Lennox G40DF-36A-070X, G40DF-36A-045, G40DF-48B-070, G40DF-36B-090, G40DF-48C-090 Unit Information
...
Page 1
© 2001 Lennox Industries Inc.
G40DF(X)
Service Literature
Corp. 0113−L6
Revised 09−2006
G40DF(X) series units are mid−efficiency gas furnaces
used for downflow applications only, manufactured with
Lennox Duralok Plus heat exchangers formed of aluminized steel. G40DF(X) units are available in heating capacities of 44,000 to 135,000 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. G40DF(X) model
units are equipped with a hot surface ignition surface. The
G40DF(X) unit meets the California Nitrogen Oxides (NO
x
)
Standards and California Seasonal Efficiency requirements.
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. Procedures outlined in this manual are presented as a recommendation 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 recommended only and do not constitute
code.
TABLE OF CONTENTS
Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Data 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
High Altitude 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Identification 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I Unit Components 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
II Installation 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
III Start Up 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV Heating System Service Checks 18. . . . . . . . . . . . . .
V Typical Operating Characteristics 20. . . . . . . . . . . . . .
VI Maintenance 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VII Wiring and Sequence of Operation 23. . . . . . . . . . .
VIII SureLight Troubleshooting Guide 33. . . . . . . . . . . .
IMPORTANT
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 qualified installer, service agency
or the gas supplier.
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at disconnect switch(es). Unit may have multiple
power supplies.
WARNING
Sharp edges.
Be careful when servicing unit to avoid sharp edges
which may result in personal injury.
Page 2
SPECIFICATIONS
Gas
Heating
ModelNo.
G40DF
−24A−045
G40DF
−36A−045
G40DF
−36A−070
G40DF
−36B−090
G40DF
−48B−070
eat g
Performance
Low NO
x
Model No. −24A−045X − − − −36A−070X − − − − − −
Input− Btuh 44,000 44,000 66,000 88,000 66,000
Output− Btuh 36,000 35,000 53,000 71,000 53,000
1
AFUE 80.0% 80.0% 80.0% 80.0% 80.0%
Highstatic(CSA)− in.w.g. .50 .50 .50 .50 .50
Temperature rise range − _F 20 − 50 20 − 50 35 − 65 45 − 75 25 − 55
Connections
Flue connection − in. (round) 4 4 4 4 4
GaspipesizeIPS− in. 1/2 1/2 1/2 1/2 1/2
Indoor
Wheelnominaldiameter xwidth −in. 10 x 7 10 x 8 10 x 8 10 x 8 10 x 10
Bl
ower
Motoroutput − hp 1/5
1/3 1/3 1/3 1/2
Tons ofadd-oncooling 1.5 − 2 2 − 3 2 − 3 2 − 3 3 − 4
ShippingData lbs. − 1 package 121 126 132 146 139
Electricalcharacteristics 120 volts − 60 hertz − 1 phase (less than 12 amps)
SPECIFICATIONS
Gas
Heating
ModelNo.
G40DF
−48C−090
G40DF
−48C−110
G40DF
−60C−110
G40DF
−60D−135
eat g
Performance
Low NO
x
Model No. −48C−090X − − − −60C−110X − − −
Input− Btuh 88,000 110,000 110,000 132,000
Output− Btuh 71,000 89,000 90,000 107,000
1
AFUE 80.0% 80.0% 80.0% 80.0%
Highstatic(CSA)− in.w.g. .50 .50 .50 .50
Temperature rise range − _F 45 − 75 45 − 75 35 − 65 40 − 70
Connections
Flue connection − in. (round) 4 4 4 4
GaspipesizeIPS− in. 1/2 1/2 1/2 1/2
Indoor
Wheelnominaldiameter xwidth −in. 10 x 10 10 x 10 11−1/2 x 10 11−1/2 x 10
Bl
ower
Motoroutput − hp 1/2
1/2 1* 1*
Tons ofadd-oncooling 3 − 4 2.5 − 4 4 − 5 4 − 5
ShippingData lbs. − 1 package 153 169 172 195
Electricalcharacteristics 120 volts − 60 hertz − 1 phase (less than 12 amps)
NOTE − Filters and provisions for mounting are not furnished and must be field provided.
