Lennox KGA, KGA092, KGA120, KGA150, KGA092S4B Service Literature

Service Literature

Corp. 1010-L8

Revised 07/2015

KGA092 through 150

The KGA 7.5, 8.5, 10 and 12.5 ton (092, 102, 120, 150)
packaged gas units are available in standard cooling effi
ciency. Units are available in 130,000, 180,000 or
240,000Btuh (38.1, 52.7 or 70.3 kW) heating inputs. Gas
heat sections are designed with aluminized steel tube heat
exchangers.

All KGA units are designed to accept any of several different
energy management thermostat control systems with mini
mum field wiring. Factory- or field-provided control options
connect to the unit with jack plugs. When ”plugged in” the
controls become an integral part of the unit wiring.

KGA UNITS

7.5 to 12.5 ton

26.3 to 42 kW

Information contained in this manual is intended for use by
qualified service technicians only. All specifications are sub
ject to change. Procedures outlined in this manual are pre
sented as a recommendation only and do not supersede or
replace local or state codes.

If the unit must be lifted for service, rig unit by attaching four
cables to the holes located in the unit base rail (two holes at
each corner). Refer to the installation instructions for the proper
rigging technique.

WARNING

Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person
al injury or loss of life. Installation and service must
be performed by a qualified installer or service
agency.

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

Electrostatic discharge can affect electronic
components. Take precautions during unit instal
lation and service to protect the unit'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 electro
static charge by touching hand and all tools on an
unpainted unit surface, such as the gas valve or
blower deck, before performing any service pro
cedure.

CAUTION

Danger of sharp metallic edges. Can cause injury.
Take care when servicing unit to avoid accidental
contact with sharp edges.

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 discon
nect switch(es). Unit may have multiple
power supplies.

Options / Accessories Page 2.......................

Specifications Page 5...............................

Blower Data Page 7................................

Electrical Data Page 12.............................

Parts Arrangement Page 14.........................

I- Unit Components Page 15.......................

II- Placement and Installation Page 24...............

III- Start-Up Page 24...............................

IV- Charging Page 26..............................

V- System Service Checks Page 27.................

VI- Maintenance Page 29...........................

VII- Accessories Page 31............................

VIII-Wiring Diagrams Page 39........................

Page 1

© 2015.

OPTIONS / ACCESSORIES

Item Description

Model

Number

Catalog

Number

COOLING SYSTEM

Compressor Crankcase Heater 208/230V-3ph - K1CCHT02B-1Y 54W17 X X X

460V-3ph - K1CCHT02B-1G 54W18 X X X

575V-3ph - K1CCHT02B-1J 54W19 X X X

Condensate Drain Trap PVC - LTACDKP09/36 76M18 X X X X

Copper - LTACDKC09/36 76M19 X X X X

Corrosion Protection Factory O O O O

Drain Pan Overow Switch K1SNSR71AB1- 74W42 X X X X

Efciency Standard O O O O

Low Ambient Kit K1SNSR33B-1 54W16 X X X X

Refrigerant Type R-410A O O O O

HEATING SYSTEM

Bottom Gas Piping Kit C1GPKT01B-01 54W95 X X X X

Combustion Air Intake Extensions T1EXTN10AN1 19W51 X X X X

Gas Heat Input 130,000 Btuh Factory O O O O

180,000 Btuh Factory O O O O

240,000 Btuh Factory O O O O

Low Temperature Vestibule Heater 208/230V-3ph - C1LTVH10B-1Y 55W91 X X X X

460V - C1LTVH10B-1G 55W92 X X X X

575V - C1LTVH10B-1J 55W93 X X X X

LPG/Propane Conversion Kits Standard Heat - E1LPCO10B-1 53W07 X X X X

Medium Heat - E1LPCO20B-1 53W08 X X X X

High Heat - E1LPCO30B-1 53W09 X X X X

Stainless Steel Heat Exchanger Factory O O O O

Vertical Vent Extension C1EXTN20FF1 42W16 X X X X

BLOWER - SUPPLY AIR

Motors Belt Drive - 2 hp Factory O O O O

Belt Drive - 3 hp Factory O O O O

Belt Drive - 5 hp Factory O O O O

Drive Kits

See Blower Data Tables for selection

Kit #1 590-890 rpm Factory O O O O

Kit #2 800-1105 rpm Factory O O O O

Kit #3 795-1195 rpm Factory O O O O

Kit #4 730-970 rpm Factory O O O O

Kit #5 940-1200 rpm Factory O O O O

Kit #6 1015-1300 rpm Factory O O O O

Kit #10 900-1135 rpm Factory O O O O

Kit #11 1040-1315 rpm Factory O O O O

Kit #12 1125-1425 rpm Factory O O O O

NOTE - Catalog and model numbers shown are for ordering eld installed accessories.
OX - Congure To Order (Factory Installed) or Field Installed
O = Congure To Order (Factory Installed)
X = Field Installed

Unit Model No

092 102 120 150

Page 2

OPTIONS / ACCESSORIES

Item Description

Model

Number

Catalog
Number

CABINET

Coil Guards K1GARD20B-1 55W08 X X X X

Hail Guards K1GARD10B1 55W11 X X X X

Hinged Access Panels Factory O O O O

Horizontal Discharge Kit K1HECK00B-1 51W25 X X X X

®

Return Air Adaptor Plate (for L Series

and T-Class™ replacement) C1CONV10B-1 54W96 X X X X

CONTROLS

Commercial Controls L Connection

®

Building Automation System - - - X X X X

Smoke Detector - Supply or Return (Power board and one sensor) C1SNSR44B-1 53W80 X X X X

Smoke Detector - Supply and Return (Power board and two sensors) C1SNSR43B-1 53W81 X X X X

INDOOR AIR QUALITY

Air Filters

Healthy Climate

®

High Efciency Air Filters

20 x 25 x 2 (Order 4 per unit)

Replacement Media Filter With Metal Mesh

MERV 8 - C1FLTR15B-1 50W61 X X X X

MERV 13 - C1FLTR40B-1 52W41 X X X X

C1FLTR30B-1- Y3063

Frame (includes non-pleated lter media)

Indoor Air Quality (CO

) Sensors

2

Sensor - Wall-mount, off-white plastic cover with LCD display C0SNSR50AE1L 77N39 X X X X

Sensor - Wall-mount, off-white plastic cover, no display C0SNSR52AE1L 87N53 X X X X

Sensor - Black plastic case with LCD display, rated for plenum
mounting

Sensor - Wall-mount, black plastic case, no display, rated for
plenum mounting

CO

Sensor Duct Mounting Kit - for downow applications C0MISC19AE1- 85L43 X X X X

2

Aspiration Box - for duct mounting non-plenum rated CO
(87N53 or 77N39)

sensors

2

C0SNSR51AE1L 87N52 X X X X

C0MISC19AE1 87N54 X X X X

C0MISC16AE1- 90N43 X X X X

UVC Germicidal Lamps

1

Healthy Climate® UVC Light Kit (208/230v-1ph) C1UVCL10B-1 54W62 X X X X

ELECTRICAL

Voltage 60 hz 208/230V - 3 phase Factory O O O O

460V - 3 phase Factory O O O O

575V - 3 phase Factory O O O O

Disconnect Switch 80 amp - C1DISC080B-1 54W56 OX OX OX OX

GFI Service Outlets LTAGFIK10/15 74M70 OX OX OX OX

1

Lamps operate on 110-230V single-phase power supply. Step-down transformer may be ordered separately for 460V and 575V units. Alternately, 110V power supply

may be used to directly power the UVC ballast(s)

NOTE - Catalog and model numbers shown are for ordering eld installed accessories.
OX - Congure To Order (Factory Installed) or Field Installed
O = Congure To Order (Factory Installed)
X = Field Installed

Unit Model No

092 102 120 150

X X X X

Page 3

OPTIONS / ACCESSORIES

Item Description

Model

Number

Catalog

Number

ECONOMIZER

Economizer

Economizer with Single Temperature Control - Downow or

K1ECON20B-1 54W55 OX OX OX OX

Horizontal With Barometric Relief Dampers (downow) and Air

Hoods

Economizer Controls

Single Enthalpy Control C1SNSR64FF1 53W64 OX OX OX OX

Differential Enthalpy Control (order 2) C1SNSR64FF1 53W64 X X X X

Horizontal Barometric Relief Dampers With Exhaust Hood

Horizontal Barometric Relief Dampers - Exhaust Hood Furnished LAGEDH03/15 53K04 X X X X

OUTDOOR AIR

Outdoor Air Dampers

Motorized Dampers with outdoor air hood C1DAMP20B-1 53W49 OX OX OX OX

Manual Dampers with outdoor air hood C1DAMP10B-1 53W48 OX OX OX OX

POWER EXHAUST

Standard Static 208/230V-3ph - K1PWRE10B-1Y 53W44 X X X X

460V-3ph - K1PWRE10B-1G 53W45 X X X X

575V-3ph - K1PWRE10B-1J 53W46 X X X X

ROOF CURBS - DOWNFLOW

Clip Curb

8 in. height C1CURB23B-1 54W46 X X X X

14 in. height C1CURB20B-1 54W47 X X X X

18 in. height C1CURB21B-1 54W48 X X X X

24 in. height C1CURB22B-1 54W49 X X X X

Standard

8 in. height C1CURB12B-1 54W44 X X X X

14 in. height C1CURB10B-1 54W43 X X X X

24 in. height C1CURB11B-1 54W45 X X X X

Adjustable Pitched Curb

14 in. height C1CURB55B-1 54W50 X X X X

CEILING DIFFUSERS

Step-Down - Order one RTD11-95 29G04 X

RTD11-135 29G05 X X

RTD11-185 29G06 X

Flush - Order one FD11-95 29G08 X

FD11-135 29G09 X X

FD11-185 29G10 X

Transitions (Supply and Return) - Order one LASRT08/10 24L14 X

LASRT10/12 49K55 X X

LASRT15 49K56 X

NOTE - Catalog and model numbers shown are for ordering eld installed accessories.
OX - Congure To Order (Factory Installed) or Field Installed
O = Congure To Order (Factory Installed)
X = Field Installed

Unit Model No

092 102 120 150

Page 4

SPECIFICATIONS

General Data Nominal Tonnage 7.5 Ton 8.5 Ton 10 Ton 12.5 Ton

Model Number KGA092S4B KGA102S4B KGA120S4B KGA150S4B

Efciency Type Standard Standard Standard Standard

Blower Type Constant Air

Volume CAV

Cooling
Performance

Gross Cooling Capacity - Btuh 88,900 100,500 119,600 144,800

1

Net Cooling Capacity - Btuh 86,000 97,000 115,000 138,000

AHRI Rated Air Flow - cfm 3,000 3,400 3,800 4,300

Total Unit Power - kW 7.8 8.8 10.4 12.8

1

EER (Btuh/Watt) 11 11 11 10.8

2

IEER (Btuh/Watt) 11.2 11.2 11.2 11

Refrigerant Type R-410A R-410A R-410A R-410A

Refrigerant

Charge

Circuit 1 7 lbs. 8 oz. 8 lbs. 8 oz. 10 lbs. 0 oz. 14 lbs. 0 oz.
Circuit 2 7 lbs. 0 oz. 8 lbs. 8 oz. 10 lbs. 0 oz. 12 lbs. 0 oz.

Furnished

Gas Heating Options Available - See page

Standard (2 stage), Medium (2 Stage), High (2 Stage)

6
Compressor Type (number) Scroll (2) Scroll (2) Scroll (2) Scroll (2)
Outdoor
Coils

Net face area (total) - sq. ft. 20.42 24.5 28.0 28.0

Tube diameter - in. 3/8 3/8 3/8 3/8

Number of rows 2 2 2 3

Fins per inch 20 20 20 20

Outdoor
Coil Fans

Motor - (No.) hp (2) 1/3 (2) 1/3 (2) 1/3 (2) 1/2

Motor rpm 1075 1075 1075 1075

Total Motor watts 670 670 670 830

Diameter - (No.) in. (2) 24 (2) 24 (2) 24 (2) 24

Number of blades 3 3 3 3

Total Air volume - cfm 7200 7400 7800 8,800

Indoor
Coils

Net face area (total) - sq. ft. 12.78 12.78 12.78 13.54

Tube diameter - in. 3/8 3/8 3/8 3/8

Number of rows 2 2 3 4

Fins per inch 14 14 14 14

Drain connection - Number

and size

Expansion device type Balance port TXV, removable head

3

Indoor
Blower and
Drive
Selection

Maximum usable motor output

Nominal motor output 2 hp, 3 hp, 5 hp

(US Only)

Motor - Drive kit number 2 hp

Blower wheel nominal

(1) 15 X 15 (1) 15 X 15 (1) 15 X 15 (1) 15 X 15

diameter x width - in.

Filters Type of lter Disposable

Number and size - in. (4) 20 x 25 x 2

Electrical characteristics 208/230V, 460V or 575V - 60 hertz - 3 phase

NOTE - Net capacity includes evaporator blower motor heat deduction. Gross capacity does not include evaporator blower motor heat deduction.

1

Certied in accordance with the ULE certication program, which is based on AHRI Standard 340/360; 95°F outdoor air temperature and 80°F db/67°F wb entering

evaporator air; minimum external duct static pressure.

2

Integrated Energy Efciency Ratio certied and tested according to AHRI Standard 340/360..

3

Using total air volume and system static pressure requirements determine from blower performance tables rpm and motor output required. Maximum usable output of

motors furnished are shown. In Canada, nominal motor output is also maximum usable motor output. If motors of comparable output are used, be sure to keep within
the service factor limitations outlined on the motor nameplate.

4

Standard motor and drive kit furnished with unit.

Constant Air

Volume CAV

(1) 1 in. NPT coupling

2.3 hp, 3.45 hp, 5.75 hp

4

Kit 1 590-890 rpm

Kit 2 800-1105 rpm
Kit 3 795-1195 rpm

3 hp

Kit 4 730-970 rpm

Kit 5 940-1200 rpm

Kit 6 1015-1300 rpm

5 hp

Kit 10 900-1135 rpm
Kit 11 1040-1315 rpm
Kit 12 1125-1425 rpm

Constant Air

Volume CAV

Constant Air

Volume CAV

Page 5

SPECIFICATIONS - GAS HEAT

Heat Input Type Standard Medium High

Number of Gas Heat Stages 2 2 2

Gas Heating
Performance

Recommended Gas Supply
Pressure - in. w.g.

