Lennox Commercial KG 180 Air Hood Instruction Manual

: June 15, 2024
: Lennox Commercial

Table of Contents

Lennox Commercial KG 180 Air Hood
Safety
Connect Gas Piping
High Altitude Derate
Pressure Test Gas Piping
Two-Stage Gas Valve Adjustment
Gas Heat Operation
Typical Gas Heat Schematic
Typical Unit Schematic
Repair Parts Listing
Read User Manual Online (PDF format)
Download This Manual (PDF format)

Lennox Commercial KG 180 Air Hood

Product Information

The product is a packaged gas unit with the model number KG 024-300. It is designed for heating and cooling purposes and has a capacity range of 2 to 25 tons. The unit is certified for installation on noncombustible floors, but it can also be installed on wood flooring or on class A, class B, or class C material-covered floors when used in specific discharge applications or when mounted on a LARMF roof mounting frame. The unit is ETL/CSA certified for outdoor installations only, and the clearances to combustible materials are specified on the unit nameplate and in Figure 1, Figure 2, and Figure 3.

Product Usage Instructions

Before proceeding with the installation or service of the product, it is important to read and understand the safety instructions provided in the user manual. Improper installation, adjustment, alteration, service, or maintenance can result in property damage, personal injury, or even loss of life. Therefore, it is recommended to have a licensed professional HVAC installer or equivalent, service agency, or gas supplier perform the installation and service.

When installing the unit, make sure to provide adequate clearance around air openings into the vestibule area. This is necessary for proper operation and for the supply of combustion air and ventilation air. Additionally, adjust the unit for the temperature rise range and ensure that it operates within the allowable external static pressure, as indicated on the unit nameplate.

If installing the unit in the United States, note that it is certified for outdoor installations only. The clearances to combustible materials specified on the unit nameplate and in Figure 1, Figure 2, and Figure 3 must be followed.Depending on the model of the unit, different clearances are required. Refer to the appropriate figure (Figure 1, Figure 2, or Figure 3) for the specific clearance requirements for your model. It is important to provide support to the entire perimeter of the unit base when elevated above the mounting surface. This ensures stability and proper functioning of the unit.For any maintenance or service activities, a service clearance is required to allow for the removal of serviceable parts. The clearance to combustible materials must also be maintained to prevent any fire hazards. Furthermore, a minimum operation clearance is necessary for the unit to operate properly.

Retain these instructions for future reference in case of any troubleshooting or further queries.

Safety

WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Installation and service must be performed by a licensed professional HVAC installer or equivalent, service agency, or the gas supplier.
Use of this unit as a construction heater or air conditioner is not recommended during any phase of construction. Very low return air temperatures, harmful vapors and operation of the unit with clogged or misplaced filters will damage the unit.
If this unit has been used for heating or cooling of buildings or structures under construction, the following conditions must be met or the warranty will be void:

The vent hood must be installed per these installation instructions.
A room thermostat must control the unit. The use of fixed jumpers that will provide continuous heating or Bcooling is not allowed
A pre-filter must be installed at the entry to the return air duct.
The return air duct must be provided and sealed to the unit.
Return air temperature range between 55°F (13°C) and 80°F (27°C) must be maintained.
Air filters must be replaced and pre-filter must be removed upon construction completion.
The input rate and temperature rise must be set per the unit rating plate.
The heat exchanger, components, duct system, air filters and evaporator coil must be thoroughly cleaned following final construction clean-up.
The unit operating conditions (including airflow, cooling operation, ignition, input rate, temperature rise and venting) must be verified according to these installation instructions.
NOTE – The Commonwealth of Massachusetts stipulates these additional requirements:
Gas units shall be installed by a licensed plumber or gas fitter only.
The gas cock must be “T handle” type.

The unit is certified for installation on noncombustible floors only. However, it may be installed on wood flooring, or on class A, class B, or class C material-covered floors when used in horizontal discharge applications or in downflow discharge applications when mounted on a LARMF roof mounting frame.
Adequate clearance shall be provided around air openings in the vestibule area. Provisions shall be made for proper operation and for combustion air and ventilation air supply. Unit must be adjusted for the temperature rise range and within the allowable external static pressure on furnaces with a duct system as listed on the unit nameplate.

United States
The unit is ETL/CSA certified for outdoor installations only at the clearances to combustible materials listed on the unit nameplate and in Figure 1, Figure 2 and Figure 3.