1
Annual Fuel Utilization Efficiency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized furnaces.
*Some units may be equipped with 3/4 hp motors.
Page 3
OPTIONAL ACCESSORIES − MUST BE ORDERED EXTRA
A" Width Models B" Width Models C" Width Models D" Width Models
CABINET ACCESSORIES
Down−Flow Additive Base 11M59 11M60 11M61 11M62
CONTROLS
Twinning Kit 15L38 15L38 15L38 15L38
1
Cleanable polyurethane frame type filter.
HIGH ALTITUDE
Input −1
1
High Altitude
High Altitude Pressure
Switch Kit
LPG/Propane Kit
through
−14
g
Orifice Kit
Natural Gas Only
4501−7500 ft.
(1373 − 2286m)
7501−10,000 ft.
(2287 − 3048m)
0−7500 ft.
(0 − 2286m)
7501−10,000 ft.
(2287 − 3048m)
−044
−070
59M16 no change no change 45L60 47M81
−090 59M16 15M22 56L32 45L60 47M81
−110 59M16 15M22 56L32 45L60 47M81
−135 59M16 49L90 15M22 45L60 47M81
Input −15
1
High Altitude
High Altitude Pressure
Switch Kit
LPG/Propane Kit
Input −15
and later
g
Orifice Kit
Natural Gas Only
4501−7500 ft.
(1373 − 2286m)
7501−10,000 ft.
(2287 − 3048m)
0−7500 ft.
(0 − 2286m)
7501−10,000 ft.
(2287 − 3048m)
−045
−070
59M17 no change no change 25W20 25W21
−090 59M17 15M22 56L32 45L60 25W21
−110 59M17 15M22 56L32 25W20 25W21
−135 59M17 49L90 15M22 25W20 25W21
1
Required for proper operation at altitudes from 7501 to 10,000 ft.
NOTE − G40DF(X) units do NOT require a manifold change due to elevation. Manifold pressureremains the same at all
elevations.
BLOWER DATA
G40DF−24A−045 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
External Static
Pressure
High Medium Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts
0.00 0 1202 565 417 1058 500 367 828 390 278
0.05 12 1185 560 410 1041 490 360 819 385 274
0.10 25 1167 550 402 1024 482 353 809 380 270
0.15 37 1147 540 396 1008 475 346 793 375 265
0.20 50 1127 530 390 991 470 338 776 365 260
0.25 62 1104 520 382 979 460 335 764 360 257
0.30 75 1081 510 374 966 455 331 752 355 254
0.40 100 1018 480 357 922 435 319 712 335 244
0.50 125 960 455 342 873 410 306 651 305 234
0.60 150 901 425 330 811 385 290 618 290 231
0.70 175 815 385 313 691 325 272 564 265 221
0.80 200 685 325 289 619 290 259 465 220 203
0.90 225 558 265 271 510 240 238 395 185 190
NOTE − All air data is measured external to unit with 1 in. (25 mm) cleanable filter (not furnished − field provided) in place. Also see Filter Air Resistance table.
Page 4
BLOWER DATA Cont.
G40DF−36A−070 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
External Static
Pressure
High Medium−High Medium−Low Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0.00 0 1475 695 616 1343 635 554 1151 545 495 989 465 415
0.05 12 1449 685 606 1321 625 543 1139 540 481 983 465 407
0.10 25 1423 670 595 1298 615 532 1127 530 466 976 460 398
0.15 37 1397 660 585 1276 600 521 1115 525 452 970 460 390
0.20 50 1371 645 574 1253 590 510 1103 520 437 963 455 381
0.25 62 1345 635 563 1228 580 494 1090 515 428 953 450 371
0.30 75 1318 620 552 1203 570 478 1077 510 418 943 445 360
0.40 100 1249 590 528 1151 545 455 1039 490 395 918 435 346
0.50 125 1200 565 508 1094 515 432 998 470 374 882 415 331
0.60 150 1112 525 475 1033 490 409 951 450 354 831 390 313
0.70 175 1032 485 455 968 455 390 856 405 338 722 340 280
0.80 200 959 455 434 876 415 359 737 350 299 666 315 266
0.90 225 770 365 389 715 335 321 667 315 278 591 280 244
NOTE − All air data is measured external to unit with 1 in. (25 mm) cleanable filter (not furnished − field provided) in place. Also see Filter Air Resistance table.