Input - Btuh First Stage 84,500 117,000 156,000

Second Stage 130,000 180,000 240,000

Output - Btuh Second Stage 104,000 144,000 192000

Temperature Rise Range - °F 15-45 30-60 40-70

Thermal Efciency 80% 80% 80%

Gas Supply Connections 3/4 in NPT 3/4 in NPT 3/4 in NPT

Natural 7 7 7

LPG/Propane 11 11 11

HIGH ALTITUDE DERATE

Units may be installed at altitudes up to 2000 feet above sea level without any modication.

At altitudes above 2000 feet, units must be derated to match gas manifold pressures shown in table below.

NOTE − This is the only permissible derate for these units.

Gas Heat

Type

Standard 2001-4500 3.4 9.6 84,500 124,000

Medium 2001-4500 3.4 9.6 117,000 172,000

High 2001-4500 3.4 9.6 156,000 230,000

Altitude

ft. In. w.g. In. w.g. Btuh Btuh

Gas Manifold Pressure

Natural Gas LPG/Propane Gas First Stage Second Stage

Natural Gas or LPG/Propane

Input Rate

Page 6

BLOWER DATA

092 AND 102 BELT DRIVE BLOWER − BASE UNIT

BLOWER TABLE INCLUDES RESISTANCE FOR BASE UNIT ONLY (NO HEAT SECTION) WITH DRY INDOOR COIL AND AIR
FILTERS IN PLACE. FOR ALL UNITS ADD:

1 − Wet indoor coil air resistance of selected unit.

2 − Any factory installed options air resistance (heat section, economizer, etc.)

3 − Any eld installed accessories air resistance (duct resistance, diffuser, etc.)

Then determine from blower table blower motor output required.

See page 10 for blower motors and drives.

See page 10 for wet coil and option/accessory air resistance data.

MAXIMUM STATIC PRESSURE WITH GAS HEAT - 2.0 in. w.g.

Total

Air

Volume

cfm

2250 - - - - - - - - - - - - 707 0.14 753 0.50 800 0.84 847 1.15 892 1.38 934 1.53 979 1.65 1051 1.86 1126 2.12 1183 2.36 1238 2.62

2500 - - - - - - - - - - - - 714 0.29 758 0.64 803 0.97 849 1.26 893 1.48 936 1.63 983 1.75 1052 1.96 1124 2.22 1184 2.49 1241 2.77

2750 - - - - - - 680 0.11 721 0.45 763 0.78 807 1.09 852 1.37 896 1.58 940 1.74 989 1.88 1053 2.08 1121 2.34 1185 2.63 1244 2.93

3000 - - - - - - 689 0.29 728 0.61 770 0.93 812 1.23 856 1.49 901 1.70 947 1.87 996 2.02 1055 2.21 1120 2.47 1186 2.78 1248 3.10

3250 661 0.17 698 0.46 737 0.78 777 1.09 819 1.38 862 1.63 908 1.84 955 2.01 1004 2.17 1059 2.36 1122 2.62 1189 2.94 1252 3.28

3500 672 0.36 708 0.65 746 0.95 786 1.25 827 1.53 870 1.78 916 1.99 965 2.17 1013 2.33 1065 2.52 1126 2.79 1193 3.12 1257 3.47

3750 684 0.56 719 0.85 756 1.14 795 1.43 836 1.70 880 1.95 927 2.16 976 2.34 1023 2.51 1073 2.71 1133 2.98 1198 3.32 1263 3.67

4000 697 0.78 731 1.05 768 1.34 807 1.62 848 1.89 892 2.13 940 2.34 988 2.53 1034 2.71 1083 2.91 1141 3.19 1205 3.53 1270 3.89

4250 710 1.00 745 1.27 781 1.55 819 1.83 861 2.09 906 2.33 954 2.55 1001 2.74 1046 2.93 1094 3.14 1151 3.42 1214 3.76 1278 4.12

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

Total Static Pressure − in. w.g.

Page 7

BLOWER DATA

120 BELT DRIVE BLOWER − BASE UNIT

BLOWER TABLE INCLUDES RESISTANCE FOR BASE UNIT ONLY (NO HEAT SECTION) WITH DRY INDOOR COIL AND AIR
FILTERS IN PLACE. FOR ALL UNITS ADD:

1 − Wet indoor coil air resistance of selected unit.

2 − Any factory installed options air resistance (heat section, economizer, etc.)

3 − Any eld installed accessories air resistance (duct resistance, diffuser, etc.)

Then determine from blower table blower motor output required.

See page 10 for blower motors and drives.

See page 10 for wet coil and option/accessory air resistance data.

MAXIMUM STATIC PRESSURE WITH GAS HEAT - 2.0 in. w.g.

Total

Air

Volume

cfm

3000 - - - - - - 677 0.24 719 0.55 764 0.87 813 1.18 866 1.45 920 1.67 975 1.82 1026 1.96 1076 2.13 1126 2.35 1176 2.63 1225 2.92

3250 650 0.14 688 0.43 730 0.73 775 1.04 823 1.34 875 1.60 930 1.81 985 1.97 1036 2.12 1086 2.31 1136 2.54 1186 2.83 1235 3.13

3500 663 0.35 700 0.63 741 0.92 786 1.22 834 1.5 886 1.76 942 1.96 997 2.14 1048 2.31 1097 2.51 1147 2.75 1196 3.04 1245 3.35

3750 676 0.57 714 0.84 754 1.12 798 1.41 846 1.68 899 1.93 956 2.14 1010 2.32 1060 2.51 1109 2.72 1158 2.98 1207 3.27 1255 3.58

4000 691 0.79 728 1.05 768 1.33 812 1.61 860 1.88 914 2.12 971 2.34 1023 2.53 1072 2.73 1121 2.95 1169 3.22 1218 3.51 1266 3.83

4250 706 1.03 743 1.28 783 1.55 827 1.82 876 2.09 931 2.33 987 2.55 1037 2.76 1085 2.97 1133 3.20 1181 3.47 1229 3.76 1277 4.08

4500 722 1.27 759 1.52 799 1.78 844 2.05 894 2.31 949 2.56 1003 2.79 1052 3.00 1098 3.22 1145 3.46 1193 3.73 1241 4.03 1289 4.34

4750 739 1.53 776 1.77 817 2.03 862 2.30 913 2.56 968 2.81 1020 3.04 1066 3.27 111 2 3.49 1158 3.74 1205 4.01 1253 4.30 1301 4.61

5000 757 1.79 794 2.04 835 2.30 882 2.56 934 2.83 988 3.08 1036 3.32 1081 3.55 1125 3.78 1171 4.02 1218 4.29 1265 4.59 1312 4.89

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

Total Static Pressure − in. w.g.

Page 8

BLOWER DATA

150 BELT DRIVE BLOWER − BASE UNIT

BLOWER TABLE INCLUDES RESISTANCE FOR BASE UNIT ONLY (NO HEAT SECTION) WITH DRY INDOOR COIL AND AIR
FILTERS IN PLACE. FOR ALL UNITS ADD:

1 − Wet indoor coil air resistance of selected unit.

2 − Any factory installed options air resistance (heat section, economizer, etc.)

3 − Any eld installed accessories air resistance (duct resistance, diffuser, etc.)

Then determine from blower table blower motor output required.

See page 10 for blower motors and drives.

See page 10 for wet coil and option/accessory air resistance data.

MAXIMUM STATIC PRESSURE WITH GAS HEAT - 2.0 in. w.g.

Total

Air

Volume

cfm

3750 689 0.68 731 0.97 775 1.27 820 1.56 865 1.81 911 2.02 957 2.19 1004 2.35 1051 2.53 1100 2.74 1151 2.99 1204 3.29 1258 3.61

4000 706 0.92 748 1.22 792 1.51 836 1.78 881 2.02 926 2.22 972 2.39 1018 2.57 1065 2.76 1113 2.98 1163 3.25 1217 3.55 1271 3.87

4250 725 1.18 766 1.47 810 1.75 854 2.02 899 2.25 943 2.44 988 2.61 1033 2.81 1079 3.01 1127 3.25 1178 3.52 1230 3.82 1284 4.14

4500 744 1.45 786 1.73 829 2.01 873 2.27 917 2.49 961 2.67 1005 2.87 1050 3.07 1096 3.29 1143 3.53 1193 3.81 1245 4.11 1298 4.43

4750 764 1.73 806 2.01 849 2.28 893 2.53 936 2.74 980 2.94 1023 3.15 1068 3.37 111 3 3.60 1160 3.84 1210 4.12 1261 4.42 1314 4.74

5000 785 2.02 827 2.30 870 2.57 914 2.81 957 3.02 1000 3.23 1043 3.46 1087 3.69 1131 3.92 1178 4.17 1227 4.44 1278 4.74 1330 5.05

5250 807 2.33 850 2.61 893 2.87 937 3.11 979 3.33 1021 3.55 1064 3.80 1107 4.03 1151 4.27 1197 4.51 1245 4.78 1295 5.08 1347 5.38

5500 831 2.66 874 2.94 917 3.2 960 3.43 1002 3.67 1043 3.91 1085 4.16 1127 4.39 1171 4.63 1216 4.87 1264 5.14 1313 5.42 1364 5.72

5750 856 3.00 899 3.29 943 3.55 985 3.79 1026 4.04 1066 4.30 1107 4.55 1149 4.78 1192 5.00 1237 5.24 1284 5.50 - - - - - - - - - - - -

6000 883 3.38 927 3.66 970 3.93 1010 4.19 1050 4.46 1089 4.72 1129 4.95 1171 5.17 1213 5.40 1257 5.63 - - - - - - - - - - - - - - - - - -

6250 912 3.78 956 4.07 997 4.35 1036 4.63 1074 4.90 111 3 5.15 1152 5.37 1193 5.58 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6

RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP

Total Static Pressure − in. w.g.

Page 9

BLOWER DATA

FACTORY INSTALLED BELT DRIVE KIT SPECIFICATIONS

Nominal

hp

2 2.3 1 590 - 890

2 2.3 2 800 - 1105

2 2.3 3 795 - 1195

3 3.45 4 730 - 970

3 3.45 5 940 - 1200

3 3.45 6 1015 - 1300

5 5.75 10 900 - 1135

5 5.75 11 1040 - 1315

5 5.75 12 1125 - 1425

POWER EXHAUST FAN PERFORMANCE

Return Air System Static Pressure Air Volume Exhausted

Maximum

hp

in. w.g. cfm

0 3175

0.05 2955

0.10 2685

0.15 2410

0.20 2165

0.25 1920

0.30 1420

0.35 1200

Drive Kit Number RPM Range

FACTORY INSTALLED OPTIONS/FIELD INSTALLED ACCESSORY AIR RESISTANCE - in. w.g.

Air Volume

cfm

2250 0.07 0.10 0.13 0.07 0.07 0.08 0.08 0.01 0.04 0.00

2500 0.09 0.12 0.15 0.09 0.10 0.11 0.11 0.01 0.05 0.00

2750 0.09 0.12 0.17 0.09 0.11 0.12 0.12 0.02 0.05 0.00

3000 0.11 0.15 0.19 0.11 0.12 0.13 0.13 0.02 0.06 0.02

3250 0.13 0.18 0.23 0.12 0.15 0.16 0.15 0.02 0.06 0.02

3500 0.14 0.21 0.26 0.12 0.16 0.17 0.15 0.03 0.07 0.04

3750 0.16 0.23 0.29 0.14 0.19 0.20 0.15 0.03 0.08 0.07

4000 0.17 0.25 0.31 0.14 0.21 0.22 0.19 0.04 0.08 0.09

4250 0.20 0.27 0.34 0.14 0.24 0.28 0.19 0.04 0.09 0.11

4500 0.21 0.30 0.37 0.15 0.26 0.32 0.22 0.04 0.09 0.12

4750 0.23 0.32 0.40 0.16 0.29 0.37 0.25 0.05 0.10 0.16

5000 0.26 0.35 0.43 0.16 0.34 0.43 0.29 0.06 0.10 0.18

5250 0.27 0.36 0.46 0.16 0.37 0.47 0.32 0.06 0.11 0.19

5500 0.29 0.40 0.50 0.18 0.44 0.54 0.34 0.07 0.12 0.22

5750 0.32 0.43 0.56 0.19 0.49 0.59 0.45 0.07 0.12 0.25

6000 0.33 0.46 0.59 0.20 0.54 0.64 0.52 0.08 0.13 0.27

Wet Indoor Coil Gas Heat Exchanger

092, 102 120 150

Standard

Heat

Medium

heat

High
Heat

Economizer

MERV 8 MERV 13

Filters

Return Air

Adaptor

Plate

Page 10

BLOWER DATA

CEILING DIFFUSERS AIR RESISTANCE - in. w.g.

Unit Size

092 Models

102 & 120 Models

150 Models

Air Volume

cfm

2 Ends Open

2400 0.21 0.18 0.15 0.14

2600 0.24 0.21 0.18 0.17

2800 0.27 0.24 0.21 0.20

3000 0.32 0.29 0.25 0.25

3200 0.41 0.37 0.32 0.31

3400 0.50 0.45 0.39 0.37

3600 0.61 0.54 0.48 0.44

3800 0.73 0.63 0.57 0.51

3600 0.36 0.28 0.23 0.15

3800 0.40 0.32 0.26 0.18

4000 0.44 0.36 0.29 0.21

4200 0.49 0.40 0.33 0.24

4400 0.54 0.44 0.37 0.27

4600 0.60 0.49 0.42 0.31

4800 0.65 0.53 0.46 0.35

5000 0.69 0.58 0.50 0.39

5200 0.75 0.62 0.54 0.43

4200 0.22 0.19 0.16 0.10

4400 0.28 0.24 0.20 0.12

4600 0.34 0.29 0.24 0.15

4800 0.40 0.34 0.29 0.19

5000 0.46 0.39 0.34 0.23

5200 0.52 0.44 0.39 0.27

5400 0.58 0.49 0.43 0.31

5600 0.64 0.54 0.47 0.35

5800 0.70 0.59 0.51 0.39

RTD11 Step-Down Diffuser

1 Side, 2 Ends

Open

All Ends & Sides

Open

FD11 Flush

Diffuser

CEILING DIFFUSER AIR THROW DATA

1

Effective Throw Range

RTD11 Step-Down FD11 Flush

Model No.

