Lennox SL280DF060NV36B User manual

Page 1 ©2021 Lennox Industries Inc.
100027 SL280DFNV
Service Literature
COMMUNICATING-ENABLED SL280DFNV SERIES UNITS
SL280DFNV series units are ultra low nox, 80% efficiency
gas furnaces used for downflow applications only,
manufactured with Lennox Duralokheat exchangers
formed of aluminized steel. SL280DFNV units are avail
able in heating capacities of 60,000 to 80,000 Btuh and
cooling applications up to 5 tons. Refer to Engineering
Handbook for proper sizing.
SL280DFNV model units are equipped with a communicat
ing enabled SureLight®two-stage variable speed integrated
control. SL280DFNV unit meets the California Nitrogen Ox
ides (NOx) Standards and California Seasonal Efficiency re
quirements. All units use a redundant gas valve to assure
safety shut-off as required by C.S.A.
All specifications in this manual are subject to change. Pro
cedures outlined in this manual are presented as a recom
mendation only and do not supersede or replace local or
state codes. In the absence of local or state codes, the
guidelines and procedures outlined in this manual (except
where noted) are recommendations only and do not consti
tute code.
TABLE OF CONTENTS
Specifications 2..................................
Blower Data 3...................................
Parts Arrangement 5.............................
I Unit Components 6.............................
II Placement 28..................................
III Start-Up 28...................................
IV Heating System Service Checks 28..............
V Typical Operating Characteristics 33..............
VI Maintenance 34...............................
VII Sequence of Operation 37.....................
VIII Field Wiring (non communicating T stat) 42......
IX Program Capacity 46...........................
X Troubleshooting 46............................
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person
al injury or loss of life. Installation and service must
be performed by a licensed professional HVAC in
staller (or equivalent), service agency or the gas sup
plier.
CAUTION
As with any mechanical equipment, contact with
sharp sheet metal edges can result in personal in
jury. Take care while handling this equipment and
wear gloves and protective clothing.

Page 2
SPECIFICATIONS
Gas
Heating
Performance
Model No. SL280DF060NV36B SL280DF080NV60C
1AFUE 80% 80%
High
Fire
Input - Btuh 60,000 80,000
Output - Btuh 48,000 64,000
Temperature rise range - °F 35 - 65 25 - 55
Gas Manifold Pressure (in. w.g.)
Natural Gas Only
3.4 3.4
Low
Fire
Input - Btuh 39,000 52,000
Output - Btuh 34,000 44,000
Temperature rise range - °F 25 - 55 15 - 45
Gas Manifold Pressure (in. w.g.)
Natural Gas Only
1.5 1.5
High static - in. w.g. Heating 0.8 0.8
Cooling 1.0 1.0
Connections
in.
Flue connection − in. round 4 4
Gas pipe size IPS 1/2 1/2
Indoor
Blower
Wheel nominal diameter x width - in. 10 x 8 11-1/2 x 10
Motor output - hp 1/2 1.0
Tons of add-on cooling 2 - 3 3 - 5
Air Volume Range - cfm 600 - 1350 890 - 2270
Electrical Data Voltage 120 volts - 60 hertz - 1 phase
Blower motor full load amps 7.7 12.5
Maximum overcurrent protection 15 15
Shipping Data lbs. - 1 package 123 145
NOTE - Filters and provisions for mounting are not furnished and must be eld provided.
1 Annual Fuel Utilization E󰀩ciency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized
furnaces.
OPTIONAL ACCESSORIES - ORDER SEPARATELY
“B” Width Models “C” Width Models
CABINET ACCESSORIES
Downow Combustible Flooring Base 11M60 11M61
High Performance Economizer (Commercial Only) 10U53 10U53
CONTROLS
iComfort®S30 Ultra-Smart Wi-Fi Thermostat 19V30 19V30
1 Remote Outdoor Temperature Sensor X2658 X2658
² Discharge Air Temperature Sensor 88K38 88K38
DOWNFLOW FILTER KITS
Downow Air Filter and Rack Kit 51W07 51W08
No. and Size of lter - in. (2) 16 x 20 x 1 (2) 16 x 20 x 1
1Remote Outdoor Temperature Sensor is used with conventional (non-iComfort®Communicating) outdoor units (sensor is furnished with iComfort®Communicating
outdoor units). Allows the thermostat to display outdoor temperature. Required in dual-fuel and EDA applications.
2Optional for service diagnostics.
GAS HEAT ACCESSORIES
Input
Natural Gas to
LPG/Propane Kit
0 - 4500 ft.
060 20P40
080 20P41

Page 3
BLOWER DATA
SL280DF060NV36B BLOWER PERFORMANCE (less lter)
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
HEATING
1Heating Speed
DIP Switch
Settings
First Stage Heating Speed - cfm Second Stage Heating Speed - cfm
+24% 1065 1175
+18% 1010 1105
+12% 965 1055
+6% 910 990
Factory Default 855 930
–6% 795 880
–12% 745 820
–18% 695 760
COOLING
1Cooling Speed
DIP Switch
Settings
First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm
Low Medium-Low Medium-High 2High Low Medium-Low Medium-High 2High
+ 730 780 840 960 1000 1090 1215 1350
Factory Default 665 705 760 870 910 990 1095 1220
– 600 635 685 765 810 885 985 1095
1 Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch Settings.
2Factory default setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan Only speed is selectable at 28% and 38% of the selected second stage cooling speed - minimum 380 cfm.
Lennox iHarmony®Zoning System Applications - Minimum blower speed is 380 cfm.
SL280DF060NV36B BLOWER MOTOR WATTS (COOLING)
1Cooling Speed
DIP Switch
Settings
Motor Watts @ Various External Static Pressures - in. wg.
First Stage Second Stage
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
+ Setting
Cooling
Speed
Low 51 65 86 106 125 148 160 179 196 89 116 143 177 193 224 251 269 297 321 350
Med-Low 58 71 98 115 133 157 177 190 215 112 146 174 200 232 261 288 317 338 372 394
Med-High 74 87 115 130 156 178 203 215 239 152 191 228 265 295 324 355 386 416 445 477
High 79 102 136 156 182 207 228 252 279 209 246 293 335 362 399 441 476 508 531 547
Factory Default
Cooling
Speed
Low 45 56 73 92 109 128 145 158 175 71 95 118 143 166 188 212 233 256 277 303
Med-Low 46 57 77 99 119 134 151 168 188 88 113 139 170 194 216 245 268 290 311 336
Med-High 58 70 90 111 134 152 169 191 213 133 146 176 205 230 260 289 320 345 370 406
High 66 87 106 129 147 174 198 216 239 154 191 228 263 294 332 360 391 413 447 475
– Setting
Cooling
Speed
Low 36 47 65 81 98 113 134 146 162 58 76 99 118 144 165 184 202 223 246 267
Med-Low 39 52 69 88 106 124 137 152 171 69 91 110 138 155 183 203 224 246 267 291
Med-High 41 55 75 96 111 131 147 168 187 86 111 139 167 189 216 240 265 289 313 341
High 51 64 89 106 130 153 169 185 211 111 150 189 217 244 270 295 327 348 374 405

