in low−heat operation.
e. Measure time (in sec) for gas meter to complete one
revolution and note reading. The 2 or 5 cubic feet dial
provides a more accurate measurement of gas flow.
f. Refer to Table 2 for cubic ft. of gas per hr.
g. Multiply gas rate cu ft./hr by heating value (Btuh/cu
ft.) to obtain input rate.
h. If clocked rate does not match required input from
Step 1, increase manifold pressure to increase input
or decrease manifold pressure to decrease input.
Repeat steps b through e of Step 1 until correct
low−heat input is achieved. Re−install low heat
regulator seal cap on gas valve.
i. Jumper R to W/W1, and W2. This keeps furnace
locked in high--heat operation when both W/W1 and
W2 are energized.
j. Repeat items (d) through (h) for high-heat operation,
repeating Step 2 and adjusting the high-heat
regulator screw, as required.
4. Restore furnace to normal operating condition.
a. Turn gas valve ON/OFF switch to OFF.
b. Remove water column manometer or similar device
from manifold pressure tap.
c. Replace manifold pressure tap plug to gas valve.
d. Turn gas valve ON/OFF switch to ON.
e. Move setup SW-1 switch (TT) on furnace control to
position required for attached thermostat (OFF for
single-stage thermostats, ON for two-stage
thermostats).
f. Check for gas leaks and verify furnace operation.
!
FIRE HAZARD
Failure to follow this warning could result in personal injury,
death, and/or property damage.
Re−install manifold pressure tap plug in gas valve to
prevent gas leak.
WARNING
440 04 4321 04 7
Specifications subject to change without notice.
SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace: (F/G)9MXT
Figure 4 Example of Two−Stage Furnace Control Board
SET UP SWITCHES
THERMOSTAT TYPE (TT)
AND HEAT OFF−DELAY
SW1
ON
OFF
Table 2
SECONDS G
FOR 1 REVOLUTION
W2 Y1 DHUM G COM W/W1 Y/Y2 R
24−V THERMOS TAT
TERMINALS
3−AMP FUSE
LED OPERATION
& DIAGNOSTIC LIGHT
COM
24V
BLOWER SPEED
TERMINALS
115−VAC (L2)
NEUTRAL
CONNECTIONS
24V
COM
HI HT
COOL
LO H T
SPARE 2
SPARE 1
L2
TEST / TWIN
24VAC
FUSE 3−AMP
COM/BLUE 24VAC/RED
24V MTR TAPS
EAC−2
Gas Rate (CU ft./hr)
1 Cu Ft. 2 Cu Ft. 5 Cu Ft. 1 Cu Ft. 2 Cu Ft. 5 Cu Ft.
SIZE OF TEST DIAL SECONDS
FOR 1 REVOLUTION
TWINNING AND/OR
SW1
ON
OFF
COMPONENT TEST
1 2 3
TT
TERMINAL
OFF
DLY
PLT
HUM
PL1
1
EAC TERMINAL
115 VAC 1.0 AMP
MAX
EAC−1
L1 BL−1 XFMR
115 VAC LINE (L1)
INPUT
HUMIDIFIER TERMINAL
(24 VAC 0.5 AMPS MAX)
TRANSFORMER
24 VAC CONNECTIONS
P−1 LOW VOLTAGE
11 5 VA C
BLOWER POWER (BL1)
CONNECTION
HUM
115 VAC HUM
11 5 VA C
TRANSFORMER
PRIMARY
P2 − HOT SURFACE
IGNITER/INDUCE R
MOTOR CONNECTION
HSIR
1
HSI HI LO
IHI/LOR
IDM
IDR
PL2
SIZE OF TEST DIAL
10 360 720 1800 50 72 144 360
11 327 655 1636 51 71 141 355
12 300 600 1500 52 69 138 346
13 277 555 1385 53 68 136 340
14 257 514 1286 54 67 133 333
15 240 480 1200 55 65 131 327
16 225 450 1125 56 64 129 321
17 212 424 1059 57 63 126 316
18 200 400 1000 58 62 124 310
19 189 379 947 59 61 122 305
20 180 360 900 60 60 120 300
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 97 243
28 129 257 643 76 47 95 237
29 124 248 621 78 46 92 231
30 120 240 600 80 45 90 225
31 11 6 232 581 82 44 88 220
32 11 3 225 563 84 43 86 214
33 109 218 545 86 42 84 209
34 106 212 529 88 41 82 205
35 103 206 514 90 40 80 200
36 100 200 500 92 39 78 196
37 97 195 486 94 38 76 192
38 95 189 474 96 38 75 188
39 92 185 462 98 37 74 184
40 90 180 450 100 36 72 180
41 88 176 439 102 35 71 178
42 86 172 429 104 35 69 173
43 84 167 419 106 34 68 170
44 82 164 409 108 33 67 167
45 80 160 400 11 0 33 65 164
46 78 157 391 11 2 32 64 161
47 76 153 383 11 6 31 62 155
48 75 150 375 120 30 60 150
49 73 147 367
8 440 04 4321 04
Specifications subject to change without notice.
