Lennox G24-200 User Manual

INSTALLATION

PRODUCT LITERATURE

2005 Lennox Industries Inc.

Dallas, Texas

RETAIN THESE INSTRUCTIONS

FOR FUTURE REFERENCE

INSTRUCTIONS

G24-200

UPFLOW GAS FURNACE
Direct Spark Ignition

503,613M
8/2005

Supersedes 7/2003

Table of Contents

G24−200 Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . .

G24−200 Parts Arrangement 4. . . . . . . . . . . . . . . . . . . .

G24−200 Gas Furnace 6. . . . . . . . . . . . . . . . . . . . . . . . .

Shipping and Packing List 6. . . . . . . . . . . . . . . . . . . . . .

Safety 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Combustion, Dilution & Ventilation Air 8. . . . . . . . . . . .

Setting Equipment 11. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Return Air Plenum / Filter Box Installation 11. . . . . . . .

Duct System 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Blower Motor and Drive Installation 13. . . . . . . . . . . . .

Venting 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas Piping 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unit Start−up 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Heating Sequence of Operation 34. . . . . . . . . . . . . . . .

Gas Pressure Adjustment 35. . . . . . . . . . . . . . . . . . . . .

High Altitude Information 35. . . . . . . . . . . . . . . . . . . . . .

Other Unit Adjustments and Operation 35. . . . . . . . . . .

Setting Blower CFM 37. . . . . . . . . . . . . . . . . . . . . . . . . .

Repair Parts List 39. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

G24−200 Start−up & Performance Check List 39. . . . .

Troubleshooting 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Litho USA

Failure to follow safety warnings exact­ly could result in serious injury, death,
or property damage.

Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.

Installation and service must be per­formed by a qualified installer, ser­vice agency or the gas supplier.

08/05

*2P0805*

WARNING

FIRE OR EXPLOSION HAZARD.

WHAT TO DO IF YOU SMELL GAS:

 Do not try to light any appliance.
 Extinguish any open flame.
 Do not touch any electrical switch; do not

use any phone in your building.

 Leave the building immediately.
 Immediately call your gas supplier from a

neighbor’s phone. Follow the gas suppli­er’s instructions.

 If you cannot reach your gas supplier, call

the fire department.

503,613M

*P504613M*

G24−200 Unit Dimensions − inches (mm)

52-1/2
(1334)

10-1/2

(267)

VENT

OUTLETS

17

(432)

5/8

(16)

VENT

OUTLETS

5-1/2
(140)

9 (229)

Either Side

29-1/4

(743)

17

(432)

HEAT

EXCHANGER

SUPPLY

AIR

OPENING

2

(51)

7/8

(22)

1-1/16

(27)

CONTROL

BOX

4-1/4 (108)

50-3/4
(1289)

Bottom Return

Air Opening

53

(1346)

7/8

(22)

Either Side

GAS

PIPING

INLET

Either Side)

ELECTRICAL

INLET

(Either Side)

BLOWER

MOTOR

(25)

1

26

(660)

FLOW

Bottom Return

Air Opening

FRONT VIEW SIDE VIEW

52-1/2
(1334)

50-3/8
(1280)

Supply Air

Opening

1-1/16

(27)

AIR

2-1/4

(57)

1

(25)

REAR RETURN

AIR OPENING

BACK VIEW

50-1/2
(1283)

27

(686)

1

(25)

1

(25)

Page 2

G24−200 Filter Box Dimensions − inches (mm)

5

(127)

AIR

FLOW

1

(25)

4-3/4
(121)

26-1/4

(667)

AIR

FLOW

50-1/2
(1283)

OPENING SAME

BOTH SIDES

1

(25)

32

(813)

5 (127)

1

(25)

5

(127)

4-3/4

(121)

26-1/4

(667)

*OPTIONAL
FILTER BOX

*NOTE  Return air filter box may be
installed at back or bottom of furnace.

50-1/2
(1283)

(127)

32

(813)

5

(25)

1

(25)

BACK VIEWSIDE VIEW

TOP VIEW

4-3/4
(121)

1

50-1/2
(1283)

26-1/4

(667)

1

*NOTE  Return air filter box may be

(25)

installed at back or bottom of furnace.

OPENING SAME

BOTH SIDES

1

(25)

FRONT VIEW

1

(25)

OPENING SAME

BOTH SIDES

32

(813)

Page 3

G24−200 Parts Arrangement

LIMIT CONTROL*

LEFT SIDE PANEL

FLUE BOX GASKET*

COMBUSTION
AIR BLOWER*

FLUE BOX*

BURNER RETENTION

BRACKET*

FLAME ROLLOUT

SWITCH*

G24−200 HEAT SECTION AND CABINET

*

(THIS UNIT CONTAINS TWO HEAT SECTIONS. EACH
HEAT SECTION CONTAINS ONE OF THESE ITEMS.)

CABINET TOP

PRESSURE SWITCH*

HEAT EXCHANGER ASSEMBLY*

FLEXIBLE CONNECTOR

PRESSURE SWITCH*

IGNITION CONTROL*

REAR PANEL − TOP

BURNER MTG

BRACKET*

SENSOR*

IGNITOR*

GAS VALVE*

(two-stage)

CONTROL BOX

REAR PANEL − BOTTOM

RIGHT SIDE PANEL

MAKE−UP BOX*

HEATING COMPARTMENT ACCESS

PANEL*

BLOWER COMPARTMENT AC-

CESS PANEL

CENTER MULLION

Page 4

G24−200 Parts Arrangement Continued

G24−200 BLOWER SECTION

DRIVE BELT

(Drive Kit)

ADJUSTMENT ARM

BLOWER

PULLEY

MOTOR PULLEY

(Drive Kit)

MOTOR BASE

SHAFT

MOTOR

(Drive

Kit)

CUT−OFF PLATE

BLOWER HOUSING

BEARING

WHEEL

BASE ASSEMBLY

MOTOR BASE

VIBRATION ISOLATOR

LOCATING ROD

Page 5

G24−200 Gas Furnace

CLEARANCE

The G24−200 upflow gas furnace is for use with natural
gas only.

Each G24−200 requires the installation of a separately or­dered drive kit. The available drive kits are listed in tables 10
and 15. Provided in each drive kit is the following: the fur­nace’s blower motor, its 24 volt control transformer, and (in
non-208/230 volt models) an autotransformer for each of the
furnaces’s induced draft blowers.
Also available for order separately is a filter box kit for rear or
bottom return air applications.
This furnace has two independently controlled heat sections,
each with an input of 100MBH and each operating in a two­stage (low heat/high heat) mode. The C17−090/120 cooling
coil has been designed for use with this furnace and can be
connected to either a single condensing unit or to two con­densing units. (See C17 coil installation instructions.)

Shipping and Packing List

Package 1 of 3 contains:

1 − Assembled unit (vent adapters are factory-installed)
1 − Flexible gas connector

Package 2 of 3 contains:

1 − Filter box assembly

Package 3 of 3 contains:

1 − Blower drive kit consisting of:

1 − Blower motor

1 − Motor pulley

1 − Belt

1 or 3 − Transformer(s)

1 − Bag assembly containing wiring parts

1 − Bag assembly containing securing hardware

Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.

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 qualified installer, service agency
or the gas supplier.

CAUTION

As with any mechanical equipment, personal injury
can result from contact with sharp sheet metal
edges. Be careful when you handle this equipment.

Use only the type of gas approved for use with this furnace.
Refer to unit nameplate.

Lennox G24−200 units are CSA international certified to
ANSI Z21.47 and CSA 2.3 standard.

In the USA, installation of Lennox gas central furnaces
must conform with local building codes. In the absence of
local codes, units must be installed in accordance with the
current National Fuel Gas Code (ANSI−Z223.1/NFPA54).
The National Fuel Gas Code is available from:

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

In Canada, installation must conform with current National
Standard of Canada CSA−B149.1 Natural Gas and Pro­pane Installation Codes", local plumbing or waste water
codes and other applicable local codes.

Adequate clearance must be made around the air open­ings into the vestibule area. Provisions must be made for
proper operation and for combustion air and ventilation air
supply according to the current National Fuel Gas Code or
CSA-B149 standards.

In the U.S.A, vent installations shall be in accordance with
the venting tables provided in this manual and the applica­ble provisions of local building codes.
In Canada, vent installations shall be in accordance with
the venting tables in the current editions of the CSA B149
codes and the applicable provisions of local building
codes.

This furnace is CSA international certified for installation
clearances to combustible material as listed on unit rating
plate and in table 1. Accessibility and service clearances
must take precedence over fire protection clearances.

TABLE 1

INSTALLATION CLEARANCES INCHES (mm)

VENT CONNECTOR TYPE

TYPE C TYPE B1

TOP 1 (25) 1 (25)

FRONT* 3 (76) 3 (76)

BACK 0 0

SIDES 0 0

VENT 6 (152) 1 (25)

FLOOR 0** 0**

* Front clearance must be 24 inches (610mm) minimum for
service access.

** For installation on combustible floors, appliance shall not be
installed directly on carpeting, tile, or other combustible materi­al other than wood flooring.

Maintain adequate clearance for filter access. See section
on Return Air Plenum/Filter Box Installation."

Page 6

For installation in a residential garage, the furnace must be
installed so that the burner(s) and the ignition source are lo­cated no less than 18 inches (457 mm) above the floor. The
furnace must be located or protected to avoid physical dam­age by vehicles. When a furnace is installed in a public garage,
hangar, or other building that has a hazardous atmosphere,
the furnace must be installed according to recommended
good practice requirements and current National Fuel Gas
Code or CSA B149.1 standard.

The furnace must be adjusted to obtain a temperature rise
range and within the allowable external static pressure on
furnaces with a duct system as listed on unit nameplate.

Installation in parking structures must be in accordance
with the Standard for Parking Structures (ANSI/NFPA No.
88A−1991). Installation in repair garages must be in accor­dance with the Standard for Repair Garages (ANSI/NFPA
No. 88B−1991).

The G24−200 furnace must be installed so that electrical
components are protected from water.

When the furnace is used with cooling units, it shall be
installed in parallel with, or on the upstream side of, cooling
units to avoid condensation in the heating compartment.
With a parallel flow arrangement, a damper (or other means
to control the flow of air) must adequately prevent chilled air
from entering the furnace. If the damper is manually oper­ated, it must be equipped to prevent operation of either the
heating or the cooling unit, unless it is in the full HEAT" or
COOL" setting.

When installed, the furnace must be electrically
grounded according to local codes. In addition, in the
United States, installation must conform with the current
National Electric Code, ANSI/NFPA No. 70. The National
Electric Code (ANSI/NFPA No. 70) is available from the
following address:

National Fire Protection Association
1 Battery March Park
Quincy, MA 02269

In Canada, all electrical wiring and grounding for the unit
must be installed according to the current regulations of the
Canadian Electrical Code Part I (CSA Standard C22.1)
and/or local codes.

Never test for gas leaks with an open flame. Check all con­nections with a commercially available soap solution made
specifically for leak detection.

NOTE − 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.

Field wiring connection must meet or exceed specifications
of type T wire and withstand a maximum temperature rise
of 180°F (82°C).

When the furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside of the space con­taining the furnace, return air shall be handled by a duct(s)
sealed to the furnace casing and terminating outside space
containing furnace.

NOTE − This furnace is designed for a minimum continu­ous return air temperature of 60°F (16°C) or an intermit­tent operation down to 55°F (13°C) dry bulb for cases
where a night setback thermostat is used. Return air
temperature must not exceed 85°F (29°C) dry bulb.

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
cooling 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−filters must be re-

moved upon construction completion.

 The input rate and temperature rise must be set per the

unit rating plate.

 The heat exchanger, components, duct system, air fil-

ters and evaporator coil must be thoroughly cleaned
following final construction clean−up.

 The unit operating conditions (including airflow, cool-

ing 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 Lennox G24−200 furnace may be installed in alcoves,
closets, basements, garages and utility rooms.

Page 7

This furnace design has not been CSA international certi­fied for installation in mobile homes, recreational vehicles,
or outdoors.

WARNING

The blower access panel must be securely in place
when the blower and burners are operating. Gas
fumes, which could contain carbon monoxide, can
be drawn into living space resulting in personal inju­ry or death.

General

These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.

In addition to the requirements indicated previously, the fol­lowing general recommendations should be considered
when installing the Lennox G24−200 furnace.

The furnace should be placed as close to the center of the
air distribution system as possible. The furnace should also
be located close to the chimney or vent termination point.