Air Volume

cfm ft. ft.

2600 24 - 29 19 - 24

2800 25 - 30 20 - 28

092 Models

3000 27 - 33 21 - 29

3200 28 - 35 22 - 29

3400 30 - 37 22 - 30

3600 25 - 33 22 - 29

3800 27 - 35 22 - 30

102, 120

Models

4000 29- 37 24 - 33

4200 32 - 40 26 - 35

4400 34 - 42 28 - 37

5600 39 - 49 28 - 37

5800 42 - 51 29 - 38

150 Models

6000 44 - 54 40 - 50

6200 45 - 55 42 - 51

6400 46 - 55 43 - 52

6600 47 - 56 45 - 56

1

Throw is the horizontal or vertical distance an air stream travels on leaving the outlet or diffuser

before the maximum velocity is reduced to 50 ft. per minute. Four sides open.

Page 11

ELECTRICAL DATA 7.5 TON

7.5 TON STANDARD EFFICIENCY (R-410A) KGA092S4

1

Voltage - 60hz 208/230V - 3 Ph 460V - 3 Ph 575V - 3 Ph

Compressor 1 Rated Load Amps 13.1 6.1 4.4

Locked Rotor Amps 83.1 41 33

Compressor 2 Rated Load Amps 13.1 6.1 4.4

Locked Rotor Amps 83.1 41 33

Outdoor Fan

Motors (2)

Power Exhaust

(1) 0.33 HP

Service Outlet 115V GFI (amps) 15 15 15

Indoor Blower

Motor

2

Maximum

Overcurrent

Protection

3

Minimum

Circuit

Ampacity

1

Extremes of operating range are plus and minus 10% of line voltage.

2

HACR type breaker or fuse.

3

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.

Full Load Amps 2.4 1.3 1

(total) (4.8) (2.6) (2)

Full Load Amps 2.4 1.3 1

Horsepower 2 2 2

Full Load Amps 7.5 3.4 2.7

Unit Only 50 25 15

With (1) 0.33 HP

50 25 20

Power Exhaust

Unit Only 42 20 15

With (1) 0.33 HP

45 22 16

Power Exhaust

8.5 TON STANDARD EFFICIENCY (R-410A) KGA102S4

1

Voltage - 60hz 208/230V - 3 Ph 460V - 3 Ph 575V - 3 Ph

Compressor 1 Rated Load Amps 14.5

Locked Rotor Amps 98

Compressor 2 Rated Load Amps 14.5

Locked Rotor Amps 98

Outdoor Fan

Motors (2)

Power Exhaust

Full Load Amps 2.4

(total) (4.8)

Full Load Amps 2.4

6.3 6

55 41

6.3 6

55 41

1.3 1

(2.6) (2)

1.3 1

(1) 0.33 HP

Service Outlet 115V GFI (amps) 15

Indoor Blower

Motor

2

Maximum

Overcurrent

Protection

3

Minimum

Circuit

Ampacity

1

Extremes of operating range are plus and minus 10% of line voltage.

2

HACR type breaker or fuse.

3

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.

Horsepower 2

Full Load Amps 7.5

Unit Only 50

With (1) 0.33 HP

Power Exhaust

Unit Only 45

With (1) 0.33 HP

Power Exhaust

60

48

15 15

2 2

3.4 2.7

25 20

25 25

21 19

22 20

Page 12

ELECTRICAL DATA 10 TON

10 TON STANDARD EFFICIENCY (R-410A) KGA120S4

1

Voltage - 60hz 208/230V - 3 Ph 460V - 3 Ph 575V - 3 Ph

Compressor 1 Rated Load Amps 16 7.8 5.7

Locked Rotor Amps 110 52 38.9

Compressor 2 Rated Load Amps 16 7.8 5.7

Locked Rotor Amps 110 52 38.9

Outdoor Fan

Motors (2)

Power Exhaust

(1) 0.33 HP

Service Outlet 115V GFI (amps) 15 15 15

Indoor Blower

Motor

2

Maximum

Overcurrent

Protection

3

Minimum

Circuit

Ampacity

1

Extremes of operating range are plus and minus 10% of line voltage.

2

HACR type breaker or fuse.

3

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.

Full Load Amps 2.4 1.3 1

(total) (4.8) (2.6) (2)

Full Load Amps 2.4 1.3 1

Horsepower 3 3 3

Full Load Amps 10.6 4.8 3.9

Unit Only 60 30 20

With (1) 0.33 HP

60 30 25

Power Exhaust

Unit Only 52 25 19

With (1) 0.33 HP

54 27 20

Power Exhaust

12.5 TON STANDARD EFFICIENCY (R-410A) KGA150S4

1

Voltage - 60hz 208/230V - 3 Ph 460V - 3 Ph 575V - 3 Ph

Compressor 1 Rated Load Amps 19 9.7 7.4

Locked Rotor Amps 123 62 50

Compressor 2 Rated Load Amps 19 9.7 7.4

Locked Rotor Amps 123 62 50

Outdoor Fan

Motors (2)

Power Exhaust

Full Load Amps 3 1.5 1.2

(total) (6) (3) (2.4)

Full Load Amps 2.4 1.3 1

(1) 0.33 HP

Service Outlet 115V GFI (amps) 15 15 15

Indoor Blower

Motor

2

Maximum

Overcurrent

Protection

3

Minimum

Circuit

Ampacity

1

Extremes of operating range are plus and minus 10% of line voltage.

2

HACR type breaker or fuse.

3

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.

Horsepower 5 5 5

Full Load Amps 16.7 7.6 6.1

Unit Only 70 35 25

With (1) 0.33 HP

70 35 25

Power Exhaust

Unit Only 53 27 22

With (1) 0.33 HP

56 29 23

Power Exhaust

Page 13

ECONOMIZER

(OPTIONAL)

COMPRESSORS

DISCONNECT /

CIRCUIT BREAKER

(FACTORY- OR FIELD-

INSTALLED OPTION)

FILTERS

(FOUR - 20 X 25 X 2”)

KGA PARTS ARRANGEMENT

EVAPORATOR

COIL

CONDENSATE

DRAIN

BLOWER

MOTOR

BLOWER

GAS VALVE

BURNERS

CONDENSER

FANS

CONDENSER

COIL

COMBUSTION

AIR INDUCER

KGA CONTROL BOX - Y, G, J-VOLT UNITS

K65

K2 K3

S42

K1

FIGURE 2

T1

T3

K10

K125

FIGURE 1

KGA CONTROL BOX - M VOLT CE UNITS

K1 K2 K3

K65

T1

K10

S176 S177

S42

FIGURE 3

Page 14

I-UNIT COMPONENTS

5-Condenser Fan Capacitors C1 & C2

All 7.5 through 12.5 ton (26.3 through 44 kW) units are con
figure to order units (CTO). The KGA unit components are
shown in figure 1. All units come standard with removable
unit panels. All L1, L2 and L3 wiring is color-coded; L1 is red,
L2 is yellow and L3 is blue.

A-Control Box Components

KGA control box components are shown in figures 2 and 3.
The control box is located in the upper portion of the com
pressor compartment.

1-Disconnect Switch S48

(Field-Installed for all units)

All units may be equipped with an optional disconnect switch
S48 or circuit breaker CB10. S48 and CB10 are toggle
switches, which can be used by the service technician to dis
connect power to the unit.

2-Control Transformer T1 all units

All use a single line voltage to 24VAC transformer in
stalled in the control box. The transformer supplies pow
er to control circuits in the unit. The transformer is rated
at 70VA and is protected by a 3.5 amp circuit breaker
(CB8). The 208/230 (Y) voltage transformers use two

208/230V TRANSFORMER

BLUE YELLOW

SECONDARY

208 VOLTS

RED

230 VOLTS

ORANGE

PRIMARY

FIGURE 4

BLACK

primary voltage taps as
shown in figure 4, while
460 (G) and 575 (J)
voltage transformers
use a single primary
voltage tap.

3-C. A. I. Transformers T3 575V units

All KGA 575 (J) voltage units use transformer T3 located in
the control box. The transformers have an output rating of

0.5A. T3 transformer supplies 230 VAC power to the combus
tion air inducer motor (B6).

4-Terminal Strip TB1

All indoor thermostat connections are made at terminal
block TB1 located in the control area. For thermostats with
out “occupied “ and “unoccupied” modes, a factory-in
stalled jumper across terminals R and OC should be in
place.

Fan capacitors C1 and C2 are used to assist in the start up of
condenser fans B4 and B5. Ratings will be on side of capaci
tor or outdoor fan motor nameplate.

6-Compressor Contactor K1 & K2

All compressor contactors are three‐pole‐double‐break
contactors with 24VAC coils. In all KGA units, K1 and K2
energize compressors B1 and B2 in response to thermo
stat demand. On CE M-voltage units, contactor is CE ap
proved by manufacturer (Siemens). See figure 5.

CONTACTOR

FIGURE 5

7-Blower Contactor K3

Blower contactor K3, used in all units, is a three‐pole‐
double‐break contactor with a 24VAC coil used to energize
the indoor blower motor B3 in response to blower demand.
K3 is energized by a thermostat cooling demand. On M-volt
CE units, the contactor is CE approved by manufacturer
(Siemens). See figure 5.

8-Condenser Fan Relay K10

Outdoor fan relay K10 is a DPDT relay with a 24VAC coil. K10
energizes condenser fans B4 and B5.

9-Power Exhaust Relay K65 (PED units)

Power exhaust relay K65 is a DPDT relay with a 24VAC
coil. K65 is used in all KGA units equipped with the op
tional power exhaust dampers. K65 is energized by the
economizer enthalpy control A6, after the economizer
dampers reach 50% open (adjustable) When K65
closes, exhaust fan B10 is energized.

Page 15

INDOOR COIL

STAGE 1

KGA092,102, 120, 150 PLUMBING AND COMPRESSOR CIRCUITS DETAIL

OUTDOOR

COIL STAGE 2

INDOOR COIL

STAGE 2

DRIERS

OUTDOOR COIL

STAGE 1

COMPRESSOR

2

S8 THERMAL
PROTECTOR

DISCHARGE

LINE

S7 HIGH

PRESSURE

SWITCH

PRESSURE

TAP

COMPRESSOR

1

COMPRESSOR 2

SUCTION

LINE

COMPRESSOR 1

S5 THERMAL
PROTECTOR

SUCTION

LINE

DISCHARGE

LINE

S4 HIGH

PRESSURE

SWITCH

PRESSURE

TAP

FIGURE 6

Page 16

B-Cooling Components

All units use independent cooling circuits consisting of sepa
rate compressors, condenser coils and evaporator coils.
See figure 6. Two draw-through-type condenser fans are
used in KGA092/150 units. All units are equipped with belt‐
drive blowers which draw air across the evaporator during
unit operation.

Cooling may be supplemented by a factory‐ or field‐
installed economizer. The evaporators are slab-type and
are stacked. Each evaporator uses a thermostatic expan
sion valve as the primary refrigerant metering device. Each
evaporator is also equipped with enhanced fins and rifled
tubing.

In all units each compressor is protected by S49 and S50
freezestats and S4 and S7 high pressure switches (on each
evaporator). Low ambient switches (S11 and S84) are avail
able as an option for additional compressor protection. On
150 units, each compressor is protected by a crankcase
heater.

1-Compressors B1 and B2

All KGA092/150 units use two scroll compressors. Com
pressor capacity may vary from stage to stage. In all cases,
the capacity of each compressor is added to reach the total
capacity of the unit. See “SPECIFICATIONS” and “ELEC
TRICAL DATA” (table of contents) or compressor nameplate
for compressor specifications.

WARNING

Electrical shock hazard. Compressor must be
grounded. Do not operate without protective cover
over terminals. Disconnect power before removing

protective cover. Discharge capacitors before ser

vicing unit. Failure to follow these precautions could

cause electrical shock resulting in injury or death.

Each compressor is energized by a corresponding com
pressor contactor.

NOTE-Refer to the wiring diagram section for specific unit
operation.

If Interlink compressor replacement is necessary, call
1-800-4-LENNOX (1-800-453-6669).

IMPORTANT

Some scroll compressors have an internal vacuum
protector that will unload scrolls when suction
pressure goes below 20 psig. A hissing sound will
be heard when the compressor is running un
loaded. Protector will reset when low pressure in
system rises above 40 psig. DO NOT REPLACE
COMPRESSOR.

2-Thermal Protectors S5, S8

Some compressors have thermal protectors located on top
of the compressor. The protectors open at 248°F +
(120°C +

5°C) and close at 169°F + 18°F (76°C + 10°C).

9°F

3-Freezestats S49 and S50

Each unit is equipped with a low temperature switch (freezes
tat) located on a return bend of each evaporator coil. S49
(first circuit) and S50 (second circuit) are located on the
corresponding evaporator coils.

Freezestats are wired in series with compressor contactors.
Each freezestat is a SPST N.C. auto-reset switch which
opens at 29°F +
and closes at 58°F +
ture rise. To prevent coil icing, freezestats open during
compressor operation to temporarily disable the re
spective compressor until the coil temperature rises.

If the freezestats are tripping frequently due to coil icing,
check the airflow/filters, economizer position and unit
charge before allowing unit back in operation. Make sure
to eliminate conditions which might promote evaporator
ice buildup.

3°F (‐1.7°C + 1.7°C) on a temperature dro p

4°F (14.4° C + 2.2° C) on a te m p e r a

4-High Pressure Switches S4 and S7

The high pressure switch is a manual reset SPST N.C. switch
which opens on a pressure rise.

S4 (first circuit) and S7 (second circuit) are located in the
compressor discharge line and are wired in series with the
respective compressor contactor coils.

When discharge pressure rises to 640 ± 10 psig (4413 ±
69 kPa) (indicating a problem in the system), the switch
opens and the respective compressor is de-energized
(the economizer can continue to operate).

5-Low Ambient Switches S11 & S84

(optional)

The low ambient switch is an auto‐reset SPST N.O. pres
sure switch which allows for mechanical cooling operation
at low outdoor temperatures. In all models, a switch is lo
cated in each liquid line prior to the indoor coil section.

In the KGA092/150, S11 and S84 are wired in parallel with
outdoor fan relay K10.