Page 4
BLOWER DATA
SL280DF080NV60C BLOWER PERFORMANCE (less lter)
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
HEATING
1Heating Speed
DIP Switch
Settings
First Stage Heating Speed - cfm Second Stage Heating Speed - cfm
+24% 1475 1610
+18% 1385 1515
+12% 1335 1445
+6% 1255 1360
Factory Default 1175 1285
–6% 1100 1195
–12% 1050 1140
–18% 980 1045
COOLING
1Cooling Speed
DIP Switch
Settings
First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm
Low Medium-Low Medium-High 2High Low Medium-Low Medium-High 2High
+ 1090 1220 1380 1575 1575 1800 2000 2270
Factory Default 990 1110 1250 1440 1400 1600 1820 2050
– 890 995 1135 1300 1270 1435 1635 1855
1 Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch Settings.
2Factory default setting.
NOTES - The e󰀨ect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan Only speed is selectable at 28% and 38% of the selected second stage cooling speed - minimum 450 cfm.
Lennox iHarmony®Zoning System Applications - Minimum blower speed is 450 cfm.
SL280DF080NV60C BLOWER MOTOR WATTS (COOLING)
1Cooling Speed
DIP Switch
Settings
Motor Watts @ Various External Static Pressures - in. wg.
First Stage Second Stage
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
+ Setting
Cooling
Speed
Low 96 117 148 175 200 228 252 276 297 270 296 336 368 404 444 478 515 545 577 611
Med-Low 121 155 184 212 243 273 302 330 354 373 408 441 484 522 554 601 641 689 731 774
Med-High 183 215 255 283 319 354 380 411 439 529 578 629 682 718 763 824 859 903 951 989
High 256 285 335 358 401 436 473 512 545 843 877 935 979 1036 1052 1058 1057 1047 1042 1035
Factory Default
Cooling
Speed
Low 77 98 121 150 173 198 221 238 262 190 221 247 293 317 362 388 417 448 483 504
Med-Low 104 126 150 179 207 233 262 286 309 291 317 350 393 432 471 503 538 572 610 642
Med-High 139 167 199 231 259 286 319 344 368 399 423 464 520 547 593 646 686 722 760 813
High 191 225 255 292 322 359 392 428 456 601 639 683 733 789 837 887 932 977 1018 1034
– Setting
Cooling
Speed
Low 65 86 110 135 157 177 197 217 238 137 164 198 228 260 288 320 349 372 399 429
Med-Low 74 95 123 148 173 202 222 241 264 206 239 269 302 343 376 411 437 472 501 534
Med-High 108 137 166 196 217 248 271 296 320 281 309 342 385 426 463 501 538 573 603 644
High 139 166 201 229 264 292 323 347 384 417 458 501 545 586 632 687 729 762 814 851

Page 5
FIGURE 1
Control box
Flue chase
Internal flue pipe assembly
Blower assemblyBlower assembly
Heat exchanger assembly
Air fuel intake assembly
Gas valve
Combustion air inducer
Access panel
Parts Arrangement

Page 6
I-UNIT COMPONENTS
SL280DFNV unit components are shown in figure 1. The
gas valve, combustion air inducer and burners can be ac
cessed by removing the access panel. Electrical compo
nents are in the control box (figure 2) found in the blower
section.
SL280DFNV units are factory equipped with a bottom return
air panel in place. The panel is designed to be field removed
as required for bottom air return. Markings are provided for
side return air and may be cut out in the field.
CAUTION
Electrostatic discharge can affect elec
tronic components. Take precautions
to neutralize electrostatic charge by
touching your hand and tools to metal
prior to handling the control.
A- Control Box
1. Control Transformer (T1)
A transformer located in the control box provides power to
the low voltage section of the unit. Transformers on all
models are rated 40VA with a 120V primary and a 24V sec
ondary.
2. Door Interlock Switch (S51)
A door interlock switch rated 14A at 125VAC is wired in se
ries with line voltage. When the inner blower access panel
is removed the unit will shut down.
FIGURE 2
CONTROL BOX SL280DFNV
SureLight®Integrated Control
Interlock Switch
Transformer
Circuit Breaker
3. Circuit Breaker (CB8)
A 24V circuit breaker is also located in the control box.
The switch provides overcurrent protection to the trans
former (T1). The breaker is rated 3A at 32V. If the current
exceeds this limit the breaker will trip and all unit opera
tion will shutdown. The breaker can be manually reset
by pressing the button on the face. See figure 3.
FIGURE 3
CIRCUIT BREAKER CB8
PRESS TO RESET
WARNING
Shock hazard.
Disconnect power before servicing. Integrated
control is not field repairable. If control is inoper
able, simply replace entire control.
Can cause injury or death. Unsafe operation will re
sult if repair is attempted.
4. Integrated Control (A92)
Units are equipped with the communicating enabled Sur
eLight®two-stage, variable speed integrated control. This
control is used with any communicating enabled thermo
stat as part of a communicating comfort system. The con
trol can also operate with a non-communicating conven
tional single or two-stage thermostat. The system consists
of a ignition / blower control (figures 4 and 5) with control
pin designations in tables 1, 2 and 3 and ignitor (figure 13).
The control and ignitor work in combination to ensure fur
nace ignition and ignitor durability. The control provides
gas ignition, safety checks and indoor blower control with
two-stage gas heating.
The furnace combustion air inducer, gas valve and indoor
blower are controlled in response to various system inputs
such as thermostat signal, pressure and limit switch signal
and flame signal. The control features a seven-segment
LED display, indicating furnace status (including indoor
blower) and error codes. The LED flashes in single digits.
For example using table 5 under LIMIT CODE, an “E” fol
lowed by “2” followed by “5” followed by “0”, the limit switch
circuit is open. The control also has two unpowered (dry)
1/4” contacts for a humidifier and a 120 volt accessory ter
minal. Both rated at (1) one amp each.
Electronic Ignition
At the beginning of the heat cycle the integrated control
monitors the first stage and second stage combustion air
inducer prove switch. The control will not begin the heating
cycle if the first stage prove switch is closed (by-passed).
Likewise the integrated control will not begin the second
stage heating cycle if the second stage prove switch is
closed, and will remain in first stage heat. However, if the
second stage prove switch closes during the first stage
heat pre-purge, the control will allow second stage heat.

Page 7
Once the first stage prove switch is determined to be open,
the combustion air inducer is energized on low (first stage)
heat speed. When the differential in the prove switch is
great enough, the prove switch closes and a 15-second
pre-purge begins.
NOTE - During abnormal conditions such as low supply
voltage or low outdoor temperatures and the low fire pres
sure switch does not close, the combustion air inducer will
switch to high fire. After a 15 second pre-purge the high fire
pressure switch will close and the unit will begin operation
on high fire. After 10 to 20 seconds of high fire operation the
unit will switch to low fire.
After the 15-second pre-purge period, the SureLight ignitor
warms up for 20 seconds after which the gas valve opens
for a 4-second trial for ignition. The ignitor energizes during
the trial until flame is sensed. If ignition is not proved during
the 4-second period, the control will try four more times with
an inter purge and warm-up time between trials of 35 sec
onds. After a total of five trials for ignition (including the ini
tial trial), the control goes into Watchguard-Flame Failure
mode. After a 60-minute reset period, the control will begin
the ignition sequence again.
Two Stage Operation / Thermostat Selection DIP
Switch
The control can be utilized in two modes: SINGLE-STAGE
thermostat or TWO-STAGE thermostat. The thermostat
selection is made using a DIP switch and must be posi
tioned for the particular application. DIP switch 1, labeled
T”STAT HEAT STAGE is factory-set in the OFF position for
use with a two-stage thermostat. Move the DIP switch to
ON for use with a single stage thermostat.
While in the single-stage thermostat mode, the burners will
always fire on first-stage heat. The combustion air inducer
will operate on low speed and indoor blower will operate on
low heat speed. The unit will switch to second stage heat
after a "recognition period". DIP switch 2, labeled SECOND
STAGE DELAY, is factory set in the OFF position for a 7
minute recognition period. The switch can be moved to the
ON position for a 12 minute recognition period, after which
time the unit will switch to secondstage heat.
While in the two-stage thermostat mode (two DIP switch
setting) the burners will fire on first-stage heat. The com
bustion air inducer will operate on low speed and indoor
blower will operate on low heat speed. The unit will switch
to second-stage heat on call from the indoor thermostat. If
there is a simultaneous call for first and second stage heat,
the unit will fire an first stage heat and switch to second
stage heat after 30 seconds of operation. See Sequence of
Operation flow charts in the back of this manual for more
detail.
TABLE 1
SureLight
®
Control 5 Pin Terminal Designation
PIN # Function
1 Ignitor
2Combustion Air Inducer High Speed
3Combustion Air Inducer Low Speed
4Combustion Air Inducer Neutral
5Ignitor Neutral
TABLE 2
SureLight
®
Control 12 Pin Terminal Designation
PIN # Function
1Gas Valve High Fire
2Second Stage Prove Switch
3Rollout In
4 Ground
524V Hot
6Primary Limit In
7Gas Valve Low Stage
8Gas Valve Common
924V Neutral
10 Ground
11 Rollout Switch Out
12 1st Stage Prove Switch
TABLE 3
SureLight
®
Control 6 Pin Terminal Designation
PIN # Function
1Data Input From Motor
2 Common
3Not Used
4Data Output To Motor
55 Volt Bias Supply
6Not Used

