Lennox G23Q4-75, G23Q2-75, G23Q5-75, G23Q3-50, G23Q3-100 Unit Information
...
G23(X)
GasPipingSizeI.P.S.
GasPipingSizeI.P.S.
Blowerwheelnomina
l
Blowerwheelnomina
l
Nominalcoolin
g
Nominalcoolin
g
Corp. 9814-L8
Service Literature
G23(X) SERIES UNITS
G23(X) series units are mid-efficiency upflow gas furnaces manufactured with Duralokt aluminized steel
clamshell type heat exchangers. G23(X) units are available in heating capacities of 50,000 to 150,000 Btuh and
cooling applications up to 6 tons. Refer to Engineering
Handbook for proper sizing.
Unitsare factory equipped for use with natural gas. A kit is
availablefor conversionto LPG operation.G23(X)-1, -2, -3
and-4modelunitsuse electronic(intermittentpilot)ignition.
G23(X)-5 and -6 model units feature the Lennox SureLightT silicon nitride ignition system. All units meet the
CaliforniaNitrogenOxides(NOx) Standardsand California
Seasonal Efficiency requirements with the installation of
flamebaffles.Allunitsusea redundantgasvalveto assure
safety shut-off as required by A.G.A. or C.G.A.
Informationcontainedin this manual is intendedforuse by
qualified service technicians only. All specifications 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.
Model No. G23Q2(X)-50 G23Q3(X)-50 G23Q2/3(X)-75 G23Q4/5(X)-75 G23Q3(X)-100
Input Btuh(kW) 50,000 (14.7) 75,000 (22.0) 100,000 (29.3)
Output Btuh (kW) 40,000 (11.7) 61,000(17.8) 80,000 (23.4)
lA.F.U.E. 80.7% 80.8% 80.4% 80.1%
California Seasonal Efficiency 75.5% 75.6% 76.9% 74.2% 76.6%
Flue size connection diameter— in. (mm) round 3 (76) 4 (102)
Temperature riserange — _F (_C) 30-60 (17-33) 35-65 (19-36) 20-50 (11-28) 45-75 (25-42)
High static certified by A.G.A. — in wg.(Pa) .50 (125)
in. 1/2
Natural or LPG/propane
diameter x width
Blower motor output — hp (W) 1/5 (149) 1/3 (249) 3/4 (560) 1/3 (249)
that canbe added
Shipping weight — lbs. (kg) 1 package 135 (61) 140 (64) 146 (66) 186 (84) 159 (72)
Electrical characteristics 120 volts — 60 hertz — 1 phase (all models) (less than12 amps)
lAnnual Fuel Utilization Efficiency based on U.S. DOE test procedures and FTC labeling regulations. Isolated combustion system rating for non-weatherized furnaces.
}Cleanable polyurethane frame type filter.
mm 12.7
in. 10 x 7 10 x 8 11-1/2 x 9 10 x 8
mm 254 x 178 254 x 203 292 x 229 254 x 203
Tons 1 to 2 1 to 3 3-1/2 to 5 1 to 3
kW 3.5 to 7.0 3.5 to 10.6 12.3 to 17.6 3.5 to 10.6
Revised 08-2001
SPECIFICATIONS
Page 1
ã 1998 Lennox Industries Inc.
SPECIFICATIONS
Gas Piping Size I.P.S
Blower wheel nominal
Nominal cooling
External Static
External Static
Model No.
Input Btuh (kW) 100,000 (29.3) 125,000 (36.6) 150,000 (44.0)
Output Btuh (kW) 80,000 (23.4) 81,000 (23.7) 100,000 (29.3) 120,000 (35.2)
R
A.F.U.E. 80.7% 80.1% 80.0% 80.4% 80.0%
California Seasonal Efficiency 77.3% 75.9% 76.3% 76.8% 76.8%
Flue size connection diameter in. (mm) round 4 (102) 5 (127)
Temperature rise range EF(EC) 40-70 (22-39) 30-60 (17-33) 45-75 (25-42) 35-65 (19-36) 40-70 (22-39)
High static certified by A.G.A. in wg. (Pa) .50 (125)
Gas Piping Size I.P.S.
Natural or LPG/propane
Blower wheel nominal
diameter x width
Blower motor output hp (W) 1/2 (373) 3/4 (560) 1/2 (373) 3/4 (560)
Nominal cooling
that can be added
Shipping weight lbs. (kg) 1 package 143 (65) 167 (76) 195 (88) 218 (99) 223 (101)
Electrical characteristics 120 volts 60 hertz 1 phase (all models) (less than 12 amps)
R
Annual Fuel Utilization Efficiency based on U.S. DOE test procedures and FTC labeling regulations. Isolated combustion system rating for non-weath erized fur-
naces.
c
Cleanable polyurethane frame type filter.
in. 1/2
.