1Unit

Clearance

| A

in.(mm)

| B

in.(mm)

| C

in.(mm)

| D

in.(mm)

| Top Clear- ance
---|---|---|---|---|---
Service Clearance| 48

(1219)

| 36 (914)| 36 (914)| 36 (914)| Unobstructed
Clearance to Combustibles| 36 (914)| 1 (25)| 1 (25)| 1 (25)| Unobstructed
Minimum Operation Clearance| 36 (914)| 36 (914)| 36 (914)| 36 (914)| Unobstructed

Note

The entire perimeter of the unit base requires support when elevated above the mounting surface.
1 Service Clearance – Required for removal of serviceable parts.
Clearance to Combustibles – Required clearance to combustible material.
Minimum Operation Clearance – Required clearance for proper unit operation.

1Unit

Clearance

| A

in.(mm)

| B

in.(mm)

| C

in.(mm)

| D

in.(mm)

| Top Clear- ance
---|---|---|---|---|---
Service Clearance| 60

(1524)

| 36 (914)| 36 (914)| 60

(1524)

| Unobstructed
Clearance to Combustibles| 36 (914)| 1 (25)| 1 (25)| 1 (25)| Unobstructed
Minimum Operation Clearance| 36 (914)| 36 (914)| 36 (914)| 36 (914)| Unobstructed

Note

The entire perimeter of the unit base requires support when elevated above the mounting surface.
1 Service Clearance – Required for removal of serviceable parts.
Clearance to Combustibles – Required clearance to combustible material.
Minimum Operation Clearance – Required clearance for proper unit operation.

1Unit

Clearance

| A

in.(mm)

| B

in.(mm)

| C

in.(mm)

| D

in.(mm)

| Top Clearance
---|---|---|---|---|---
Service Clearance| 60

(1524)

| 36 (914)| 36 (914)| 66

(1676)

| Unobstructed
Clearance to Combustibles| 36 (914)| 1 (25)| 1 (25)| 1 (25)| Unobstructed
Minimum Operation Clearance| 45

(1143)

| 36 (914)| 36 (914)| 41

(1041)

| Unobstructed

Note

The entire perimeter of the unit base requires support when elevated above the mounting surface.
1 Service Clearance – Required for removal of serviceable parts.
Clearance to Combustibles – Required clearance to combustible material.
Minimum Operation Clearance – Required clearance for proper unit operation.

Installation of the ETL/CSA-certified units must conform with local building codes. In the absence of local codes, units must be installed according to the current National Fuel Gas Code ANSI Z223.1/NFPA 54. When installed, the unit must be electrically wired and grounded according to local codes or, in the absence of local codes, with the current National Electric Code, ANSI/ NFPA 70.
The current American National Standard (ANSIZ233.1/ NFPA54) National Fuel Gas Code is available from the following address:

American National Standard Institute Inc.
11 West 42nd Street New York, NY 10036

The current National Electric Code (ANSI/NFPA 70) is available from the following address:

National Fire Protection Association
1 Batterymarch Park PO Box 9101
Quincy, MA 02269-9101 Use only the type of gas approved for use with this furnace. Refer to the unit nameplate. Never test for gas leaks with an open flame. Check all connections with a commercially available soap solution made specifically for leak detection.

NOTE – The furnace must be adjusted to obtain a temperature rise (high and low fire) within the range(s) specified on the unit nameplate. Failure to do so may cause erratic limit operation.

The unit is CSA International (CSA) certified for combination heating/cooling for outdoor installations and non-residential use only at the clearances to combustible materials as listed on the unit nameplate.
Installation of CSA international certified units must conform with current standard CSA B149.1, “Natural Gas and Propane Installation Codes” and applicable local codes. Authorities having jurisdiction should be consulted before installation.
The unit must be wired and electrically grounded according to local codes or, in the absence of local codes, current CSA Standard C22.1 Canadian Electrical Code Part 1. Installation of combination heating/cooling units must also conform with the current CSA Standard B52 “Mechanical Refrigeration Code.”

Connect Gas Piping

A manual main shut-off valve must be installed external to the unit when local codes require the installation of such a valve.
Install a ground joint union between the gas control manifold and the main manual shut-off valve. When making piping connections a drip leg should be installed on vertical pipe runs to serve as a trap for sediment or condensate.
A 1/8” N.P.T. plugged tap is located on gas valve for test gauge connection. See Figure 4, Figure 5, Figure 6 or Figure 7 for tap location. See Figure 8 for gas supply piping entry through the side of the unit and Figure 9 for gas piping through the bottom of the unit. A kit is required when routing gas supply piping through the bottom of the unit. Compounds used on threaded joints of gas piping must be resistant to the actions of liquified petroleum gases.