G40DF−36B−090 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
External Static
Pressure
High Medium−High Medium−Low Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0.00 0 1598 755 608 1408 665 526 1166 550 436 963 455 355
0.05 12 1579 745 599 1398 660 518 1164 550 428 966 455 351
0.10 25 1559 735 589 1388 655 509 1161 550 420 968 455 346
0.15 37 1528 720 573 1369 645 497 1156 545 413 966 455 341
0.20 50 1497 705 556 1350 635 485 1150 545 406 964 455 335
0.25 62 1465 690 544 1326 625 473 1137 535 398 955 450 329
0.30 75 1432 675 532 1301 615 460 1124 530 389 945 445 323
0.40 100 1370 645 509 1248 590 438 1093 515 373 933 440 313
0.50 125 1294 610 482 1198 565 420 1055 500 355 902 425 302
0.60 150 1213 575 456 1141 540 397 1012 480 343 862 405 285
0.70 175 1139 540 437 1054 495 371 917 435 313 802 380 272
0.80 200 1002 475 401 948 445 342 850 400 295 728 345 251
0.90 225 901 425 374 822 390 313 740 350 272 − − − − − − − − −
NOTE − All air data is measured external to unit with 1 in. (25 mm) cleanable filter (not furnished − field provided) in place. Also see Filter Air Resistance table.
Page 5
BLOWER DATA Cont.
G40DF−36C−110 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
External Static
Pressure
High Medium−High Medium−Low Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0.00 0 1660 785 668 1425 675 589 1205 570 489 1015 480 409
0.05 12 1635 770 652 1415 670 575 1205 570 480 1010 475 405
0.10 25 1610 760 636 1405 665 560 1205 570 471 1010 475 402
0.15 37 1575 745 617 1395 660 544 1200 565 460 1005 475 395
0.20 50 1535 725 597 1380 650 524 1200 565 449 1005 475 387
0.25 62 1490 705 576 1350 635 506 1190 560 436 1000 470 380
0.30 75 1450 685 556 1320 625 488 1175 555 422 1000 470 372
0.40 100 1350 635 516 1250 590 456 1125 530 400 970 460 347
0.50 125 1230 580 472 1150 545 416 1045 495 365 910 430 319
0.60 150 1110 525 438 1025 485 374 950 450 329 820 385 284
0.70 175 950 450 396 870 410 329 800 380 286 695 330 251
0.80 200 800 380 362 715 390 294 675 320 245 − − − − − − − − −
0.90 225 685 325 300 625 295 237 560 265 208 − − − − − − − − −
NOTE − All air data is measured external to unit with 1 in. (25 mm) cleanable filter (not furnished − field provided) in place. Also see Filter Air Resistance table.
G40DF−48C−090 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
External Static
Pressure
High Medium−High Medium−Low Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0.00 0 2039 960 749 1852 875 657 1595 755 562 1325 625 466
0.05 12 1998 945 727 1826 860 638 1576 745 547 1338 632 460
0.10 25 1956 925 704 1800 850 619 1556 735 532 1351 640 453
0.15 37 1921 905 692 1770 835 602 1541 725 518 1340 630 441
0.20 50 1885 890 679 1739 820 585 1526 720 503 1329 625 428
0.25 62 1844 870 662 1701 805 568 1502 710 488 1301 615 414
0.30 75 1802 850 645 1663 785 551 1477 695 473 1272 600 399
0.40 100 1693 800 606 1583 745 517 1415 670 448 1226 580 378
0.50 125 1600 755 570 1491 705 485 1334 630 414 1170 550 360
0.60 150 1494 705 540 1406 665 457 1248 590 389 1110 525 337
0.70 175 1378 650 509 1300 615 426 1166 550 367 1026 485 316
0.80 200 1248 590 478 1161 550 390 1027 485 331 − − − − − − − − −
0.90 225 1097 520 439 1028 485 360 925 435 307 − − − − − − − − −
NOTE − All air data is measured external to unit with 1 in. (25 mm) cleanable filter (not furnished − field provided) in place. Also see Filter Air Resistance table.