mm 12.7
in. 10x8 11-1/2 x 9 10x10 12x12
mm 254 x 203 292 x 229 254 x 254 305 x 305
Tons 2to4 3-1/2 to 5 2to4 5 and 6
kW 7.0 to 14.1 12.3 to 17.6 7.0 to 14.1 17.6 and 21.1
G23Q3/4(X)-100G23Q4/5(X)-100G23Q3/4(X)-12
5
G23Q5/6(X)-125
G23Q5/6(X)-15
0
G23Q2(X)-50 BLOWER PERFORMANCE
Air Volume and Motor Watts at Specific Blower Taps
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 1225 580 530 950 450 375 785 370 295
.10 25 1215 575 520 945 445 375 770 365 290
.20 50 1190 560 505 925 435 360 745 350 280
.30 75 1150 545 485 895 420 350 720 340 275
.40 100 1090 515 460 865 410 335 690 325 265
.50 125 1030 485 440 820 385 320 645 305 250
.60 150 960 455 415 760 360 300 595 280 235
.70 175 865 410 390 690 325 285 535 250 225
.80 200 760 360 365 600 285 260 445 210 200
.90 225 630 295 340 520 245 240 ---- ---- ----
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium Low
G23Q3(X)-50 BLOWER PERFORMANCE
External Static
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 1620 765 630 1380 650 510 1110 525 405 875 415 310
.10 25 1575 745 605 1350 635 490 1090 515 390 870 410 305
.20 50 1520 715 580 1315 620 465 1080 510 375 860 405 295
.30 75 1455 685 550 1275 600 445 1050 495 355 840 395 285
.40 100 1390 655 525 1230 580 425 1015 480 340 815 385 275
.50 125 1320 625 505 1165 550 400 975 460 325 775 365 265
.60 150 1240 585 480 1100 520 375 920 435 310 715 335 245
.70 175 1160 545 460 1030 485 360 830 390 280 620 295 220
.80 200 1075 505 440 900 425 320 700 330 250 535 250 205
.90 225 900 425 395 720 340 285 600 285 230 ---- ---- ----
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium-High Medium-Low Low
Air Volume and Motor Watts at Specific Blower Taps
3DJH
G23Q2/3(X)-75 BLOWER PERFORMANCE
External Static
External Static
External Static
External Static
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 1600 755 620 1355 640 510 1080 510 395 865 410 310
.10 25 1545 730 595 1320 625 485 1060 500 385 855 405 305
.20 50 1490 705 570 1275 600 465 1035 490 370 830 390 295
.30 75 1425 670 550 1240 585 445 1010 475 360 810 380 285
.40 100 1370 645 530 1185 560 425 975 460 345 780 370 275
.50 125 1300 615 500 1135 535 405 940 445 330 735 345 260
.60 150 1240 585 485 1075 505 380 890 420 310 700 330 250
.70 175 1155 545 465 1000 470 360 830 390 290 625 295 230
.80 200 1045 495 430 905 425 330 720 340 265 555 260 215
.90 225 930 440 405 810 380 305 640 300 245 ---- ---- ----
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium-High Medium-Low Low
Air Volume and Motor Watts at Specific Blower Taps
G23Q4/5(X)-75 BLOWER PERFORMANCE
External Static
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 2365 1115 1360 2130 1005 1180 1850 875 995 1600 755 840 1360 640 710
.10 25 2360 1115 1355 2105 995 1175 1830 865 995 1575 745 835 1350 635 710
.20 50 2290 1080 1325 2055 970 1155 1800 850 985 1560 735 830 1325 625 705
.30 75 2235 1055 1310 2010 950 1135 1780 840 970 1530 720 820 1310 620 700
.40 100 2175 1025 1275 1970 930 1115 1735 820 945 1500 710 910 1290 610 690
.50 125 2110 995 1250 1910 900 1085 1700 800 930 1480 700 800 1265 610 685
.60 150 2030 960 1215 1855 875 1060 1650 780 910 1450 685 790 1250 590 675
.70 175 1955 925 1185 1765 835 1030 1610 760 895 1410 665 775 1220 575 670
.80 200 1890 890 1165 1695 800 1005 1550 730 875 1370 645 760 1190 560 655
.90 225 1800 850 1145 1600 755 980 1490 705 850 1340 630 730 1160 545 625
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium-High Medium Medium-Low Low
Air Volume and Motor Watts at Specific Blower Taps
G23Q3(X)-100 BLOWER PERFORMANCE
Air Volume and Motor Watts at Specific Blower Taps
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 1615 760 630 1300 615 500 1030 485 400
.10 25 1585 750 615 1290 610 490 1015 480 395
.20 50 1530 720 595 1255 590 475 1000 470 380
.30 75 1470 695 570 1220 575 455 975 460 365
.40 100 1400 660 545 1175 555 435 950 450 350
.50 125 1330 630 510 1125 530 415 910 430 340
.60 150 1250 590 485 1065 505 390 870 410 320
.70 175 1155 545 455 995 470 365 810 380 300
.80 200 1055 500 425 915 430 345 735 345 275
.90 225 950 450 400 820 385 320 650 305 250
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium Low
3DJH
G23Q3/4(X)-100 BLOWER PERFORMANCE
External Static
External Static
External Static
Air Volume and Motor Watts at Specific Blower Taps
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 1970 930 925 1675 790 750 1500 710 655 1180 555 505
.10 25 1895 895 880 1635 770 710 1480 700 635 1175 555 495
.20 50 1850 875 855 1600 755 680 1450 685 605 1170 550 485
.30 75 1790 845 825 1560 735 655 1420 670 580 1155 545 465
.40 100 1710 805 790 1515 715 630 1370 645 550 1130 535 450
.50 125 1635 770 760 1460 690 600 1315 620 520 1100 520 425
