Lennox EL297DFV Series Installation and operation manual

Page 1
UNIT INFORMATIONUNIT INFORMATION
Service Literature
©2016 Lennox Industries, Inc.
WARNING
Improper installation, adjustment, alteration,
service or maintenance can cause property damage,
personal injury or loss of life. Installation and service
must be performed by a licensed professional HVAC
installer (or equivalent), service agency or the gas
supplier.
CAUTION
As with any mechanical equipment, contact with
sharp sheet metal edges can result in personal
injury. Take care while handling this equipment and
wear gloves and protective clothing.
EL297DFV(X) series units are 90% e󰀩ciency gas furnac-
es used for upow or horizontal applications only, man-
ufactured with Lennox Duralok heat exchangers formed
of aluminized steel. EL297DFV(X) units are available in
heating capacities of 44,000 to 110,000 Btuh and cooling
applications up to 5 tons. Refer to Engineering Handbook
for proper sizing.
Units are factory equipped for use with natural gas. Kits
are available for conversion to LPG operation. EL297D-
FV(X) model units are equipped with a communicating
enabled SureLight® two-stage variable speed integrated
control.
EL297DFV(X) unit meets the California Nitrogen Oxides
(NOx) Standards and California Seasonal E󰀩ciency re-
quirements. All units use a redundant gas valve to assure
safety shut-o󰀨 as required by C.S.A.
All specications in this manual are subject to change.
Procedures outlined in this manual are presented as a
recommendation only and do not supersede or replace lo-
cal or state codes. In the absence of local or state codes,
the guidelines and procedures outlined in this manual (ex-
cept where noted) are recommendations only and do not
constitute code.
TABLE OF CONTENTS
Specications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
I Unit Components . . . . . . . . . . . . . . . . . . . . . . . . Page 9
II Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 39
III Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 60
IV Heating System Service Checks . . . . . . . . . Page 61
V Typical Operating Characteristics . . . . . . . . . Page 64
VI Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 64
VII Wiring and Sequence of Operation . . . . . . Page 67
Program Unit Capacity Size Mode . . . . . . . Page 85
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . Page 86
EL297DFV
100089
Communicating-Enabled EL297DFV SERIES UNITS

Page 2
SPECIFICATIONS
Gas
Heating
Performance
Model No. EL297DF045XV36BEL297DF070XV48BEL297DF090XV60CEL297DF110XV60C
1 AFUE 97% 97% 97% 97%
High
Fire
Input - Btuh 44,000 66,000 88,000 110,000
Output - Btuh 43,000 64,000 86,000 108,000
Temperature rise range - °F 35-65 35-65 40-70 45-75
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0 3.5 / 10.0 3.5 / 10.0
Low
Fire
Input - Btuh 29,000 43,000 57,000 72,000
Output - Btuh 28,000 42,000 56,000 70,000
Temperature rise range - °F 20 - 50 25 - 55 30 - 60 35 - 65
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
1.7 / 4.5 1.7 / 4.5 1.7 / 4.5 1.7 / 4.5
High static -
in. w.g.
Heating 0.8 0.8 0.8 0.8
Cooling 1.0 1.0 1.0 1.0
Connections
in.
Intake / Exhaust Pipe (PVC) 2 / 2 2 / 2 2 / 2 2 / 2
Gas pipe size IPS 1/2 1/2 1/2 1/2
Condensate Drain Trap (PVC pipe) - i.d. 3/4 3/4 3/4 3/4
with furnished 90° street elbow 3/4 slip x 3/4 Mipt 3/4 slip x 3/4 Mipt 3/4 slip x 3/4 Mipt 3/4 slip x 3/4 Mipt
with eld supplied (PVC coupling) - o.d. 3/4 slip x 3/4 MPT 3/4 slip x 3/4 MPT 3/4 slip x 3/4 MPT 3/4 slip x 3/4 MPT
Indoor
Blower
Wheel nom. diameter x width - in. 10 x 9 11 x 10 11 x 11 11 x 11
Motor output - hp 1/2 3/4 1 1
Tons of add-on cooling 2 - 3 2.5 - 4 3 - 5 3 - 5
Air Volume Range - cfm 545 - 1360 575 - 1800 890 - 2130 860 - 2180
Electrical
Data
Voltage 120 volts - 60 hertz - 1 phase
Blower motor full load amps 7.7 10.1 12.8 12.8
Maximum overcurrent protection 15 20 20 20
Shipping Data lbs. - 1 package 131 136 164 176
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.