Page 8
FIGURE 4
THERMOSTAT CONNECTIONS (TB1)
1/4” QUICK CONNECT TERMINALS
RS-BUS LINK (TB82, future use)
I+ = DATA HIGH CONNECTION
I - = DATA LOW CONNECTION
RS-BUS OUTDOOR (TB83)
R = 24VAC
I + = DATA HIGH CONNECTION
I - = DATA LOW CONNECTION
C = 24VAC COMMON
RS-BUS INDOOR (TB84)
R = 24VAC
I + = DATA HIGH CONNECTION
I - = DATA LOW CONNECTION
C = 24VAC COMMON
FLAME SENSE
DIP SWITCHES
OUTDOOR AIR
SENSOR
TERMINALS
DISCHARGE AIR
SENSOR
TERMINALS
INDOOR
BLOWER
CONNECTOR
NEUTRAL
DIAGNOSTIC
PUSH BUTTON
TB83
COMMUNICATING
OUTDOOR
EQUIPMENT
TB84
COMMUNICATING
INDOOR
THERMOSTAT
DS = DEHUMIDIFICATION SIGNAL
W2 = HEAT DEMAND FROM 2ND STAGE T/STAT
W1 = HEAT DEMAND FROM 1ST STAGE T/STAT
R = CLASS 2 VOLTAGE TO THERMOSTAT
G = MANUAL FAN FROM T'STAT
C = THERMOSTAT SIGNAL GROUND CONNECTED TO
TRANSFORMER GRD (TR) & CHASIS GROUND (GRD)
Y1 = THERMOSTAT 1ST STAGE COOL SIGNAL
Y2 = THERMOSTAT 2ND STAGE COOL SIGNAL
O = THERMOSTAT SIGNAL TO HEAT PUMP
REVERSING VALVE
L = USE ONLY WITH A COMMUNICATING THERMOSTAT
AND A NON-COMMUNICATING OUTDOOR UNIT
DH = DEHUMIDIFICATION OUTPUT COMMUNICATING
THERMOSTAT ONLY
HUM = UNPOWERED NORMALLY OPEN (DRY) CONTACTS
XMFR = 120 VAC OUTPUT TO TRANSFORMER
LI = 120 VAC INPUT TO CONTROL
ACC = 120 VAC OUTPUT TO OPTIONAL ACCESSORY
NEUTRALS = 120 VAC NEUTRAL
W915 Y1 TO Y2
2 STAGE COMPR
W951 R TO O
HEAT PUMP
W914 R TO DS
DEHUM OR
HARMONY
W1 W2 G Y2 Y1 CCRDHLODS
RI + I - CRI + I - C
7 SEGMENT LED
ACC
LINE 1
HUM
12 PIN LOW
VOLTAGE
CONNECTOR
NON-COMMUNICATINGNG
24V TERMINALS
HS/ CAI
INTEGRATED CONTROL

Page 9
FIGURE 5
HEATING BLOWER−OFF DELAY
60 SECOND
HTG BLOWER
OFF DELAY
120 SECOND
HTG BLOWER
OFF DELAY
180 SECOND
HTG BLOWER
OFF DELAY
FLAME
15
HSI/CAI
2ND STAGE HEAT ON DELAY
7 MIN
UPSTAGE
DELAY
12 MIN
UPSTAGE
DELAY
*CONTINUOUS FAN MODE BLOWER SPEED
COOLING MODE BLOWER RAMPING
CLG BLOWER SPEED ADJUSTMENT
COOLING MODE BLOWER SPEED
W915
2 STAGE
COMPR
1−STG COMPRESSOR
2−STAGE
COMPRESSOR LINK
(JUMPERS Y1 to Y2)
W915
DO NOT CUT
2−STG COMPRESSOR
HEAT PUMP LINK
(JUMPERS R to O)
W951
DEHUMIDIFICATION−
HARMONY LINK
(JUMPERS R to DS)
W914
W915
2 STAGE
COMPR
CUT LINK
A/C UNIT
DO NOT CUT
HEAT PUMP UNIT
CUT LINK
W951
HEAT
PUMP
W951
HEAT
PUMP
W914
DEHUM
or
NO HARMONY ZONING
OR
NO SIGNATURESTAT
W/ DS CONNECTION
DO NOT CUT
HARMONY ZONING
OR
SIGNATURESTAT W/
DS CONNECTION
CUT LINK
HARMONY
W914
DEHUM
or
HARMONY
1
1
1
ON−BOARD LINK
OPTION SELECTION
1234567
1234567
123567
4
123567
4
NEUTRALS
L1
ACC
HUM
14
36
P79
110
312
J2
4 7
W915
2 STAGE
COMPR
W951
HEAT
PUMP
W914
DEHUM
HARMONY
CUT FOR
OPTION
SELECTION
OUTDOOR SENSOR
DISCHARGE AIR SENSOR
123456
10 12
911
13
ON
ON
SureLight
®
W1W2 GY2 Y1 C C DH L O DSR
W1 W2
G
Y2 Y1
C C
R
L
DH
HIGH
SPEED
(100%)
MEDIUM−HIGH
SPEED
(70%)
MEDIUM−LOW
SPEED
(38%)
LOW
SPEED
(28%)
*
OPTION A
OFF−50%−82%−
100%−50%−OFF
OPTION B
OFF−82%−100%−OFF
OPTION C
OFF−100%−100%−OFF
OPTION D
OFF−100%−OFF
*
DEFAULT
+ 10%
−10%
*
HIGH
SPEED
MEDIUM−HIGH
SPEED
MEDIUM−LOW
SPEED
LOW
SPEED
*
7
−PROTECTIVE PLASTIC FILM ON DIP SWITCHES MAY BE
REMOVED FOR EASE IN SETTING OF DIP SW.
−CUT ON−BOARD LINK (SOLDER TRACE) COMPLETELY THROUGH
BOTH LAYERS ON THE CONTROL BOARD
−LINKS CUT IN ERROR −INSTALL A JUMPER ON THE APPROPRIATE
TERMINALS ON THE TERMINAL STRIP
1
9
10 11
12 13
14
ON
ON
ON
ON
ON
ON
ON
ON
90 SECOND
HTG BLOWER
OFF DELAY
*1234567
ON
1234567
ON
THERMOSTAT SELECTION
1−STAGE
THERMOSTAT
(TIMED STAGING)
−SEE SW #2
TWO STAGE
THERMOSTAT
*1234567
1234567
ON
ON
−BLOWER ON DELAY −30 SEC. FIXED
15
9
10 11
12 14 15
9
10 11
12 14 15
9
10 11
12 14 15
8
8
8
8
8
8
8
8
1234567
1234567
ON
ON
1234567
ON
1234567
ON
8
8
8
8
9
10 11
12 13
14
ON
ON
ON
ON
15
9
10 11
12 14 15
9
10 11
12 14 15
9
10 11
12 14 15
9
10 11
12 13
14
ON
ON
ON
ON
15
9
10 11
12 14 15
9
10 11
12 14 15
9
10 11
12 14 15
HEATING MODE BLOWER SPEED
1234567
ON
1234567
ON
1234567
ON
8
8
8
9
10 11
12 13
14
ON
ON
ON
ON
15
9
10 11
12 14 15
9
10 11
12 14 15
9
10 11
12 14 15
FACTORY
DEFAULT
+ 24%
+ 18%
+ 12%
+ 6%
−6%
−12%
−18%
8
14 15
INCREASE AIR HTG CFM
DECREASE AIR HTG CFM
SENSE
RI+ I−CRI+ I−C
OUTDOOR EQUIPMENT
I+ I−
INDOOR EQUIPMENT
IGN
CAI2
CAI1
N N
J3
S1
S4S3
13
13
13
13
13
13
13
* FACTORY DEFAULT
13
13
*
DIAGNOSTIC
LED
DIAGNOSTIC
PUSH BUTTON
INTEGRATED CONTROL CONFIGURATION GUIDE