Do not install the furnace where drafts might blow directly
into it. This could cause improper combustion and unsafe
operation.

Do not block furnace combustion air openings with cloth­ing, boxes, doors, etc. Combustion air is needed for proper
combustion and safe unit operation.

When the furnace is installed in an attic or other insulated
space, keep insulation away from the furnace.

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 Cal­ifornia 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 below, or contact your
supervisor.

Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379−9900 USA

Combustion, Dilution & Ventilation Air

In the past, there was no problem in bringing in sufficient
outdoor air for combustion. Infiltration provided all the air
that was needed. In today’s homes, tight construction
practices make it necessary to bring in air from outside for
combustion. Take into account that exhaust fans, ap­pliance vents, chimneys, and fireplaces force additional
air that could be used for combustion out of the house. Un­less outside air is brought into the house for combustion,
negative pressure (outside pressure is greater than inside
pressure) will build to the point that a downdraft can occur
in the furnace vent pipe or chimney. As a result, combus­tion gases enter the living space creating a potentially
dangerous situation.

In the absence of local codes concerning air for combus­tion and ventilation, use the guidelines and procedures in
this section to install G24−200 furnaces to ensure efficient
and safe operation. You must consider combustion air
needs and requirements for exhaust vents and gas piping.
A portion of this information has been reprinted with per­mission from the National Fuel Gas Code
(ANSI-Z223.1/NFPA54). This reprinted material is not the
complete and official position of the ANSI on the refer­enced subject, which is represented only by the standard
in its entirety.

In Canada, refer to the standard CSA B149.1 installation
code.

CAUTION

Do not install furnace in a corrosive or contaminated
atmosphere. Meet all combustion and ventilation air
requirements, as well as all local codes.

Combustion Air Requirements

Page 8

CAUTION

Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rust­ing and premature heat exchanger failure. Excessive
exposure to contaminated combustion air will result
in safety and performance related problems. Avoid
exposure to the following substances in the combus­tion air supply:

Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine base swimming pool chemicals
Water softening chemicals
De-icing salts or chemicals
Carbon tetrachloride
Halogen type refrigerants
Cleaning solvents (such as perchloroethylene
Printing inks, paint removers, varnishes, etc.
Hydrochloric acid
Cements and glues
Antistatic fabric softeners for clothes dryers
Masonry acid washing materials

All gas-fired appliances require air for the combustion pro­cess. If sufficient combustion air is not available, the fur­nace or other appliance will operate inefficiently and
unsafely. Enough air must be provided to meet the needs of
all fuel-burning appliances and appliances such as ex­haust fans which force air out of the house. When fire­places, exhaust fans, or clothes dryers are used at the
same time as the furnace, much more air is required to en­sure proper combustion and to prevent a downdraft. Insuf­ficient air causes incomplete combustion which can result
in carbon monoxide.

In addition to providing combustion air, fresh outdoor air
dilutes contaminants in the indoor air. These contami­nants may include bleaches, adhesives, detergents, sol­vents and other contaminants which can corrode furnace
components.

The requirements for providing air for combustion and ven­tilation depend largely on whether the furnace is installed in
an unconfined or a confined space.

Unconfined Space

An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cubic
feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the com­bined input rating of all appliances installed in that space.
This space also includes adjacent rooms which are not
separated by a door. Though an area may appear to be un­confined, it might be necessary to bring in outdoor air for
combustion if the structure does not provide enough air by

infiltration. If the furnace is located in a building of tight
construction with weather stripping and caulking around
the windows and doors, follow the procedures in the air
from outside section.

Confined Space

A confined space is an area with a volume less than 50 cu­bic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the
combined input rating of all appliances installed in that
space. This definition includes furnace closets or small
equipment rooms.

When the furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space contain­ing the furnace, the return air must be handled by ducts
which are sealed to the furnace casing and which terminate
outside the space containing the furnace. This is especially
important when the furnace is mounted on a platform in a
confined space such as a closet or small equipment room.
Even a small leak around the base of the unit at the platform
or at the return air duct connection can cause a potentially
dangerous negative pressure condition. Air for combustion
and ventilation can be brought into the confined space either
from inside the building or from outside.

Air from Inside

If the confined space that houses the furnace adjoins a
space categorized as unconfined, air can be brought in by
providing two permanent openings between the two
spaces. Each opening must have a minimum free area of 1
square inch (645 mm2) per 1,000 Btu (.29 kW) per hour of
total input rating of all gas−fired equipment in the confined
space. Each opening must be at least 100 square inches
(64516 mm2). One opening shall be within 12 inches (305
mm) of the top of the enclosure and one opening within 12
inches (305 mm) of the bottom. See figure 1.

Air from Outside

If air from outside is brought in for combustion and ventila­tion, the confined space must have two permanent open­ings. One opening shall be within 12 inches (305 mm) of the
top of the enclosure and one opening within 12 inches (305
mm) of the bottom. These openings must communicate di­rectly or by ducts with the outdoors or spaces (crawl or at­tic) that freely communicate with the outdoors or indirectly
through vertical ducts. Each opening shall have a minimum
free area of 1 square inch (645 mm2) per 4,000 Btu (1.17
kW) per hour of total input rating of all equipment in the en­closure. See figures 2 and 3. When communicating with
the outdoors through horizontal ducts, each opening shall
have a minimum free area of 1 square inch (645 mm2) per
2,000 Btu (.56 kW) per total input rating of all equipment in
the enclosure. See figure 4.

Page 9

EQUIPMENT IN CONFINED SPACE

ALL AIR FROM INSIDE

CHIMNEY

OR GAS

VENT

G24−200

FURNACE

OPENINGS

(To Adjacent

Room)

NOTE−Each opening shall have a free area of at least one square
inch (645 mm2) per 1,000 Btu (.29 kW) per hour of the total input rat­ing of all equipment in the enclosure, but not less than 100 square
inches (64516 mm2).

FIGURE 1

When ducts are used, they shall be of the same cross−sec­tional area as the free area of the openings to which they
connect. The minimum dimension of rectangular air ducts
shall be no less than 3 inches (75 mm). In calculating free
area, the blocking effect of louvers, grilles, or screens
must be considered. If the design and free area of protec­tive covering is not known for calculating the size opening
required, it may be assumed that wood louvers will have
20 to 25 percent free area and metal louvers and grilles
will have 60 to 75 percent free area. Louvers and grilles
must be fixed in the open position or interlocked with the
equipment so that they are opened automatically during
equipment operation.

EQUIPMENT IN CONFINED SPACE ALL AIR FROM OUTSIDE

(Inlet Air from Crawl Space and Outlet Air to Ventilated Attic)

CHIMNEY OR

GAS VENT

VENTILATION LOUVERS

(Each end of attic)

G24−200

FURNACE

VENTILATION

LOUVERS

(For unheated crawl space)

NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch (645 mm2)
per 4,000 Btu (1.17 kW) per hour of the total input rating of all equipment in the enclosure.

OUTLET

AIR

INLET

AIR

FIGURE 2

Page 10

EQUIPMENT IN CONFINED SPACE

ALL AIR FROM OUTSIDE

(All Air Through Ventilated Attic)

CHIMNEY

OR GAS

VENT

OUTLET

AIR

G24−200

FURNACE

NOTE−The inlet and outlet air openings shall each have a
free area of at least one square inch (645 mm2) per 4,000
Btu (1.17 kW) per hour of the total input rating of all equip­ment in the enclosure.

VENTILATION LOUVERS

(Each end of attic)

INLET AIR

(Ends 12 in.

above bottom)

Setting Equipment

WARNING

Do not install the furnace on its front or its back. Do­ing so will adversely affect the operation of the safety
control devices, which could result in personal inju­ry or death.

The Lennox G24−200 upflow gas furnace can be
installed with rear or bottom return air. If unit is installed
on a platform with bottom return air, furnace/filter box must
be sealed airtight at the platform to ensure proper and safe
operation.

Select a location that allows for required clearances listed
on unit rating plate. Also consider gas supply connections,
electrical supply, vent connection, installation and service
clearances [24 inches (610mm) at unit front] and filter ac­cessibility.

The furnace must be leveled using shims or leveling bolts
(field provided). The corner gussets provided in the furnace
base will accept leveling bolts.

FIGURE 3

EQUIPMENT IN CONFINED SPACE

(ALL AIR FROM OUTSIDE)

CHIMNEY

OR GAS

VENT

G24−200

FURNACE

NOTE−Each air duct opening shall have a free area of at least
one square inch (645 mm2) per 2,000 Btu (.59 kW) per hour of
the total input rating of all equipment in the enclosure. If the
equipment room is located against an outside wall and the air
openings communicate directly with the outdoors, each open­ing shall have a free area of at least one square inch (645 mm2)
per 4,000 Btu (1.17 kW) per hour of the total input rating of all
other equipment in the enclosure.

OUTLET AIR

INLET AIR

FIGURE 4

Return Air Plenum / Filter Box Installation

Return air openings are provided at rear and in bottom of
unit. A return air closure panel is shipped secured to the
rear opening.

A − Bottom Return Air (Refer to figure 5)

1 − Determine the location of the furnace/filter box.

2 − Cut 50-5/8 x 26-1/8 (128.6cm x 66.4cm) opening in the

return air platform.

3 − Fabricate the return air plenum with right angle flanges

and insert into the floor opening.

4 − Remove filter box access door and filters.

5 − Apply adhesive-backed foam tape to the bottom of the

filter box all around the opening. Position the filter box
over the return air plenum. Fasten as required using
self-tapping screws provided.

Make sure there is an air tight seal between the
platform/return air plenum and filter box.

6 − Apply adhesive-backed foam to the top of the filter box

all around the opening. Place furnace over the filter box
with sides and rear of furnace and filter box flush. Fas­ten as required.

Make sure there is an air tight seal between the fur­nace and the filter box.

Page 11

7 − Install the filters and the filter access door.

BOTTOM RETURN AIR FILTER BOX INSTALLATION

2-3/4

(70)

1

(25)

4-3/4
(121)

ADHESIVE­BACKED
FOAM TAPE

RETURN AIR PLENUM

29-1/4 (743)

27-1/4 (692)

26-1/4 (667)

26-1/8 (664) x 50-5/8 (1286)

Floor Opening

Furnace

Opening

Filter Box

Opening

AIR

FLOW

UNIT

1

(25)

FILTER
BOX

PLATFORM

INCHES (mm)

SIDE VIEW

FIGURE 5

WARNING

Improper installation of the furnace can result in per­sonal injury or death. Combustion and flue products
must never be allowed to enter the return air system
or the living space. Use screws and joint tape to seal
the return air system to the furnace.
In platform installations with bottom return air, the
furnace should be sealed airtight to the return air ple­num. A door must never be used as a portion of the
return air duct system. The base must provide a
stable support and an airtight seal to the furnace. Al­low absolutely no sagging, cracks, gaps, etc.
The return and supply air duct systems must never
be connected to or from other heating devices such
as a fireplace or stove, etc. Fire, explosion, carbon
monoxide poisoning, personal injury and/or proper­ty damage could result.

Page 12

B − Rear Return Air (Refer to figure 6)

Duct System

REAR RETURN AIR FILTER BOX INSTALLATION

UNIT

FILTER

ACCESS

PANEL

REPOSITION REAR PANEL WITH FLANGES AS SHOWN.

(Seal air-tight with adhesive-backed foam tape.)

FOUR FILTERS (Filters may be
also installed through top of frame)

ADHESIVE-BACKED

FOAM TAPE

(Apply to filter box)

FILTER

ACCESS

PANEL

RETURN AIR
FILTER BOX

FIGURE 6

1 − Determine the location of the furnace/filter box.

NOTE − Filter box can be installed with right or left side
filter access or top-rear filter access. Allow enough
room when positioning the furnace for filter access.

2 − Remove the bottom-rear panel from the furnace and

re-install on the bottom of the furnace as shown. Seal

air-tight with adhesive-backed foam tape.

3 − Apply adhesive-backed foam tape to the filter box (side

facing furnace) all around the opening. Refer to figure 6.

4 − Position the filter box over the furnace return air open-

ing. The top of the filter box should be in the up" posi­tion and the filter box and the furnace edges flush at the
sides and bottom.

5 − Fasten using self-drilling self-tapping screws provided

with the filter box. Use the frame clearance holes as a
guide.

6 − Install the four filters and the filter access door.

7 − Size the return air plenum to fit the filter box and then

seal the joint air tight.