.60 150 1555 735 725 1390 655 565 1270 600 495 1060 500 410
.70 175 1470 695 690 1300 615 525 1195 565 470 1015 480 385
.80 200 1370 645 660 1225 580 500 1110 525 435 970 460 370
.90 225 1265 595 625 1115 525 455 1025 485 400 895 420 340
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium-High Medium-Low Low
G23Q4/5(X)-100 BLOWER PERFORMANCE
External Static
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 2465 1165 1305 2230 1050 1115 1985 935 940 1735 820 770 1530 720 650
.10 25 2425 1145 1295 2170 1025 1085 1950 920 930 1700 800 765 1500 710 645
.20 50 2375 1120 1265 2130 1005 1065 1920 905 915 1670 790 750 1470 695 635
.30 75 2315 1090 1235 2090 985 1050 1880 885 895 1645 775 745 1440 680 630
.40 100 2255 1065 1210 2045 965 1040 1840 870 890 1610 760 735 1420 670 625
.50 125 2195 1035 1185 1995 940 1010 1815 855 880 1575 745 725 1390 655 615
.60 150 2135 1010 1155 1950 920 1000 1770 835 870 1530 720 715 1350 635 600
.70 175 2075 980 1145 1890 890 985 1710 805 850 1490 705 700 1295 610 595
.80 200 1985 935 1105 1825 860 960 1650 780 830 1435 675 690 1245 590 585
.90 225 1895 895 1080 1745 825 925 1585 750 810 1365 645 675 1170 550 570
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium-High Medium Medium-Low Low
Air Volume and Motor Watts at Specific Blower Taps
G23Q3/4(X)-125 BLOWER PERFORMANCE
External Static
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 1980 935 800 1690 800 700 1470 695 610 1165 550 465
.10 25 1905 900 770 1670 790 680 1465 690 595 1160 545 455
.20 50 1850 875 740 1630 770 650 1430 675 570 1125 530 445
.30 75 1780 840 705 1580 745 620 1410 665 545 1120 530 430
.40 100 1695 800 670 1530 720 590 1375 650 520 1095 515 410
.50 125 1605 755 640 1455 685 550 1310 620 485 1065 505 390
.60 150 1525 720 605 1380 650 520 1245 590 455 1015 480 370
.70 175 1405 665 565 1280 605 485 1165 550 425 950 450 345
.80 200 1275 600 525 1160 545 440 1030 485 385 860 405 315
.90 225 1120 530 480 1000 470 390 915 430 355 780 370 295
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium-High Medium-Low Low
Air Volume and Motor Watts at Specific Blower Taps
3DJH
G23Q5/6(X)-125 BLOWER PERFORMANCE
External Static
External Static
External Static
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 2460 1160 1295 2220 1050 1050 2000 945 900 1775 840 755 1595 755 645
.10 25 2455 1160 1285 2210 1045 1050 1990 940 900 1755 830 760 1570 740 645
.20 50 2450 1155 1280 2180 1030 1040 1965 925 895 1720 810 755 1535 725 645
.30 75 2445 1155 1270 2155 1015 1035 1930 910 885 1690 800 745 1500 710 645
.40 100 2440 1150 1265 2125 1005 1025 1890 890 875 1660 785 750 1470 695 640
.50 125 2430 1145 1255 2090 985 1020 1860 880 870 1620 765 745 1435 675 635
.60 150 2350 1110 1235 2040 965 1000 1810 855 855 1585 750 735 1395 660 635
.70 175 2300 1085 1210 1990 940 990 1770 835 845 1540 725 725 1345 635 620
.80 200 2220 1050 1185 1925 910 970 1715 810 830 1490 705 715 1270 600 605
.90 225 2120 1000 1140 1850 875 950 1640 775 800 1420 670 690 1200 565 590
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium-High Medium Medium-Low Low
Air Volume and Motor Watts at Specific Blower Taps
G23Q5/6(X)-150 BLOWER PERFORMANCE
External Static
Pressure
in. w.g. Pa cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts cfm L/s Watts
0 0 2565 1210 1430 2300 1085 1160 2055 970 970 1840 870 825 1620 765 680
.10 25 2560 1210 1420 2265 1070 1155 2020 955 960 1810 855 825 1590 750 680
.20 50 2555 1205 1410 2225 1050 1140 1980 935 955 1770 835 810 1555 735 680
.30 75 2550 1205 1400 2185 1030 1130 1935 915 945 1740 820 805 1515 715 675
.40 100 2500 1180 1380 2150 1015 1115 1900 440 935 1700 800 800 1470 695 670
.50 125 2440 1150 1365 2100 990 1105 1860 435 925 1645 775 790 1430 675 665
.60 150 2370 1120 1335 2045 965 1085 1790 430 910 1585 750 780 1380 650 660
.70 175 2300 1085 1310 1960 925 1055 1730 815 895 1530 720 770 1315 620 645
.80 200 2210 1045 1270 1920 905 1035 1640 415 875 1470 695 755 1210 570 635
.90 225 2110 995 1240 1855 875 1030 1550 730 855 1345 635 725 1100 520 625
NOTE All air data is measured external to unit with 1 in. (25 mm) cleanable foam filter (not furnished) in place. Also see Filter Air Resistance table.
High Medium-High Medium Medium-Low Low
Air Volume and Motor Watts at Specific Blower Taps
FILTER AIR RESISTANCE
CFM (L/S) in. w.g. (Pa)
0 (0) 0.00 (0)
200 (95) 0.01 (0)
400 (190) 0.03 (5)
600 (285) 0.04 (10)
800 (380) 0.06 (15)
1000 (470) 0.09 (20)
1200 (565) 0.12 (30)
1400 (660) 0.15 (35)
1600 (755) 0.19 (45)
1800 (850) 0.23 (55)
2000 (945) 0.27 (65)
2200 (1040) 0.33 (80)
2400 (1130) 0.38 (95)
2600 (1225) 0.44 (110)
3DJH
OPTIONAL ACCESSORIES (Must be Ordered Extra)
LPG/Propane kit
LPG/Propane kit
Model No.