Page 10
TABLE 4
Integrated Control Diagnostic Modes
Display Action (when button released)
No change (idle)* Remain in idle mode
Solid “E” Enter diagnostic recall mode
Solid “D” Discharge Air Installed
Solid “F” Enter flame signal mode
Solid “P” (variable speed only) Program unit capacity/size (Unit Code)
__
Two horizontal bars __ Soft disable
* No change implies the display will continue to show whatever is currently being displayed for normal operation (blinking
decimal, active error code, heat state, etc..)
Diagnostic LED (Figure 5)
The seven-segment diagnostic LED displays operating
status, target airflow, error codes and other information.
The table beginning on Page 11 lists diagnostic LED
codes.
Diagnostic Push Button (Figure 4)
The diagnostic push button is located adjacent to the
seven-segment diagnostic LED. This button is used to en
able the Error Code Recall “E” mode and the Flame Signal
“F” mode. Press the button and hold it to cycle through a
menu of options. Every five seconds a new menu item will
be displayed. When the button is released, the displayed
item will be selected. Once all items in the menu have been
displayed, the menu resumes from the beginning until the
button is released.
Error Code Recall Mode
Select ”E” from the menu to access the most recent 10 error
codes. Select “c” from the Error Code Recall menu to clear
all error codes. Button must be pressed a second time
while “c” is flashing to confirm command to delete codes.
Press the button until a solid “≡” is displayed to exit the Error
Code Recall mode.
Flame Signal Mode
Select ”F” from the menu to access the flame signal mode.
The integrated control will display the flame current on 7
segment LED in in micro amps (uA).
Flame signal mode is exited after any of the following:
Power is reset
Pressing and holding push button until 3 horizontal
lines “≡” are displayed
10 minutes after entering the flame sense mode.
Program Unit Capacity/Size Mode
After the “P” is selected (by releasing the push button) the
integrated control will start flashing the “P” on display for 90
seconds. If push button is pressed again and held during
that time, the control will start to display characters corre
sponding to different variable speed furnace models for 3
seconds each. While the wanted character-model is dis
played push button has to be released. Selected option will
flash display for 10 seconds and during that time push but
ton has to be pressed and held for 5 seconds. Once control
accepts new setting it will store data in non-volatile memory
and reset itself. If 10 seconds expires or push button is held
less than 5 seconds, control will exit field test mode and go
into idle without changing programming the unit size.
Soft Disable
Soft disabling is when thermostat finds a device on the BUS
that it does not recognize and the thermostat sends a the
device a message to be in soft disabling mode until proper
ly configured. Two horizontal bars will display.
Steps to follow if the damper control module is displaying
the soft disable code.
1- Confirm proper wiring between all devices (thermo
stat, damper control module, indoor and outdoor).
2- Cycle power to the control that is displaying the soft
disable code.
3- Put the room thermostat through set up.
4- Go to setup / system devices / thermostat / edit /
then push reset.
5- Go to setup / system devices / thermostat / edit /
then push resetAll.

Page 11
TABLE 5
Integrated Diagnostic Codes/Status of Equipment I.
Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover
.Idle mode (Decimal blinks at 1 Hertz -- 0.5 second ON, 0.5 second OFF).
ACubic feet per minute (cfm) setting for indoor blower (1 second ON, 0.5
second OFF) / cfm setting for current mode displayed.
CCooling stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed / Pause
/ cfm setting displayed / Pause / Repeat codes).
dDehumidification mode (1 second ON) / 1 second OFF) / cfm setting dis
played / Pause / Repeat Codes).
hHeat pump stage (1 second ON, 0.5 second OFF) / % of input rate dis
played / Pause / cfm setting / Pause / Repeat codes.
HGas Heat Stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed /
Pause / cfm
setting displayed / Pause / Repeat codes. Blinking during ignition.
dF Defrost mode.
UDischarge Air Temperature
E 105 Device communication problem - No other devices on RS BUS (Commu
nication
system).
Equipment is unable to communicate. Indicates
numerous message errors. In most cases errors are
related to electrical noise. Make sure high voltage
power is separated from RSBus. Check for mis-
wired and/or loose connections between the stat,
indoor unit and outdoor unit. Check for a high volt
age source of noise close to the system. Fault
clears after communication is restored.
E 110 Low line voltage. Line Voltage Low (Voltage lower than nameplate
rating). Check power line voltage and correct. Alarm
clears 5 seconds after fault recovered.
E 111 Line voltage polarity reversed. Reverse line power voltage wiring. System resumes
normal operation 5 seconds after fault recovered.
E 112 Ground not detected System shuts down. Provide proper earth ground.
System resumes normal operation 5 seconds after
fault recovered.
E 113 High line voltage. Line Voltage High (Voltage higher than nameplate
rating). Provide power voltage within proper range.
System resumes normal operation 5 seconds after
fault recovered.
E 114 Line voltage frequency out-of-range. No 60 Hertz Power. Check voltage and line power
frequency. Correct voltage and frequency problems.
System resumes normal operation 5 seconds after
fault recovered.
E 115 Low 24V - Control will restart if the error recovers. 24-Volt Power Low (Range is 18 to 30 volts). Check
and correct voltage. Check for additional power-rob
bing equipment connected to system. May require
installation of larger VA transformer to be installed
in furnace / air handler. Clears after fault recovered.
E 116 High 24V. 24 Volt Power High (Range is 18 to 30 volts). Check
and correct voltage. Check for proper line voltage
(120V, 240V, etc.) to equipment. Clears when con
trol senses proper voltage.
E 117 Poor ground detected (Warning only) Provide proper grounding for unit. Check for proper
earth ground to the system. Warning only will clear
30 seconds after fault recovered.
E 120 Unresponsive device. Communication only. Usually caused by delay in outdoor unit responding
to indoor unit poling. Recycle power. Check all wir
ing connections. Cleared after unresponsive device
responds to any inquiry.