Size and install supply and return air duct system using in­dustry-approved standards that result in a quiet and low­static system with uniform air distribution.

Supply Air Plenum

Furnaces installed without a cooling coil require the installa­tion of a removable access panel in the supply air duct. The
access panel should be large enough to permit inspection (ei­ther by smoke or reflected light) of the heat exchanger for
leaks after installation. The furnace access panel must al­ways be in place when the furnace is operating and it must
not allow leaks into the supply air duct system.

In applications requiring air conditioning, see installation
instructions provided with C17-090/120 evaporator coil for
supply air plenum size and connection.

Return Air Plenum

Return air must not be drawn from a room where this
furnace, or any other gas appliance (i.e., a water heat­er), is installed. When return air is drawn from a room, a

negative pressure is created in the room. If a gas ap­pliance is operating in a room with negative pressure, the
flue products can be pulled back down the vent pipe and
into the room. This reverse flow of the flue gas may result
in incomplete combustion and the formation of carbon
monoxide gas. This toxic gas might then be distributed
throughout the house by the furnace duct system.

Size and install return air plenum as indicated in previous
section.

Blower Motor / Drive Installation

A − Motor Installation

Refer to figure 7.

1 − Check the box on the rating plate to indicate which of

the drive kits are being installed.

2 − Secure the blower motor to the motor base with the

hardware provided.

3 − Slide the motor pulley onto the motor shaft and align

with the blower pulley.

4 − Install the belt.

5 − Refer to Setting Blower CFM Section" to determine

blower RPM setting and the following section for ad­justing belt tension.

Page 13

TYPICAL MOTOR/DRIVE INSTALLATION

MOTOR PULLEY

MOTOR

MOTOR SECURING
HARDWARE

MOTOR BASE

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

3 − Measure the 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 under-ten­sioned belt. A force above these values indicates an
over-tensioned belt.

MEASURE BELT TENSION

BELT TENSION ADJUSTING HARDWARE

PULLEY ALIGNMENT

BLOWER
PULLEY

MOTOR
PULLEY

FIGURE 7

B − Blower Belt Adjustment

Maximum life and wear can be obtained from belts only if
the proper pulley alignment and belt tension are main­tained. Tension new belts after a 24 to 48 hour period of op­eration. This will allow the belt to stretch and seat in the
grooves.

1 − Loosen belt adjusting hardware. See figure 7.

2 − To increase belt tension −

Move the motor base away from the blower housing.

To loosen belt tension −

Move the motor toward the blower housing.

3 − Tighten the belt adjusting hardware.

C − Check Belt Tension

Over-tensioning a belt shortens belt and bearing life.
Check belt tension as follows:

1 − Measure span length X. See figure 8.

2 − Apply perpendicular force to the center of span (X)

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

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

FORCE

DEFLECTION 1/64 INCH PER INCH OF SPAN

OR 1.5 mm PER 100 mm OF SPAN

FIGURE 8

Venting

A vent adapter is factory-installed on each of the combus­tion air blower outlets. Modification of, or removal of the

adapter(s) will cause unsafe unit operation and will
void CSA unit certification. The vent adapter does not re-

quire insulation.

The G24−200 units are classified as fan assisted Category I
type furnaces when vertically vented according to the latest
edition of ANSI Z21.47 Gas-fired Central Furnace Standard
in the USA and the current standard CSA 2.3 Gas-fired Cen­tral Furnace in Canada. The definition of a fan assisted fur­nace is an appliance equipped with an integral mechanical
means to either draw or force products of combustion
through the combustion chamber and/or heat exchanger.

NOTE − Use these instructions as a guide. They do not su­persede local codes.

The vent sizing tables in this manual have been extracted
from the Current edition of the National Fuel Gas Code
(NFPA 54 / ANSI Z223.1) and are provided as a guide for
proper vent installation. Proper application, termination,
construction and location of vents must conform to local
codes having jurisdiction. In the absence of local codes,
the NFGC serves as the defining document in the U.S.A.,
while the CSA−B149 codes serve as the defining docu­ments in Canada.

Refer to the tables and the venting information contained in
these instructions to properly size and install the venting
system.

Install the first vent connector elbow a minimum of 6 in.
(152mm) from the furnace vent outlet.

Page 14

Venting Using a Masonry Chimney

The following additional requirements apply when a lined
masonry chimney is used to vent a G24−200 furnace:

Masonry chimneys used to vent Category I central fur­naces must be either tile-lined or lined with a listed metal
lining system or dedicated gas vent. Unlined masonry
chimneys are prohibited. See figures 9 and 10 for common
venting.

A Category I appliance must never be connected to a chim­ney that is servicing a solid−fuel appliance. If a fireplace
chimney flue is used to vent this appliance, the fireplace
opening must be permanently sealed.

A fan−assisted furnace may be commonly vented into an
existing lined masonry chimney if the following conditions
are met:

1 − The chimney is currently serving at least one drafthood

equipped appliance.

2 − The vent connectors and chimney are sized according

to the provided venting tables for the USA, and the ap­propriate venting tables in the standards of CSA
B149.1 of the Natural Gas and Propane Installation
Code in Canada.

A type B1 vent or masonry chimney liner shall terminate above
the roof surface with a listed cap or a listed roof assembly ac­cording to the terms of their respective listings and the vent
manufacturer’s instructions.

Do not install a manual damper, barometric draft regula­tor, or flue restrictor between the furnace and the chimney.

If type B1 double-wall vent is used inside a chimney, no oth­er appliance can be vented into the chimney. Outer wall of
type B1 vent pipe must not be exposed to flue products.

Insulation for the flexible vent pipe must be an encapsu­lated fiberglass sleeve recommended by the flexible vent
pipe manufacturer. See figure 9.

The space between the liner and the chimney wall
should NOT be insulated with puffed mica or any other
loose granular insulating material.

If B1 vent or an insulated flexible vent pipe cannot be used
as liners, the chimney must be rebuilt to accommodate one
of these methods or some alternate approved method
must be found to vent the appliance.

IMPORTANT

SINGLE appliance venting of a fan-assisted furnace
into a tile-lined masonry chimney (interior or outside
wall) is PROHIBITED. The chimney must first be lined
with either type B1 vent or an insulated single wall
flexible vent lining system, sized according to the
provided venting tables.

COMMON VENTING USING METAL−LINED MASONRY CHIMNEY

NOTE 1 − Refer to the provided venting tables
for installations in the USA and the venting
tables in CSA−B149.1 for installations Canada.

NOTE 2 − Either single-walled or double-walled
vent connector may be used. Refer to the ca­pacity requirements shown in the provided
venting tables for installations in USA and the
venting tables in current CSA−B149.1 for
installations in Canada.

5 FT.

(1.5m)

MIN.

VENT

CONNECTOR

SEE NOTE 2

MIN. LENGTH − AS SHORT

When inspection reveals that an existing chimney is not
safe for the intended purpose, it shall be rebuilt to conform
to nationally recognized standards, lined or relined with
suitable materials or replaced with a gas vent or chimney
suitable for venting G24−200 units. The chimney passage­way must be checked periodically to ensure that it is clear
and free of obstructions.

MAX. LENGTH − SEE

NOTE 1 BELOW.

AS PRACTICAL

G24−200

SEALED

EXTERIOR CHIMNEY WITH

B1" VENT OR INSULATED

FLEXIBLE VENT PIPE

PERMANENTLY

SEALED FIRE-

PLACE OPENING

JOIN HEAT

SECTIONS

WITH A ’TEE−Y’

FIGURE 9

Page 15

COMMON VENTING USING TILE−LINED INTERIOR MASONRY CHIMNEY AND COMBINED VENT CONNECTOR

NOTE 1 − Refer to provided venting tables
for installations in the USA and the vent­ing tables in current CSA−B149.1 for
installations in Canada.

VENT

CONNECTOR

SEE NOTE 2

Note 2 − Either single-walled or double-walled vent
connector may be used. Refer to the capacity re­quirements as shown in the provided venting tables
for installations in USA and the venting tables in cur­rent CSA−B149.1 for installations in Canada.

MIN. LENGTH = AS SHORT AS PRACTICAL.

FOR MAX. LENGTH SEE NOTE 1

JOIN HEAT SECTIONS

WITH A ’TEE−Y’

G24−200

INTERIOR TILE−LINED

MASONRY CHIMNEY

NOTE − The chimney must be
properly sized per provided vent­ing tables and lined with a listed
metal lining system.

PERMANENTLY SEALED

FIREPLACE OPENING

FIGURE 10

General Venting Requirements

All G24−200 furnaces must be vented according to these
instructions.

1 − Vent diameter recommendations and maximum al-

lowable piping runs are found in the provided venting
tables for the USA, and the appropriate venting tables
in the standards of CSA B149.1 of the Natural Gas and
Propane Installation Code for Canada.

2 − In no case should the vent or vent connector diameter

be less than the diameter specified in the provided
venting tables for the USA, and the appropriate vent­ing tables in the standards of CSA B149.1 of the Natu­ral Gas and Propane Installation Code for Canada.

3 − Single Appliance Vent − If the vertical vent or tile-lined

chimney has a larger diameter or flow area than the
vent connector, use the vertical vent diameter to de­termine the minimum vent capacity and the vent

connector diameter to determine the maximum
vent capacity. The flow area of the vertical vent, how-

ever, shall not exceed 7 times the flow area of the
listed appliance categorized vent area, drafthood out­let area or flue collar area unless designed according
to approved engineering methods.

4 − Multiple Appliance Vents − The flow area of the largest

section of vertical vent or chimney shall not exceed 7
times the smallest listed appliance categorized vent
area, flue collar area or drafthood outlet area unless
designed according to engineering methods.

5 − The entire length of single wall metal vent connector

shall be readily accessible for inspection, cleaning,
and replacement.

6 − Single appliance venting configurations with zero lat-

eral lengths, see tables 3 and 4, are assumed to have
no elbows in the vent system. For all other vent config­urations, the vent system is assumed to have two 90
elbows. For each additional 90 elbow or equivalent
(for example two 45 elbows equal one 90 elbow) be­yond two, the maximum capacity listed in the venting
table should be reduced by 10 percent (0.90 x maxi­mum listed capacity).

7 − The common venting tables 5, 6, 7, and 8 were gener-

ated using a maximum horizontal vent connector
length of 1-1/2 feet (18 inches) for each inch of con­nector diameter as follows:

TABLE 2

Connector

Diameter

inches (mm)

3 (76) 4−1/2 (1.37)

4 (102) 6 (1.83)

5 (127) 7−1/2 (2.29)

6 (152) 9 (2.74)

7 (178) 10−1/2 (3.20)

Maximum Horizontal

Connector Length

feet (m)

8 − If the common vertical vent is offset, the maximum

common vent capacity listed in the common venting
tables should be reduced by 20%, the equivalent of
two 90 elbows (0.80 x maximum common vent ca­pacity). The horizontal length of the offset shall not ex­ceed 1-1/2 feet (.46 m) for each inch (25 mm) of
common vent diameter.

9 − The vent pipe should be as short as possible with

the least number of elbows and angles to do the job.
The vent connector should be routed to the vent using
the shortest possible route.

Page 16

10− A vent connector shall be supported without any dips

or sags and shall slope a minimum of 1/4inch (6.4 mm)
per linear foot (305 mm) of connector, back toward the
appliance. See local and national installation codes for
support intervals and methods. National installation
code in the U.S.A is current edition of National fuel Gas
Code (ANSI−Z223.1/NFPA54). National installation
codes in Canada are current editions of CSA−B149
codes.

11− Vent connectors shall be firmly attached to furnace flue

collars by sheet metal screws or other approved
means, except vent connectors of listed Type B vent
material which shall be assembled according to the
manufacturer’s instructions. Joints between sections
of single wall connector piping shall be fastened by
sheet metal screws or other approved means.

15− Vent connectors serving Category I appliances shall

not be connected to any portion of mechanical draft
systems operating under positive pressure such as
Category III or IV venting systems.

16− If vent connectors are combined prior to entering the

common vent, the maximum common vent capacity
listed in the common venting tables must be reduced by
10 percent, the equivalent of one 90 elbow (0.90 x
maximum common vent capacity).

17− The common vent diameter must always be at least as

large as the largest vent connector diameter.

18− In no case, shall the vent connector be sized more than

two consecutive table size diameters over the size of
the flue collar outlet.