Standard
LPG/Propane kit
Filter and Filter Rack Kits
c
No. & size of filters - in. (mm)
Horizontal Power Venter Kit
Twinning Kits
Continuous Low Speed Blower Switch (option-
al)
Non-continuous low speed
Continuous low speed
models
X models
OPTIONAL ACCESSORIES (Must be Ordered Extra)
Model No. G23Q2(X)-50 G23Q3(X)-50 G23Q2/3(X)-75 G23Q4/5(X)-75 G23Q3(X)-100
Standard
LPG/Propane kit
Filter and Filter Rack Kits
c
No. & size of filters - in. (mm)
Horizontal Power Venter Kit
Twinning Kits
Continuous Low Speed Blower Switch
Non-continuous low speed
Continuous low speed
models
X models
G23Q3/4(X)-100G23Q4/5(X)-100G23Q3/4(X)-12
15K03 15K04 15K05
Single
(44J21)
(1) 20 x 25 x 1 (508 x 635 x 25)
79J15
64H88
35J93
44J06
(all models) Not used with Twinning Kits
15K01 15K02 15K03
Single
(44J20)
(1) 14 x 25 x 1 (356 x 635 x 25)
Ten Pack
44J06
(66K61)
79J15
64H88
35J93
(all models) Not used with Twinning Kits
5
71K82
Ten Pack
(all models)
(all models)
(all models)
71K82
(all models)
(all models)
(all models)
G23Q5/6(X)-125
(66K62)
Single
Ten Pack
(44J21)
(66K62)
(1) 20 x 25 x 1
(508 x 635 x 25)
G23Q5/6(X)-15
0
Single
(44J22)
Ten Pack
(66K63)
(1)16x25x1
(406 x 635 x 25)
HIGH ALTITUDE
Pressure regulator adjustment may be required depending on alti-
tude. See table below for proper pressure regulator setting.
Manifold Absolute Pressure (Outlet) in. w.g. (kPa)
ALTITUDE ft. (m)
FUEL
Natural Gas 3.5 (.87) 3.3 (.82) 3.1 (.77) 3.0 (.75)
LPG/Propane 10.0 (2.49)
Pressure switch is factory set. No adjustment necessary. G23(X)-50/75 units use the
factory pressure switch from 0-7500 feet (0-2286 m). G23(X)-100/125 and G23(X)-150
units require a High Altitude Pressure Switch for units installed above 5000 feet (1524
m). Order (
97J50
) for G23(X)-100/125 and (
0-4500
(0-1372)
4501-5500
(1373-1676)
18J35
5501-6500
(1677-1981)
) for G23(X)-150.
6501-7500
(1982-2286)
3DJH
TOP PANEL
BURNER ACCESS PANEL
BLOWER ACCESS
DOOR
G23(X) ORIENTATION
SUPPLY AIR OPENING
HEATING COMPARTMENT
MAKE-UP BOX ASSEMBLY
BLOWER COMPARTMENT
SureLight Control
(-5 and -6 models only)
FLUE TRANSITION
COMBUSTION AIR BLOWER
PRIMARY LIMIT
GAS VALVE
ROLLOUT SWITCH
BURNERS
MANIFOLD
BLOWER DOOR
INTERLOCK SWITCH
CIRCUIT BREAKER
SUPPLY AIR BLOWER
FIGURE 1
G23(X) GENERAL PARTS ORIENTATION
SUPPLY AIR DUCT FLANGE
COMBUSTION AIR BLOWER
PROVE (PRESSURE)
SWITCH
IGNITION CONTROL
(-1 through -4 models only)
HEATING COMPARTMENT
CONTROL BOX
BLOWER COMPARTMENT
BLOWER CAPACITOR
FIGURE 2
3DJH
(FLUE TRANSITION ASSEMBLY)
FIGURE4
FIGURE5
ORIFICE PLATE
FLUE OUTLET
GLASS FIBER GASKET
UPPER VEST
PANEL
G23(X) HEAT EXCHANGE ASSEMBLY
-5 and -6 G23X Models
TOP CAP
GLASS FIBER
GASKET
FLUE BOX
GLASS FIBER GASKET
COMBUSTION BLOWER
GLASS FIBER GASKET
FLUE COLLECTOR
BOX
COMBUSTION AIR BLOWER
MID VEST PANEL
PRIMARY LIMIT
PRIMARY LIMIT
ALTERNATE STYLE
ROLLOUT SWITCH
ROLLOUT BRACKET
ORIFICE
MANIFOLD END PLUG
MANIFOLD AND GAS VALVE
CONTROL BOX
(-1 through -4 G23X models)
DOOR INTERLOCK
SWITCH
BURNER ASSEMBLY
TRANSFORMER
HEATEXCHANGER
(Heat Train
Assembly)
CLAMSHELL
(Each Segment)
FLAME BAFFLES (NOx UNITS ONLY)
FLAME SENSE ASSEMBLY
RIGHT MANIFOLD BRACKET
LEFT MANIFOLD BRACKET
FIGURE 3
CONTROL BOX
(-5 and -6 G23X models))
DOOR INTERLOCK
SWITCH
TRANSFORMER
CIRCUIT BREAKER
LOW VOLTAGE STRIP
BCC CONTROL
CIRCUIT BREAKER
SURELIGHT CONTROL
LOW VOLTAGE STRIP
Page 8
I-UNIT COMPONENTS (Figures 1 and 2)
G23(X)unitcomponentsareshowninfigures1and2.The
gasvalve,ignitioncontrolandburnerscanbeaccessedby
removing the burner access panel. The blower, blower
control and SureLight control can be accessed by removing the blower access door.
G23(X) units are factory equipped with bottom and side return
air panels in place. The panels are designed to be field removed as required for bottom air return or side air return.
A-Make-Up Box (Figure 6)
Thelinevoltagemake-upboxisshowninfigure6.Thebox
may be installed inside or outside the unit and may be
installed on the unit left or right side (figure 8).
MAKE-UP BOX
POWER ENTRY KNOCKOUT
BOX
120V LINE VOLTAGE
PIGTAIL CONNECTIONS
COVER
B-Control Box Components (Figures 4 & 5)
SureLight control (A3), Electrical blower control components (A15), unit transformer (T1) and 24V circuit breaker
(CB8)are located in the controlbox. In addition, a door interlockswitch(S51)islocatedin thecontrolbox.Jackplugs
allow the control box to be easily removed for blower service.