Page 12
TABLE 5 Continued
Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover
E 124 Active communicating thermostat signal missing for more than 3 min
utes.
Equipment lost communication with the thermostat.
Check four wiring connections, ohm wires and cycle
power at the thermostat. Alert stops all services and
waits for heartbeat message from thermostat (sub
net controller). Cleared after valid thermostat (sub
net controller) message is received.
E 125 Control failed self-check, internal error, failed hardware. Will restart if
error
recovers. Integrated control not communicating. Covers hardware errors
(flame sense circuit faults, pin shorts, etc.).
Hardware problem on the control. Cycle power on
control. Replace if problem prevents service and is
persistent. Critical alert. Cleared 300 seconds after
fault recovered.
E 126 Control internal communication problem. Hardware problem on the control. Cycle power on
control. Replace if problem prevents service and is
persistent. Cleared 300 seconds after fault recov
ered.
E 131 Corrupted control parameters (Verify configuration of system). Communi
cating only.
Reconfigure the system. Replace control if heating
or cooling is not available. Only applicable in the
communicating mode, not in startup. Exit from Com
missioning and Execute 'Set Factory Default mode'.
Control will still operate on default parameter set
tings.
E 180 Outdoor air temperature sensor failure. Only shown if shorted or out-of-
range.
Compare outdoor sensor resistance to temperature/
resistance charts in unit installation instructions.
Replace sensor pack if necessary. At beginning of
(any) configuration, furnace or air handler control
will sense outdoor air and discharge air temperature
sensor(s). If detected (reading in range), appropri
ate feature will be set as 'installed' and that could be
seen in 'About' screen. In normal operation after
control recognizes sensors, alarm will be sent if
valid temperature reading is lost. To get rid of set
ting and alarm, redo configuration and make sure
that temperature sensor is marked as 'not installed'
in Indoor Unit 'About' screen. When Indoor unit con
trol is replaced, thermostat will 'tell' new control if
temperature sensor is in system or not. Clears 30
seconds after fault recovered.
E 200 Hard lockout - Rollout circuit open or previously open. Correct cause of rollout trip, or replace flame rollout
switch. Test furnace operation. Cleared after fault
recovered.
E 201 Indoor blower communication failure - Unable to communicate with blow
er motor.
Indoor blower communication failure (including pow
er outage). Lost communication with indoor blower
motor. Possible causes: motor not powered, loose
wiring. Problem may be on control or motor side.
Cleared after fault recovered.
E 202 Indoor blower motor mis-match - Indoor motor horsepower does not
match unit capacity. See NO TAG.
Incorrect appliance capacity code selected. Check
for proper configuring under: Unit Size Codes for
Furnace/Air Handler on configuration guide or in
installation instructions. Cleared after the correct
match is detected following a reset. (Remove ther
mostat from system while applying power and re
programming.)
E 203 Appliance capacity / size is NOT programmed. Invalid unit codes refer to
configuration flow chart.
No appliance capacity code selected. Check for
proper configuring under: Unit Size Codes for Fur
nace on configuration guide or in installation instruc
tions. Critical Alert. Cleared after valid unit code is
read following a reset. (Remove thermostat from
system while applying power and reprogramming.)
E 204 Gas valve mis-wired. Check gas valve operation and wiring. Clears when
repaired.
E 205 Gas valve control relay contact shorted. Check wiring on control and gas valve. If wiring is
correct, replace control.

Page 13
TABLE 5 Continued
Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover
E 206 Gas valve second-stage relay failure Furnace will operate on 1s
t
stage for remainder of
the heating demand. Will clear after fault recovered.
If unable to operate 2nd stage, replace control.
E 207 Hot surface ignitor sensed open - Refer to troubleshooting. Measure resistance of hot surface ignitor. Replace if
open or not within specified range found in IOM.
Resumes normal operation after fault is cleared.
E 223 Low pressure switch failed open. Check pressure (inches w.c.) of low pressure switch
closing on heat call. Measure operating pressure
(inches w.c.). Inspect vent and combustion air in
ducer for correct operation and restriction. Re
sumes normal operation after fault is cleared
E 224 Low pressure switch failed closed - Refer to troubleshooting. Check operation of low pressure switch to see if it is
stuck closed on heat call longer than 150 seconds.
Measure operating pressure (inches w.c.). Inspect
vent and combustion air inducer for correct opera
tion and restriction. Resumes normal operation after
fault is cleared.
E 225 High pressure switch failed open - Refer to troubleshooting. Check pressure (inches w.c.) of high pressure
switch closing on heat call. Measure operating pres
sure (inches w.c.). Inspect vent and combustion air
inducer for correct operation and restriction. Re
sumes normal operation after fault is cleared.
E 226 High pressure switch failed closed - Refer to troubleshooting. Check operation of high pressure switch closing on
heat call. Measure operating pressure (inches w.c.).
Inspect vent and combustion air inducer for correct
operation and restriction. Resumes normal opera
tion after fault is cleared.
E 227 Low pressure switch open during trial for ignition or run mode. Refer to
troubleshooting.
Check pressure (inches w.c.) of low pressure switch
closing on heat call. Measure operating pressure
(inches w.c.). Inspect vent and combustion air in
ducer for correct operation and restriction. Re
sumes normal operation after fault is cleared.
E 228 Combustion air inducer calibration failure Unable to perform pressure switch calibration.
Check vent system and pressure switch wiring con
nections. Resumes normal operation after fault is
cleared.
E 229 Ignition on High Fire - Information Only Code is displayed if 1) low pressure switch fails to
close, then furnace will switch to high speed inducer
to close both low and high pressure switches, then
furnace lights on high fire, or 2) if continuous fan is
active, furnace lights on high fire for 60 seconds to
improve heat exchanger warm up time.
E 240 Low flame current - Run mode - Refer to troubleshooting. Check micro-amperes of flame sensor using control
diagnostics or field-installed mode. Clean or replace
sensor. Measure voltage of neutral to ground to
ensure good unit ground. Alert clears after current
heat call has been completed.
E 241 Flame sensed out of sequence - Flame still present. Shut off gas. Check for gas valve leak. Replace, if
necessary. Alert clears when fault is recovered.
E 250 Limit switch circuit open - Refer to troubleshooting. Check for proper firing rate on furnace. Ensure
there is no blockage in heater. Check for proper air
flow. If limit not closed within 3 minutes, unit will go
into 1-hour soft lockout. Resumes normal operation
after fault is cleared.
E 252 Discharge air temperature too high (gas heat only). Check temperature rise, air flow and input rate.
Cleared when heat call is finished.
E 270 Soft lockout - Exceeded maximum number of retries. No flame current
sensed.
Check for proper gas flow. Ensure that ignitor is
lighting burner. Check flame sensor current. Clears
when heat call finishes successfully.