When liquid pressure rises to 450 ± 10 psig (3102 ± 69
kPa), the switch closes and the condenser fans are ener
gized. When liquid pressure in both refrigerant circuits
drops to 240 ± 10 psig (1655 ± 69 kPa), the switches open
and the condenser fans are de-energized. This intermittent
fan operation results in higher evaporating temperature al
lowing the system to operate without icing the evaporator
coil and losing capacity.

6-Crankcase Heaters HR1, HR2

150S units use insertion-type heaters. Heater HR1 is
installed around compressor B1 and heater HR2 is
installed around compressor B2. Crankcase heater watt
age varies by compressor manufacturer.

Page 17

C-Blower Compartment

The blower compartment in all KGA092/150S units is located
between the evaporator coil and the condenser coil section.
The blower assembly is accessed by disconnecting the blow
er motor .See Blower Access in the Operation/ Adjustment
section. The blower pulls out as shown in figure 7.

1-Blower Wheels

All KGA092/150 units have one 15 in. x 15 in. (381 mm x 381
mm) blower wheel.

2-Indoor Blower Motor B3

All units use three‐phase single‐speed blower motors. CFM
adjustments are made by adjusting the motor pulley (sheave).
Motors are equipped with sealed ball bearings. All motor speci
fications are listed in the SPECIFICATIONS(table of contents)
in the front of this manual. Units may be equipped with motors
manufactured by various manufacturers, therefore electrical
FLA and LRA specifications will vary. See unit rating plate for
information specific to your unit.

OPERATION / ADJUSTMENT

Blower Operation

Initiate blower demand at thermostat according to instruc

tions provided with thermostat. Unit will cycle on thermostat
demand. The following steps apply to applications using a
typical electro-mechanical thermostat.

1- Blower operation is manually set at the thermostat sub

base fan switch. With fan switch in ON position, blow
ers will operate continuously.

2- With fan switch in AUTO position, the blowers will cycle

with demand. Blowers and entire unit will be off when
system switch is in OFF position.

Determining Unit CFM

1- The following measurements must be made with a dry

indoor coil. Run blower without a cooling demand.
Measure the indoor blower shaft RPM. Air filters must
be in place when measurements are taken.

2- With all access panels in place, measure static pres

sure external to unit (from supply to return). Measure

static below roof curb if roof curb is used.

3- Refer to blower tables in BLOWER DATA (table of con

tents) in the front of this manual. Use static pressure an d
RPM readings to determine unit air volume.

TO INCREASE BELT TENSION

1- Loosen four bolts securing motor mounting base

to frame.

2- Turn adjusting bolt to the right, or clockwise, to

move the motor away from the blower housing.

IMPORTANT - Gap between end of frame and motor
mounting base should be equal at both ends, i.e. par
allel along gap.

3- Tighten four bolts securing motor mounting base

to frame.

4- Relieve tension on two adjusting bolts.

MOTOR MOUNTING

BASE

BELT ADJUSTING BOLTS

- TURN CLOCKWISE
TO TIGHTEN BELT

GAP BETWEEN

EDGES SHOULD BE

PARALLEL ON BOTH

ENDS BEFORE

TIGHTENING MOTOR

MOUNTING BASE IN

PLACE

BLOWER ASSEMBLY

BLOWER

HOUSING

MOTOR

SIDE VIEW

MOTOR

BLOWER

FRAME

ALLEN

SCREW

PULLEY

REMOVE TWO SCREWS
TO COMPLETELY SLIDE

BLOWER OUT OF UNIT

LOOSEN BEFORE

ADJUSTING BELT TENSION

(TWO EACH SIDE)

REMOVE TWO SCREWS ON EACH
SIDE TO SLIDE FRAME PARTIALLY

OUT OF UNIT FOR SERVICE ACCESS

FIGURE 7

Page 18

4- The blower RPM can be adjusted at the motor pulley.

Loosen Allen screw and turn adjustable pulley clock
wise to increase CFM. Turn counterclockwise to de
crease CFM. See figure 7. Do not exceed minimum and
maximum number of pulley turns as shown in table 1.

TABLE 1

MINIMUM AND MAXIMUM PULLEY ADJUSTMENT

Belt

A Section No minimum 5

B Section 1* 6

*No minimum number of turns open when B belt is used on
pulleys 6” O.D. or larger.

Minimum

Turns Open

Maximum

Turns Open

Blower Belt Adjustment

Maximum life and wear can be obtained from belts only if
proper pulley alignment and belt tension are main
tained. Tension new belts after a 24-48 hour period of op
eration. This will allow belt to stretch and seat grooves.
Make sure blower and motor pulley are aligned as shown in
figure 8.

PULLEY ALIGNMENT

Check Belt Tension

Overtensioning belts shortens belt and bearing life. Check
belt tension as follows:

1- Measure span length X. See figure 9.

2- Apply perpendicular force to center of span (X) with

enough pressure to deflect belt 1/64” for every inch of
span length or 1.5mm per 100mm of span length.

Example: Deflection distance of a 40” span would be
40/64” or 5/8”.

Example: Deflection distance of a 400mm span would
be 6mm.

3- Measure belt deflection force. For a used belt, the

deflection force should be 5 lbs. (35kPa). A new belt
deflection force should be 7 lbs. (48kPa).

A force below these values indicates an underten
sioned belt. A force above these values indicates an
overtensioned belt.

MEASURE BELT TENSION

ALIGNED

BLOWER

PULLEY

BELT

NOT ALIGNED

MOTOR
PULLEY

FIGURE 8

1- Loosen four bolts securing motor base to mounting

frame. See figure 7.

2- To increase belt tension -

Turn adjusting bolt to the right, or clockwise, to move
the motor outward and tighten the belt. This increases
the distance between the blower motor and the blower
housing.

To loosen belt tension -

Turn the adjusting bolt to the left, or counterclockwise
to loosen belt tension.

IMPORTANT - Align top edges of blower motor base and
mounting frame base parallel before tightening two bolts on
the other side of base. Motor shaft and blower shaft must be
parallel.

3- Tighten bolts on side of base.

FORCE

DEFLECTION 1/64” PER INCH OF SPAN

OR 1.5mm PER 100mm OF SPAN

FIGURE 9

Page 19

D-GAS HEAT COMPONENTS

KGA092/150 units are available in 130,000 BTUH (38.1
kW), 180,000 BTUH (52.7 Kw) or 240,000 BTUH (70.3
kW) heat sizes.

1-Heat Exchanger Figure 10

The KGA units use aluminized steel inshot burners with
tubular aluminized steel heat exchangers and two‐stage
redundant gas valves. KGA092/150 units use one eleven­tube/burner for high heat, one eight-tube/burner for me
dium heat and one six-tube/burner for standard heat. Burn
ers in all units use a burner venturi to mix gas and air for
proper combustion. Combustion takes place at each tube
entrance. As hot combustion gases are drawn upward
through each tube by the combustion air inducer, exhaust
gases are drawn out the top and fresh air/gas mixture is
drawn in at the bottom. Heat is transferred to the air stream
from all surfaces of the heat exchanger tubes. The supply
air blower forces air across the tubes to extract the heat of
combustion. The shape of the tubes ensures maximum
heat exchange.

The gas valves accomplish staging by allowing more or less
gas to the burners as called for by heating demand.

Orifice

Each burner uses an orifice which is matched to the burn
er input. The orifice is threaded into the burner manifold.
The burner is supported by the orifice and will easily slide
off for service once the mounting screws are removed from
the burners.

NOTE-Do not use thread sealing compound on the
orifices. Using thread sealing compound may plug
the orifices.

Each orifice and burner are sized specifically to the unit.
Refer to Lennox Repair Parts Listing for correct sizing infor
mation.

BURNER BOX ASSEMBLY

GAS

VALV E

FLAME ROLLOUT LIMIT SWITCH

HEAT EXCHANGER ASSEMBLY

HEAT

EXCHANGER

TUBE

COMBUSTION

AIR INDUCER

VENT

CONNECTOR

GAS VALVE

BURNER

FIGURE 10

2-Burner Box Assembly (Figure 11)

The burner assembly consists of a spark electrode, flame
sensing electrode and gas valve. Ignition board A3 controls all
functions of the assembly.

Burners

All units use inshot burners. Burners are factory-set and do
not require adjustment. A peep h o l e with a cover i s fur
nished in the heating access panel for viewing the
burner flame. Always operate the unit with the ac
cess panel in place.
Burners can be removed individually for service.
Burner maintenance and service is detailed in the
SERVICE CHECKS section of this manual.

BURNERS

IGNITOR
(not shown)

GAS MANIFOLD

FLAME

SENSOR

FIGURE 11

3-Primary High Temperature Limit S10

S10 is a SPST N.C. high-temperature primary limit for gas
heat in KGA092/150 units. On KGA092/150 units, S10 is lo
cated next to the blower. See figure 12.

S10 LIMIT LOCATION

FIGURE 12

Page 20

Primary limit S10 is wired to the ignition control A3. Its N.C.
contacts open to de-energize the ignition control when ex
cessive temperature is reached in the blower compart
ment. If the limit trips, the blower relay coil K3 will be ener
gized by ignition control A3. Three limits with different
actuating temperatures are used for limits S10. Use appro
priate limit when replacement is required.

4-Flame Rollout Limit Switch S47

Flame rol l o ut limit switc h S4 7 is a SPST N.C. high-temper
ature limit located just above the burner air intake opening in
the burner enclosures (see figure 11 ). S47 is wired to the igni
tion control A3. When S47 senses flame rollout (indicating
a blockage in the combustion air passages), the flame
rollout limit trips and the ignition control immediately
closes the gas valve.

Limit S47 is factory-set to open at 290_F +

12_F (143_C +

6.7_C) on a temperature rise on all units. All flame rollout lim
its are manual reset.

5-Combustion Air Prove Switch S18

Prove switch S18 is a SPST N.O. switch located to the right
of the induced draft assembly. S18 monitors combustion air
inducer operation. Switch S18 is wired to the ignition control
A3. The switch closes on a negative pressure fall. This neg
ative pressure fall and switch actuation allows the ignition
sequence to continue (proves, by closing, that the combus
tion air inducer is operating before allowing the gas valve to
open.) The combustion air prove switch is factory-set and is
not adjustable. The switch will automatically open on a
pressure rise (less negative pressure). Table 2 shows
prove switch settings.

TABLE 2

S18 Prove Switch Settings

Close“ w.c. (Pa) Open “ w.c. (Pa)

0.25 + 5 (62.3 + 12.4) 0.10 + 5 (24.8 + 12.4)

6-Combustion Air Inducer B6

Combustion air inducers on KGA092/150 units provide air
to the corresponding burners while clearing the combustion
chamber of exhaust gases. The inducer begins operating
immediately upon receiving a thermostat demand and is
de-energized when thermostat demand is satisfied.

The inducer uses a 208/230V single‐phase PSC motor
and a 4.81in. x 1.25in. (122mm x 32mm) blower wheel. All
motors operate at 3200RPM and are equipped with auto‐
reset overload protection. Inducers are supplied by vari
ous manufacturers. Ratings may vary by manufacturer.
Specific inducer electrical ratings can be found on the unit
rating plate.

On a heating demand (W1), the ignition control A3 initiates
the heating cycle. A3 then allows 30 seconds for the com
bustion air inducer to vent exhaust gases from the burners.
When the combustion air inducer is purging the exhaust
gases, the combustion air prove switch closes, proving that
the combustion air inducer is operating before allowing the
ignition sequence to continue. When the combustion air
prove switch is closed and the delay is over, the ignition
control activates the first-stage operator of the gas valve
(low fire), the spark and the flame sensing electrode.
Sparking stops immediately after flame is sensed or at the
end of the eight-second trial for ignition.

All combustion air inducer motors are sealed and cannot
be oiled. The inducer is not adjustable; but, it can be dis
assembled for cleaning.

7-Combustion Air Motor Capacitor C3

The combustion air inducer motors in all KGA units re
quire run capacitors. Capacitor C3 is connected to com
bustion air inducer B6. Ratings will be on the side of
capacitor or combustion air motor nameplate.

8-Gas Valves GV1

Gas valve GV1 is a two‐stage redundant valve. Units are
equipped with valves manufactured by White-Rodgers or
Honeywell. On a call for first-stage heat (low fire), the valve is
energized by the ignition control simultaneously with the spark
electrode. On a call for second-stage heat (high fire), the sec
ond-stage operator is energized directly from A3. A manual
shut-off knob is provided on the valve for shutoff. The man
ual shut‐off knob immediately closes both stages without
delay. On both valves, the first stage (low fire) is quick-opening
(on and off in less than 3 seconds).

On the White-Rodgers valve, the second stage is slow-open
ing (on to high fire pressure in 40 seconds and off to low fire
pressure in 30 seconds). The White-Rodgers valve is ad
justable for high fire only. Low fire is not adjustable. On the
Honeywell valve, the second stage is quick-opening. The
Honeywell valve is adjustable for both low fire and high
fire. Figures 17 and 18 show gas valve components. Table
3 shows factory gas valve regulation for KGA series units.

TABLE 3

GAS VALVE REGULATION

Max. Inlet

Pressure

13.0” W.C.

Low High Low High

1.6 + 0.2”
W.C .

Operating Manifold Pressure

Natural L.P.

3.7 + 0.3”
W.C .

6.5” + 0.3”
W.C

10.5” + 0.5”
W.C .

Page 21

9-Spark Electrode Figure 13

An electrode assembly is used for ignition spark. The elec
trode is inserted through holes under the left-most burner.
The electrode tip protrudes into the flame envelope of the
adjacent burner. The electrode assembly is fastened to
burner supports and can be removed for service without re
moving any part of the burners.

During ignition, spark travels through the spark electrode
(figure 13) and ignites the left burner. Flame travels from
burner to burner until all are lit.

The spark electrode is connected to the ignition control by
an 8 mm silicone‐insulated, stranded, high-voltage wire.
The wire uses a 1/4” (6.35 mm) female quick connect on
both ends of the wire.

NOTE - If the electrode wire is replaced, wire and sup
pression must be same type of cable. See repair parts
listing for correct replacement.

The spark electrode assembly can be removed for inspec
tion by removing the screw securing the electrode assem
bly and sliding it out of unit.

For proper unit operation, electrodes must be positioned
and gapped correctly.