1. Control Transformer (T1)
Atransformer locatedinthe controlbox provides powerto
thelow voltage 24volt section of the unit.Transformers on
all models are rated 40VA with a 120V primary and a 24V
secondary.
2. Circuit Breaker (CB8)
A24Vcircuit br eaker isalso locate d in the c ontrol box .
The switch provides ove rcurr ent protec tion to the
transformer ( T1). Thebreaker is rated3A at 32V.Ifthe
currente xcee dsthis limitthebreakerwill tr ipand allunit
operation will shut down. T he brea ker can bemanually
reset by pres sing the button on the face. See figure 7.
CIRCUIT BREAKER CB8
UNIT
GROUND
JACK J69
Box may be installed inside or outside unit. See Figure 8.
TO BLOWER MULLION
FIGURE 6
MAKE-UP BOX INSTALLATION
OUTSIDE INSTALLATION
MAKE-UP BOX
Line Voltage Enters Through
Knockout In Make-Up Box. J69
Passes Through Side Knockout
Into Side Of Unit.
Box may be installed inside or outside cabinet and may
be installed on left side or right side of cabinet
STARWASHERS
MUST BREAK
PAINT ON UNIT
CABINET FOR
PROPER
GROUND.
UNIT
CABINET
JACK J69
PRESS TO RESET
FIGURE 7
3.Door Interlock Switch (S51)
A door interlock switch rated 14A at 125VACislocated on
the blower access door.The switch is wired in series with
linevoltage. When the blower dooris removed theunitwill
shut down.
INSIDE INSTALLATION
MAKE-UP BOX
Line Voltage Enters Make-Up
Box Through Side Of Unit and
J69 Passes Through Bottom
Knockout in Make-Up Box.
BLOWER MULLION
BLOWER MULLION
PLUG P69
FIGURE 8
3DJH
4. BCC Blower Control (A15)
-1 Through -4 Models
G23(X)-1, -2, -3 and -4 model units utilize the BCC blower
controlmanufacturedby Heatcraft. Seefigure10.TheBCC
is a printed circuit board which controls the supply air blower and monitors primary limit and gas valve operation. The
BCC is equipped with a jumper for electronic (isolation
relay) or electro-mechanical thermostat selection.The controlhasanon-adjustable,factorypresetfan“on”timing.Fan
“off”timing is adjustable. The board is divided into two sections, 120 and 24VAC. Line voltage comes into the board
on the 120VACside. See table 1 for terminal designations.
Fan Timings
Fan“off”timing (time that thebloweroperates after theheat
demand has been satisfied) is determined by the arrangement of a jumper across pins on the BCC blower control
board.Seefigure9.To adjust fan“off”timing,gentlydisconnect jumper and reposition across pins corresponding with
newtiming.Fan “on” time is factoryset at 45 seconds andis
not adjustable.
NOTE—If fan “off” time is set too low, residual heat in
heat exchanger may cause primary limit S10 to trip resulting in frequent cycling of blower. If this occurs, adjust blower to longer time setting.
Figure 9 shows the various fan “off” timings and how jumper
should be positioned. Unit is shipped with a factory fan “off”
setting of 90 seconds. Fan “off” time will affect comfort and
efficiency and is adjustable to satisfy individual applications.
Thefan “off” timing is initiated aftera heating demand butnot
after a blower or cooling demand (that is, when indoor thermostat switch is changed from ON to AUTO and heating/
cooling demand is not present, the blower stops immediately).
FAN-OFF TIME ADJUSTMENT
TIMING
JUMPER
To adjust fan-off timing:
Remove jumper from BCC and select
one of the other pin combinations to
achieve the desired time.
TIMING PINS
(seconds)
Leave jumper off for
330 second fan-off timing.
SHOCK HAZARD. MAKE SURE TO DISCONNECT
POWER BEFORE CHANGING FAN OFF TIMING.
FIGURE 9
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic
components. Take precautions during furnace
installation and service to protect the furnace’s
electroniccontrols.Precautions will helptoavoid
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.
NEUTRAL
TERMINALS
ELECT
MECH
THERMOSTATJUMPER
(Electronic or Mechanical)
G23(X)-1, -2 ,-3 and -4 MODELS
BLOWER CONTROL - BCC
COOLING
SPEED TAP
TERMINAL
(DETACHABLE ON EARLY BOARDS ONLY))
TERMINALS
THERMOSTATTERMINAL STRIP
CONTINUOUS FAN
DUMMY
TERMINAL
BLOWER TIME
ADJUSTMENT
JUMPER
(A15)
HEATING
SPEED TAP
TERMINAL
FIGURE 10
ACCESSORY
TERMINAL
Heat Anticipator Settings
Beginning with the BCC3-2 series, a 3 pin jumper
has been installed on the board next to the removable 24V terminal strip to account for both programmable and electromechanical thermostat usage in
the field. For electromechanical thermostat, position
the jumper over the middle and bottom pin labeled
”MECH.” Set the heat anticipator setting to 0.65
amps for Honeywell valves or 0.50 amps for White
Rodgers valves. For programmable (electronic) thermostats, position the jumper over the middle and
top pin labeled ”ELECT.” Set the heat anticipator
setting to 0.1 amps.