Page 14
TABLE 5 Continued
Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover
E 271 Soft lockout - Exceeded maximum number of retries. Last retry failed due
to the pressure switch opening.
Check pressure (inches w.c.) of low pressure switch
closing on heat call. Measure operating pressure
(inches w.c.). Inspect vent and combustion air in
ducer for correct operation and restriction. Clears
when heat call finishes successfully.
E 272 Soft lockout - Exceeded maximum number of recycles. Last recycle due
to the pressure switch opening.
Check operation of low pressure switch to see if it is
stuck closed on heat call. Check pressure (inches
w.c.) of high pressure switch closing on heat call.
Measure operating pressure (inches w.c.). Inspect
vent and combustion air inducer for correct opera
tion and restriction. Clears when heat call finishes
successfully.
E 273 Soft lockout - Exceeded maximum number of recycles. Last recycle due
to flame failure.
Check micro-amperes of flame sensor using control
diagnostics or field-installed mode. Clean or replace
sensor. Measure voltage of neutral to ground to
ensure good unit ground. Clears when heat call
finishes successfully.
E 274 Soft lockout - Exceeded maximum number of recycles. Last recycle
failed due to the limit circuit opening or limit remained open longer than
3 minutes.
Shut down system. 1-hour soft lockout. Check firing
rate and air flow. Check for blockage. Clears when
heat call finishes successfully.
E 275 Soft lockout - Flame sensed out of sequence. Flame signal is gone. Shut off gas. Check for gas valve leak. 1-hour soft
lockout. Clears when flame has been proven stable.
E 276 Watchguard calibration failure. Unable to perform pressure switch calibration.
Check vent system and pressure switch wiring con
nections. 1-hour soft lockout. Clears when calibra
tion has finished successfully.
E 290 Ignitor circuit fault - Failed ignitor or triggering circuitry. Measure resistance of hot surface ignitor. Replace if
open or not within specifications. 1-hour soft lock
out. Clears when flame has been proven stable.
E 291 Heat air flow restricted below the minimum. Check for dirty filter and air flow restriction. Check
blower performance. 1-hour soft lockout. Cleared
when heat call finishes successfully.
E 292 Indoor blower motor unable to start due to obstructed wheel, seized
bearings.
Indoor blower motor unable to start (seized bear
ing, stuck wheel, etc.). Replace motor or wheel if
assembly does not operate or meet performance
standards. 1-hour soft lockout. Clears after circula
tor successfully starts.
E 294 Combustion air inducer over current. Check combustion blower bearings, wiring and
amps. Replace if does not operate or does not meet
performance standards. Clears after inducer current
is sensed to be in-range after the ignition following
the soft lockout or reset.
E 295 Indoor blower motor temperature is too high. Indoor blower motor over temperature (motor
tripped on internal protector). Check motor bearings
and amps. Replace if necessary. Cleared after
blower demand is satisfied.
E 310 Discharge error temperature sensor failure. Only shown if shorted or
out of range.
Compare outdoor sensor resistance to temperature/
resistance charts in installation instructions. Re
place sensor if necessary. Cleared in Communicat
ing mode: 30 seconds after fault recovered. In Non-
Communicating mode: Cleared after the current
heat call is completed.
E 311 Heat rate reduced to match indoor blower air flow. Warning Only. Furnace blower in cutback mode due
to restricted airflow. Reduce firing rate every 60
seconds to match available CFM. Check filter and
duct system. To clear, replace filter if needed or re
pair/add duct. 2-stage controls will reduce firing rate
to 1st stage. Clears when heat call finishes success
fully.

Page 15
TABLE 5 Continued
Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover
E 312 Restricted air flow in cooling or continuous fan mode is lower than cfm
setting.
Warning Only. Restricted airflow - Indoor blower is
running at a reduced CFM (Cutback Mode - The
variable speed motor has pre-set speed and torque
limiters to protect the motor from damage caused
by operating outside of design parameters (0 to 0.8”
W.C.. total external static pressure). Check filter
and duct system. To clear, replace filter if needed or
repair/add duct. Cleared after the current service
demand is satisfied.
E 313 Indoor or outdoor unit capacity mismatch. Communication only. Incorrect indoor/outdoor capacity code selected.
Check for proper configuring in installation instruc
tions. Alarm is just a warning. The system will oper
ate, but might not meet efficiency and capacity pa
rameters. Alarm will clear when commissioning is
exited. Cleared after commissioning is complete.
E 331 Global network connection - Communication link problem. For Future Use.
E 334 Relay “Y1” stuck on interated control. Replace integrated control.
E 347 No 24 Volt output on Y1 of ”integrated control” with non communicating
outdoor unit.
Operation stopped. Y1 relay / Stage 1 failed. (Pilot
relay contacts did not close or the relay coil did not
energize; no input back to IFC chip). Critical Alert.
Cleared after reset and Y1 input sensed.
E 348 No 24 Volt output on Y2 of ”integrated control” with non?communicating
outdoor unit.
Y2 relay / Stage 2 failed. (Pilot relay contacts did
not close or the relay coil did not energize; no input
back to IFC chip). Critical Alert. Cleared after reset
and Y1 input sensed.
E 349 No 24 Volts between R & O on ”integrated control” with non communi
cating outdoor unit (Dual fuel module required for heat pump applica
tion).
Configuration link R to O needs to be restored. Re
place link or hard-wire. Applicable in non communi
cating mode. Critical Alert.
E 370 Interlock switch sensed open for 2 minutes. Control sees the loss of 24VAC for 2 minutes .Ter
minate all services and wait for interlock switch to
close. The alarm will clear when 24VAC is continu
ously sensed on DS terminal for a minimum of 10
seconds or on a power reset.
E 400 LSOM - Compressor internal overload tripped. Thermostat demand Y1 is present; but, compressor
is not running. Check power to outdoor unit. Clears
the error after current is sensed in both RUN and
START sensors for at least 2 seconds, or after ser
vice is removed, or after power reset.
E 401 LSOM Compressor long run cycle or low system pressure. Compressor ran more than 18 hours to satisfy a
single thermostat demand. Critical Alert. Clears the
error after 30 consecutive normal run cycles or
power reset. Also monitors low pressure switch
trips.
E 402 LSOM - Outdoor unit system pressure trip. Discharge or suction pressure out-of-limits, or com
pressor overloaded. Clears the error after 4 consec
utive normal compressor run cycles.
E 403 LSOM - Compressor short-cycling. .(Running less than 4 minutes). Out
door unit pressure trip
Compressor runs less than 3 minutes to satisfy a
thermostat demand. Clears the error after 4 consec
utive normal run cycles or power reset.
E 404 LSOM - Compressor rotor locked. Compressor short-cycling. (Running
less than 4 minutes).
Compressor rotor locked up due to run capacitor
short, bearings are seized, excessive liquid refriger
ant, etc. Clears the error after 4 consecutive normal
run cycles or after power reset.
E 405 LSOM - Compressor open circuit. Compressor circuit open (due to power disconnec
tion, open fuse, etc.) Clears the error after 1 normal
compressor run cycle.