High Altitude Derate

Locate the high altitude conversion sticker in the unit literature bag. Fill out the conversion sticker and affix it next to the unit nameplate.
Refer to Table 1 for high altitude adjustments.

Unit	Altitude Ft.*	Gas Manifold Pressure
All	2000-4500	See Unit Nameplate
036-074	4500 And Above	Derate 2% / 1000 Ft. Above Seal Level

092-150

130-180KBtuh

| 4500 And Above| Derate 2% / 1000 Ft. Above Sea Level
092-150

240KBtuh

| 4500 And Above| Derate 4% / 1000 Ft. Above Sea Level
156-300

260K-480KBtuh

| 4500 And Above| Derate 4% / 1000 Ft. Above Sea Level

*Units installed at 0-2000 feet do not need to be modified.
NOTE – This is the only permissible derate for these units.

Pressure Test Gas Piping

Operating pressures at the unit gas connection must be as shown in Table 2.

Model

| Natural Gas| LP/ Propane Gas
---|---|---
Min.| Max.| Min| Max.
KG 024-074| 4.5| 10.5| 11| 13
KG 092-300| 4.7| 10.5| 11| 13

TABLE 2
OPERATING PRESSURE AT GAS CONNECTION “w.c

When testing the pressure of gas lines, the gas valve must be disconnected and isolated. Gas valves can be damaged if subjected to more than 0.5 psig.
WARNING
FIRE OR EXPLOSION HAZARD Failure to follow the safety warnings exactly could result in serious injury, death or property damage. Never test for gas leaks with an open flame. Use a commercially available soap solution made specifically for the detection of leaks to check all connections. A fire or explosion may result causing property damage, personal injury or loss of life.

Two-Stage Gas Valve Adjustment

Gas manifold pressures should match the pressures shown in Table 3. On two- stage gas valves, initiate a W2 thermostat demand to check high fire pressure before low fire pressure. With high fire operating, reduce the thermostat demand to W1 and check the low fire pressure. Refer to the Unit Controller manual to initiate a thermostat demand.
IMPORTANT – Do not set low fire pressure lower than the certified minimum input rating listed in Table 3.
TABLE 3
MANIFOLD INPUT PRESSURES in. wg. (kPa)

Unit

| Natural Gas| Propane (LP)Gas
---|---|---
1st Stage

±0.2

| 2nd Stage

± 0.3.

| 1st Stage

±0.2

| 2nd Stage

± 0.3.

024, 030, 036, 048, 060,

074 Std./Med./High Heat

| ****

NA

| ****

3.5

| ****

NA

| ****

10.5

036, 048, 060, 074,

Dual Heat

| ****

2.0

| ****

3.5

| ****

5.9

| ****

10.5

092-300| 1.6| 3.7| 5.5| 10.5

Gas Heat Operation

See the operating instruction plate on the unit for details
Proper Gas Flow (Approximate)

Operate the unit at least 15 minutes before checking gas flow. Determine the time in seconds for two revolutions of gas through the meter. (Two revolutions assures a more accurate time.) A portable LP gas meter (17Y44) is available for LP applications.
Divide the number of seconds by two and compare to the time in table 4. If manifold pressure is correct and rate is incorrect, check gas orifices for proper size and restriction.
Remove the temporary gas meter if installed.
NOTE – To obtain accurate readings, shut off all other gas appliances connected to meter. Unit Input Rate (Btuh)| Seconds for One Revolution
---|---
Natural| LP
1 cu ft Dial| 2 cu ft Dial| 1 cu ft Dial| 2 cu ft Dial
65,000| 55| 111| 138| 277
70,000| 51| 103| 129| 257
105,000| 34| 69| 86| 171
108,000| 33| 67| 83| 167
130,000| 28| 55| 69| 138
150,000| 24| 48| 60| 120
169,000| 21| 43| 53| 107
180,000| 20| 40| 50| 100
240,000| 15| 30| 38| 75
260,000| 14| 28| 35| 69
360,000| 10| 20| 30| 50
480,000| 8| 15| 19| 38
Natural-1000 btu/cu ft

NOTE – Table assumes standard temperature (60°F), pressure (30in.Hg.), and fuel heating values (Btuh/Ft.3). Apply pressure corrections in altitudes above 2000 ft.