3DJH
TABLE 1
BLOWER CONTROL A15 TERMINAL DESIGNATIONS
Terminal
(Designa-
tion on Wir-
ing
Diagram)
Y
G
R
W
T
IBN (N)
N1 (N)
CABN (N) 1/4 Spade
XFMRN (N) 1/4 Spade 120VAC Transformer Common
HSIN (N) 1/4 Spade
CAB 1/4 Spade
L1 1/4 Spade 120VAC Line Voltage In
A 1/4 Spade
XFMR 1/4 Spade 24VAC In From Transformer
D 1/4 Spade
CF 1/4 Spade
H 1/4 Spade
ACC 1/4 Spade
24V
(24)
LIMIT
(L)
W 1/4 Spade
VALVE
SENSE (V)
T 1/4 Spade
COM (C) 1/4 Spade 24VAC Common To Transformer
Type Function
Detachable
or Screw
Strip
Detachable
or Screw
Strip
Detachable
or Screw
Strip
Detachable
or Screw
Strip
Detachable
or Screw
Strip
1/4
Spade
1/4
Spade
3/16 or
1/4 Spade
1/4 Spade
3/16 or
1/4 Spade
120VAC Indoor Blower Common
(Electronic Air Cleaner, Humidifier,
24VAC In From Primary Limit. Limit
Open: Closes Gas Valve and Turns
24VAC Thermostat Demand Output
Through Rollout and Prove Switch
to TH Terminal of Ignition Con-
Cooling Demand
Blower Demand
24VAC to Thermostat
Heating Demand
24VAC Common
To Indoor Thermostat
120VAC Neutral
(L2 Line Voltage Neutral)
120VAC Combustion Air Blower
120VAC Hot Surface Ignition
Switched 120VAC to Accessory
24VAC Input From Transformer
On Blower Limit Closed: Allows
24VAC Input From Gas Valve
Ignition Control and Gas Valve
Common
Common (Not Used)
Switched 120VAC to
Combustion Air Blower
Switched 120VAC
to Blower Cooling Tap
Dummy Connection for
Unused Blower Leads
Switched 120VAC to
Continuous Blower Tap
Switched 120VAC to
Blower Heating Tap
24VAC Common From
Etc.)
Ignition
trol
C-Ignition Control (-1 Through -4 Models)
G23(X) -1, -2, -3 and -4 model units use an intermittent pilot
ignitioncontrol manufacturedby Johnson Controls. The ignition control is located on a bracket on the upper vest panel.
Unit Operation
When there is a call for heat, the control is prevented from
beginning an ignition sequence until the pressure switch
proves combustion air blower operation. When the pressure
switch closes, the control generates a spark and opens the
pilot valve to ignite the pilot. When flame is sensed, the control opens the main gas valve and the pilot ignites the main
burners. The indoor blower starts after a 45 second delay.
Gas valve remains open and combustion air blower continues to run until demand stops, flame sensor senses loss of
flame,alimit opens ortheprove switchopens. If anyofthese
events occur during a thermostat demand, the gas valve
closes.
Thecontrolwillattempt ignitionfor85seconds.Ifignitionis
not successful, the control will lockout (indicated by flashing LED). Within one hour the control will momentarily remove then reapply the thermostat signal and the ignition
sequence will begin again (Watchguard circuit). If pilot
ignitionissuccessful, but flameislost whenthemainvalve
opens,theignitionsequencewill retry up to 15moretimes.
Ifignitionisnotsuccessfulafterthe16thtry,thecontrolwill
shut-down and must be reset manually. Manual reset is
accomplished by removing then reapplying thermostat
demand for at least 30 seconds.
IGNITION CONTROL A3
SPARK
OUTPUT
SEE TABLE 2
FOR TERMINAL
DESIGNATIONS
FIGURE 11
DANGER
Shock hazard.
Spark related components contain high voltage.
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.
3DJH
TABLE 2
IGNITION CONTROL A3 TERMINAL DESIGNATIONS
Terminal Type Function
GROUND 1/4 Spade Cabinet Ground
THS 2 1/4 Spade
P.V.1
M.V.3
SENSE 4 1/4 Spade Microamp Flame Sensing Input
Unmarked
1/4 or
3/16Spade
1/4 or 3/16
Spade
Pin Type
Bare Wire
Safety Limit 24VAC Input
From Rollout and Prove Switch
24VAC Output to Pilot Operator
24VAC Output to Main Operator
of Gas Valve
of Gas Valve
High Voltage Spark Output
Diagnostic LED
The furnace ignition control is equipped with a diagnostic
LEDusedfortroubleshootingtheunitandthe control.LED
functions are shown in table 3.
TABLE 3
Furnace Control A3 Diagnostic LED
LED Stat
e
Steady On
Slow Flash
(1 sec. on/
5 sec. off)
Off
Meaning Remedy
Normal Opera-
tion
Control Retry
Period
Control Failure
or Power Fail-
ure or Hard
Lockout
Failed to Sense Flame. Ignition
Control Will Retry
Before Locking Out.
If Power and Gas Supply are OK,
Try Removing Tstat Demand For
At Least 30 Seconds. If LED Re-
mains Off When Demand Is Re-
turned, Replace Control.
----
Johnson G776 Ignition Control Operation
The information inthis section is protected by a copyright issued by
Johnson Controls, Inc., and is reproduced with permission.
On a call for heat from the indoor thermostat, the ignition
control energizes and the ignition control LED lights
(steady on). The combustionair blower is energized.After
a 15 second pre-purge period, the control simultaneously
opens the pilot valve and sends spark to the pilot electrode.
If the pilot ignites within 85 seconds, the flame sensor detects pilot flame and signals the ignition control to to energize the main valve. The main valve cannot be energized
until the sensor detects pilot flame. Spark continues until
pilotflameissensed or 85 secondshas elapsed, whichever happens first.
When pilot flame is sensed, the main valve is energized
and the spark turns off. The ignition control remains in
“run” mode until the indoor thermostat is satisfied or flame
is lost.
Ifpilotflame is not sensedbefore the end of the85second
trialfor ignition, thecontrol enters the 100% shutoffmode.