Page 3
OPTIONAL ACCESSORIES - ORDER SEPARATELY
NOTE - FURNACES CANNOT BE TWINNED!
“B” Width Models “C” Width Models
CABINET ACCESSORIES
Downow Combustible Flooring Base 11M60 11M61
High Performance Economizer (Commercial Only) 10U53 10U53
CONDENSATE DRAIN KITS
Condensate Drain Heat Cable 6 ft. 26K68 26K68
24 ft. 26K69 26K69
Crawl Space Vent Drain Kit US 51W18 51W18
Canada 15Z70 15Z70
CONTROLS
S40 Smart Wi-Fi Thermostat 22V24 22V24
1Discharge Air Temperature Sensor 88K38 88K38
E30 Smart Wi-Fi Thermostat 20A65 20A65
2Remote Outdoor Temperature Sensor X2658 X2658
FILTERS
3 Downow Filter Cabinet 51W07 51W08
No. and Size of lter - in. (2) 16 x 20 x 1 (2) 16 x 20 x 1
VENTING
Flue Coupling 2 in. 17H92 17H92
⁴ Left Side Vent Kit 2 or 3 in. 87W73 87W73
1 Optional for service diagnostics.
2 Remote Outdoor Temperature Sensor is used with conventional (non-Lennox® Communicating) outdoor units (sensor is furnished with Lennox® Communicating
outdoor units). Allows the thermostat to display outdoor temperature. Required in dual-fuel and EDA applications.
3 Cleanable polyurethane, frame-type lter.
4 NOTE - The curved exhaust pipe furnished with the Left Side Vent Kit counts as one additional 2 in. diameter 90° elbow. When using 3 in. diameter pipe, the furnished
curved exhaust pipe and eld provided ttings to transition from 2 in. to 3 in. count as 20 feet of equivalent pipe on all units.
NOTE - Termination Kits (44W92, 44W93, 30G28, 51W12, 81J20) and Crawl Space Vent Drain Kit (15Z70) are certied to ULC S636 standard for use in Canada only.

Page 4
BLOWER DATA
EL297DF045XV36B BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR
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% 910 1150
+18% 855 1095
+12% 820 1040
+6% 770 990
Factory Default 745 935
–6% 700 880
–12% 665 820
–18% 635 755
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
[phone] 1050 1210 1360
Factory Default 580 695 780 880 805 965 1105 1250
–545 645 720 795 735 865 1000 1130
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.
2 Factory 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 250 cfm.
Lennox® Smart Zoning System Applications - Minimum blower speed is 250 cfm.
EL297DF045XV36B 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 28 44 60 77 93 112 128 144 158 59 77 97 121 138 160 182 197 216 241 256
Med-low 47 67 88 105 121 138 161 179 201 131 154 177 202 228 250 277 299 320 344 370
Med-High 69 91 113 132 160 183 204 220 246 199 215 248 275 308 340 360 390 407 431 445
High 100 117 153 172 192 215 240 260 286 292 313 363 379 419 452 488 511 526 523 524
Factory Default
Cooling
Speed
Low 17 34 52 65 82 97 121 132 148 61 79 98 125 141 164 185 201 219 246 259
Med-low 35 50 70 85 105 125 140 155 175 99 115 148 167 188 211 236 256 279 303 317
Med-High 54 72 95 113 131 148 173 189 210 147 170 197 223 252 278 301 330 355 373 398
High 74 96 118 141 168 190 212 233 252 216 229 258 303 325 356 390 410 426 448 465
– Setting
Cooling
Speed
Low 17 31 49 61 75 91 107 123 136 46 64 82 101 115 134 155 174 196 205 221
Med-low 28 45 61 77 93 112 129 144 159 72 92 114 133 160 184 204 221 247 263 282
Med-High 40 57 77 93 112 130 148 165 186 112 130 161 183 205 226 252 272 294 319 341
High 57 76 97 119 136 156 179 195 214 155 174 207 235 265 292 311 343 370 386 414