Spark gap may be checked with appropriately sized twist
drills or feeler gauges. Disconnect power to the unit and re
move electrode assembly. The gap should be between

0.125” +

0.015” (3.2 mm + .4 mm). See figure 13.

NOTE - IN ORDER TO MAXIMIZE SPARK ENERGY
TO ELECTRODE, HIGH-VOLTAGE WIRE SHOULD
TOUCH UNIT CABINET AS LITTLE AS POSSIBLE.

IGNITOR

SPARK GAP

SHOULD BE 1/8”

(3mm)

FIGURE 13

10-Flame Sensor Figure 14

A flame sensor is located under the right-most burner. The
sensor is inserted through a hole in the burner support and
the tip protrudes into the flame envelope of the right-most burn
er. The sensor assembly is fastened to burner supports and
can be removed for service without removing any part of the
burners.

When flame is sensed by the flame sensor (indicated by
microamp signal through the flame) sparking stops imme
diately or after the eight-second trial for ignition. During
operation, flame is sensed by current passed along the

ground electrode (located on the spark electrode),
through the flame, and into the sensing electrode. The ig
nition control allows the gas valve to stay open as long as a
flame signal (current passed through the flame) is sensed.

SIDE VIEW SENSOR

Gas Flow

1-3/4”

(45mm)

3/8”

(10mm)

FIGURE 14

INTEGRATED CONTROL BOARD A3
11-Burner Control A3

WARNING

Shock hazard. Spark related compo
nents contain high voltage which can
cause personal injury or death. Discon
nect power before servicing. Control is
not field repairable. Unsafe operation
will result. If control is inoperable, sim
ply replace the entire control.

The burner control A3 is located in the gas heat section. See
figures 16 and 15.

The ignition control provides four main functions: gas
valve control, blower control, ignition and flame sensing.
The control has a green LED to show control status (table

4). The unit will usually ignite on the first trial and A3 allows
three trials for ignition before locking out. The lockout time is
1 hour. After lockout, the ignition control automatically resets
and provides three more attempts at ignition. Manual reset
after lockout requires removing power from the control for
more than 1 second or removing the thermostat call for heat
for more than 1 second but no more than 20 seconds. 24 volt
thermostat connections (P2) and heating component con
nections (J1) are made through separate jackplugs. See ta
ble 5 for thermostat terminations and table 6 for heating
component terminations.

TABLE 4

LED

Slow Flash Normal operation. No call for heat.

Fast Flash Normal operation. Call for heat.

Steady Off

Steady On Control Internal Failure.

2 Flashes Lockout. Failed to detect or sustain flame.

Internal Control Fault, No Power To Board

or Gas Valve Relay Fault

STATUS

Page 22

3 Flashes

Rollout switch open / Prove switch open or

closed.

4 Flashes Primary High Limit switch open.

5 Flashes Flame sensed but gas valve not open.

6 Flashes On Board Microprocessors Disagree

TABLE 5

P2 TERMINAL DESIGNATIONS

Pin # Function

1 R 24 Volts to thermostat

2 W1 Heat Demand

3 Y Cool Demand

4 C Common

5 G Indoor Blower

6 BL OUT Indoor Blower Relay

7 W2 Second Stage Heat

TABLE 6

J1 TERMINAL DESIGNATIONS

Pin # Function

1 Limit Switch Out

2 Rollout Switch / Prove Switch Out

3 Gas Valve Common

4 Gas Valve Out

5 Rollout Switch / Prove Switch In

6 Limit Switch In

IGNITION CONTROL A3

FLAME

LED

CAI Line

Line voltage

FIGURE 15

IGNITION CONTROL A3

S18 COMBUSTION

AIR PROVING SWITCH

A3 IGNITION

CONTROL

FIGURE 16

Flame rectification sensing is used on all KGA units.
Loss of flame during a heating cycle is indicated by an ab
sence of flame signal (0 microamps). If this happens, the con
trol will immediately restart the ignition sequence and then lock
out if ignition is not gained after the third tria l . See Syst e m
Service Checks section for flame current measurement.

The control shuts off gas flow immediately in the event of a
power failure. Upon restoration of gas and power, the control
will restart the ignition sequence and continue until flame is
established or system locks out.

Operation

On a heating demand, the ignition control checks for a
closed limit switch and open combustion air prove
switch. Once this check is complete and conditions are
correct, the ignition control then allows 30 seconds for
the combustion air inducer to vent exhaust gases from
the burners. When the combustion air inducer is purging
the exhaust gases, the combustion air prove switch
closes proving that the combustion air inducer is operat
ing before allowing the ignition control to energize.
When the combustion air prove switch is closed and the
delay is over, the ignition control activates the gas valve,
the spark electrode and the flame sensing electrode.
Once the gas valve is energized, the non-adjustable
40-second indoor blower delay period begins. Sparking
stops immediately after flame is sensed or at the end of
the 8-second trial for ignition.

The control then proceeds to “steady state” mode where
all inputs are monitored to ensure the limit switch, rollout
switch and prove switch are closed as well as flame is
present. When the heat call is satisfied and the gas valve
is de-energized, a combustion air inducer post purge pe
riod of 5 seconds begins along with a 120-second blower
off delay.

Page 23

II-PLACEMENT AND INSTALLATION

Make sure the unit is installed in accordance with the in
stallation instructions and all applicable codes. See ac
cessories section for conditions requiring use of the op
tional roof mounting frame (LARMF18/36 or
LARMFH18/24).

III-STARTUP - OPERATION

A-Preliminary and Seasonal Checks

1- Make sure the unit is installed in accordance with the

installation instructions and applicable codes.

2- Inspect all electrical wiring (both field- and factory-in

stalled) for loose connections. Tighten as required. Refer
to unit diagram located on inside of unit compressor ac
cess panel.

3- Check to ensure that refrigerant lines are in good

condition and do not rub against the cabinet or other
refrigerant lines.

4- Check voltage at the disconnect switch. Voltage must

be within the range listed on the nameplate. If not, con
sult the power company and have the voltage correct
ed before starting the unit.

5- Recheck voltage and amp draw with unit running. If

voltage is not within range listed on unit nameplate,
stop unit and consult power company. Refer to unit
nameplate for maximum rated load amps.

6- Inspect and adjust blower belt (see section on Blower

Compartment - Blower Belt Adjustment).

B-Heating Startup

FOR YOUR SAFETY READ BEFORE LIGHTING

WARNING

Electric shock hazard. Can cause injury
or death. Do not use this unit if any part
has been under water. Immediately call
a qualified service technician to inspect
the unit and to replace any part of the
control system and any gas control
which has been under water.

WARNING

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

SMOKE POTENTIAL

The heat exchanger in this unit could be a source of
smoke on initial firing. Take precautions with respect
to building occupants and property. Vent initial sup
ply air outside when possible.

BEFORE LIGHTING smell all around the appliance area for
gas. Be sure to smell next to the floor because some gas is
heavier than air and will settle on the floor.

Use only your hand to push in or turn the gas control knob.
Never use tools. If the knob will not push in or turn by hand,
do not try to repair it, call a qualified service technician.
Force or attempted repair may result in a fire or explosion.

WARNING

Danger of explosion. Can cause injury or
death. Do not attempt to light manually.
Unit has a direct spark ignition system.

This unit is equipped with an automatic spark ignition sys
tem. There is no pilot. In case of a safety shutdown, move
thermostat switch to OFF and return the thermostat switch
to HEAT to reset ignition control.

Placing Unit In Operation

WARNING

Danger of explosion and fire. Can cause
injury or product or property damage.
You must follow these instructions
exactly.

Danger of explosion. Can cause injury
or product or property damage. If over
heating occurs or if gas supply fails to
shut off, shut off the manual gas valve
to the appliance before shutting off
electrical supply.

Gas Valve Operation for White Rodgers 36C (figure 17)
and Honeywell VR8205Q/VR8305Q (figure 18)

1- Set thermostat to lowest setting.

2- Turn off all electrical power to appliance.

Page 24

WHITE RODGERS 36C76 GAS VALVE

HIGH FIRE MANIFOLD PRESSURE

INLET

PRESSURE

TAP (SIDE)

ADJUSTMENT SCREW UNDER CAP

GAS VALVE SHOWN

IN “OFF” POSITION

D-1

MANIFOLD

PRESSURE

TAP (SIDE)

12- If the appliance does not light the first time (gas line

not fully purged), it will attempt up to two more ignitions
before locking out.

13- If lockout occurs, repeat steps 1 through 10.

14- If the appliance will not operate, follow the instructions

“Turning Off Gas to Appliance” and call your service
technician or gas supplier.

Turning Off Gas to Unit

1- If using an electromechanical thermostat, set to the

lowest setting.

GV-1

GV-2

C-1

C2

FIGURE 17

HONEYWELL VR8205Q/VR8305Q SERIES GAS VALVE

HIGH FIRE

ADJUSTMENT

INLET

PRESSURE

TAP

Gas valve knob is shown in OFF position.

LOW FIRE

ADJUSTMENT

MANIFOLD

PRESSURE

TAP

FIGURE 18

3- This appliance is equipped with an ignition device

which automatically lights the burner. Do not try to light
the burner by hand.

4- Open or remove the heat section access panel.

5- Turn the knob on the gas valve clockwise

to “OFF”.

Push in 36C knob slightly. Do not force.

6- Wait five (5) minutes to clear out any gas. If you then

smell gas, STOP! Immediately call your gas suppli
er from a neighbor's phone. Follow the gas supplier's
instructions. If you do not smell gas, go to the next step.

7- Turn the knob on the gas valve counterclockwise

to “ON”. Do not force.

8- Close or replace the heat section access panel.

9- Turn on all electrical power to appliance.

10- Set thermostat to desired setting.

11- The combustion air inducer will start. The burners will

light within 40 seconds.

2- Before performing any service, turn off all electrical

power to the appliance.

3- Open or remove the heat section access panel.

4- Turn the knob on the gas valve clockwise

to “OFF”.

Push in 36C knob slightly. Do not force.

5- Close or replace the heat section access panel.

C-Cooling Startup

1- Initiate first- and second-stage cooling demands ac

cording to instructions provided with thermostat.

2- First-stage thermostat demand will energize compres

sor 1. Second-stage thermostat demand will energize
compressor 2. On units with an economizer, when out
door air is acceptable, a first-stage demand will ener
gize the economizer; a second-stage demand will en
ergize compressor 1.

3- Units contain two refrigerant circuits or stages. See fig

ure 19.

4- Each refrigerant circuit is separately charged with re

frigerant. See unit rating plate for correct amount of
charge.

NOTE - Refer to IV-CHARGING for proper method to check
refrigerant charge.

Three-Phase Scroll Compressor Voltage Phasing

Three-phase power supplied to the unit disconnect
switch must be phased sequentially to ensure the scroll
compressor and indoor blower rotate in the correct direc
tion. Compressor and blower are wired in phase at the
factory. Power wires are color-coded as follows: line
1-red, line 2-yellow, line 3-blue.

1- Observe suction and discharge pressures and blower

rotation on unit start-up.

2- Suction pressure must drop, discharge pressure must

rise and blower rotation must match rotation marking.

If pressure differential is not observed or blower rotation is
not correct:

3- Disconnect all remote electrical power supplies.

4- Reverse any two field-installed wires connected to the

line side of K2 contactor or disconnect switch if in
stalled. Do not reverse wires at blower contactor.

Page 25

5- Make sure the connections are tight.

Discharge and suction pressures should operate at their
normal start‐up ranges.

REFRIGERANT CIRCUITS

092/150

(BOTH FANS ARE ENERGIZED

WITH A Y1 DEMAND)

EVAPORATOR
COIL STAGE 2

2

1

EVAPORATOR
COIL STAGE 1

FIGURE 19

D-Safety or Emergency Shutdown

Turn off power to unit. Close manual and main ga valves.

IV-CHARGING

WARNING

Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.

Failure to follow this warning may result in person
al injury or death.

WARNING-Do not exceed nameplate charge under any
condition.

This unit is factory-charged and should require no further
adjustment. If the system requires additional refrigerant, re

claim the charge, evacuate the system and add required
nameplate charge.

NOTE - System charging is not recommended below 60°F
(15°C). In temperatures below 60°F (15°C) , the charge
must be weighed into the system.

If weighing facilities are not available, or to check the
charge, use the following procedure:

1- Attach gauge manifolds and operate unit in cooling

mode with economizer disabled until system stabilizes
(approximately five minutes). Make sure outdoor air
dampers are closed.

2- Check each system separately with all stages operating.

3- Use a thermometer to accurately measure the outdoor

ambient temperature.

4- Apply the outdoor temperature to tables 7 through 10

to determine normal operating pressures.

Pressures are

listed for sea level applications at 80°F dry bulb and 67°F wet
bulb return air.

5- Compare the normal operating pressures to the pres

sures obtained from the gauges. Minor variations in
these pressures may be expected due to differences in
installations. Significant differences could mean that
the system is not properly charged or that a problem
exists with some component in the system. Correct

any system problems before proceeding.

6- If discharge pressure is high, remove refrigerant from

the system. If discharge pressure is low, add refrigerant
to the system.

S Add or remove charge in increments.

S Allow the system to stabilize each time refrigerant

is added or removed.

7- Use the following approach method along with the nor

mal operating pressures to confirm readings.

TABLE 7

KGA092 NORMAL OPERATING PRESSURES

Outdoor

Coil

Entering

Air Temp

655 F 260 130 269 132
755 F 301 133 311 133
855 F 343 135 354 136

955 F 388 138 401 139
1055 F 435 140 449 141
1155 F 481 142 497 144

CIRCUIT 1 CIRCUIT 2

Dis
charge
10 psig

+

Suction

5 psig

+

Dis

charge

10 psig

+

Suction

5 psig

+

TABLE 8

KGA102 NORMAL OPERATING PRESSURES

Outdoor

Coil

Entering

Air Temp

655 F 262 128 270 129
755 F 299 131 310 131
855 F 342 134 353 134

955 F 386 137 399 136
1055 F 434 140 448 139
1155 F 487 143 501 142

CIRCUIT 1 CIRCUIT 2

Dis
charge
10 psig

+

Suction

5 psig

+

Dis

charge

10 psig

+

Suction

5 psig

+

TABLE 9

KGA120 NORMAL OPERATING PRESSURES

Outdoor

Coil

Entering

Air Temp

655 F 275 135 282 136
755 F 313 137 323 138
855 F 355 140 366 141

955 F 400 142 414 143
1055 F 447 145 464 145
1155 F 499 148 517 148

CIRCUIT 1 CIRCUIT 2

Dis
charge
10 psig

+

Suction

5 psig

+

Dis

charge

10 psig

+

Suction

5 psig

+

Page 26

KGA150 NORMAL OPERATING PRESSURES

TABLE 10

Outdoor

Coil

Entering

Air Temp

655 F 279 132 283 136
755 F 318 134 323 138
855 F 360 136 364 139

955 F 406 138 411 140
1055 F 456 141 462 142
1155 F 508 145 515 145

CIRCUIT 1 CIRCUIT 2

Dis

charge

10 psig

+

Suction

5 psig

+

Dis

charge

10 psig

+

Suction

5 psig

+

Charge Verification - Approach Method - AHRI Testing

1- Using the same thermometer, compare liquid tempera

ture

(at condenser outlet) to outdoor ambient tempera

ture.