Page 16
TABLE 5 Continued
Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover
E 406 LSOM - Compressor open start circuit. Required amount of current is not passing through
Start current transformer. Clears the error after cur
rent is sensed in START sensor, or after power re
set.
E 407 LSOM - Compressor open run circuit. Required amount of current is not passing through
Run current transformer. Clears the error after cur
rent is sensed in RUN sensor, or 1 normal compres
sor run cycle, or after power reset.
E 408 LSOM - Compressor contactor is welded. Compressor runs continuously. Clears the error
after 1 normal compressor run cycle or after power
reset.
E 409 LSOM - Compressor low voltage. Secondary voltage is below 18VAC. After 10 min
utes, operation is discontinued. Clears the code
after voltage is higher than 20 VAC for 2 seconds or
after power reset.
DIP Switch Settings
NOTE - All communicating are set at the communicating
thermostat. See thermostat installation instruction. In a
communication system all DIP switch and clippable link
settings are ignored. For conventional thermostats pro
ceed with DIP switch and clippable link settings as outlined
in the following.
Heating Operation DIP Switch Settings
Switch 1 -- Thermostat Selection -- This unit may be
used with either a single-stage or two-stage thermostat.
The thermostat selection is made using a DIP switch which
must be properly positioned for the particular application.
The DIP switch is factory-positioned for use with a two-
stage thermostat. If a single-stage thermostat is to be used,
the DIP switch must be repositioned.
a - Select “OFF” for two-stage heating operation con
trolled by a two-stage heating thermostat (factory set
ting);
b - Select “ON” for two-stage heating operation con
trolled by a single-stage heating thermostat. This set
ting provides a timed delay before second-stage heat
is initiated.
Switch 2 -- Second Stage Delay (Used with Single-
Stage Thermostat Only) -- This switch is used to deter
mine the second stage on delay when a single-stage ther
mostat is being used. The switch is factory-set in the OFF
position, which provides a 7-minute delay before second-
stage heat is initiated. If the switch is toggled to the ON
position, it will provide a 12-minute delay before second-
stage heat is initiated. This switch is only activated when
the thermostat selector jumper is positioned for SINGLE-
stage thermostat use.
Switches 3 and 4 -- Blower-Off Delay -- The blower-on
delay of 30 seconds is not adjustable. The blower-off delay
(time that the blower operates after the heating demand
has been satisfied) can be adjusted by moving switches 3
and 4 on the integrated control. The unit is shipped from the
factory with a blower-off delay of 90 seconds. The blower
off delay affects comfort and is adjustable to satisfy individ
ual applications. Adjust the blower off delay to achieve a
supply air temperature between 90° and 110°F at the exact
moment that the blower is de-energized. Longer off delay
settings provide lower supply air temperatures; shorter set
tings provide higher supply air temperatures.Table 6 pro
vides the blower off timings that will result from different
switch settings.
TABLE 6
Blower Off Delay Switch Settings
Blower Off Delay
(
Seconds
)
Switch 3 Switch 4
60 On Off
90 (Factory) Off Off
120 Off On
180 On On
Indoor Blower Operation DIP Switch Settings
Switches 5 and 6 -- Cooling Mode Blower Speed -- The
unit is shipped from the factory with the dip switches posi
tioned for high speed (4) indoor blower motor operation
during the cooling mode. Table 7 provides the cooling
mode blower speeds that will result from different switch
settings. Switches 5 and 6 set the blower cfm for second-
stage cool. The integrated control automatically ramps
down to 70% of the second-stage cfm for first-stage cfm.
Refer to tables for corresponding cfm values.
TABLE 7
Cooling Mode Blower Speeds
Speed Switch 5 Switch 6
Low On On
Medium Low Off On
Medium High On Off
High (Factory) Off Off
Switches 7 and 8 -- Cooling Blower Speed Adjustment
-- The unit is shipped from the factory with the dip switches
positioned for NORMAL (no) adjustment. The dip switches
may be positioned to adjust the blower speed by +10% or

Page 17
-10% to better suit the application. Table 8 below provides
blower speed adjustments that will result from different
switch settings. Refer to tables for corresponding cfm val
ues.
TABLE 8
Cooling Blower Speed Adjustment
Adjustment Switch 7 Switch 8
+10% (approx.) On Off
Factory Default Off Off
-10% (approx.) Off On
Switches 9 and 10 -- Cooling Mode Blower Speed
Ramping -- Blower speed ramping may be used to en
hance dehumidification performance. The switches are
factory set at option A which has the greatest effect on de-
humidification performance. Table 9 provides the cooling
mode blower speed ramping options that will result from
different switch settings. The cooling mode blower speed
ramping options are detailed below.
TABLE 9
Cooling Mode Blower Speed Ramping
Ramping Option Switch 9 Switch 10
A (Factory) Off Off
B Off On
C On Off
D On On
Ramping Option A (Factory Selection)
Motor runs at 50% for 30 seconds.
Motor then runs at 82% for approximately 7-1/2 minu
tes.
If demand has not been satisfied after 7-1/2 minutes,
motor runs at 100% until demand is satisfied.
Once demand is met, motor runs at 50% for 30 sec
onds then ramps down to stop.
OFF
OFF
1/2 MIN
50% CFM
COMPRESSOR DEMAND
7 1/2 MIN
82% CFM
100%
CFM
1/2 MIN
50% CFM
Ramping Option B
SMotor runs at 82% for approximately 7-1/2 minutes. If
demand has not been satisfied after 7-1/2 minutes,
motor runs at 100% until demand is satisfied.
SOnce demand is met, motor ramps down to stop.
OFF
OFF 82%CFM 100% CFM
COMPRESSOR DEMAND
7 1/2 MIN
Ramping Option C
SMotor runs at 100% until demand is satisfied.
SOnce demand is met, motor runs at 100% for 45 sec
onds then ramps down to stop.
OFF
OFF 100% CFM 100% CFM
45 SEC.
COMPRESSOR
DEMAND
Ramping Option D
SMotor runs at 100% until demand is satisfied.
SOnce demand is met, motor ramps down to stop.
OFFOFF 100% CFM
COMPRESSOR
DEMAND
Switches 11, 12 and 13 -- Heating Mode Blower Speed --
The switches are factory set to the OFF position which pro
vides factory default heat speed. Refer to table 10 for
switches 11, 12 and 13 that provided the corresponding in
creases or decrease to both high and low heat demand.
TABLE 10
Heating Mode Blower Speeds
Heat Speed Switch
11
Switch
12
Switch
13
Increase 24% On On On
Increase 18% On On Off
Increase 12% On Off On
Increase 6% On Off Off
Factory Default Off Off Off
Decrease 6% Off Off On
Decrease 12% Off On Off
Decrease18% Off On On
Switches 14 and 15 -- Continuous Blower Speed --
Table 11 provides continuous blower speed adjustments
that will result from different switch settings.
TABLE 11
Continuous Blower Speed
Continuous
Blower Speed Switch 14 Switch 15
28% of High Cool Speed Off On
38% of High Cool Speed
(Factory) Off Off
70% of High Cool Speed On Off
100% of High Cool Speed On On

Page 18
On-Board Links
Note: In communicating systems with a conventional out
door unit (non-communicating), the on-board clippable
links must be set to properly configure the system.
WARNING
Carefully review all configuration information pro
vided. Failure to properly set DIP switches, jumpers
and on-board links can result in improper operation!
On-Board Link W914 Dehum or Harmony (R to DS)
On-board link W914, is a clippable connection between ter
minals R and DS on the integrated control. W914 must be
cut when the furnace is installed with either the Harmony
IIIzone control or a thermostat which features humidity
control. If the link is left intact the PMW signal from the Har
mony III control will be blocked and also lead to control
damage. Refer to table 12 for operation sequence in ap
plications including SL280DFNV, a thermostat which fea
tures humidity control and a single-speed outdoor unit.
Table 13 gives the operation sequence in applications with
a two-speed outdoor unit.
On-Board Link W951 Heat Pump (R to O)
On-board link W951 is a clippable connection between ter
minals R and O on the integrated control. W951 must be cut
when the furnace is installed in applications which include a
heat pump unit and a thermostat which features dual fuel
use. If the link is left intact, terminal “O” will remain ener
gized eliminating the HEAT MODE in the heat pump.
On-Board Link W915 2 Stage Compr (Y1 to Y2)
On-board link W915 is a clippable connection between ter
minals Y1 and Y2 on the integrated control. W915 must be
cut if two-stage cooling will be used. If the Y1 to Y2 link is
not cut the outdoor unit will operate in second-stage cool
ing only.
TABLE 12
OPERATING SEQUENCE
SL280DFNV, Non-Communicating Thermostat with Humidity Control Feature and Single-Speed Outdoor Unit
OPERATING
SEQUENCE SYSTEM DEMAND SYSTEM RESPONSE
System
Condition Step
Thermostat Demand Relative Humidity
Compres
sor
Blower
CFM
(COOL)
Comments
Y1 O G W
1Status D
NO CALL FOR DEHUMIDIFICATION
Normal Operation 1 On On On Acceptable 24
VAC High 100%
Compressor and indoor
blower follow thermostat
demand
BASIC MODE (only active on a Y1 thermostat demand)
Normal Operation 1 On On On Acceptable 24
VAC High 100% ComfortSense®7500
thermostat energizes Y1
and de-energizes D on a
call for de-humidification
Dehumidification
Call 2 On On On Demand 0 VAC High 70%*
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Operation 1 On On On Acceptable 24
VAC High 100% Dehumidification mode
begins when humidity is
greater than set point
Dehumidification
call 2 On On On Demand 0 VAC High 70%*
Dehumidification
call ONLY 1 On On On Demand 0 VAC High 70%* ComfortSense®7500
thermostat will try to
maintain room humidity
setpoint by allowing the
room space to maintain a
cooler room thermostat
setpoint**
Jumpers at indoor unit with a single stage outdoor unit.
With Condensing unit - Cut W914 (R to DS) on SureLight®control.
With Heat Pump - Cut W914 (R to DS) & W951 (R to O) on SureLight®control
Use Dave Lennox ComfortSense®7500 thermostat Y2081 4 heat / 2 cool for this application
*Dehumidification blower speed is 70% of COOL speed for all units .
**In Precision mode, ComfortSense®7000 thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room setting.