Page 5
BLOWER DATA
EL297DF070XV48B BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR
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% 1085 1635
+18% 1030 1525
+12% 950 1450
+6% 910 1365
Factory Default 850 1310
–6% 790 1225
–12% 740 1135
–18% 680 1060
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
[phone] 1110 1340 1575 1800
Factory Default 660 820 940 1120 995 1230 1420 1650
–575 735 850 995 880 1085 1290 1460
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.
2 Factory 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® Smart Zoning System Applications - Minimum blower speed is 380 cfm.
EL297DF070XV48B 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 68 88 109 132 154 178 199 213 238 144 169 208 244 270 310 343 378 401 432 457
Med-low 93 120 147 172 198 220 254 274 304 257 276 326 370 398 437 470 492 531 558 598
Med-High 120 152 180 220 254 281 318 344 380 390 428 472 526 574 611 659 706 745 788 820
High 214 237 284 324 352 390 424 456 474 627 604 663 721 775 825 869 908 915 881 864
Factory Default
Cooling
Speed
Low 35 54 74 92 109 129 147 163 191 104 137 162 189 219 254 278 312 341 369 400
Med-low 75 100 115 140 165 190 210 230 255 188 203 250 297 327 374 399 432 454 486 513
Med-High 99 129 159 179 209 236 270 293 329 304 340 376 418 450 495 533 567 613 637 674
High 157 184 232 264 285 335 365 406 419 454 469 537 589 634 669 724 770 818 833 840
– Setting
Cooling
Speed
Low 27 49 63 73 98 116 135 155 168 86 111 135 162 186 206 236 257 283 306 339
Med-low 67 87 109 132 154 177 199 212 238 129 156 187 226 258 288 325 353 385 409 441
Med-High 82 105 127 153 176 196 223 243 269 226 244 290 335 364 402 435 465 485 516 556
High 107 141 164 195 224 263 282 321 347 329 375 403 444 481 526 570 612 656 680 718

Page 6
BLOWER DATA
EL297DF090XV60C BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR
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% 1425 1895
+18% 1355 1825
+12% 1280 1740
+6% 1215 1660
Factory Default 1160 1575
–6% 1055 1455
–12% 1010 1365
–18% 950 1265
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
[phone] 1600 1600 1750 1970 2130
Factory Default 1005 1150 1275 1450 1450 1630 1810 1975
–890 1065 1150 1270 1270 1450 1645 1810
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.
2 Factory 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® Smart Zoning System Applications - Minimum blower speed is 450 cfm.
EL297DF090XV60C 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 79 108 144 162 207 242 262 293 323 275 299 366 399 449 483 532 584 605 644 680
Med-low 120 156 187 233 261 279 329 368 401 387 409 471 521 562 606 650 688 716 762 800
Med-High 155 202 235 293 317 369 407 453 502 547 577 622 667 744 795 835 872 910 950 963
High 268 299 366 399 449 483 532 584 605 780 775 811 898 942 994 1048 1071 1082 1080 1073
Factory Default
Cooling
Speed
Low 56 86 111 140 170 200 232 259 282 186 219 270 308 361 390 431 489 517 555 590
Med-low 93 118 152 195 223 254 283 306 344 278 304 365 420 450 510 544 592 640 665 698
Med-High 123 161 201 228 260 310 341 381 416 446 475 528 582 616 662 686 747 780 823 855
High 182 219 270 308 361 390 431 489 517 576 603 654 704 756 809 871 902 939 972 975
– Setting
Cooling
Speed
Low 48 69 101 120 152 175 201 218 249 118 155 181 232 259 299 340 376 402 438 476
Med-low 65 94 123 150 185 220 250 278 296 177 205 267 304 353 390 430 486 515 563 587
Med-High 93 118 152 195 223 254 283 306 344 301 322 392 439 468 531 568 599 647 678 721
High 116 155 181 232 259 299 340 376 402 446 475 528 582 616 662 686 747 780 823 855