L12F037
SERVICE AND TECHNICAL SUPPORT MANUAL Gas Furnace: (F/G)9MXT
Table 3 Orifice Size and Manifold Pressure (in. w.c.) for Gas Input Rate
TWO-STAGE FURNACE
(TABULATED DATA BASED ON 20,000 BTUH HIGH-HEAT / 13,000 BTUH LOW-HEAT PER BURNER,
DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL)
ALTITUDE
RANGE
ft (m)
092543 3.6 / 1.5 43 3.7 / 1.6 43 3.8 / 1.6 42 3.2 / 1.4
(0) 950 43 3.4 / 1.4 43 3.5 / 1.5 43 3.6 / 1.5 43 3.7 / 1.6
to 1000 44 3.5 / 1.5 44 3.6 / 1.5 44 3.8 / 1.6 43 3.4 / 1.4
U.S.A. and CanadaU.S.A. On
y U.S.A. Only U.S.A. and Canada
l
U.S.A. On
ly
ly
U.S.A. On
2000 1050 44 3.2 / 1.3 44 3.3 / 1.4 44 3.4 / 1.4 44 3.5 / 1.5
(610) 1075 45 3.7 / 1.6 45 3.8 / 1.6 44 3.3 / 1.4 44 3.4 / 1.4
U.S.A. 800 42 3.4 / 1.4 42 3.5 / 1.5 42 3.6 / 1.5 42 3.7 / 1.6
2001 (611) 825 43 3.8 / 1.6 42 3.3 / 1.4 42 3.4 / 1.4 42 3.5 / 1.5
to 850 43 3.6 / 1.5 43 3.7 / 1.6 42 3.2 / 1.3 42 3.3 / 1.4
3000 (914) 875 43 3.4 / 1.4 43 3.5 / 1.5 43 3.7 / 1.5 43 3.8 / 1.6
Canada 925 44 3.5 / 1.5 44 3.6 / 1.5 44 3.8 / 1.6 43 3.4 / 1.4
2001 (611) 950 44 3.3 / 1.4 44 3.4 / 1.5 44 3.6 / 1.5 44 3.7 / 1.6
to 975 44 3.2 / 1.3 44 3.3 / 1.4 44 3.4 / 1.4 44 3.5 / 1.5
4500 (1372) 1000 46 3.8 / 1.6 45 3.8 / 1.6 44 3.2 / 1.4 44 3.3 / 1.4
3001 800 43 3.8 / 1.6 42 3.2 / 1.4 42 3.3 / 1.4 42 3.4 / 1.4
(915) 825 43 3.6 / 1.5 43 3.7 / 1.6 43 3.8 / 1.6 42 3.2 / 1.4
to
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
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 43 3.7 / 1.6 43 3.8 / 1.6
to
5000 875 44 3.3 / 1.4 44 3.5 / 1.5 44 3.6 / 1.5 44 3.7 / 1.6
(1524) 900 44 3.2 / 1.3 44 3.3 / 1.4 44 3.4 / 1.4 44 3.5 / 1.5
5001 750 43 3.7 / 1.5 43 3.8 / 1.6 42 3.2 / 1.4 42 3.3 / 1.4
(1525) 775 43 3.4 / 1.4 43 3.5 / 1.5 43 3.7 / 1.5 43 3.8 / 1.6
to