12− When the vent connector used for Category I ap-

pliances must be located in or pass through a crawl
space or other areas which may be cold, that portion
of the vent connector shall be constructed of listed
double−wall Type B vent material or material having
equivalent insulation qualities.

13− All venting pipe passing through floors, walls, and ceil-

ings must be installed with the listed clearance to com­bustible materials and be fire stopped according to
local codes. In absence of local codes, refer to NFGC
(Z223.1/NFPA54).

14− No portion of the venting system can extend into, or pass

through any circulation air duct or plenum.

19− Do not install a manual damper, barometric draft regu-

lator or flue restrictor between the furnace and the
chimney.

20− When connecting this appliance to an existing dedicated

or common venting system, the venting system must be
inspected for signs of corrosion and general condition.
The sizing of the vent system must be reviewed and
must conform to these instructions and the provided
venting tables for the USA, and the appropriate venting
tables in the standards of CSA B149.1 of the Natural
Gas and Propane Installation Code for Canada. If the ex­isting system is in conflict with these requirements, the
venting system must be resized.

Page 17

TABLE 3

(

)L(

)

(feet)

(feet)

CAPACITY OF TYPE B DOUBLE-WALL VENTS WITH TYPE B DOUBLE-WALL CONNECTORS

SERVING A SINGLE CATEGORY I APPLIANCE

Vent and Connector Diameter − D (inches)

Height

H

feet

6

8

10

15

20

30

NOTE − Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent configurations, the vent
system is assumed to have two 90 elbows. For each additional 90 elbow or equivalent (for example two 45 elbows equal one 90 elbow) beyond two, the maximum
capacity listed in the venting table should be reduced by 10 percent (0.90 x maximum listed capacity).

Lateral

feet

0 0 78 0 152 0 251 0 375

2 13 51 18 97 27 157 32 232

4 21 49 30 94 39 153 50 227

6 25 46 36 91 47 149 59 223

0 0 84 0 165 0 276 0 415

2 12 57 16 109 25 178 28 263

5 23 53 32 103 42 171 53 255

8 28 49 39 98 51 164 64 247

0 0 88 0 175 0 295 0 447

2 12 61 17 11 8 23 194 26 289

5 23 57 32 11 3 41 187 52 280

10 30 51 41 104 54 176 67 267

0 0 94 0 191 0 327 0 502

2 11 69 15 136 20 226 22 339

5 22 65 30 130 39 219 49 330

10 29 59 40 121 51 206 64 315

15 35 53 48 112 61 195 76 301

0 0 97 0 202 0 349 0 540

2 10 75 14 149 18 250 20 377

5 21 71 29 143 38 242 47 367

10 28 64 38 133 50 229 62 351

15 34 58 46 124 59 217 73 337

20 48 52 55 116 69 206 84 322

0 0 100 0 213 0 374 0 587

2 9 81 13 166 14 283 18 432

5 21 77 28 160 36 275 45 421

10 27 70 37 150 48 262 59 405

15 33 64 44 141 57 249 70 389

20 56 58 53 132 66 237 80 374

30 NR NR 73 11 3 88 214 104 346

3 Inch 4 Inch 5 Inch 6 Inch

Appliance Input Rating in Thousands of Btu Per Hour

MIN MAX MIN MAX MIN MAX MIN MAX

Page 18

TABLE 4

(

)L(

)

(feet)

(feet)

CAPACITY OF TYPE B DOUBLE-WALL VENTS WITH SINGLE-WALL METAL CONNECTORS

SERVING A SINGLE CATEGORY I APPLIANCE

Vent and Connector Diameter − D (inches)

Height

H

feet

6

8

10

15

20

30

NOTE − Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent configurations, the vent
system is assumed to have two 90 elbows. For each additional 90 elbow or equivalent (for example two 45 elbows equal one 90 elbow) beyond two, the maximum
capacity listed in the venting table should be reduced by 10 percent (0.90 x maximum listed capacity).

Lateral

feet

0 38 77 59 151 85 249 126 373

2 39 51 60 96 85 156 123 231

4 NR NR 74 92 102 152 146 225

6 NR NR 83 89 11 4 147 163 220

0 37 83 58 164 83 273 123 412

2 39 56 59 108 83 176 121 261

5 NR NR 77 102 107 168 151 252

8 NR NR 90 95 122 161 175 243

0 37 87 57 174 82 293 120 444

2 39 61 59 11 7 82 193 119 287

5 52 56 76 111 105 185 148 277

10 NR NR 97 100 132 171 188 261

0 36 93 56 190 80 325 116 499

2 38 69 57 136 80 225 115 337

5 51 63 75 128 102 216 144 326

10 NR NR 95 11 6 128 201 182 308

15 NR NR NR NR 158 186 220 290

0 35 96 54 200 78 346 114 537

2 37 74 56 148 78 248 113 375

5 50 68 73 140 100 239 141 363

10 NR NR 93 129 125 223 177 344

15 NR NR NR NR 155 208 216 325

20 NR NR NR NR 186 192 254 306

0 34 99 53 211 76 372 110 584

2 37 80 55 164 76 281 109 429

5 49 74 72 157 98 271 136 417

10 NR NR 91 144 122 255 171 397

15 NR NR 115 131 151 239 208 377

20 NR NR NR NR 181 223 246 357

30 NR NR NR NR NR NR NR NR

3 Inch 4 Inch 5 Inch 6 Inch

Appliance Input Rating in Thousands of Btu Per Hour

MIN MAX MIN MAX MIN MAX MIN MAX

Page 19

TABLE 5

V

C

Height

Rise

6

V

Height

CAPACITY OF TYPE B DOUBLE-WALL VENTS WITH TYPE B DOUBLE-WALL CONNECTORS

SERVING TWO OR MORE CATEGORY I APPLIANCES

VENT CONNECTOR CAPACITY

ent

Height

H

(feet) (feet)

6

8

10

15

20

30

onnector

Rise

4 Inch 5 Inch 6 Inch 7 Inch

R

MIN MAX MIN MAX MIN MAX MIN MAX

1 35 66 46 106 58 164 77 225

2 37 75 48 121 60 183 79 253

3 38 81 49 132 62 199 82 275

1 35 72 49 11 4 64 176 84 243

2 36 80 51 128 66 195 86 269

3 37 87 53 139 67 210 88 290

1 34 78 49 123 65 189 89 257

2 36 86 51 136 67 206 91 282

3 37 92 52 146 69 220 94 303

1 33 89 47 142 64 220 88 298

2 35 96 49 153 66 235 91 320

3 36 102 51 163 68 248 93 339

1 33 99 46 157 62 246 86 334

2 34 105 48 167 64 259 89 354

3 35 11 0 50 176 66 271 91 371

1 31 11 3 45 181 60 288 83 391

2 33 11 8 47 190 62 299 85 408

3 34 123 48 198 64 309 88 423

Vent and Connector Diameter − D (inches)

Appliance Input Rating in Thousands of Btu Per Hour

TABLE 6

CAPACITY OF TYPE B DOUBLE-WALL VENTS WITH TYPE B DOUBLE-WALL CONNECTORS

SERVING TWO OR MORE CATEGORY I APPLIANCES

COMMON VENT CAPACITY

ent

Height

H

(feet)

6 92 81 140 11 6 204 161 309 248

8 101 90 155 129 224 178 339 275

10 110 97 169 141 243 194 367 299

15 125 112 195 164 283 228 427 352

20 136 123 215 183 314 255 475 394

30 152 138 244 210 361 297 547 459

FAN + FAN FAN + NAT FAN + FAN FAN + NAT FAN + FAN FAN + NAT FAN + FAN FAN + NAT

4 Inch 5 Inch 6 Inch 7 Inch

Appliance Input Rating in Thousands of Btu Per Hour

Common Vent Diameter − D (inches)

Page 20

TABLE 7

V

C

Height

Rise

6

V

Height

CAPACITY OF TYPE B DOUBLE-WALL VENT WITH SINGLE-WALL METAL CONNECTORS

SERVING TWO OR MORE CATEGORY I APPLIANCES − VENT CONNECTOR CAPACITY

ent

Height

H

(feet) (feet)

6

15

30

onnector

Rise

4 Inch 5 Inch 6 Inch 7 Inch

R

MIN MAX MIN MAX MIN MAX MIN MAX

1 NR NR NR NR NR NR 207 223

2 NR NR NR NR 168 182 215 251

3 NR NR 121 131 174 198 222 273

1 79 87 11 6 138 177 214 238 291

2 83 94 121 150 185 230 246 314

3 87 100 127 160 193 243 255 333

1 77 11 0 11 3 175 169 278 226 380

2 81 11 5 11 7 185 177 290 236 397

3 85 11 9 122 193 185 300 244 412

Vent and Connector Diameter − D (inches)

Appliance Input Rating in Thousands of Btu Per Hour

TABLE 8

CAPACITY OF TYPE B DOUBLE-WALL VENTS WITH SINGLE-WALL METAL CONNECTORS

SERVING TWO OR MORE CATEGORY I APPLIANCES − COMMON VENT CAPACITY

ent

Height

H

(feet)

6 89 78 136 11 3 200 158 304 244

8 98 87 151 126 218 173 331 269

10 106 94 163 137 237 189 357 292

15 121 108 189 159 275 221 416 343

20 131 118 208 177 305 247 463 383

30 145 132 236 202 350 286 533 446

FAN + FAN FAN + NAT FAN + FAN FAN + NAT FAN + FAN FAN + NAT FAN + FAN FAN + NAT

4 Inch 5 Inch 6 Inch 7 Inch

Appliance Input Rating in Thousands of Btu Per Hour

Common Vent Diameter − D (inches)

Removal of the Furnace from Common Vent

In the event that an existing furnace is removed from a
venting system commonly run with separate gas ap­pliances, the venting system is likely to be too large to prop­erly vent the remaining attached appliances. The following
test should be conducted while each appliance in operation
and the other appliances not in operation remain con­nected to the common venting system. If the venting sys­tem has been installed improperly, the system must be
corrected as indicated in the general venting requirements
section.

1 − Seal any unused openings in the common venting

system.

2 − Visually inspect the venting system for proper size and

horizontal pitch. Determine there is no blockage or re­striction, leakage, corrosion, or other deficiencies which
could cause an unsafe condition.

3 − To the extent that it is practical, close all building doors

and windows and all doors between the space in which
the appliances remaining connected to the common
venting system are located and other spaces of the build­ing. Turn on clothes dryers and any appliances not con­nected to the common venting system. Turn on any
exhaust fans, such as range hoods and bathroom ex-

hausts, so they will operate at maximum speed. Do not
operate a summer exhaust fan. Close fireplace dampers.

4 − Follow the lighting instructions. Place the appliance being

inspected in operation. Adjust thermostat so appliance
will operate continuously.

5 − Test for spillage of the flue gases at the draft hood relief

opening after 5 minutes of main burner operation. Use
the flame of a match or candle, or smoke from a cigarette,
cigar or pipe.

6 − After determining that each appliance remaining con-

nected to the common venting system properly vents
when tested as indicated instep 3, return doors, windows,
exhaust fans, fireplace dampers and any other gas−burn­ing appliance to their previous condition of use.

7 − If improper venting is observed during any of the

above tests, the common venting system must be cor­rected. The common venting system should be re­sized to approach the minimum size as determined by
using the appropriate tables in appendix G in the cur­rent standards of the National Fuel Gas Code ANSI
Z223.1 /NFPA54 in the USA, and the appropriate
Category 1 Natural Gas appliances venting sizing
tables in the current standards of the CSA−B149.1
Natural Gas Installation Code in Canada.

Page 21

Testing for Proper Venting and Sufficient Combustion Air
(Non−Direct Vent Applications Only)

WARNING

CARBON MONOXIDE POISONING HAZARD!

Failure to follow the steps outlined below for each
appliance connected to the venting system being
placed into operation could result in carbon monox­ide poisoning or death.
The following steps shall be followed for each ap­pliance connected to the venting system being
placed into operation, while all other appliances con­nected to the venting system are not in operation.

After the furnace has been started, the following test
should be conducted to ensure proper venting and suffi­cient combustion air has been provided to the furnace, as
well as to other gas-fired appliances which are separately
vented. The test should be conducted while all appliances
(both in operation and those not in operation) are con­nected to the venting system being tested.

1 − Seal any unused openings in the venting system.

2 − Visually inspect the venting system for proper size and

horizontal pitch. Determine there is no blockage or re­striction, leakage, corrosion, or other deficiencies
which could cause an unsafe condition.