Approach Temperature = Liquid temperature minus
ambient temperature.

2- Approach temperature should match values shown in

table 11. An approach temperature greater than

indicates an undercharge. An approach tempera

ue

ture less than

this value indicates an overcharge.

this val

3- The approach method is not valid for grossly over

charged or undercharged systems.
through 10

as a guide for typical operating pressures.

Use tables 7

TABLE 11

APPROACH TEMPERATURE

Unit

092 9°F + 1 (5.0°C + 0.5) 8°F + 1 (4.4°C + 0.5)

102 7°F + 1 (3.9°C + 0.5) 6°F + 1 (3.3°C + 0.5)

120 8°F + 1 (4.4°C + 0.5) 6°F + 1 (3.3°C + 0.5)

150 6°F + 1 (3.3°C + 0.5) 6°F + 1 (3.3°C + 0.5)

Liquid Temp. Minus Ambient Temp.

1st Stage 2nd Stage

V- SYSTEMS SERVICE CHECKS

A-Heating System Service Checks

All KGA units are ETL/CSA design certified without mod
ification.

Before checking piping, check with gas company or au
thorities having jurisdiction for local code requirements.
Refer to the KGA Installation instruction for more infor
mation.

GAS PIPING COMPONENTS

REFER TO INSTALLATION INSTRUCTIONS

GROUND

JOINT UNION

MANUAL MAIN

SHUT-OFF VALVE

(REFER TO LOCAL CODES)

CAP HERE TO

ISOLATE VALVE

WHEN PRESSURE

TESTING LINE

ROOF

MOUNTING

FRAME

DRIP LEG

GAS PIPING

SUPPORT

VALV E

UNIT

FIGURE 20

1-Gas Piping

Gas supply piping must not allow more than 0.5”W.C.
(124.3 Pa) drop in pressure between the gas meter and
the unit. Supply gas pipe must not be smaller than the unit
gas connection. Refer to installation instructions for de
tails.

2-Testing Gas Piping

NOTE-In case emergency shutdown is required, turn off
the main manual shut‐off valve and disconnect the main
power to the unit. These controls should be properly la
beled by the installer.

When pressure testing gas lines, the gas valve must be dis
connected and isolated. Gas valves can be damaged if
subjected to more than 0.5 psig [14”W.C. (3481 Pa)]. See
figure 20.

When checking piping connection for gas leaks, use the
preferred means. Common kitchen detergents can
cause harmful corrosion on various metals used in gas
piping. The use of specialty Gas Leak Detector is strong
ly recommended. It is available as part number
31B2001. See CORP 8411-L10, for further details.

Do not use matches, candles, flame or any other source of
ignition to check for gas leaks.

3-Testing Gas Supply Pressure

When testing gas supply pressure, connect test gauge to the
inlet pressure tap locat e d on unit gas valve GV 1. Test sup
ply gas pressure with unit firing at maximum rate (both
stages energized). Make sure the reading falls within the
range of the following values. Low pressure may result in
erratic operation or “underfire.” High pressure can result in
permanent damage to the gas valve or “overfire.” For nat
ural gas units, operating pressure at the unit gas connec
tion must be between 4.7”W.C. and 10.5”W.C. (1168 Pa
and 2610 Pa). For L.P. gas units, operating pressure at
the unit gas connection must be between 10.8”W.C. and

13.5”W.C. (2685.3 Pa and 3356.7 Pa).

Page 27

On multiple unit installations, each unit should be checked
separately while operating at maximum rate, beginning with
the one closest to the supply gas main and pro g ressing to
the one furthest from the main. Multiple units should also
be tested with and without the other units operating.
Supply pressure must fall within the range listed in the
previous paragraph.

4-Check and Adjust Manifold Pressure

After line pressure has been checked and adjusted,
check manifold pressure. Move test gauge to the outlet
pressure tap located on unit gas valve GV1. See figure 17
for location of pressure tap on the gas valve.

The manifold pressure is factory set and should not re
quire adjustment. See table 12. If manifold pressure is incor
rect and no other source of improper manifold pressure can be
found, the valve must be replaced. See figure 17 or 18 for lo
cation of gas valve (manifold pressure) adjustment screw.

All gas valves are factory-regulated. The gas valve should
completely and immediately cycle off in the event of gas or
power failure. The manual shut‐off knob can be used to imme
diately shut off gas supply.

CAUTION

For safety, connect a shut‐off valve between the
manometer and the gas tap to permit shut off of

gas pressure to the manometer.

Manifold Adjustment Procedure

1- Connect test gauge to the outlet pressure tap on the

gas valve. Start the unit (call for second-stage heat)
and allow five minutes for the unit to reach steady
state.

2- While waiting for the unit to stabilize, notice the

flame. The flame should be stable without flashback
and should not lift from the burner heads. Natural
gas should burn basically blue with some clear
streaks. L.P. gas should burn mostly blue with some
clear yellow streaks.

3- After allowing the unit to stabilize for five minutes,

record the manifold pressure and compare to the val
ues given in table 3.

5-High Altitude

Units may be installed at altitudes up to 2000 feet (610 m)
above sea level without any modification. At altitudes
above 2000 feet (610 m), units must be derated to match
the gas manifold pressures shown in table 12.

NOTE ‐ This is the only permissible derate for these units.

TABLE 12

Gas Manifold Pressure

Altitude - ft. (m)

Natural LP (Propane)

0 - 2000 ( 610) 3.7 (0.92) 10.5 (2.61)

2001 - 3000 ( 610 - 915) 3.6 (0.90) 10.2 (2.54)

3001 - 4000 ( 915 - 1220) 3.5 (0.87) 9.9 (2.46)

4001 - 5000 (1220 - 1525) 3.4 (0.85) 9.6 (2.39)

5001 - 6000 (1525 - 1830) 3.3 (0.82) 9.4 (2.34)

6001 - 7000 (1830 - 2135) 3.2 (0.80) 9.1 (2.26)

7001 - 8000 (2135 - 2440) 3.1 (0.77) 8.8 (2.19)

*Contact Technical Support for altitudes higher than 8000 ft. (2400m).

in. w.g. (kPa)

IMPORTANT

Disconnect heating demand as soon as an

accurate reading has been obtained.

6-Proper Gas Flow

Furnace should operate at least 5 minutes before checking
gas flow. Determine time in seconds for two revolutions of
gas through the meter. (Two revolutions assures a more ac
curate time.) Divide by two and compare to time in table 13.
Seconds in table 13 are based on a 1 cu.ft. dial and gas val
ue of 1000 btu's for natural and 2500 btu's for LP. Adjust
manifold pressure on gas valve to match time needed.

NOTE - To obtain accurate reading, shut off all other gas
appliances connected to meter.

TABLE 13

Unit in Btu's

130,000 28 69

180,000 20 50

240,000 15 37

Seconds for

Natural

7-Heat Exchanger

To Access or Remove Heat Exchanger From Unit:
1- Turn off gas and electric power.
2- Remove access panel(s) and unit center mullion.
3- Remove gas valve, manifold assembly and burn

ers.

4- Remove combustion air inducer and flue box cover.

Pay careful attention to the order in which gaskets and
orifice are removed.

5- Support heat exchanger (to prevent it from falling

when final screws are removed.)
6- Remove screws supporting heat exchanger.
7- To install heat exchanger, reverse procedure. Be sure

to secure all wires and check plumbing and burner

plate for airtight seal. Screws must be torqued to 35

in.‐lbs. to ensure proper operation.

Seconds for

Propane

Page 28

8-Flame Sensing

Flame current is an electrical current which passes from the
ignition control through the sensor electrode during unit op
eration. The current passes from the sensor through the
flame to the ground electrode (located on the flame elec
trode) to complete a safety circuit. The electrodes should be
located so the tips are at least 1/2” (12.7 mm) inside the
flame envelope. Do not bend electrodes. To measure flame
current, follow the procedure on the following page:

NOTE - Electrodes are not field-adjustable. Any al
terations to the electrode may create a hazardous
condition that can cause property or personal injury.

1- Disconnect power to unit.

2- Remove lead from sensing electrode and install a

0-50DC microamp meter in series between the sens
ing electrode and the sensing lead.

3- Reconnect power and adjust thermostat for

heating demand.

4- When flame is established, microamp reading

should be 0.5 to 1.0. Do not bend electrodes.

Dropout signal is .09 or less.

5- Disconnect power to unit before disconnecting me ter.

Make sure sensor wire is securely reconnected
before reconnecting power to unit.

NOTE-If the meter scale reads 0, the leads are re
versed. Disconnect power and reconnect leads for
proper polarity.

B-Cooling System Service Checks

KGA units are factory-charged and require no further adjust
ment; however, charge should be checked periodically using
the approach method. The approach method compares actual
liquid temperature with the outdoor ambient temperature. See
section IV- CHARGING.

WARNING

Product contains fiberglass wool.
Disturbing the insulation in this product during
installation, maintenance, or repair will expose you
to fiberglass wool. Breathing this may cause lung
cancer. (Fiberglass wool is known to the State of Cali
fornia to cause cancer.)
Fiberglass wool may also cause respiratory, skin and
eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown on unit nameplate or
contact your supervisor.

IMPORTANT

The Clean Air Act of 1990 bans the intentional vent
ing of refrigerant (CFC's and HCFC's) as of July 1,

1992. Approved methods of recovery, recycling or re
claiming must be followed. Fines and/or incarcera
tion may be levied for non-compliance.

A-Filters

Units are equipped with four 20 X 25 X 2” filters. Filters
should be checked and replaced when necessary with fil
ters of like kind and size. Take note of air flow direction
marking on filter frame when reinstalling filters. See figure

21. Filters must be U.L.C. certified or equivalent for use in

Canada.

B-Lubrication

All motors are lubricated at the factory. No further lubrica
tion is required.

REMOVE FILTERS

NOTE - When unit is properly charged, discharge line pres
sures should approximate those in tables 7 through 10.

VI-MAINTENANCE

The unit should be inspected once a year by a qualified ser
vice technician.

!

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.

CAUTION

Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and dan
gerous operation. Verify proper operation after ser
vicing.

PULL TO
REMOVE

FILTERS

FIGURE 21

C-Evaporator Coil

Inspect and clean coil at beginning of each cooling season.
Clean using mild detergent or commercial coil cleanser.
Flush coil and condensate drain with water taking care not to
get insulation, filters and return air ducts wet.

Page 29

D-Burners

Periodically examine burner flames for proper appearance
during the heating season. Before each heating season, ex
amine the burners for any deposits or blockage which may
have occurred.

Clean burners as follows:

1- Turn off both electrical power and gas supply to unit.

2- Remove burner compartment access panel.

3- Remove two screws securing burners to burner sup

port and lift the burners from the orifices. See figure 11.
Clean as necessary.

4- Locate the ignitor under the left burners. Check ignitor

spark gap with appropriately sized twist drills or feeler
gauges. See figure 13.

5- Replace burners and screws securing gas manifold.

WARNING

Danger of explosion. Can cause injury or
death. Do not overtighten main burner
mounting screws. Snug tighten only.

7- Replace access panel.

8- Restore electrical power and gas supply. Follow light

ing instructions attached to unit and use inspection port
in access panel to check flame.

E-Combustion Air Inducer

A combustion air proving switch checks combustion air in
ducer operation before allowing heating sequence to con
tinue. The sequence will not be allowed to continue if induc
er is obstructed.

The combustion air inducer wheel should be checked and
cleaned prior to the heating season. It should be examined
periodically during the heating season to establish an ideal
cleaning schedule. With power supply disconnected, the
condition of the inducer wheel can be determined by re
moving the vent pipe and inspecting the wheel through the
outlet opening.

Clean combustion air inducer as follows:

CLEAN CONDENSER COIL

ENDPLATE IS SECURED

TOP VIEW

EVAPORATOR COIL

BLOWER

CONDENSER ACCESS PANEL

TO MULLION

CONDENSER

COILS

FIGURE 22

1- Shut off power supply and gas to unit.

2- Disconnect pressure switch air tubing from combustion

air inducer port.

3- Remove and retain screws securing combustion air in

ducer to flue box. Remove and retain two screws from
bracket supporting vent connector. See figure 10.

4- Clean inducer wheel blades with a small brush and

wipe off any dust from housing. Clean accumulated
dust from front of flue box cover.

5- Return combustion air inducer motor and vent connec

tor to original location and secure with retained screws.
It is recommended that the combustion air inducer gas
ket be replaced during reassembly.

6- Clean combustion air inlet louvers on heat access pan

el using a small brush.

F-Flue Passageway and Flue Box

1- Remove combustion air inducer assembly as de

scribed in section D.

2- Remove flue box cover. Clean with a wire brush as re

quired.
3- Clean tubes with a wire brush.
4- Reassemble the unit. The flue box cover gasket and

combustion air inducer gasket should also be replaced

during reassembly.

G-Condenser Coil

Clean condenser coil annually with detergent or commercial
coil cleaner and inspect monthly during the cooling season.

Condenser coils are made of one, two and three formed
slabs. Dirt and debris may become trapped between the
slabs. To clean between slabs, carefully separate coil slabs
and wash them thoroughly. See figure 22. Flush coils with
water following cleaning.

NOTE - Remove all screws and gaskets prior to cleaning
procedure and replace upon completion.

H-Supply Blower Wheel

Annually inspect supply air blower wheel for accumulated
dirt or dust. Turn off power before attempting to remove ac
cess panel or to clean blower wheel.