The spark circuit and pilot valve de-energize and the ignitioncontrol automatically begins the60 minute retry delay
period. During the 60 minute delay the diagnostic LED
continually flashes on for one second and off for five seconds. After the delay period, another trial for ignition sequence starts, beginning with pre-purge.
Ifpilotflamegoesoutwhiletheindoorthermostat is calling
forheat, both main and pilotvalves de-energizewithin 0.8
seconds and remain de-energized for five seconds. After
this delay, the spark and pilot valve energize until flame is
sensedorthe85secondtrialforignitionperiod ends.Ifthis
“flameout” cycle repeats 16 times (pilot flame is established and then lost), the control locks out and the LED
goes off. A new trial for ignition sequence begins after the
thermostat contacts are opened for 30 seconds and then
closed.
If flame is detected when the thermostat calls for heat, it
must extinguish within30 seconds for normaloperation. If
flameisstillpresentafter30seconds,thecontrolgoesinto
lockout and the LED goes off.
D-Combustion Air Blower (B6)
All G23(X) units use a combustion air blower to move air
through the burners and heat exchanger during heating operation. The blower uses a shaded pole 120VAC motor.
Shaded pole motors do not use run capacitors. The motor
operates during all heating operation and is controlled by
blower control A15. The blower operates continuously while
there is a call for heat. The ignition control is prevented from
proceeding through the ignition sequence until combustion
air blower operation is sensed by the prove switch.
The pressure switch connected to the upper vest panel is
used to prove combustion air blower operation. The switch
monitors air pressure in the blower housing. During normal
operation, the pressure in the housing is negative. If the
pressure drops (becomes more positive), the pressure
switch opens. When the pressure switch opens, the ignition
control (A3) immediately closes the gas valve to prevent
burner operation.
3DJH
G23(X) UPPER VEST PANEL
(FLUE TRANSITION ASSEMBLY)
ORIFICE PLATE
FLUE OUT-
LET
GLASS FIBER
GASKET
UPPER VEST
PANEL
IGNITION CONTROL
BRACKET
IGNITION CONTROL
(-1 through -4 model units)
FIGURE 12
E-Blower Motors and Capacitors
All G23(X) units use direct drive blower motors. All motors
used are 120V permanent split capacitor motors to ensure
maximum efficiency. See table 4 for ratings.
TABLE 4
G23(X) BLOWER RATINGS 120V 1PH
BLOWER MOTOR HP
G23Q2(X) 1/5 5MFD 370V
G23Q2/3(X)
G23Q3(X)
G23Q3/4(X)
G23Q4/5(X)
G23Q5/6(X)
1/3
1/3
1/2
3/4 40MFD 370V
3/4 40MFD 370V
CAP
5MFD 370V
5MFD 370V
7MF 370V
F-Flame Rollout Switch (S47)
Flame rollout switch is a high temperature limit located on
rollout switch bracket (over burner assembly). The limit is a
N.C. SPST manual-reset limit connected in series with the
ignition control (A3). When S47 senses rollout, the ignition
controlimmediately stops ignitionandcloses the gas valve.
If unit is running andflame rollout is detected, the gasvalve
will close and ignition control will be disabled. Rollout can
be caused by a reverse draft, blocked flue or lack of combustion air. The switch is factory set and cannot be adjusted. The switch may have different setpoints for each
unitmodel number.However,thesetpoint will beprinted on
the side of the limit. The switch can be manually reset. To
manually reset a tripped switch, push the reset button located on the control (see figure 13).
FLUE BOX
GLASS FIBER GASKET
FLUE COLLECTOR BOX
COMBUSTION AIR BLOWER
GLASS FIBER GASKET
COMBUSTION AIR BLOWER
COMBUSTION AIR BLOWER MOTOR
COMBUSTION AIR BLOWER
PROVE (PRESSURE)
NOTE-ALL components located behind up-
per vest panel including combustion air blow-
er are exposed to supply air stream.
SWITCH
ROLLOUT SWITCH (S47)
MANUAL
RESET BUTTON
FIGURE 13
G-Primary Limit Control (S10)
Primary limit (S10) on G23(X) units is located in the middle of
the vestibule panel. When excess heat is sensed in the heat
exchanger ,the limit will open. If the limit is tripped, the furnace
control energizes the supply air blower and closes the gas
valve. The limit automatically resets when temperature retur ns to nor mal .The switch is factory set and cannot be adjusted. The switch may have different setpoints for each
unitmodel number.However,thesetpoint will be printed on
the side of the limit.
SPADE CONNECTORS
G23(X) SERIES UNITS AND ALTERNATE STYLE
LIMIT CONTROL (S10) FOR
Units may be equipped with
either style limit.
LIMIT
INSULATING COVER (s)
FIGURE 14
3DJH
Units may be equipped with either flush style or extended
(masted) limit (figure14). Masted limits may be installed
with limit facing blower or away from blower. This orientationcannotbechanged.Whenremovinglimitfromunit,pay
careful attentionto its orientation and make sure limit is reinstalled facing same direction.
H-Pilot, Spark Electrode, Flame Sensor
and Burners (-1 Through -4 Models)
Figure 17 shows the arrangement of pilot, flame sensor,
spark electrode and burners. The ignition control uses direct spark to ignite the pilot. The pilot ignites the burners
and the burners cross-light. The flame sensor uses flame
rectification to sense ignition. The ignition control requires
that pilot flame must be sensed before the main gas valve
is allowed to open. Typically, a 2 to 4 second delay occurs
between the pilot ignition and the main valve opening.
Figure16showsthe gap between tip of the electrodesand
the burner surface. It is important that the gap be maintained for consistent ignition of pilot flame.