Page 19
TABLE 13
OPERATING SEQUENCE
SL280DFNV, Non-Communicating Thermostat with Humidity Control Feature and Two-Speed Outdoor Unit
OPERATING
SEQUENCE SYSTEM DEMAND SYSTEM RESPONSE
System
Condition
Ste
p
Thermostat Demand Relative Humidity
Compressor
Blower
CFM
(COOL)
Comments
Y1 Y2 O G W
1
W
2Status D
NO CALL FOR DEHUMIDIFICATION
Normal Opera
tion - Y1 1 On On On Acceptable 24 VAC Low 70%* Compressor and indoor
blower follow thermostat
demand
Normal Opera
tion - Y2 2 On On On On Acceptable 24 VAC High 100%
ROOM THERMOSTAT CALLS FOR FIRST STAGE COOLING
BASIC MODE (only active on a Y1 thermostat demand)
Normal Opera
tion 1 On On On Acceptable 24 VAC Low 70%* ComfortSense®7500
thermostat energizes Y2
and de-energizes D on a
call for de-humidification
Dehumidification
Call 2 On On On On Demand 0 VAC High 70%**
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Opera
tion 1 On On On Acceptable 24 VAC Low 70%* Dehumidification mode
begins when humidity is
greater than set point
Dehumidification
call 2 On On On On Demand 0 VAC High 70%**
Dehumidification
call ONLY 1 On On On On Demand 0 VAC High 70%**
ComfortSense
®
7500
thermostat will try to
maintain room humidity
setpoint by allowing the
room space to maintain
a cooler room thermostat
setpoint***
ROOM THERMOSTAT CALLS FOR FIRST AND SECOND STAGE COOLING
BASIC MODE (only active on a Y1 thermostat demand)
Normal Opera
tion 1 On On On On Acceptable 24 VAC High 100% ComfortSense®7500
thermostat energizes Y2
and de-energizes D on a
call for de-humidification
Dehumidification
Call 2 On On On On Demand 0 VAC High 70%**
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Opera
tion 1 On On On Acceptable 24 VAC Low 70%* Dehumidification mode
begins when humidity is
greater than set point
Dehumidification
call 2 On On On On Demand 0 VAC High 70%**
Dehumidification
call ONLY 1 On On On On Demand 0 VAC High 70%** ComfortSense®7500
thermostat will try to
maintain room humidity
setpoint by allowing the
room space to maintain
a cooler room thermostat
setpoint***
Jumpers at indoor unit with a two stage outdoor unit
Cut factory jumper from Y1 to Y2 or cut W915 (Y1 to Y2)
With Condensing unit - Cut W914 (R to DS) on SureLight®control
With Heat Pump - Cut W914 (R to DS) & W951 (R to O) on SureLight®control
Use Dave Lennox ComfortSense®7500 thermostat Y2081 4 heat / 2 cool for this application.
*Normal operation first stage cooling blower speed is 70% COOL speed.
**Dehumidification blower speed is, reduced to 70% of COOL.
***In Precision mode, ComfortSense®7000 thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room setting.

Page 20
B- Indoor Blower Motor
FIGURE 6
To Remove Blower From Unit:
1. Disconnect Power, 2. Remove internal flue pipe and chase
3. Remove Control Box 4. Remove Bolts. 5. Unplug Motor
Wires From Control Board. Then Slide Out Front of Unit.
Supply Air Blower secondary
limit
power
choke
blower wheel
blower motor
WARNING
During blower operation, the ECM motor emits ener
gy that may interfere with pacemaker operation. In
terference is reduced by both the sheet metal cabinet
and distance.
The motor communicates with the integrated control via a
2-way serial connection. The motor receives all necessary
functional parameters from the integrated control and does
not rely on a factory program like traditional variable speed
motors. SL280DFNV units use a three‐phase, electronically
controlled D.C. brushless motor (controller converts single
phase a.c. to three phase D.C.), with a permanent‐magnet‐
type rotor (figure 7). Because this motor has a permanent
magnet rotor it does not need brushes like conventional D.C.
motors.
The stator windings are split into three poles which are electri
cally connected to the controller. This arrangement allows
motor windings to turn on and off in sequence by the con
troller.
IMPORTANT
Earlier ECM motors used on other Lennox furnace
models are not interchangeable with motors used on
the SL280DFNV furnace line.
A solid‐state controller is permanently attached to the
motor. The controller is primarily an A.C. to D.C. con
verter. Converted D.C. power is used to drive the motor.
The controller contains a microprocessor which moni
tors varying conditions inside the motor (such as motor
workload).
BLOWER MOTOR COMPONENTS
FIGURE 7
STATOR
(WINDINGS)
BEARING
ROTOR
The controller uses sensing devices to sense what position
the rotor is in at any given time. By sensing the position of the
rotor and then switching the motor windings on and off in se
quence, the rotor shaft turns the blower.
All SL280DFNV blower motors use single phase power.
An external run capacitor is not used. The motor uses
permanently lubricated ball‐type bearings.
Internal Operation
The motor is controlled via serial communication between
the integrated control on the furnace and the controller at
tached to the motor shell. The messages sent back and
forth between the two controls serve to communicate rota
tional direction, demand, motor size, current draw, torque,
and rpm, among other variables.
Motor rpm is continually adjusted internally to maintain
constant static pressure against the blower wheel. The control
ler monitors the static work load on the motor and motor amp‐
draw to determine the amount of rpm adjustment. Blower rpm
may be adjusted any amount in order to maintain a constant
cfm as shown in Blower Ratings Tables. The cfm remains rel
atively stable over a broad range of static pressure. Since the
blower constantly adjusts rpm to maintain a specified cfm, mo
tor rpm is not rated. Hence, the terms “cool speed”, “heat
speed ” or “speed tap” in this manual, on the unit wiring dia
gram and on blower B3, refer to blower cfm regardless of mo
tor rpm.
Initial Power Up
When line voltage is applied to B3, there will be a large inrush
of power lasting less than 1/4 second. This inrush charges a
bank of DC filter capacitors inside the controller. If the discon
nect switch is bounced when the disconnect is closed, the dis
connect contacts may become welded. Try not to bounce the
disconnect switch when applying power to the unit.