1- Remove unit top panel and condenser section access

panel.

2- Remove screws securing coil end plate to mullion.

3- Remove clips connecting coils slabs and separate

slabs 3-4” (76-102mm).

4- Clean coils with detergent or commercial coil cleaner.

5- Rinse thoroughly with water and reassemble

.

Page 30

VII-ACCESSORIES

The accessories section describes the application of most of
the optional accessories which can be factory- or field-installed
in or on the KGA units. OPTIONAL ACCESSORIES section
(see table of contents) shows specific sizes per unit.

TYPICAL FLASHING DETAIL

UNIT BASE

BOTTOM

UNIT BASE RAIL

A-LARMF Mounting Frames

When installing units on a combustible surface for downflow
discharge applications, the Lennox C1CURB roof mounting
frame is used. The roof mounting frames are recommended
in all other applications but not required. If the KGA units are
not installed on a flat (roof) surface, they MUST be support
ed under all edges and under the middle of the unit to pre
vent sagging. The units MUST be installed level within 1/16”
per linear foot or 5mm per meter in any direction.

The assembled C1CURB mounting frame is shown in fig
ure 23. Refer to the roof mounting frame installation instruc
tions for details of proper assembly and installation. The
roof mounting frame MUST be squared to the roof and level
before installation. Plenum system MUST be installed be
fore the unit is set on the mounting frame. Typical roof curb
ing and flashing is shown in figure 24. Refer to the roof
mounting frame installation instructions for proper plenum
construction and attachment.

ASSEMBLED ROOF MOUNTING FRAME

SUPPLY AIR

OPENING

RETURN AIR

OPENING

FIBERGLASS

INSULATION

(Furnished)

COUNTER FLASHING

NAILER STRIP

(Furnished)

RIGID INSULATION

(Field Supplied)

ROOF

MOUNTING FRAME

(Extends around entire

perimeter of unit)

(Field Supplied)

CANT STRIP

(Field Supplied)

ROOFING

MATERIAL

FIGURE 24

B-Transitions

Optional supply/return transition LASRT08/10 is available
for use with the KGA 7.5 ton units and LASRT10/12 is avail
able for the 8.5 and 10 ton units, utilizing optional C1CURB
roof mounting frames. KGA 12.5 ton units will use LAS
RT15 with C1CURB roof mounting frame. Transition must
be installed in the C1CURB mounting frame before setting
the unit on the frame. Refer to the manufacturer's instruc
tions included with the transition for detailed installation
procedures.

C-Supply and Return Diffusers

Optional flush-mount diffuser/return FD11 and extended
mount diffuser/return RTD11 are available for use with all KGA
units. Refer to manufacturer's ins t r uction s in c l uded with
transition for detailed installation procedures.

FIGURE 23

D-LAOAD(M) Outdoor Air Dampers

Field- or Factory-Installed

Optional manual and motorized outdoor air dampers pro
vide up to 25 percent fresh air for return. Motorized damper
opens to minimum position simultaneously with the blower
during the occupied period and remains closed during the
unoccupied period. Manual damper assembly is manually
operated; damper position is manually set at installation
and remains in that position.

Page 31

HORIZONTAL

SUPPLY AIR

OPENING

LAOAD(M) MOTORIZED OUTDOOR AIR DAMPER

MOTORIZED

DAMPER

COVER PANEL

HORIZONTAL

SUPPLY AIR

OPENING

HORIZONTAL

RETURN AIR

OPENING

MANUAL OUTDOOR AIR DAMPER

COMPRESSOR

SECTION

LOWER PANEL

COVER PANEL

MANUAL DAMPER

HORIZONTAL

RETURN AIR

OPENING

COMPRESSOR

SECTION

LOWER PANEL

FIGURE 25

Page 32

ECONOMIZER

ECONOMIZER

FIGURE 26

E-K1ECON20B Economizer

(Field- or Factory-Installed)

Economizers use outdoor air for free cooling when temper
ature and/or humidity is suitable. See figure 26.

The mixed air temperature sensor (R1) measures the sup
ply air sensible temperature. See figure 27. The outdoor air
sensible control is the default economizer control. An out
door air single sensible sensor, S175, is also provided. See
table 14 for outdoor and return air (OA and RA) sensor op
tions. Refer to instructions provided with sensors for instal
lation.

An IAQ sensor is used when demand control ventilation
(DCV) is specified. Damper minimum position can be set
lower than traditional minimum air requirements resulting in
cost savings. The IAQ sensor allows the A6 to open
dampers to traditional ventilation requirements as room oc
cupancy (CO

2

Sensors

) increases.

TABLE 14

Dampers will modulate to 55°F

discharge air (RT6) when:

ACCESSORY

PANEL MULLION

DIVIDER PANEL
(Attach with two

provided screws)

BOTTOM OF

COMPRESSOR

SECTION

FLANGED

RETURN AIR

OPENING

MIXED AIR SENSOR (R1) LOCATION

R1 MIXED

AIR SENSOR

Single OA Sensible

Single OA Sensible

Differential Enthalpy ­1 in OA and 1 in RA

IAQ Sensor

OA temperature (S175) is lower
than free cooling setpoint.

OA temperature and humidity (A7)
is lower than free cooling setpoint.

OA temperature and humidity (A7)
is lower than RA temperature and
humidity (A62).

CO2 sensed (A63 ) is higher than

setpoint.

CO

2

FIGURE 27

Page 33

A6 Enthalpy Control LEDs

A steady green Free Cool LED indicates that outdoor air is
suitable for free cooling.

When an optional IAQ sensor is installed, a steady green
DCV LED indicates that the IAQ reading is higher than set
point requiring more fresh air. See figure 28.

A6 ENTHALPY CONTROLLER

EXH

Set

2V 10V

EXH

Min

Pos

Open

DCV

Max

2V 10V

DCV

DCV

Set

2V 10V

Free
Cool

C

B

A

D

FREE COOLING SETPOINT;

A=Completely counterclockwise

D=Completely clockwise

DAMPER

MINIMUM

POSITION

IAQ MAXIMUM

POSITION

(set higher than

minimum position)

IAQ READING IS

ABOVE SETPOINT

IAQ SETPOINT

OUTDOOR AIR

SUITABLE LED

FIGURE 28

ENTHALPY CONTROL SETPOINTS

TABLE 15

Control Setting Free Cooling Setpoint At 50% RH

A

B

C

D

73° F (23° C)

70° F (21° C)

67° F (19° C)

63° F (17° C)

Damper Minimum Position

NOTE - A jumper is factory-installed between TB1 R and
OC terminals to maintain occupied status (allowing mini
mum fresh air). When using an electronic thermostat or
energy management system with an occupied/unoccu
pied feature, remove jumper.

1- Set thermostat to occupied mode if the feature is avail

able. Make sure jumper is in place between TB1 termi

nals R and OC if using a thermostat which does not

have the feature.

2- Rotate MIN POS SET potentiometer to approximate

desired fresh air percentage.

NOTE - Damper minimum position can be set lower than
traditional minimum air requirements when an IAQ sensor
is specified. Dampers will open to DCV MAX setting (if CO2
is above setpoint) to meet traditional ventilation require
ments.

3- Measure outdoor air temperature. Mark the point on

the bottom line of chart 1 and label the point “A” (40_F,

4_C shown).

4- Measure return air temperature. Mark that point on the

top line of chart 1 and label the point “B” (74_F, 2 3 _C

shown).

Free Cooling Setpoint

Outdoor air is considered suitable when temperature and
humidity are less than the free cooling setpoints shown in
table 15. Setting A is recommended. See figure 28. At set
ting A, free cooling will be energized when outdoor air is ap
proximately 73°F (23°C) and 50% relative humidity. If in
door air is too warm or humid, lower the setpoint to B. At
setting B, free cooling will be energized at 70°F (21°C) and
50% relative humidity.

When an optional A62 differential sensor is installed, turn
A6 enthalpy control free cooling setpoint potentiometer
completely clockwise to position “D”.

5- Measure mixed air (outdoor and return air) tempera

ture. Mark that point on the top line of chart 1 and label

point “C” (70_F, 21_C shown).

6- Draw a straight line between points A and B.

7- Draw a vertical line through point C.

8- Draw a horizontal line where the two lines meet. Read

the percent of fresh air intake on the side.

9- If fresh air percentage is less than desired, adjust MIN

POS SET potentiometer higher. If fresh air percentage

is more than desired, adjust MIN POS SET poten

tiometer lower. Repeat steps 3 through 8 until calcula

tion reads desired fresh air percentage.

Page 34

_F

_C

10

CHART 1

CALCULATE MINIMUM FRESH AIR PERCENTAGE

MIXED AND RETURN AIR TEMPERATURE

-20

-10

-29

-230-1810-1220-730-140450106016702180279032

0

100

_F

38

_C

BC

0

10

20

30

40

50

60

70

80

90

2

A

ris

100

_F

38

_C

Outdoor Air Not Suitable:

During the unoccupied time period dampers are closed.

During the occupied time period a cooling demand will open
dampers to minimum position and mechanical cooling
functions normally.

During the occupied time period dampers will open to DCV
MAX when IAQ reading is above setpoint (regardless of
thermostat demand or outdoor air suitability).

Outdoor Air Suitable:
See table 16 for economizer operation with a standard two­stage thermostat.
During the occupied period, dampers will open to DCV
MAX when IAQ reading is above setpoint (regardless of
thermostat demand or outdoor air suitability). DCV MAX will

100

-20

_F

_C

-10

-29

-230-1810-1220-730-140450106016702180279032

OUTDOOR AIR TEMPERATURE

DCV Set and Max Settings

Adjust settings when an optional IAQ sensor is installed.

The DCV SET potentiometer is factory-set at approxi
mately 50% of the potentiometer range. Using a standard
1-2000ppm CO

sensor, dampers will start to open when

2

the IAQ sensor reads approximately 1000ppm. Adjust
the DCV SET potentiometer to the approximate setting
specified by the controls contractor. Refer to figure 28.

The DCV MAX potentiometer is factory-set at approxi
mately 50% of the potentiometer range or 6VDC.
Dampers will open approximately halfway when CO
es above setpoint. Adjust the DCV MAX potentiometer to
the approximate setting specified by the controls con
tractor. Refer to figure 28.

NOT override damper fully open position. When an R1

NOTE - DCV Max must be set higher than economizer mini
mum position setting for proper demand control ventilation.

Economizer Operation

mixed air sensor for modulating dampers is installed, DCV
MAX may override damper free cooling position when oc
cupancy is high and outdoor air temperatures are low. If R1
senses discharge air temperature below 45_F (7_C),

The occupied time period is determined by the thermostat
or energy management system.

dampers will move to minimum position until discharge air
temperature rises to 48_F (9_C).

TABLE 16

ECONOMIZER OPERATION - OUTDOOR AIR IS SUITABLE FOR FREE COOLING -- FREE COOL LED “ON”

THERMOSTAT DEMAND

OFF

G

Y1

Y2

UNOCCUPIED

CLOSED

CLOSED

OPEN*

OPEN*

DAMPER POSITION

OCCUPIED

CLOSED

MINIMUM

OPEN*

OPEN*

* Dampers will open to maintain 55°F (13°C) supply air when an R1 mixed air sensor is installed.

20

30

40

50

60

70

80

90

100

MECHANICAL COOLING

NO

NO

NO

STAGE 1

Page 35

B-Outdoor Air Dampers

Optional manual and motorized outdoor air dampers pro
vide fresh outdoor air. The motorized damper assembly
opens to minimum position during the occupied time peri
od and remains closed during the unoccupied period.
Manual damper assembly is set at installation and re
mains in that position.

Set damper minimum position in the same manner as
economizer minimum position. Adjust motorized damper
position using the thumbwheel on the damper motor. See
figure 29. Manual damper fresh air intake percentage can
be determined in the same manner.

DAMPER MOTOR

THUMBWHEEL

F-Gravity Exhaust Dampers

Dampers are used in downflow (see figure 30) and horizon
tal (see figure 31) air discharge applications. Horizontal
gravity exhaust dampers are installed in the return air duct.
The dampers must be used any time an economizer and a
power exhaust fan is applied to KGA series units.

Gravity exhaust dampers allow exhaust air to be dis
charged from the system when an economizer and/or pow
er exhaust is operating. Gravity exhaust dampers also pre
vent outdoor air infiltration during unit off cycle. See
installation instructions for more detail.

NOTE - GED is optional except when used with power
exhaust dampers, where it is required..

GRAVITY EXHAUST DAMPERS - DOWNFLOW

FIGURE 29

GRAVITY EXHAUST DAMPERS - HORIZONTAL

RETURN AIR PLENUM

29-1/2

(749)

13

(330)

HOOD TOP

HOOD TOP
SUPPORT

FIGURE 30

DAMPER

ASSEMBLY

6-1/2

(165)

FIGURE 31

Page 36

G-Power Exhaust Fan

The power exhaust fan (PEF) requires the use of a gravity
exhaust damper and economizer and is used in downflow
applications only. See figure 32. The PEF provides exhaust
air pressure relief and also runs when return air dampers
are closed and the supply air blower is operating. See in
stallation instructions for more detail.

GED AND PEF INSTALLATION

GED GRAVITY

EXHAUST
DAMPERS

P18

PEF POWER

EXHAUST FAN ASSEMBLY

(ORDERED SEPARATELY)

FIGURE 32

Power Exhaust Setpoint Adjustment

Locate the A6 enthalpy control in the control area. The EXH
SET potentiometer is factory-set at approximately 50% of
the dial range. See figure 33. Power exhaust fans will be en
ergized 30 seconds after dampers are 50% open. Adjust the
EXH SET potentiometer higher (clockwise toward 10V) to
energize fans when dampers are further open. Adjust the
EXH SET potentiometer lower (counterclockwise toward
2V) to energize fans when dampers are further closed. (Thir
ty-second delay allows dampers to partially open before ex
haust fan starts.)

H-Optional Cold Weather Kit (Canada only)

Electric heater is available to automatically control the
minimum temperature in the gas burner compartment.
Heater is ETL/CSA certified to allow cold weather opera
tion of unit down to ‐60° F (‐50° C ).

The kit includes the following parts:

1- Transformer (T20) is a 600V to 120/240V step-down trans

former mounted in the blower compartment.

2- T20 has two in line fuses (F20), one on each leg of the trans

former. Both are rated at 15 amps.