A flame retention ring in the end of each burner is used to
maintain correct flame length and shape and to keep the
flamefrom lifting offthe burner head. In addition, the burner entrance to each clamshell (Figure 3) is fitted with a
flamebaffle or corbel toenhance the combustion process.
G23(X)-1, -2, -3 AND -4 MODELS BURNER PILOT/ELECTRODE
ORIENTATION
view looking at side of burners
TYPICAL BURNER ASSEMBLY
FIGURE 15
PILOT, SPARK ELECTRODE AND FLAME SENSOR
PILOT HOOD
PILOT
FLAME SENSOR
SENSE WIRE
1/8 (.125) Inch + ”1/32 (.031)
GAP
SPARKELECTRODE
SPARKWIRE
FIGURE 16
PILOT HOOD
FLAME SENSOR
ORIFICE
RETAINER
PRIMARY
AIR INLET
BURNER
SPARK
ELECTRODE
PILOT MOUNTING
BRACKET
FIGURE 17
Page 14
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DANGER
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.
I- SureLight Ignition System A3
(-5 and -6 models)
All G23(X)-5 and -6 model units are equipped with the
Lennox SureLight ignition system. The system consists
of ignition control board (figure 21 with control terminal
designationsintable5)and ignitor(figures 18,19and20.
The board and ignitor work in combination to ensure furnace ignition and ignitor durability. The SureLight integrated board controls all major furnace operations. The
board also features two LED lights for troubleshooting
and two accessory terminals rated at (4) four amps. See
table6 for troubleshooting diagnostic codes. Table7and
8 show jack plug terminal designations. Units equipped
withtheSureLightboardcanbeusedwitheitherelectronic or electro-mechanical thermostats without modification. The SureLight ignitor is made of durable silic on-nitride. Ignitor longevity isalso enhanced by voltage ramping by the control board. The board finds the lowest ignitor temperature which will succes s fully light the burner,
thus increasing the life of t he ignitor.
NORMAL FLAME SIGNAL0.7 MICROAMPS
1/4”
IGNITOR
LOW FLAME SIGNAL
MINIMUM FLAME SIGNAL$0.15 MICROAMPS
19/64”
$
0.7 MICROAMPS
SENSOR
3/8”
FIGURE 18
SENSOR
IGNITOR
FIGURE 19
NOTE -Donotremove blower access panel to read
SureLight LED lights. A sight glass is provided on
the access panel for viewing.
SURELIGHT IGNITOR (I) AND SENSOR (S)
LOCATION
)ODPH 6HQVRU
Aflamesensorislocatedontheleftside of the burner support. See figures 18,19and 20. The sensoris mounted on
a bracket in the burner support and the tip protrudes into
the flame envelope of the left-most burner. The sensor is
fastened to burner supports and can be removed for service without removing any part of the burners. During operation, flame is sensed by current passed through the
flameandsensingelectrode.TheSureLightcontrolallows
the gas valve to remain open as long as flame signal is
sensed.
FIGURE 20
3DJH
SURELIGHT CONTROL BOARD
TABLE 5
SURELIGHT CONTROL TERMINAL DESIGNATIONS
ACB COOL
ACB HEAT
PARK
ACB LOW
ACC
TX
HOT
HTG ACC
NEUTRALS
24VACHOT
24VACRTN
FLAME SENSE
Blower - Cooling Speed (Line Volt)
Blower - Heating Speed (Line Volt)
Alternate Blower Speeds (Dead)
Continuous Low Speed Blower
Accessory Terminal (Line Volt)
120VACHot to Transformer
120VACHot Input
Heat Only Accessory (Line Volt)
120VACNeutrals
24VACHot from Transformer
24VACReturn from Transformer
Flame Sense Terminal
FIGURE 21
TABLE 6
DIAGNOSTIC CODES
MAKE SURE TO ID LED’S CORRECTLY: REFER TO INSTALLATION INSTRUCTIONS FOR CONTROL BOARD LAYOUT.
LED #1 LED #2 DESCRIPTION
SIMULTANEOUS
SLOW FLASH
SIMULTANEOUS FAST
FLASH
SLOW FLASH ON
OFF SLOW FLASH
ALTERNATING SLOW
FLASH
SLOW FLASH OFF
ON SLOW FLASH
ON
ON
OFF
FAST FLASH SLOW FLASH
SLOW FLASH FAST FLASH
ALTERNATING FAST
FLASH
SIMULTANEOUS
SLOW FLASH
SIMULTANEOUS FAST
ALTERNATING SLOW
ALTERNATING FAST
FLASH
FLASH
ON
OFF
ON
FLASH
Also signaled during cooling and continues fan.
Normal operation - signaled when heating demand initiated at thermostat.
Primary or Secondary limit open. Units with board 63K8901 or 24L85: Limit must
close within 5 trials for ignition or board goes into one hour limit Watchguard.
Units with board 56L83 or 97L48: Limit must close within 3 minutes or board
Pressure switch open or has opened 5 times during a single call for heat; OR:
Blocked inlet/exhaust vent; OR: Condensate line blocked; OR: Pressure switch
closed prior to activation of combustion air blower.
Flame sensed without gas valve energized.
Rollout switch open. OR: 9 pin connector improperly attached.
Circuit board failure or control wired incorrectly.
Main power polarity reversed. Switch line and neutral.
Low flame signal. Measures below .7 microAmps. Replace flame sense rod.
Improper main ground or line voltage below 75 volts; OR: Broken ignitor; OR:
Power - Normal operation
goes into one hour limit Watchguard.
Watchguard - burners fail to ignite.
Open ignitor circuit.
NOTE - Slowflash equals1 Hz (oneflash persecond). Fast flashequals 3Hz (threeflashes per second).Drop out flamesense current< 0.15microAmps
Page 16
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