G40DF−48C−110 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
External Static
Pressure
High Medium−High Medium−Low Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0.00 0 2034 960 846 1790 845 712 1508 710 595 1226 580 477
0.05 12 2001 945 825 1761 830 694 1493 705 581 1224 580 470
0.10 25 1968 930 803 1731 815 675 1477 695 567 1222 575 463
0.15 37 1924 910 781 1708 805 657 1470 695 555 1219 575 455
0.20 50 1879 885 758 1685 795 638 1463 690 542 1216 575 447
0.25 62 1837 865 736 1654 780 618 1442 680 528 1201 565 437
0.30 75 1794 845 714 1623 765 597 1420 670 514 1186 560 427
0.40 100 1681 795 669 1548 730 564 1361 640 483 1134 535 400
0.50 125 1622 765 630 1445 680 524 1280 605 447 1065 505 371
0.60 150 1447 685 592 1312 620 479 1165 550 404 1000 470 343
0.70 175 1289 610 545 1178 555 434 1056 500 369 907 430 319
0.80 200 1157 545 502 1067 505 406 956 450 348 816 385 296
0.90 225 1012 480 472 931 440 372 840 395 320 690 325 265
NOTE − All air data is measured external to unit with 1 in. (25 mm) cleanable filter (not furnished − field provided) in place. Also see Filter Air Resistance table.
Page 6
BLOWER DATA Cont.
5 ton units with 3/4 hp
G40DF−60C−110 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
Pressure
High Medium−High Medium−Low Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
.00 0 2450 1155 1170 2355 1110 1005 2145 1015 840 1845 870 705
.05 10 2430 1150 1165 2340 1105 995 2130 1005 835 1840 870 695
.10 25 2380 1120 1145 2315 1090 985 2105 995 825 1830 865 690
.15 35 2350 1110 1135 2260 1065 965 2085 985 815 1815 855 680
.20 50 2300 1085 1115 2235 1055 955 2060 975 805 1805 850 675
.25 60 2270 1070 1105 2205 1040 945 2015 950 785 1780 840 665
.30 75 2245 1060 1100 2150 1015 925 1995 940 775 1770 835 655
.40 100 2135 1010 1060 2070 975 895 1925 910 750 1730 815 640
.50 125 2055 970 1035 1990 940 870 1855 875 725 1695 800 625
.60 150 1975 930 1010 1910 900 845 1785 845 705 1650 775 605
.70 175 1870 880 980 1830 865 820 1695 800 680 1575 745 585
.80 200 1760 830 950 1720 815 795 1605 755 655 1505 710 570
.90 225 1625 765 915 1560 735 755 1515 715 640 1435 675 555
G40DF−60D−135 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
External Static
Pressure
High Medium−High Medium−Low Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0.00 0 2845 1345 1143 2692 1270 961 2451 1155 818 2054 970 686
0.05 12 2774 1310 1128 2628 1240 948 2354 1110 809 2022 955 680
0.10 25 2702 1275 1112 2564 1210 935 2256 1065 799 1989 940 674
0.15 37 2629 1240 1095 2494 1175 918 2203 1040 784 1933 910 666
0.20 50 2556 1205 1077 2424 1145 901 2150 1015 769 1877 885 657
0.25 62 2471 1165 1061 2309 1090 890 2089 985 759 1835 865 649
0.30 75 2385 1125 1045 2194 1035 878 2028 955 749 1792 845 640
0.40 100 2184 1030 1022 2066 975 851 1900 895 727 1697 800 626
0.50 125 2019 955 990 1917 905 830 1779 840 707 1584 750 602
0.60 150 1865 880 957 1760 830 796 1630 770 676 1491 705 583
0.70 175 1697 800 927 1592 750 768 1475 695 656 1364 645 557
0.80 200 1513 715 897 1485 700 740 1378 650 627 1266 600 538
0.90 225 1385 655 863 1305 615 712 1206 570 598 1120 530 516
NOTE − All air data is measured external to unit with 1 in. (25 mm) cleanable filter (not furnished − field provided) in place. Also see Filter Air Resistance table.