Page 7
BLOWER DATA
EL297DF110XV60C BLOWER PERFORMANCE (less lter)
BOTTOM RETURN AIR
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% 1535 2015
+18% 1445 1935
+12% 1370 1855
+6% 1300 1760
Factory Default 1220 1645
–6% 1135 1545
–12% 1070 1420
–18% 1000 1335
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
[phone] 1585 1585 1790 1990 2180
Factory Default 965 1130 1285 1440 1440 1630 1845 2005
–860 1035 1130 1275 1275 1475 1655 1845
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.
2 Factory 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® Smart Zoning System Applications - Minimum blower speed is 450 cfm.
EL297DF110XV60C 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 71 99 147 166 202 240 271 302 337 248 280 333 374 429 469 511 548 594 619 677
Med-low 127 159 198 225 256 301 325 365 390 409 427 496 531 587 632 665 721 742 781 805
Med-High 162 204 242 287 316 371 408 446 487 563 589 651 703 755 808 860 888 932 970 1007
High 243 280 333 374 429 469 511 548 594 866 850 915 963 1020 1056 1091 1127 1141 1136 1131
Factory Default
Cooling
Speed
Low 57 88 117 140 165 196 232 259 283 167 214 244 291 331 380 405 467 497 539 583
Med-low 77 112 147 172 209 250 283 317 345 275 321 348 418 447 505 546 597 632 668 716
Med-High 122 154 199 230 268 300 331 373 411 461 493 547 572 628 666 703 745 777 819 860
High 167 214 244 291 331 380 405 467 497 601 626 688 730 787 823 880 924 963 994 1011
– Setting
Cooling
Speed
Low 44 67 99 115 144 167 197 215 245 126 165 201 232 262 305 334 373 417 451 479
Med-low 66 97 123 153 186 216 247 275 303 187 219 272 308 360 391 432 479 514 559 588
Med-High 77 112 147 172 209 250 283 317 345 308 341 390 430 490 528 569 617 640 691 724
High 127 165 201 232 262 305 334 373 417 461 493 547 572 628 666 703 745 777 819 860

Page 8
PARTS IDENTIFICATION
CONTROL BOX
(Includes integrated control,
transformer and door switch)
BAG ASSEMBLY
(shipping location)
VARIABLE SPEED MOTOR
(hidden)
OUTER
ACCESS
PANEL
COMBUSTION
AIR INDUCER
BURNER BOX ASSEMBLY
(includes sensor, rollout switches and ignitor)
GAS VALVE
BLOWER DECK
COLD END HEADER BOX
PRIMARY LIMIT
DuralokPlusTM
HEAT EXCHANGER
ASSEMBLY
COMBUSTION AIR INDUCER
PRESSURE SWITCH
FIGURE 1