3 − To the extent that it is practical, close all building doors

and windows and all doors between the space in which
the appliances connected to the venting system are lo­cated and other spaces of the building.

4 − Close fireplace dampers.

5 − Turn on clothes dryers and any appliances not con-

nected to the venting system. Turn on any exhaust
fans, such as range hoods and bathroom exhausts, so
they will operate at maximum speed. Do not operate a
summer exhaust fan.

6 − Follow the lighting instruction to place the appliance

being inspected into operation. Adjust thermostat so
appliance will operate continuously.

7 − Test for spillage of flue gases at the draft hood relief

opening after 5 minutes of main burner operation. Use
the flame of match or candle, or smoke from a ciga­rette, cigar.

8 − If improper venting is observed during any of the

above tests, the venting system must be corrected or
sufficient combustion/make-up air must be provided.
The venting system should be re-sized to approach
the minimum size as determined by using the ap­propriate tables in appendix G in the current stan­dards of the National Fuel Gas Code
ANSI−Z223.1/NPFA 54 in the U.S.A., and the ap­propriate Natural Gas and Propane appliances vent­ing sizing tables in the current standard of the
CSA−B149.1 Natural Gas and Propane Installation
Code in Canada.

9 − After determining that each appliance remaining

connected to the common venting system properly
vents when tested as indicated in step 3, return
doors, windows, exhaust fans, fireplace dampers
and any other gas-burning appliance to their pre­vious condition of use.

General Guidelines for Vent Terminations for Non-Direct
Vent Installations.

In Non-Direct Vent applications, combustion air is taken
from indoors and the flue gases are discharged to the out­doors. The furnace is then classified as a non-direct vent,
Category IV gas furnace. In Non-Direct Vent applications,
the vent termination is limited by local building codes. In
the absence of local codes, refer to the current National
Fuel Gas Code ANSI Z223−1/NFPA 54 in U.S.A., and cur­rent standards CSA−B149.1 of the Natural Gas and Pro­pane Installation Codes in Canada for details.

Position termination end according to location given in fig­ure 11. In addition, position termination end so it is free
from any obstructions and above the level of snow accu­mulation (where applicable). The termination should be at
least 12 inches (305mm) from any opening through which
flue products could enter the building.

Page 22

VENT TERMINATION CLEARANCES

FOR INSTALLATIONS IN THE USA AND CANADA*

− VENT TERMINATION

C

A − Clearance above grade − 12 in. (305mm) minimum.
B − Clearance to window or door −

for vent installations in USA − 48 in. (1219mm) minimum
horizontal and below, 12 in. (305mm) minimum above.
for vent installations in Canada − 12 in. (305mm) minimum
for appliances  100,000 Btuh (30 kW);
36 in. (0.9m) minimum for appliances > 100,000 Btuh (30

kW).
C − Do not position terminations directly under roof eaves.
D − Clearance to electric meters, gas meters, regulators, and

relief equipment −

for vent installations in USA − 48 in (1219mm) minimum.

for vent installations in Canada − see current edition of

CSA B149 Code.

− AIR INLET OF OTHER APPLIANCE

less than
10 ft (3.048M)

D

D

E

E − Clearance to non−mechanical air supply inlet

for vent installations in USA − 48 in. (1219mm) minimum hor­izontal and below, 12 in. (305mm) minimum above.
for vent installations in Canada − 12 in. (305mm) minimum for
appliances  100,000 Btuh (30 kW);
36 in. (0.9m) minimum for appliances > 100,000 Btuh (30 kW).

F − Clearance to mechanical air supply inlet −−

for vent installations in USA − 36 in. minimum (914mm).

G − Clearance to mechanical air supply inlet −−

for vent installations in Canada − 72 in. (1829mm) minimum.

H − Do not point terminations into recessed areas such as window

wells, stairwells or alcoves.

J − Do not position terminations directly above a walkway.

F

G

* Note −

(I) Dimensions are from the current edition of The National Fuel Gas Code − ANSI-Z223.1/NFPA 54 for USA installations.
In Canada, refer to current edition of CSA building code. Local codes or regulations may require different clearances.

(II) In Non-Direct Vent installations, combustion air is taken from indoors and the flue gases are discharged to the outdoors.

FIGURE 11

Page 23

Horizontal Venting

This furnace design is certified by CSA international for
horizontal venting through an outside wall, only with the
use of two Field Controls Company Model SWG-4L side­wall venting kits, available from any Lennox Dealer Service
Center. No other Field brand venting kits or any other
manufacturer’s venting kits are acceptable. Horizontal
venting of this furnace without the use of the above stated
kits is prohibited.

NOTE − Each heat section of the G24−200 unit re­quires its own sidewall venting kit. The two venting
systems shall be completely separate starting at the
outlet of each heat section and ending with the vent
terminal of each Field Controls Venting Kit. (See fig-
ure 12 for field wiring of the two sidewall horizontal
venting kits.)

WIRING FOR SIDEWALL VENTING KITS

(Two kits are required − one for each heat section.)

24 VAC

THERMOSTAT

W2 R Y2 GCW1 Y1

When horizontally vented, the minimum clearance for
terminations from electric meters, gas meters, regula­tors and relief equipment is 4 ft. (1.2m) for US installa­tions. Refer to the current CSA−B149.1 for installations in
Canada or with authorities having local jurisdiction.

At vent terminations, care must be taken to maintain pro­tective coatings over building materials (prolonged expo­sure to exhaust condensate can destroy protective
coatings). It is recommended that the exhaust outlet not
be located within 6 feet (1.8 m) of a condensing unit be­cause the condensate can damage the painted coating.

FIELD INSTALLED WIRING

FACTORY INSTALLED WIRING

CK−43 CONTROL BOX

PRESSURE

SWITCH

C

NO

L1 MN

2

1

354

RELAY

T1 T2 T3

M

SWG

POWER

VENTER

MOTOR

W2 R Y2 G

W1 Y1

CONNECTIONS IN FURNACE JUNCTION BOX

C

C

TERMINAL STRIP FOR THERMOSTAT

L2

L1

120VAC

CK−43 CONTROL BOX

PRESSURE

SWITCH

NO

L1 MN

2

1

354

RELAY

T1 T2 T3

M

SWG

POWER

VENTER

MOTOR

FIGURE 12

Page 24

Gas Piping

NOTE − The flexible connector supplied with the unit
must not be modified and must be installed between
the two combination gas controls.

1 − Piping can be installed to enter either side of cabinet.

Refer to figure 13.
Left-Side Installation − Install flexible connector
(supplied with unit) between gas valves and connect
supply piping as shown.

Right-Side Installation −

a − Remove tee and 1/2 in. NPTx1/2 in. male brass

fitting from left side gas valve.

b − Remove 1/2 in. elbow and nipple from right side

gas valve and re-install on left side gas valve fac­ing toward right side cabinet entry.

c − Re-install tee and 1/2 in. NPTx1/2 in. male brass

fitting on right side gas valve with 3/4 in. side of
tee facing the right side cabinet entry.

d − Install flexible connector (supplied with unit) be-

tween gas valves and connect supply piping as
shown.

NOTE − Flexible gas connector must be routed so that
connector does NOT come in contact or interfere with
any wiring.

2 − When connecting the gas supply, factors such as

length of run, number of fittings and furnace rating
must be considered to avoid excessive pressure drop.
Table 9 lists recommended pipe sizes for typical ap­plications.

3 − The gas piping must not run in or through air ducts,

clothes chutes, gas vents or chimneys, dumbwaiters
or elevator shafts.

4 − The piping should be sloped 1/4 inch (6.4 mm) per 15

feet (4.57 m) upward toward the meter from the fur­nace. The piping must be supported at proper inter­vals [every 8 to 10 feet (2.44 to 3.01 m) using suitable
hangers or straps. A drip leg should be installed in ver­tical pipe runs to the unit.

5 − In some localities, codes may require installation of a

manual main shut-off valve and union (furnished by
the installer) external to the unit. Union must be of the
ground joint type.

6 − A 1/8" N.P.T. plugged tap is located on gas valve for

test gauge connection. See figure 20 for tap location.

IMPORTANT

Compounds used on threaded joints of gas piping
must be resistant to the actions of liquified petro­leum gases.

LEFT SIDE GAS LINE INSTALLATION

MANUAL MAIN SHUT-OFF VALVE

1/2 in. NPT X 1/2 in. MALE

BRASS FITTING

(Provided with flex connector)

DRIP LEG

TEE

AUTOMATIC GAS VALVE

(WITH MANUAL SHUT-OFF VALVE)

FIELD PROVIDED AND

(3/4 in. X 1/2 in. X 1/2 in.)

GROUND JOINT UNION

FLEXIBLE CONNECTOR

SHIPPED WITH UNIT

AND FIELD INSTALLED

INSTALLED

1/2 in. STREET

ELBOW

RIGHT SIDE GAS LINE INSTALLATION

(See item # 1 on previous page for installation instructions)

FLEXIBLE CONNECTOR
SHIPPED WITH UNIT
AND FIELD INSTALLED

1/2 in. STREET

ELBOW

AUTOMATIC GAS VALVE

(WITH MANUAL SHUT-OFF VALVE)

1/2 in. NPT X 1/2 in. MALE

FIELD PROVIDED AND

INSTALLED

BRASS FITTING

(Provided with

flex connector)

MANUAL MAIN SHUT-OFF VALVE

(3/4 in. X 1/2 in. X 1/2in. )

DRIP LEG

GROUND JOINT UNION

TEE

FIGURE 13

Page 25

TABLE 9

Nominal

Internal

GAS PIPE CAPACITY − FT3/HR (KL/HR)

Nominal Internal

Iron Pipe Size

Inches(mm)

1/4

(6.35)

3/8

(9.53)

1/2

(12.7)

3/4

(19.05)

1

(25.4)

1−1/4

(31.75)

1−1/2

(38.1)

2

(50.8)

2−1/2

(63.5)

3

(76.2)

4

(101.6)

Diameter

Inches(mm)

.364

(9.246)

.493

(12.522)

.622

(17.799)

.824

(20.930)

1.049

(26.645)

1.380

(35.052)

1.610

(40.894)

2.067

(52.502)

2.469

(67.713)

3.068

(77.927)

4.026

(102.260)

10

(3.048)20(6.096)30(9.144)40(12.192)50(15.240)60(18.288)70(21.336)80(24.384)90(27.432)

43

(1.13)

95

(2.69)

175

(4.96)

360

(10.19)

680

(919.25)

1400

(39.64)

2100

(59.46)

3950

(111.85)

6300

(178.39)

11000

(311.48)

23000

(651.27)

29

(.82)

65

(1.84)

120

(3.40)

250

(7.08)

465

(13.17)

950

(26.90)

460

(41.34)

2750

(77.87)

4350

(123.17)

7700

(218.03)

15800

(447.39)

24

(.68)

52

(1.47)

97

(2.75)

200

(5.66)

375

(10.62)

770

(21.80)

1180

(33.41)

2200

(62.30)

3520

(99.67)

6250

(176.98)

12800

(362.44)

NOTE − Capacity given in cubic feet (m3 ) of gas per hour and based on 0.60 specific gravity gas.

Length of Pipe - Feet (m)

20

(.57)

45

(1.27)

82

(2.32)

170

(4.81)

320

(9.06)

660

(18.69)

990

(28.03)

1900

(53.80)

3000

(84.95)

5300

(150.07)

10900

(308.64)

18

(.51)

40

(1.13)

73

(2.07)

151

(4.28)

285

(8.07)

580

(16.42)

900

(25.48)

1680

(47.57)

2650

(75.04)

4750

(134.50)

9700

(274.67)

(121.76)

(249.18)

16

(.45)

36

(1.02)

66

(1.87)

138

(3.91)

260

(7.36)

530

(15.01)

810

(22.94)

1520

(43.04)

2400

(67.96)

4300

8800

15

(.42)

33

(.73)

61

(1.73)

125

(3.54)

240

(6.80)

490

(13.87)

750

(21.24)

1400

(39.64)

2250

(63.71)

3900

(110.43)

8100

(229.36)

14

(.40)

31

(.88)

57

(1.61)

118

(3.34)

220

(6.23)

460

(13.03)

690

(19.54)

1300

(36.81)

2050

(58.05)

3700

(104.77)

7500

(212.37)

13

(.37)

29

(.82)

53

(1.50)

110

(3.11)

205

(5.80)

430

(12.18)

650

(18.41)

1220

(34.55)

1950

(55.22)

3450

(97.69)

7200

(203.88)

100

(30.480)

12

(.34)

27

(.76)

50

(1.42)

103

(2.92)

195

(5.52)

400

(11.33)

620

(17.56)

1150

(32.56)

1850

(52.38)

3250

(92.03)

6700

(189.72)

Leak Check

After gas piping is completed, carefully check all piping
connections (factory- and field-installed) for gas leaks. Use
a leak detecting solution or other preferred means.