Page 7
BLOWER DATA Cont.
5 ton units with 1 hp
G40DF−60C−110 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
External Static
Pressure
High Medium−High Medium−Low Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
.00 0 2475 1170 1276 2280 1075 987 1995 940 845 1690 795 698
.10 25 2390 1125 1248 2235 1055 955 1990 940 829 1675 790 690
.20 50 2330 1100 1223 2180 1030 945 1975 930 809 1665 785 675
.30 75 2245 1060 1192 2125 1000 911 1940 915 786 1660 785 657
.40 100 2175 1025 1187 2050 965 880 1895 895 757 1650 780 636
.50 125 2085 985 1145 1970 930 849 1835 870 734 1625 765 619
.60 150 2020 955 1129 1880 885 815 1750 825 695 1580 745 599
.70 175 1920 905 1094 1775 835 785 1660 785 669 1525 720 579
.80 200 1785 840 1052 1685 795 762 1585 745 645 1440 680 556
.90 225 1670 790 1020 1600 755 741 1520 715 633 1370 645 538
G40DF−60D−135 PERFORMANCE
External Static
Air Volume / Watts at Different Blower Speeds
External Static
Pressure
High Medium−High Medium−Low Low
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
.00 0 2660 1255 1379 2325 1095 1059 1960 925 864 1655 780 684
.10 25 2560 1210 1353 2310 1090 1030 1945 915 840 1640 775 667
.20 50 2490 1175 1325 2280 1075 1000 1940 915 824 1630 770 661
.30 75 2415 1140 1293 2225 1050 972 1930 910 801 1625 765 649
.40 100 2345 1105 1264 2170 1025 941 1910 900 779 1620 760 638
.50 125 2265 1070 1235 2115 1000 918 1870 880 754 1615 760 624
.60 150 2165 1020 1199 2020 955 880 1830 865 733 1585 745 604
.70 175 2050 965 1160 1940 915 854 1755 830 705 1570 740 604
.80 200 1955 920 1112 1865 880 828 1680 790 683 1515 715 584
.90 225 1865 880 1096 1760 830 797 1605 755 656 1465 690 567
NOTE − All air data is measured external to unit with 1 in. (25 mm) cleanable filter (not furnished − field provided) in place. Also see Filter Air Resistance table.
FILTER AIR RESISTANCE
cfm L/s in. w.g. Pa cfm L/s in. w.g. Pa
0 0 0.00 0 1400 660 0.15 35
200 95 0.01 0 1600 755 0.19 45
400 190 0.03 5 1800 850 0.23 55
600 285 0.04 10 2000 945 0.27 65
800 380 0.06 15 2200 1040 0.33 80
1000 470 0.09 20 2400 1130 0.38 95
1200 565 0.12 30 2600 1225 0.44 11 0
Data is for 1 inch (25 mm) cleanable filter (field provided).