Page 9
I-UNIT COMPONENTS
EL297DFV(X) unit components are shown in FIGURE 1.
The gas valve, combustion air inducer and burners can be
accessed by removing the access panel. Electrical com-
ponents are in the control box (FIGURE 2) found in the
blower section.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can a󰀨ect
electronic 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
secondary.
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.
CONTROL BOX
Transformer
SureLight®Integrated Control
Interlock Switch
Circuit Breaker
FIGURE 2
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.
CIRCUIT BREAKER CB8
PRESS TO RESET
FIGURE 3
WARNING
Shock hazard.
Disconnect power before servicing. Integrated
control is not eld repairable. If control is inoperable,
simply replace entire control.
Can cause injury or death. Unsafe operation will
result if repair is attempted.
4. Integrated Control (A92)
Units are equipped with a communicating enabled Sure-
Light ® two-stage, variable speed integrated control. This
control is used with a communicating thermostat as part
of a communicating comfort system. The control can also
operate with a non-communicating conventional single or
two-stage thermostat. The system consists of a ignition /
blower control (FIGURE 4 and FIGURE 6) with control pin
designations in TABLE 1, TABLE 2, TABLE 3 and ignitor
(FIGURE 14). The control and ignitor work in combination
to ensure furnace ignition and ignitor durability. The con-
trol provides gas ignition, safety checks and indoor blower
control with two-stage gas heating. The furnace combus-
tion 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 ame signal.
The control features a seven-segment LED display, indi-
cating furnace status (including indoor blower) and error
codes. The LED ashes in single digits. The control also
has two unpowered (dry) 1/4” contacts for a humidier and
a 120 volt accessory terminal. Both rated at (1) one amp
each.
Electronic Ignition
At the beginning of the heat cycle the integrated control
monitors the rst stage and second stage combustion air
inducer prove switch. The control will not begin the heating
cycle if the rst 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 rst stage heat. However, if the
second stage prove switch closes during the rst stage
heat pre-purge, the control will allow second stage heat.
Once the rst stage prove switch is determined to be open,
the combustion air inducer is energized on low (rst stage)
heat speed. When the di󰀨erential in the prove switch is
great enough, the prove switch closes and a 15-second
pre-purge begins.

Page 10
NOTE - During abnormal conditions such as low supply
voltage or low outdoor temperatures and the low re pres-
sure switch does not close, the combustion air inducer will
switch to high re. After a 15 second pre-purge the high
re pressure switch will close and the unit will begin op-
eration on high re. After 10 to 20 seconds of high re
operation the unit will switch to low re.
After the 15-second pre-purge period, the SureLight ig-
nitor warms up for 20 seconds after which the gas valve
opens for a 4-second trial for ignition. The ignitor remains
energized during the trial until ame 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 seconds. After a total of ve trials for
ignition (including the initial trial), the control goes into
Watchguard- Flame Failure mode. After a 60-minute reset
period, thecontrol 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 re
on rst-stage heat. The combustion air inducer will oper-
ate on low speed and indoor blower will operate on low
heat speed. The unit will switch to second stage heat af-
ter 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 secondstage heat. While in the
two-stage thermostat mode, the burners will re on rst-
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 on call from the
indoor thermostat. If there is a simultaneous call for rst
and second stage heat, the unit will re an rst stage heat
and switch to second stage heat after 30 seconds of oper-
ation. See Sequence of Operation ow charts in the back
of this manual for more detail.
TABLE 1
SureLight® Control 5 Pin Terminal Designation
Pin # Function
1Ignitor
2Combustion Air Inducer High
Speed
3 Combustion Air Inducer Low
Speed
4 Combustion Air Inducer Neutral
5 Ignitor Neutral
TABLE 2
SureLight®Control 12 Pin Terminal Designation
Pin # Function
1Gas Valve Second Stage
2Second Stage Prove Switch
3 Rollout Switch In
4 Ground
5 24V Hot
6 Primary Limit In
7Gas Valve First Stage
8 Gas Valve Common
924V Neutral
10 Ground
11 Rollout Switch Out
12 First Stage Prove Switch
TABLE 3
SureLight® Control 6 Pin Terminal Designation
Pin # Function
1Data Input From Motor
2Common
3 Not Used
4 Data Output To Motor
5 5 Volt Bias Supply
6 Not Used