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.

NOTE − In case emergency shutdown is required, shut off
the main manual gas valve and disconnect the main power
to the furnace. These devices should be properly labeled
by the installer.

The furnace must be isolated from the gas supply system
by closing its individual manual shut-off valve during any
pressure testing of the gas supply system at pressures
equal to or less than 1/2 psig (3.48 kPa).

IMPORTANT

When testing pressure of gas lines, gas valve must
be disconnected and isolated. See figure 14. Gas
valves can be damaged if subjected to more than 1/2
psig (3.48 kPa).

MANUAL MAIN

SHUT−OFF VALVE

WILL NOT HOLD

NORMAL TEST

PRESSURE

CAP

FIGURE 14

ISOLATE

GAS

VALVES

FURNACE

Page 26

Electrical

CAUTION

Electrostatic discharge can affect electronic com­ponents. Take precautions during furnace installa­tion and service to protect the furnace’s electronic
controls. Precautions will help to avoid control ex­posure to electrostatic discharge by putting the fur­nace, the control and the technician at the same
electrostatic potential. Neutralize electrostatic
charge by touching hand and all tools on an un­painted unit surface, such as the gas valve or blow­er deck, before performing any service procedure.

Refer to figure 15, 16, and 17 for field wiring and figures 18
and 19 for schematic wiring diagram and troubleshooting.

1 − Select circuit protection and wire size according to re-

quirements listed on unit rating plate.

2 − Install a separate disconnect switch (protected by ei-

ther fuse or circuit breaker) near the unit so power can
be turned off for servicing.

3 − Make power supply wire connections at unit make-up

boxes (both left and right side boxes are provided).

4 − Install the room thermostat according to the instruc-

tions provided with the thermostat and make connec­tions according to the appropriate field wiring
diagram. Install a field-provided 150 ohm, 10 watt re­sistor (Lennox part number P−8−6256) in two-stage
applications when using an electro-mechanical ther­mostat.

5 − All applications require a control transformer to power

the furnace’s 24 volt circuit. In all applications except

TABLE 10

DRIVE KIT TRANSFORMER VOLTAGES AND PART NUMBERS

Drive Kit

Model No.

Furnace

Supply

Voltage,

Phase,

Frequency

**Induced Draft Blower Autotransformers Control Circuit Transformer

Transformer
Part Number
& (Quantity)

Wiring

Diagram

Designation

Input

Voltage

those where a 208/230 volt power supply is used, an
autotransformer is required to power each of the in­duced draft blowers. These transformer(s) are pro­vided in the drive kit which has been selected for use
with the furnace. Transformer part numbers and volt­ages are given in table 10.
Install the transformer(s) in the control box using the
holes pre-drilled for them.
Select a field wiring diagram according to the power
supply voltage and phase being used (see figure 15,
16, or 17), and make the wiring connections between
the transformers and the furnace.

6 − Select a field wiring diagram according to the power

supply voltage and phase being used (see figure 15,
16, or 17), and make wiring connections between the
blower motor and the furnace. The connecting wires
are provided in the drive kit.

7 − An accessory relay (K109) is provided with the

G24−200 furnace. Any accessory with a rated voltage
equal to the supply voltage can be connected to termi­nal 5" of this relay. The relay is energized with the
blower.

8 − To add an accessory which is energized on a heating

demand (such as a humidifier), a relay with coil wired
to terminal W1" of the TB1 terminal strip must be add­ed.

9 − The TB1" terminal strip includes a terminal for econo-

mizer connection. See the field wiring diagrams.

10 −Electrically ground the unit according to local codes or,

in the absence of local codes, according to the current
National Electric Code (ANSI/NFPA No. 70) for the
USA or current Canadian Electric Code part 1 (CSA
standard C22.1) for Canada.

Output

Voltage

Transformer

Part Number

Wiring

Diagram

Designation

Primary

Voltage

Secondary-

Voltage

DKG24−200−1

DKG24−200−2

DKG24S−200−3,

DKG24−200−6

DKG24S−200−4,

DKG24−200−7

DKG24S−200−5,

DKG24−200−8

*Note − This transformer has a nominal 230 volt output rating and a 460 volt input rating; however, when wired to the furnace as shown in figure 15, a 115 volt input will produce a 230
volt output.
**Note − The induced draft blowers are rated at 230 volts, single phase, 60 hz.

120v,

1ph, 60hz

208/230v,

1ph, 60hz

208/230v,

3ph, 60hz

460v,

3ph, 60hz

575v,

3ph, 60hz

54G5201*

(2)

− − − − − − − − − − − − − − − −

− − − − − − − − − − − − − − − −

54G5201

(2)

54G3101

(2)

T3, T13 115* 230*

T3, T13 460 230

T3, T13 575 230

LB−66256G

(99K0601)

LB−66256G

(99K0601)

LB−66256K

(13H2801)

LB−66256H

(51H7901)

LB−66256J

(66J5401)

T1 120 24

T1 208 or 240 24

T1 208 or 240 24

T1 480 24

T1 600 24

Page 27

G24−200 FIELD WIRING DIAGRAM (120V SINGLE PH 60HZ)

COMBUSTION

AIR BLOWER

(Alternate make-up
box right side)

MAKE-UP BOX

T3 TRANSFORMER

TERMINAL STRIP

See Note 1

RELAY

K109

RELAY

K105

RELAY

K13

CONTROL BOX

RED

L1

RED

L3

RED

See Note 3

5

7

7

4

PRIMARY

LIMIT

GAS

VALV E

PRESSURE

IGNITION

CONTROL

DOOR

INTERLOCK

RED

TB34

1
1

2

2

YELLOW
YELLOW

BLUE

BLUE

GROUND
LUG

BLACK

K3 CONTACTOR

T1 TRANSFORMER

24v: blue − yellow

120v: black − white

SWITCH

BOARD

BLACK

RED

WHITE

WHITE

COMBUSTION

AIR BLOWER

FLAME ROLLOUT

DOOR

INTERLOCK

J84

31 2 4

PLUG

BLUE

WHITE

BLACK

BLUE

L3

L1

L2

T1

T3T2

PRIMARY

LIMIT

GAS

VALV E

SWITCH

T13 TRANSFORMER

See Note 3

RED

C

W1

G

W2

Y1

Y2

R

ECON

TB1 TERMINAL STRIP

PRESSURE

IGNITION

CONTROL

BOARD

RED

L1

RED

L3

MAKE−UP BOX

SWITCH

BLOWER DECK

R3

See Note 2

FUSED OR CIRCUIT BREAKER

DISCONNECT

(Furnished by

installer)

L1 N

GND

(Alternate make-up
box left side)

REMOVE FACTORY­INSTALLED JUMPER IN
TWO-STAGE MODE

THERMOSTAT

C

W1

G

W2

Y1

Y2

R

ECONOMIZER

NOTES :

BLOWER MOTOR

1 − Relay K109 can be used for an accessory rated at the same voltage as power supply.
2 − Field installed and supplied resistor (R3), is required in two-stage applications when using electro-mechanical thermo-

stat. (Use a 150 ohm, 10 watt resistor − Lennox part number P−8−6256.)
3 − The T3 and T13 transformers (54G5201) are marked as follows: 230v between white and black leads and 460v between

white and red leads. However, in this application, each transformer has been used to supply 230v (available between the
white and red leads) to an induce draft blower when 115v is applied between the white and black leads of each transformer.

FIELD-INSTALLED DRIVE KIT COMPONENT

FACTORY INSTALLED

LINE VOLTAGE FIELD INSTALLED
24 VOLTS FIELD INSTALLED

FIGURE 15

Page 28

COMBUSTION

AIR BLOWER

PRIMARY

LIMIT

GAS

VALV E

G24-200 FIELD WIRING DIAGRAM

P UNITS − 208/230V 1PH 60 HZ

Y UNITS − 208/230V 3PH 60HZ

PRESSURE

SWITCH

IGNITION

CONTROL

BOARD

COMBUSTION

AIR BLOWER

GAS

VALV E

PRIMARY

LIMIT

PRESSURE

IGNITION

CONTROL

BOARD

SWITCH

Three phase shown. L2 not used

in single phase applications

FUSED OR CIRCUIT BREAKER

DISCONNECT (Furnished by

installer)

L1

GND

L3L2

RELAY

K109

RELAY

K105

FLAME ROLLOUT

SWITCH

BLOWER DECK

RED

RED

RED

MAKE−UP BOX

L1

L2

L3

(Alternate make−up
box right side)

TERMINAL STRIP

SEE NOTE 1

5

7

7

T1 TRANSFORMER

24v: blue − yellow

208v: red − black

240v: orange − black

TB34

1
1

2

2

YELLOW
YELLOW

BLUE

BLUE

Three phase shown.

This lead not used in

single phase applications

FLAME ROLLOUT

SWITCH

31 2 4

DOOR

INTERLOCK

J84

PLUG

DOOR

INTERLOCK

Three phase shown. L2 not used

in single phase applications

REMOVE JUMPER IN
TWO-STAGE MODE

GROUND
LUG

BLACK

K3 CONTACTOR

RED

ORANGE

BLOWER MOTOR

L1

T1

L2

L3

T3T2

RED

L1

RED

L2

RED

L3

MAKE−UP BOX

C

W1

G

W2

Y1

Y2

R

ECON

TB1

TERMINAL STRIP

CONTROL BOX

R3
See Note 2

(Alternate make−up
box left side)

THERMOSTAT

C

W1

G

W2

Y1

Y2

R

ECONOMIZER

NOTES :

1 − Relay K109 can be used
for an accessory rated at the
same voltage as power sup­ply.

2 − Field installed and supplied re­sistor (R3), is required in two-stage
applications when using electro­mechanical thermostat.
(Use a 150 ohm, 10 watt resistor −
Lennox part number P−8−6256.)

FIELD-INSTALLED DRIVE KIT COMPONENT

FACTORY INSTALLED

LINE VOLTAGE FIELD INSTALLED
24 VOLTS FIELD INSTALLED

FIGURE 16

Page 29

COMBUSTION

AIR BLOWER

(Alternate make-up
box right side)

RED

RED

RED

PRIMARY

LIMIT

GAS

VALV E

DOOR

INTERLOCK

L1

L2

L3

G24−200 FIELD WIRING DIAGRAM

G UNITS − 460V 3PH 60HZ

J UNITS − 575V 3PH 60HZ

PRESSURE

SWITCH

IGNITION

CONTROL

BOARD

RED

COMBUSTION

AIR BLOWER

FLAME ROLLOUT

SWITCH

PLUG

J84

31 2 4

GAS

VALV E

DOOR

INTERLOCK

BLUE

PRIMARY

LIMIT

IGNITION

CONTROL

BOARD

L1

L2

L3

PRESSURE

SWITCH

BLOWER DECK

RED

RED

RED

FUSED OR

CIRCUIT BREAKER

DISCONNECT

(Furnished by

installer)

L1 L2

L1

L3

GND

MAKE-UP BOX

RELAY

K109

RELAY

K105

RELAY

K13

RED

T3 TRANSFORMER

460v: white − red

230v: white − black

TERMINAL STRIP

TB34

SEE NOTE 1

1

5

1

2

7

7

2

YELLOW
YELLOW

BLUE

BLUE

4

T1 TRANSFORMER

24v: blue − yellow

460v: black − black

RED

BLACK

WHITE

GROUND
LUG

BLACK

BLACK

BLACK

BLACK

K3 CONTACTOR

WHITE

RED

BLUE

L3

L1

L2

T1

T3T2

BLOWER MOTOR

T13 TRANSFORMER

BLACK

460v: white − red

230v: white − black

C

W1

G

W2

Y1

Y2

R

ECON

TB1 TERMINAL STRIP

CONTROL BOX

MAKE−UP BOX

R3

See Note 2

(Alternate make-up
box left side)

REMOVE JUMPER IN
TWO-STAGE MODE

THERMOSTAT

C

W1

G

W2

Y1

Y2

R

ECONOMIZER

NOTES :

1 − Relay K109 can be used
for an accessory rated at the
same voltage as power supply.