Page 8
G40DF(X) PARTS ARRANGEMENT
FIGURE 1
Blower Assembly
Blower Motor
Capacitor
Internal Flue Pipe
Assembly
Flue Box Gasket
Flue Collector Box
Gasket
Combustion Air Inducer
Gasket
Manifold
Burner
Gas Valve
Flame Rollout
Switches
Flame
Sensor
Primary
Limit
Ignitor
Heat Exchanger
Ignitor
Bracket
Combustion Air
Pressure Switch
Combustion
Air Orifice
Gas
Orifices
Flue
Chase
Gasket
Limit Sheild with
−3 Units only
Ignition
Control
Transformer
DoorInterlock Switch
Pressure Port
Pressure Port
Location for
−1 to −14 units
Page 9
I−UNIT COMPONENTS
G40DF(X) unit components are shown in figure 1. The gas
valve, combustion air inducer and burners can be accessed by removing the burner access panel. Electrical
components are in the control box (figure 2) found in the
blower section.
CAUTION
Electrostatic discharge can affect electronic
components. Take precautions during furnace
installation and service to protect the furnace’s
electronic controls. Precautions will help to
avoid control exposure to electrostatic discharge by putting the furnace, the control and
the technician at the same electrostatic potential. Neutralize electrostatic charge by touching
hand and all tools on an unpainted unit surface,
such as the gas valve or blower deck, before performing any service procedure.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
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 series with line voltage. When the blower door is removed the
unit will shut down.
FIGURE 2
CONTROL BOX
G40UH(X)
SureLight Control
Transformer
DoorInterlock Switch
WARNING
Shock hazard.
Disconnect power before servicing. Control is
not field repairable. If control is inoperable, simply replace entire control.
Can cause injury or death. Unsafe operation will
result if repair is attempted.
3. SureLight Ignition Control (A92) Figure 3
Control 56L84, 10M93 & 32M88
The Lennox SureLight ignition system consists of ignition
control board, ignitor and sensor. The board and ignitor
work in combination to ensure furnace ignition and ignitor
durability. The SureLight integrated board controls all ma-
jor furnace operations. The board also features two LED
lights (DS1, DS2) for troubleshooting and two accessory
terminals rated at (1) one amp. Table 1 gives control termi-
nal designations. Tables 2 and 3 show jack plug terminal
designations. See table 11 for troubleshooting diagnostic
codes. Units equipped with the SureLight board can be
used with either electronic or electro−mechanical thermo-
stats without modification. The SureLight ignitor is made
of durable silicon−nitride. Ignitor longevity is also en-
hanced by voltage ramping by the control board. The
board finds the lowest ignitor temperature which will suc-
cessfully light the burner, thus increasing the life of the ig-
nitor.
TABLE 1
PARK
TERMINAL DESIGNATIONS
COOL−H
HEAT−H
EAC−H
HUM−H
XFMR−H
LINE−H
LINE−N
HUM−N
EAC−N
XFMR−N
CIR−N
Blower − Cooling Speed (120VAC)
Blower − Heating Speed (120VAC)
Electronic Air Cleaner (120VAC)
Humidifier (120VAC)
Transformer (120VAC)
Input (120VAC)
Input (Neutral)
Humidifier (Neutral)
Electronic Air Cleaner (Neutral)
Transformer (Neutral)
Blower − Neutral
(FLAME SENSE)
Alternate Blower Speeds (Dead)
Flame Sensor
120V HOT
120V NEUT
Page 10
SURELIGHT INTEGRATED CONTROL BOARD
FIGURE 3
J156
FLAME SENSE
J58
XFMR−N
TABLE 2
SureLight BOARD J156 (J2) TERMINAL
DESIGNATIONS
PIN # FUNCTION
1 Combustion Air Inducer Line
2
Ignitor Line
3
Combustion Air Inducer Neutral
4
Ignitor Neutral
TABLE 3
SureLight BOARD J58 (J1) TERMINAL
DESIGNATIONS
PIN # FUNCTION
1 Secondary Limit
2
Not Used
3
24V
4
Not Used
5
Rollout Switch In
6
24V
7
Primary Limit
8
Ground
9
Gas Valve In
10
Pressure Switch Out
11
Rollout Switch Out
12
Gas Valve Out
a−Electronic Ignition (See Figure 8)
On a call for heat the SureLight control monitors the combustion air inducer prove switch. The control will not begin
the heating cycle if the prove switch is closed (by−passed).