6000 850 44 3.3 / 1.4 44 3.4 / 1.4 44 3.5 / 1.5 44 3.6 / 1.5
(1829) 875 45 3.7 / 1.6 44 3.2 / 1.3 44 3.3 / 1.4 44 3.4 / 1.4
6001 700 42 3.2 / 1.3 42 3.3 / 1.4 42 3.4 / 1.4 42 3.5 / 1.5
(1830) 725 43 3.6 / 1.5 43 3.7 / 1.6 43 3.8 / 1.6 42 3.3 / 1.4
to
7000 800 44 3.4 / 1.4 44 3.5 / 1.5 44 3.6 / 1.5 44 3.7 / 1.6
(2133) 825 44 3.2 / 1.3 44 3.3 / 1.4 44 3.4 / 1.4 44 3.5 / 1.5
HEATVALUE0.580.600.620.64
AT ALTITUDE Orifice Mnfld Press Orifice Mnfld Press Orifice Mnfld Press Orifice Mnfld Press
(Btu/cu ft) No. High/Low No. High/Low No. High/Low No. High/Low
900 43 3.8 / 1.6 42 3.2 / 1.4 42 3.3 / 1.4 42 3.4 / 1.4
975 44 3.7 / 1.6 44 3.8 / 1.6 43 3.4 / 1.5 43 3.6 / 1.5
1025 44 3.3 / 1.4 44 3.5 / 1.5 44 3.6 / 1.5 44 3.7 / 1.6
1100 46 3.7 / 1.6 46 3.8 / 1.6 45 3.8 / 1.6 44 3.2 / 1.4
900 44 3.7 / 1.6 44 3.8 / 1.6 43 3.5 / 1.5 43 3.6 / 1.5
775 42 3.3 / 1.4 42 3.4 / 1.4 42 3.5 / 1.5 42 3.6 / 1.5
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
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
825 44 3.8 / 1.6 43 3.4 / 1.4 43 3.5 / 1.5 43 3.6 / 1.5
850 44 3.5 / 1.5 44 3.7 / 1.5 44 3.8 / 1.6 43 3.4 / 1.4
925 46 3.8 / 1.6 45 3.7 / 1.6 44 3.2 / 1.4 44 3.3 / 1.4
725 42 3.2 / 1.4 42 3.3 / 1.4 42 3.4 / 1.5 42 3.5 / 1.5
800 44 3.7 / 1.6 44 3.8 / 1.6 43 3.4 / 1.5 43 3.5 / 1.5
825 44 3.5 / 1.5 44 3.6 / 1.5 44 3.7 / 1.6 44 3.8 / 1.6
900 46 3.7 / 1.6 46 3.8 / 1.6 45 3.8 / 1.6 44 3.2 / 1.4
675 42 3.4 / 1.4 42 3.5 / 1.5 42 3.6 / 1.5 42 3.8 / 1.6
750 43 3.4 / 1.4 43 3.5 / 1.5 43 3.6 / 1.5 43 3.7 / 1.6
775 44 3.6 / 1.5 44 3.7 / 1.6 43 3.4 / 1.4 43 3.5 / 1.5
850 46 3.8 / 1.6 45 3.8 / 1.6 44 3.2 / 1.4 44 3.3 / 1.4
SAGLARUTANFOYTIVARGCIFICEPSSAG.GVA
A11252A
440 04 4321 04 9
Specifications subject to change without notice.
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