2 − Field installed and supplied
resistor (R3), is required in two­stage applications when using
electro-mechanical thermostat.
(Use a 150 ohm, 10 watt resistor

− Lennox part number P−8−6256.)

FIELD-INSTALLED DRIVE KIT COMPONENT

FACTORY INSTALLED

LINE VOLTAGE FIELD INSTALLED
24 VOLTS FIELD INSTALLED

FIGURE 17

Page 30

SCHEMATIC WIRING DIAGRAM FOR G24−200 UNITS (120V SINGLE PHASE 60HZ )

FIGURE 18

Page 31

WIRING SCHEMATIC DIAGRAM FOR G24−200

P UNITS − 208/230V 1PH 60 HZ

Y UNITS − 208/230V 3PH 60HZ

G UNITS − 460V 3PH 60HZ

J UNITS − 575V 3PH 60HZ

FIGURE 19

Page 32

Unit Start−Up

FOR YOUR SAFETY READ BEFORE LIGHTING

WARNING

Do not use this furnace if any part has been under
water. A flood−damaged furnace is extremely dan­gerous. Attempts to use the furnace can result in
fire or explosion. A qualified service agency
should be contacted to inspect the furnace and to
replace all gas controls, control system parts, elec­trical parts that have been wet or the furnace if
deemed necessary.

WARNING

Danger of explosion. Can cause injury
or product or property damage. Should
the gas supply fail to shut off or if
overheating occurs, shut off the gas
valve to the furnace before shutting off
the electrical supply.

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 sup­ply air outside when possible.

Placing Furnace Into Operation

G24−200 units are equipped with two direct spark ignition
systems − one for each heat section. Do not attempt to
manually light burners on these furnaces. Each time ther­mostat calls for heat, the burners will automatically light.

WARNING

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

Gas Valve Operation − White Rodgers 36E Two-Stage
Gas Valve (Figure 20)

1 − Set the thermostat to the lowest setting.

2 − Turn off all electrical power to the unit.

3 − This furnace is equipped with an ignition device

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

4 − Remove the control access panels.

WHITE RODGERS 36E GAS VALVE

LOW HEAT MANIFOLD
PRESSURE FACTORY-SET,
NOT FIELD-ADJUSTABLE.

HIGH HEAT MANIFOLD

PRESSURE ADJUSTMENT

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

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

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.

MANIFOLD

PRESSURE

OUTLET ON SIDE.

GAS VALVE KNOB SHOWN IN OFF" POSITION

FIGURE 20

5 − Perform the following to both gas valves − Turn knob

on gas valve 180 either way to OFF. Do not force.

6 − Wait five minutes to clear out any gas. If you then

smell gas, STOP! Immediately call your gas supplier
from your neighbor’s phone. Follow the gas supplier’s
instructions. If you don’t smell gas go to next step.

7 − Perform the following to both gas valves − Turn knob

on gas valve 180 either way to ON position.

8 − Replace the control access panels.

9 − Turn on all electrical power to the unit.

10 −Set the thermostat to desired setting.

11 −Both combustion air blowers will start. The burners

in both heat sections will light after a 45-second pre­purge.

Page 33

12 −If the furnace does not light the first time (the gas line

may not be 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 Unit" and call your service techni­cian or gas supplier.

B − Turning Off Gas To Unit

1 − Set the thermostat to the lowest setting.

7 − For troubleshooting purposes, an ignition attempt after

lockout may be re-established manually. Move thermo­stat from Heat" to OFF" then back to Heat." The heat­ing sequence then restarts at step 1.

B − Applications with Two-Stage Thermostat

1 − When the thermostat calls for heat, the K13 relay con-

tacts close (W1 and W2 not jumpered on furnace ter-
minal strip) and both combustion air blowers (B6 and
B16) start.

2 − Turn off all electrical power to the unit if service is to be

performed.

3 − Remove the control access panels.

4 − Perform the following to both gas valves − Turn knob on

gas valve 180 either way to OFF. Do not force.

5 − Replace the control access panels.

Heating Sequence of Operation

A − Applications with Single-Stage Thermostat

1 − When the thermostat calls for heat, the K13 and K19

relay contacts close (W1 and W2 jumpered on furnace
terminal strip) and both combustion air blowers (B6
and B16) start.

2 − The combustion air pressure switches (S18 and S45)

prove blower operation, then ignition controls (A3 and
A12) are energized. The pressure switches are factory
set and require no adjustment.

3 − After a pre-purge of 30 seconds, the two spark ignitors

energize and the gas valves (GV1 and GV3) open on

low heat and after approximately 3 seconds open on
high heat.

4 − The sparks ignite the gas, the ignition sensors prove

the flames and the combustion process continues.

5 − In the event that the flames are not detected after the

first trial for ignition (8 seconds trial duration), the igni­tion controls will repeat steps 3 and 4 two more times
before locking out. (The two ignition controls operate
independently. If one control locks out its gas valve, the
other control maintains its gas valve in operation.)

2 − The combustion air pressure switches (S18 and S45)

prove blower operation, then the ignition controls (A3
and A12) are energized. The pressure switches are
factory set and require no adjustment.

3 − After a pre-purge of 30 seconds, the two spark ignitors

energize and the gas valves (GV1 and GV3) open on
low heat.

4 − The sparks ignite the gas, the ignition sensors prove

the flames and the combustion process continues.

5 − In the event that the flames are not detected after the

first trial for ignition, the ignition controls will repeat
steps 3 and 4 two more times before locking out. (The
two ignition controls operate independently. If one con­trol locks out its gas valve, the other control maintains
its gas valve in operation.)

6 − If the temperature of the conditioned space continues

to drop, the thermostat’s second-stage contacts close
(W2 powered).

7 − The K19 relay contacts close and the gas valves (GV1

and GV3) open on high heat after approximately 3
seconds.

8 − When the W2 heating demand is satisfied, the K19

relay contacts open and both gas valves (GV1 and
GV3) close second-stage after 3 seconds and then re­turn to low heat operation. When the W1 heating de­mand is satisfied, the K13 relay contacts open and
both gas valves (GV1 and GV3) close first-stage.

6 − When W1 heating demand is satisfied, the K13 and

K19 relay contacts open and both gas valves (GV1 and
GV3) close on second-stage after 3 seconds and then
close on first-stage.

9 − For troubleshooting purposes,an ignition attempt after

lock-out may be re-established manually. Move the
thermostat from Heat" to OFF" then back to Heat."
The heating sequence then restarts at step 1.

Page 34

Gas Pressure Adjustment

Unit

Input

High Altitude Information

Gas Flow (Approximate)

1− Operate unit at least 15 minutes before checking gas

flow. Determine the time in seconds for two revolu-
tions of gas through the meter. (Two revolutions as­sures a more accurate time.) A portable LP gas meter
(17Y44) is available for LP applications.

2− Divide the number of seconds by two and compare

to the time in table 11. If manifold pressure is correct
and rate is incorrect, check gas orifices for proper size
and restriction.

3− Remove temporary gas meter if installed.

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

TABLE 11

GAS METER CLOCKING CHART

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

75,000 48 96 120 240
125,000 29 58 72 144
130,000 28 55 69 138
235,000 15 31 38 77
260,000 14 28 35 69
470,000 8 15 19 38

Natural−1000 btu/cu ft LP−2500 btu/cu ft

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

3

). Apply pressure

Gas Pressure

1 − Check the gas line pressure with the unit (both heat sec-

tions) firing at the high heat input rate. A minimum of 4.5
in. w.c. for natural gas should be maintained.

2 − After the line pressure has been checked and ad-

justed, check the high heat regulator pressure on both
gas valves. See figure 20 for gas pressure adjustment
screw location. The low heat setting is factory-set and
is not field-adjustable. The high heat manifold pres­sure settings are given in table 12.

TABLE 12

MANIFOLD GAS PRESSURES (HIGH HEAT)

ALTITUDE

feet (m)

0 − 2000 (0 − 610) Natural 3.5 (0.87)

2000 − 4500 (610 − 1372) Natural 3.5 (0.87)

4500 − 7500* (1372 −

2286)

GAS

FUEL

Natural 3.2 (0.80)

MANIFOLD PRESSURE

in. w.c. (kPa)

*In Canada, certification for installation at altitudes over
4500 feet (1372m) above sea level is the jurisdiction of the
local authorities.

In Canada, certification for installation at altitudes over
4500 feet (1372m) above sea level is the jurisdiction of the
local authorities.

See table 12 for the correct high heat manifold pressures to
be maintained for natural gas.

Check the gas line pressure with the unit (both heat sections)
firing at high heat input rate The minimum pressure as
shown on the nameplate for natural gas must be main­tained.

No orifice change is required. No pressure switch change
is required.

Other Unit Adjustments and Operation

Primary (S10 and S99) Limits

Each heat sec tion ha s a pr imary limit locat ed on the heat­ing compartment vestibule panel. These limits are facto­ry set and do not require field adjustment.

Flame Rollout Switches (S47 and S69)

Each heat section has a manually reset flame rollout switch.
Each switch is located on the burner top plate. If tripped, a
check for adequate combustion air should be made before
resetting. The switches are non-adjustable.

Combustion Air Pressure Switches (S18 and S45)

Each heat section has a combustion air pressure switch lo­cated on the heating compartment vestibule panel. Each
switch checks for proper combustion air blower operation
before allowing ignition trial. The switches are factory set
and require no field adjustment.

Blower Motor Controls (K25 Circuit Board),
(K20 Relay), (K123 Relay) and (K36 Relay)

When the gas valves are powered, the blower motor starts
after a delay of 45 seconds. When the gas valves lose pow­er because the thermostat demand is satisfied, the blower
motor remains running for 150 seconds. These timings are
programmed into the K25 control board and are non-ad­justable. The board is located in the control box.
If abnormal furnace operation causes either high limit (S10
or S99) to open, the relays K20, K123 and K36 maintain
blower operation until the limit(s) is reset.

Page 35

Temperature Rise

Burner Flame Adjustment

Check the temperature rise and, if necessary, adjust the
blower speed to maintain the temperature rise within the
range shown on the unit rating plate.

Electro-mechanical Thermostat Heat Anticipation

In single-stage heat applications, set the heat anticipation
to 0.2 amps.
In two-stage heat applications, set the heat anticipation to

0.26 amps and install a field-provided resistor (150 ohm, 10
watt rating −Lennox part number P−8−6256) in parallel with
K13 relay coil.

Electrical

1 − Check all wiring for loose connections.

2 − Check for the correct voltage at the furnace (furnace

operating).

3 − Check amp-draw on blower motor.

Motor service factor amps
Nameplate __________Actual__________

Flue And Chimney

The G24−200 burner flame is not adjustable; however, the
flame should be inspected at the beginning of each heating
season. If necessary, clean the burners. Burner flame
should be blue when burning natural gas. See figure 21.

BURNER FLAME

FLAME APPEARS

BLUE IF BURNING

NAT. GAS.

BURNER

FLAME

HEAT

EXCHANGER

TUBE

VEST

PANEL

FIGURE 21

Failure To Operate

If unit fails to operate check the following:

1 − Is the thermostat calling for heat?

2 − Are access panels securely in place?

3 − Is the main disconnect switch closed?

1 − Check flue pipe, chimney and all connections for tight-

ness and to make sure there is no blockage.

2 − Check unit for proper draft.

3 − Are pressure switches closed? Obstructed flue will

open pressure switches and cause unit to shut down.
Check flue and outlet for blockages.

4 − Reset manual flame rollout switches on burner box

covers.

4 − Is there a blown fuse or tripped circuit breaker?

5 − Are the filters dirty or plugged? Dirty or plugged filters

will cause the limit controls to shut the unit off.

6 − Is gas turned on at the meter?

7 − Is the manual main shut-off valve open?

8 − Are the internal manual shut-off valves open?

9 − Are the unit ignition systems in lock out mode? If unit

locks out again, call serviceman to inspect unit for block­ages.

Page 36

Setting blower CFM

Vol um e

Note − Turn electrical power off when adjusting mo­tor pulley. Blower RPM adjustment is accomplished by

changing the motor pulley opening. Loosen Allen screw
and turn pulley clockwise to increase RPM or turn coun­terclockwise to decrease. Re-tighten Allen screw. (See
Blower motor/drive installation section for the pulley
alignment and belt tensioning method.)