Once the proving switch is determined to be open, the combustion air inducer is energized. When the differential in the
prove switch is great enough, the prove switch closes and a
15−second pre−purge begins. If the prove switch is not
proven within 2−1/2 minutes, the control goes into Watchguard−Pressure Switch mode for a 5−minute re−set period.
After the 15−second pre−purge period, the SureLight ignitor
warms up for 20 seconds during which the gas valve opens
at 19 seconds for a 4−second trial for ignition. Control
10M93 and 32M88 energizes the ignitor during the trial until flame is sensed. Control 56L84 energizes the ignitor for 1
second only. 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 five trials for ignition (including the initial trial),
the control goes into Watchguard−Flame Failure mode. After a 60−minute reset period, the control will begin the ignition sequence again.
The SureLight control board has an added feature that prolongs the life of the ignitor. After a successful ignition, the
SureLight control utilizes less power to energize the ignitor
on successive calls for heat. The control continues to ramp
down the voltage to the ignitor until it finds the lowest
amount of power that will provide a successful ignition. This
amount of power is used for 255 cycles. On the 256th call
for heat, the control will again ramp down until the lowest
power is determined and the cycle begins again.
b−Fan Time Control
The fan on time of 45 seconds is not adjustable. Fan off
time (time that the blower operates after the heat demand
has been satisfied) can be adjusted by flipping the dip
switches located on the SureLight integrated control. The
unit is shipped with a factory fan off setting of 90 seconds.
For customized comfort, monitor the supply air temperature once the heat demand is satisfied. Note the supply air
temperature at the instant the blower is de−energized. Adjust the fan−off delay to achieve a supply air temperature
between 90° − 110° at the instant the blower is de−energized. (Longer delay times allow for lower air temperature,
shorter delay times allow for higher air temperature). See
figure 4.
FIGURE 4
FAN-OFF TIME ADJUSTMENT
To adjust fan−off timing, flip dip switch to desired setting.
60sec. 90sec. 120sec. 180sec.
Page 11
WARNING
Shock hazard.
Disconnect power before servicing. Control is
not field repairable. If control is inoperable, simply replace entire control.
Can cause injury or death. Unsafe operation will
result if repair is attempted.
4. SureLight Ignition Control (A92) Figure 5
Control 69M08
The Lennox SureLight ignition system consists of ignition
control board, ignitor and sensor. The board and ignitor
work in combination to ensure furnace ignition and ignitor
durability. The SureLight integrated board controls all ma-
jor furnace operations. The board also features two LED
lights (DS1 red and DS2 green) for troubleshooting and
two 120 volt accessory terminals, each rated at (1) one
amp. The board also features a 3 amp fuse for low voltage
overcurrent protection. Table 4 gives control terminal des-
ignations. Tables 5 and 6 show jack plug terminal designa-
tions. See table 11 for troubleshooting diagnostic codes.
Units equipped with the SureLight board can be used with
either electronic or electro−mechanical thermostats with-
out modification. The SureLight ignitor is made of durable
silicon−nitride. Ignitor longevity is also enhanced by volt-
age ramping by the control board. The board finds the low-
est ignitor temperature which will successfully light the
burner, thus increasing the life of the ignitor.
TABLE 4
SURELIGHT BOARD TERMINAL DESIGNATIONS
COOL Blower − Cooling Speed (120V)
HEAT Blower − Heating Speed (120V)
PARK
Unused Blower Lead (not energized)
FAN
Continuous Low Blower Speed
EAC
Accessory Terminal (120V)
XFMR
Transformer (120V)
LINE
Input (120V)
HUM
Heat Only Accessory (120V)
5 Terminals
120V Neutral
FS
Flamer Sensor
SURELIGHT INTEGRATED CONTROL BOARD
FIGURE 5
3 AMP, 32
VAC FUSE
TABLE 5
SURELIGHT BOARD 4 PIN DESIGNATIONS
PIN # FUNCTION
1 Combustion Air Inducer Line
2
Ignitor Line
3
Combustion Air Inducer Neutral
4
Ignitor Neutral
TABLE 6
SURELIGHT BOARD 12 PIN DESIGNATIONS
PIN # FUNCTION
1 Prove Switch and Limit Out
2
Not Used
3
24V Hot
4
Not Used
5
Rollout Switch In 1
6
24V Common
7
Limit In
8
Ground
9
Gas Valve Common
10
Prove Switch In
11
Rollout Switch Out 2
12
Gas Valve Hot
Page 12
c−Electronic Ignition (See Figure 8)
On a call for heat the SureLight control monitors the combustion air inducer prove switch. The control will not begin
the heating cycle if the prove switch is closed (by−passed).