3- The strip heater (HR6) is located as close as possible to the

gas valve. It is wired in series with T20. The strip heater is
rated at 500 Watts

4- A thermostat mounting box is installed on the

vestibule of the heating compartment. Included in the
box are the following thermostat switches:

A6 ENTHALPY CONTROLLER

EXH

Set

2V 10V

EXH

2V 10V

DCV

2V 10V

Free
Cool

B

A

Open

DCV

Max

DCV

Set

C

D

ADJUST POWER

EXHAUST FAN

Min

Pos

ENERGIZED WHEN

DAMPER POSITION

SETPOINT

IS HIGHER THAN

EXHAUST FAN

SETPOINT

FIGURE 33

a - Thermostat switch (S59) is an auto‐reset SPST N.C.

switch which opens on a temperature drop. The
switch is wired in series with 24V power and the com
bustion air blower switch. When the temperature
drops below ‐30° F (-35° C) the switch opens and the
gas heat section is de‐energized. The switch automati
cally resets when the heating compartment tempera
ture reaches -10° F (-12° C).

b - Thermostat switch (S60) is an auto‐reset SPST

N.C. switch which opens on a temperature rise.
The switch is wired in series with HR6 and T20.
When the temperature rises above 20° F (‐7° C) the
switch opens and the electric heater is de‐energized.
The switch automatically resets when the heating
compartment temperature reaches ‐10° F (23.3° C).

c -Thermostat switch (S61) is an auto‐reset SPST

N.O. switch which closes on a temperature drop.
The switch is wired in series with HR6 and T20.
When temperature drops below 20° F (‐7° C) the
switch closes and electric heater is energized.
The switch automatically opens when heating
compartment temperature reaches 76° F (24° C).

I-Control Systems

Three different types of control systems may be used with
the KGA series units. All thermostat wiring is connected to
TB1 located in the control area. Each thermostat has addi
tional control options available. See thermostat installation
instructions for more detail.

1- Electro‐mechanical thermostat (13F06)

The electro‐mechanical thermostat is a two stage heat /
two stage cool thermostat with dual temperature lever s.
A non‐switching or manual system switch subbase
may be used.

Page 37

2- Electronic thermostat

Any two stage heat / two stage cool electronic ther
mostat may be used.

3- Honeywell T7300 thermostat (60L59)

The Honeywell T7300 thermostat is a programmable, in
ternal or optional remote temperature sensing thermo
stat. The T7300 provides occupied and unoccupied
changeover control.

J-Smoke Detectors A171 and A172

Photoelectric smoke detectors are a field-installed option.
The smoke detectors can be installed in the supply air sec
tion (A172), return air section (A171), or in both the supply
and return air sections.

K-LP / Propane Kit

KGA092/150 units require a natural to LP /propane kit.
The kit includes one LP spring conversion kit, up to eleven
burner orifices and three stickers. For more detail refer to the
natural to LP gas changeover kit installation instructions.

L-Drain Pan Overflow Switch S149 (optional)

The overflow switch is used to interrupt cooling operation
when excessive condensate collects in the drain pan. The
N.O. overflow switch is controlled by K220 and DL46 re
lays, located in the unit control panel. When the overflow
switch closes, 24VAC power is interrupted and after a five­second delay unit compressors are de-energized. Once
the condensate level drops below the set level, the switch
will open. After a five-minute delay the compressor will be
energized.

Page 38

VIII-Wiring Diagrams and Sequence of Operation

WHITE

BLACK

460V - 575V

UNITS

J11

H

120/

N

GROUND

P86

P132

P250

P251

P252

P253

P255

S3

S4

S5

S7

S8

S11

S30

S42

S48

S49

S50

S84

S149

T1

L1

T18

L2

60/

1

A

K220

220-240V

2

1

B

NOTE - IF ANY WIRE IN THIS APPLIANCEIS REPLACEDIT MUST BE
REPLACEDWITH WIRE OF LIKE SIZE, RATING, TERMINATION AND

INSULATION THICKNESS

WARNING - ELECTRIC SHOCK HAZARD, CAN CAUSE INJURY ORDEATH
UNIT MUST BE GROUNDEDIN ACCORDANCEWITH NATIONAL AND
LOCAL CODES

DISCONNECT ALL POWER BEFORE SERVICING.

L3

K2-1

T3

B2

B3

HR2

7

PLUG, OUTDOOR FANS 1

PLUG, EXHAUST FAN MOTOR 1

JACK, SMOKE DETECTOR ONE

JACK, SMOKE DETECTOR ONE

JACK, SMOKE DETECTOR TWO

JACK, SMOKE DETECTOR TWO

PLUG, MODULE, CONTROL SMOKE DETECTION

SWITCH, LIMIT LOW COMPRESSOR 1

SWITCH, LIMIT HI PRESS COMP 1

SWITCH, LIMIT HI TEMP COMPRESSOR 1

SWITCH, LIMIT HI PRESS COMP 2

SWITCH, LIMIT HI TEMP COMPRESSOR 2

SWITCH, LOW PRESS, LOW AMBIENT KIT

SWITCH, LIMIT

SWITCH, OVERLOAD RELA

SWITCH, DISCONNECT

SWITCH, FREEZESTAT COMP 1

SWITCH, FREEZESTAT COMP 2

SWITCH, LOW PRESS, LOW AMBIENT KIT COMP 2

SWITCH, OVERFLOW

TRANSFORMER, CONTROL

LOW COMPRESSOR 2

Y BLOWER MOTOR

KGA092/150 UNIT DIAGRAM

TO
L1

TO

380-420V

N

UNITS

P2 IS USED ON KCA UNITS ONLY

IMPORTANT: TO PREVENTMOTORBURNOUT, NEVER

CONNECTMORETHAN ONEMOTORLEADTO ANY ONE
CONNECTION. TAPE UNUSED MOTOR LEADS

S42 USEDON ”M” VOLTAGEUNITS AND UNITS
WITH HIGH EFFICIENCY MOTORS

CONNECT A172 SENSOR TO J2 61 ON SUPPLY AIR
SMOKE DETECTOR ONLY

S48 OR CB10 MAY BE USED

JUMPER WHEN S11 AND S84 ARE NOT USED

3

24V POWER

ECONOMIZER

BLOWER(G)

HEAT 1(W1)

HEAT 2(W2)

DESCRIPTION

KEY COMPONENT

MONITOR, PHASE PROTECTION

A42

MODULE, VOLTAGE REDUCTION

5

6

8

A

2

B

L3

T3

A

K3

HR1

K10

B

L3

T3

7

9

K10-2

6

A

B

K2

7

K65-1

4

2 3

A

K1

B

6

5

321

321

B4

DENOTES OPTIONAL COMPONENTS
LINE VOLTAGE FIELD INSTALLED

B5

A144

SENSOR ONE, SMOKE, RETURN AIR

A171

SENSOR TWO, SMOKE, SUPPLY AIR

A172

MODULE, CONTROL SMOKE DETECTION

A173

B1 COMPRESSOR 1

COMPRESSOR 2

B2

MOTOR, BLOWER

B3

MOTOR, OUTDOOR FAN 1

B4

MOTOR, OUTDOOR FAN 2

B5

MOTOR, EXHAUST FAN 1

B10

CAPACITOR, OUTDOOR FAN 1

C1

CAPACITOR, OUTDOOR FAN 2

C2

CAPACITOR, EXHAUST FAN 1

C6

CIRCUIT, BREAKER T1

CB8

DELAY, OVERFLOW SWITCH

DL46

HR1 HEATER COMPRESSOR 1

HEATER COMPRESSOR 2

HR2

JACK, HEAT

J2

JACK, GFI, RECEPTICLE

J11

JACK, EXHAUST FAN COMPT

J18

JACK, EXHAUST FAN

J24

JACK, TEST

J35

JACK, TEST COOL

J36

9

K65-2

6

4

JACK, OUTDOOR FANS 1

J86

JACK, BLOWER , EXHAUST FAN MOTOR 1

J132

JACK, SMOKE DETECTOR ONE

J250

JACK, SMOKE DETECTOR ONE

J251

JACK, SMOKE DETECTOR TWO

J252

JACK, SMOKE DETECTOR TWO

J253

JACK, MODULE, CONTROL SMOKE DETECTION

J255

JACK, SMOKE DETECTOR JUMPER

J261

K1,-1 CONTACTOR, COMPRESSOR 1

K2,-1 CONTACTOR, COMPRESSOR 2

K3, -1 CONTACTOR, BLOWER

K10,-1,2 RELAY, OUTDOOR FAN

K65-1,2 RELAY, EXHAUST FAN

K220, -1 RELAY, OVERFLOW DELAY

JACK, HEAT

P2

PLUG, EXHAUST FAN COMPT

P18

PLUG, EXHAUST FAN

P24

JACK, TEST

P35

PLUG, TEST COOL

P36

COOL 1(Y1)

COOL 2 (Y2)

24V COMMON

COOLING

REV. 0.0

Lennox Commercial

Page 39

KGA092/150 Sequence of Operation

Power:

1- Line voltage from unit disconnect energizes trans

former T1. T1 provides 24VAC power to terminal strip
TB1. TB1 provides 24VAC to the unit cooling, heating
and blower controls.

Blower Operation:

2- Indoor thermostat terminal G energizes blower contac

tor K3 with 24VAC. N.O. K3 closes, energizing blower
B3.

Economizer Operation:

3- The economizer control module receives a demand

and energizes exhaust fan relay K65 with 24VAC at
50% outside air damper open (adjustable).

4- N.O. K65-1 and N.O. K65-2 both close, energizing ex

haust fan motor B10.

1st Stage Cooling (compressor B1)

5- First stage cooling demand Y1 and G are energized by

the thermostat. G energizes blower. 24VAC is routed
through TB1 passing N.C. freezestat S49 and optional
N.C. high pressure switch S4. Compressor contactor
K1 is energized. N.O. contacts K1 close energizing
compressor B1.

6- Optional N.O. low ambient switch S11 closes to ener

gize condenser fan relay K10. N.O. contacts K10-1 and
K10-2 close energizing condenser fans B4 and B5.
N.C. contacts K10-1 open de-energizing crankcase
heaters HR1 and HR2.

2nd Stage Cooling (compressor B2 is energized)

7- 24VAC is routed through TB1 and proves N.C. freezes

tat S50 and optional N.C. high pressure switch S7.
Compressor contactor K2 is energized. N.O. K2 con
tacts close energizing compressor B2.

8- Optional N.O. low ambient switch S84 closes to ener

gizing condenser fan relay K10. N.O. contacts K10-1
and K10-2 close energizing condenser fans B4 and B5.
N.C. contacts K10-1 open de-energizing crankcase
heaters HR1 and HR2.

Page 40

GAS HEAT FOR KGA092/150 UNITS

1

11

7 9

13

2

4

8

5

10 12

13

Page 41

3

GAS HEAT SEQUENCE OF OPERATION

First Stage Heat:

1- The thermostat initiates W1 heating demand.

2- 24VAC is routed from TB1 to ignition control A3

through P2. A3 proves N.C. primary limit S10 and N.C.
rollout switch S47.

3- Combustion air inducer blower B6 is energized.

4- After the combustion air inducer B6 has reached full

speed, the combustion air proving switch S18 con
tacts close.

5- After a 30 second delay, A3 energizes the ignitor and

LO terminal (low fire) of gas valve GV1.

Second Stage Heat:

6- With first stage heat operating, an additional heating

demand from the thermostat initiates W2.

7- A second stage heating demand is received by TB1.

The second stage heat signal passes from TB1 to A3.

8- A3 energizes HI terminal (high fire) of gas valve GV1.

End of Second Stage Heat:

9- Heating demand is satisfied. Terminal W2

(high fire) is de-energized.

10- Terminal HI of GV1 is de-energized by A3

control module.

End of First Stage Heat:

11- Heating demand is satisfied. Terminal W1

(low fire) is de-energized.

12- Ignition A3 is de-energized in turn de-ener

gizing terminal LO of GV1.

Optional Low Ambient Kit:
(ETL/CSA -50° C Low Ambient Kit)

13- Line voltage is routed through the N.C. low

ambient kit thermostats S60 and S61.
K125 relay is energized closing N.O.
K125-1 contacts and energizing the low
ambient kit heater HR6.

Page 42

ELECTRONIC OR ELECTROMECHANICAL THERMOSTAT

24V POWER

ECONOMIZER

BLOWER(G)

HEAT 1(W1)

HEAT 2(W2)

COOL 1(Y1)

COOL 2(Y2)

A

k65

B

24V COMMON

24V POWER

COOL 1 (Y1)

COOL 2 (Y2)

24V COMMON

CONNECTION SCHEME FOR KCA, KGA AND KHA
092 THROUGH 150 UNITS WITHOUT

ECONOMIZER ONLY

KEY COMPONENT

SENSOR, ELECTRONIC THERMOSTAT

A2

SENSOR, CO2

A63

CLOCK, TIME

CMC3

JACK, UNIT ECONOMIZER

J3

RELAY, EXHAUST FAN

K65

PLUG, ECONOMIZER BYPASS

P3

SENSOR, MIXED AIR OR SUPPLY AIR

R1

SENSOR, REMOTE THERMOSTAT

RT2

TERMINAL STRIP, CLASS II VOLTAGE

TB1

REMOVEP3 WHENECONOMIZERIS USED, ONLYON KCA,
KGA AND KHA 180 THROUGH 300 UNITS.

TOUCHSCREEN THERMOSTAT

DESCRIPTION

ACCESSORIES

POWER:

1- Terminal strip TB1 energizes thermostat components with 24VAC.

OPERATION:

2- TB1 receives data from the electronic thermostat A2 (Y1, Y2, W1, W2, G, OCP). The 24VAC signal from TB1 ener

gizes the appropriate components for heat or cool demand.

REV. 2.0

Lennox Commercial

Page 43

ECONOMIZER

SEQUENCE OF OPERATION

POWER:

1- Terminal strip TB1 energizes the economizer components with 24VAC.

OPERATION:

2- Enthalpy sensor A7 and A62 (if differential enthalpy is used) communicates to the economizer control

module A6 when to power the damper motor B7.

3- Economizer control module A6 supplies B7 with 0 - 10 VDC to control the positioning of economizer.

4- The damper actuator provides 2 to 10 VDC position feedback.

Page 44