Once the proving switch is determined to be open, the combustion air inducer is energized. When the differential in the
prove switch is great enough, the prove switch closes and a
15−second pre−purge begins. If the prove switch is not
proven within 2−1/2 minutes, the control goes into Watchguard−Pressure Switch mode for a 5−minute re−set period.
After the 15−second pre−purge period, the SureLight ignitor
warms up for 20 seconds during which the gas valve opens
at 19 seconds for a 4−second trial for ignition. The ignitor
stays energized 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 seconds. After a total of five trials
for ignition (including the initial trial), the control goes into
Watchguard−Flame Failure mode. After a 60−minute reset
period, the control will begin the ignition sequence again.
The SureLight control board has an added feature that prolongs the life of the ignitor. After a successful ignition, the
SureLight control utilizes less power to energize the ignitor
on successive calls for heat. The control continues to ramp
down the voltage to the ignitor until it finds the lowest
amount of power that will provide a successful ignition. This
amount of power is used for 255 cycles. On the 256th call
for heat, the control will again ramp down until the lowest
power is determined and the cycle begins again.
d−Heating Fan Delay Time
The heating fan on time of 45 seconds is not adjustable.
Fan off time (time that the blower operates after the heat
demand has been satisfied) can be adjusted by setting the
S1 dip switches located on the SureLight integrated control. The unit is shipped with a factory fan off setting of 90
seconds. Fan off time will affect comfort and is adjustable
to satisfy individual applications. For customized comfort,
monitor the supply air temperature once the heat demand
is satisfied. Note the supply air temperature at the instant
the blower is de−energized. Adjust the fan−off delay to
achieve a supply air temperature between 90° − 110° at the
instant the blower is de−energized. (Longer delay times allow for lower air temperature, shorter delay times allow for
higher air temperature). See table 7 for switch settings and
fan delay times.
e−Cooling Fan Delay Time
The cooling fan on time is fixed at 2 seconds and cannot be
adjusted. G40DF units do not have a cooling fan off delay
time.
TABLE 7
S1 DIP SWITCH SETTINGS
Heat Off Delay
Switch 1 Switch 2 Seconds
OFF OFF 60
OFF ON 90
ON OFF 120
ON ON 180
5. Ignition Control (A92) Figure 6
Control 78M47 & 100973−01
WARNING
Shock hazard.
Disconnect power before servicing. Control is
not field repairable. If control is inoperable, simply replace entire control.
Can cause injury or death. Unsafe operation will
result if repair is attempted.
The hot surface ignition system consist of an integrated
control board (figure 6 with control terminal designations
in table 10), sensor (figure 9) and ignitor (figure 10). The
control board and ignitor work in combination to ensure
furnace ignition and ignitor durability. The control board
controls all major furnace operations. The control board
also features two LED lights (AN1 red and AN2 green) for
troubleshooting and two accessory terminals rated at (1)
one amp. The control board also features a (3) amp fuse for
overcurrent protection. Tables 8 and 9 show jack plug terminal designations. See table 11 for troubleshooting diagnostic codes. The mini−nitride ignitor is made from a non−
porous, high strength proprietary ceramic material that
provides long life and trouble free maintenance. The control board continuously monitors line voltage and maintains the ignitor power at a consistent level to provide
proper lighting and maximum ignitor life.
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