1 − Enter table 13 at design CFM and total external static

pressure. (Design total external static pressure
equals the sum of all pressure drops across all acces­sories which are installed external to furnace and all
ductwork/accessories. See table 14 for external filter
box with filters pressure drops, C17 coil pressure
drops and EMD17M economizer pressure drops.)

TABLE 13

CFM vs TOTAL EXTERNAL STATIC PRESSURE

Air

Vol um e

cfm

(L/s)

.10 (25) .20 (50) .30 (75) .40 (100) .50 (125) .60 (150) .70 (175) .80 (200) .90 (225) 1.00 (250) 1.10 (275)

RPM BHP

(kW)

RPM BHP

(kW)

RPM BHP

(kW)

Total External Static Pressure − in. w.g. (Pa)

RPM BHP

(kW)

RPM BHP

(kW)

2 − The table yields a value for design BHP and RPM.

3 − Select drive kit so that motor maximum BHP (as

shown in table 15) exceeds the value from table13.

4 − Run the blowers and measure the actual blower shaft

RPM and total external static pressure.

5 − Adjust RPM to the value in table13 which will result in the

design CFM. From design CFM and actual Total Exter­nal Static Pressure reading, Table 13 gives required
BHP. This value should still be lower than the maximum
BHP delivered by the motor as shown in table 15.

6 − As a final check, measure the motor’s current draw and

compare it to the motor’s nameplate service factor amps
rating (SFA). If the current draw is not less than or equal
to the SFA rating, reduce the motor’s load until it is.

RPM BHP

(kW)

RPM BHP

(kW)

RPM BHP

(kW)

RPM BHP

(kW)

RPM BHP

(kW)

RPM BHP

(kW)

2400

(1135)

2600

(1225)

2800

(1320)

3000

(1415)

3200

(1510)

3400

(1605)

3600

(1700)

3800

(1795)

4000

(1890)

4200

(1980)

4400

(2075)

- - - - - - - -

- - - - - - - -

- - - - - - - -

- - - - - - - -

- - - - - - - -

- - - -

- - - -

- - - -

- - - -

550 0.70

(0.52)

570 0.80

(0.60)

535 0.50

(0.37)

550 0.55

(0.41)

570 0.60

(0.45)

585 0.70

(0.52)

605 0.80

(0.60)

625 0.90

(0.67)

535 0.30

(0.22)

545 0.35

(0.26)

560 0.40

(0.30)

570 0.45

(0.34)

585 0.50

(0.37)

595 0.55

(0.41)

610 0.65

(0.48)

625 0.70

(0.52)

645 0.80

(0.60)

660 0.90

(0.67)

675 1.00

(0.75)

600 0.35

(0.26)

610 0.40

(0.30)

620 0.45

(0.34)

630 0.55

(0.41)

640 0.85

(0.45)

655 0.65

(0.48)

665 0.75

(0.56)

680 0.80

(0.60)

695 0.90

(0.67)

710 1.00

(0.75)

725 1.10

(0.82)

665 0.45

(0.34)

670 0.50

(0.37)

680 0.55

(0.41)

690 0.60

(0.45)

685 0.70

(0.52)

710 0.75

(0.56)

720 0.85

(0.63)

730 0.90

(0.67)

745 1.00

(0.75)

760 1.10

(0.82)

770 1.20

(0.90)

720 0.55

(0.41)

725 0.60

(0.45)

735 1.05

(0.48)

740 0.70

(0.52)

750 0.80

(0.60)

760 0.85

(0.63)

770 0.95

(0.71)

780 1.05

(0.78)

790 1.10

(0.82)

805 1.25

(0.93)

815 1.35

(1.01)

755 0.65

(0.48)

780 0.70

(0.52)

785 0.75

(0.56)

790 0.90

(0.60)

800 0.90

(0.67)

805 0.95

(0.71)

815 1.05

(0.78)

825 1.15

(0.86)

835 1.25

(0.93)

850 1.35

(1.01)

860 1.45

(1.08)

825 0.75

(0.56)

830 0.80

(0.60)

835 0.85

(0.63)

840 0.90

(0.67)

845 1.00

(0.75)

855 1.05

(0.78)

860 1.15

(0.86)

870 1.25

(0.93)

880 1.35

(1.01)

890 1.45

(1.08)

900 1.60

(1.19)

875 0.85

(0.63)

875 0.90

(0.67)

880 0.95

(0.71)

865 1.00

(0.75)

890 1.10

(0.82)

895 1.20

(0.90)

905 1.25

(0.93)

910 1.35

(1.01)

920 1.45

(1.08)

930 1.60

(1.19)

940 1.70

(1.27)

920 0.95

(0.71)

920 1.00

(0.75)

925 1.05

(0.78)

930 1.15

(0.86)

935 1.20

(0.90)

940 1.30

(0.97)

945 1.40

(1.04)

955 1.50

(1.12)

960 1.60

(1.19)

970 1.70

(1.27)

- - - - - - - -

965 1.05

(0.78)

965 1.10

(0.82)

965 1.15

(0.86)

970 1.25

(0.93)

975 1.35

(1.34)

- - - -

- - - -

- - - -

- - - -

- - - -

4600

(2170)

4800

(2265)

5000

(2360)

NOTE − All air data is measured external to furnace using rear return air opening without air filters in place.

Bold text indicates 2 H.P. (1.5 kW) drive kits.

590 0.90

(0.67)

610 1.00

(0.75)

630 1.10

(0.82)

645 1.00

(0.75)

660 1.10

(0.82)

680 1.25

(0.93)

695 1.10

(0.82)

710 1.25

(0.93)

730 1.35

(1.01)

740 1.25

(0.93)

755 1.35

(1.01)

775 1.50

(1.12)

785 1.35

(1.01)

800 1.45

(1.08)

815 1.60

(1.19)

830 1.45

(1.08)

845 1.60

(1.19)

860 1.75

(1.31)

870 1.60

885 1.75

900 1.90

Page 37

(1.19)

(1.31)

(1.42)

915 1.75

(1.31)

925 1.85

(1.38)

940 2.00

(1.49)

950 1.85

(1.38)

965 2.00

(1.49)

975 2.15

(1.60)

- - - - - - - -

- - - - - - - -

- - - - - - - -

TABLE 14

Circuit

Belt

Weight

(

)

(35.2)

ACCESSORY AIR RESISTANCE

Model C17−090/120 Coil

cfm L/s in. w.g. Pa in. w.g. Pa in. w.g. Pa in. w.g. Pa in. w.g. Pa

2400 1135 0.14 35 0.17 42 0.05 12 .04 10 −−−− −−−−

2600 1225 0.16 40 0.18 45 0.06 15 .05 12 −−−− −−−−

2800 1320 0.19 47 0.20 50 0.07 17 .06 15 −−−− −−−−

3000 1415 0.22 55 0.22 55 0.08 20 .07 17 .03 7

3200 1510 0.24 60 0.23 57 0.09 22 .08 20 .04 10

3400 1605 0.27 67 0.25 62 0.10 25 .09 22 .05 12

3600 1700 0.30 75 0.27 67 0.10 25 .10 25 .06 15

3800 1795 0.33 82 0.29 72 0.11 27 .11 27 .07 17

4000 1890 0.36 90 0.31 77 0.12 30 .12 30 .07 17

4200 1980 0.38 95 0.34 85 0.13 32 −−−− −−−− .08 20

4400 2075 0.42 104 0.36 90 0.14 35 −−−− −−−− .09 22

4600 2170 0.45 11 2 0.39 97 0.16 40 −−−− −−−− .10 25

4800 2265 0.48 11 9 0.42 104 0.17 42 −−−− −−−− .11 27

5000 2360 0.51 127 0.44 109 0.18 45 −−−− −−−− .11 27

* Furnished with filter box.

Pleated Filter −

1 in. (25 mm)

*Disposable Filter −

1 in. (25 mm)

EMD17M−95 EMD17M−135

TABLE 15

DRIVE KIT SPECIFICATIONS

Additive

Cooling

Tons

(kW)

Drive Kit

Model No. & Phase

Voltage

Motor Output

hp (kW)

min. max.

Minimum

Circuit

Ampacity

Motor Pulley

(in.) & Groove (in.) & Groove Range

Blower Pulley

RPM

Belt

Shipping

Weight

lbs. (kg)

DKG24−200−1 115v−1ph 25 42 (19)

DKG24−200−2 230v−1ph 14 42 (19)

7.5 or 10
(26.4 or

35.2)

10

35.2

 Maximum usable output of motors furnished by Lennox are shown. In Canada, nominal motor output is also maximum usable motor output. If motors of comparable output are used,
keep within the service factor limitations specified on motor nameplate.
 At rated voltages shown.
NOTE − All drive kits include matching 24 volt control transformer. All kits (except 208/230v) include matching auto−transformer for combustion air blower operation.

DKG24S−200−3 208/230v−3ph

DKG24S−200−4 460v−3ph 4 48 (22)

DKG24S−200−5 575v−3ph 3 48 (22)

DKG24−200−6 208/230v−3ph 9 57 (26)

DKG24−200−7 460v−3ph

DKG24−200−8 575v−3ph 3 57 (26)

1.5 (1.1) 1.7 (1.3)

2 (1.5) 2.3 (1.7)

9

4

7/8 x 4−3/4 − A 1 x 10 − A 535 − 772 A − 52

7/8 x 6 − A 1 x 10 − A 802 − 977 A − 52

48 (22)

57 (26)

Page 38

Repair Parts List

The following repair parts are available through independent Lennox dealers. When ordering parts, include the complete fur­nace model number listed on the CSA international. rating plate  Example: G24−200. Refer to page 4 and 5 for parts identifi­cation.

Cabinet Parts Electrical Parts Heating Parts Blower Parts

Front louver door (2) Transformer(s) Heat exchanger (2) Wheel (2)

Blower access panel (2) Ignition control board (2) Main burners Motor

Cabinet cap Door interlock (2) Main burner orifices Cut-off plate (2)

Cabinet top-rear Ignition cable (2) Gas manifold/burner

box assembly (2)

Cabinet bottom-rear Ignitor (2) Gas valve (2) Motor pulley

Flue adapter (2) Flame sensor (2) Flue box (2) Wheel pulley

Roll-out switch (2) Combustion air blower (2) Belt

Primary limit (2) Flexible gas connector Bearing (2)

Pressure switch (2) Vibration isolators (4)

Blower timing control board Locating rods (2)

Accessory relay

Blower operation relays

Contactor

Combustion air blower

operation relays

Shaft

G24−200 Start−up and Performance Check List

Job Name Job Number Date
Job Location City State/Province Installer

City State/Province

Unit Model No. Serial Number Serviceman

HEATING SECTION

Electrical Connections Tight? Supply Voltage

Blower Motor Amps Blower Motor Horsepower/Kw

Blower Motor Lubrication OK? Blower Shaft Lubrication OK?

Gas Piping Connections Tight & Leaks Tested?

Fuel Type: Natural Gas?

Furnace Btu (kw) Input Line Pressure w.c./Pa − Nat.

Regulator Pressure w.c./Pa −− Nat.

Connections Tight? Proper Draft?

Temperature Rise Filter Clean & Secure? Vent Clear?

THERMOSTAT

Calibrated? Heat Anticipator Properly Set? Level?

Page 39

Troubleshooting

HEATING SEQUENCE OF OPERATION WITH TWO-STAGE THERMOSTAT

NOTE − THIS FURNACE FUNCTIONS WITH TWO INDEDPENDENTLY CONTROLLED HEAT SECTIONS.

THE GRAY BOXES INDICATE COMPONENTS WHICH EFFECT BOTH HEAT SECTIONS SIMULTANEOUSLY.

NORMAL HEATING MODE

POWER ON

THERMOSTAT CALLS FOR HEAT

(W1 ENERGIZED)

K13 RELAY ENERIZED.

A3 (A12) IGNITION CONTROL LED ON.

IS THE S10 (S99) HIGH LIMIT CLOSED?

YES

IS THE S47 (S69) ROLLOUT SWITCH CLOSED?

YES

IS THE B6 (B15) COMBUSTION

AIR BLOWER ON?

YES

IS THE S18 (S45) COMBUSTION AIR

BLOWER PROVING SWITCH CLOSED?

YES

NO

NO

NO

NO

ABNORMAL HEATING MODE

DETERMINE WHY AUTOMATIC-RESET

S10 (S99) HIGH LIMIT OPEN.

CHECK VENTING SYSTEM

OPERATION/BLOCKAGE BEFORE

RESETTING THE MANUALLY-RESET S47

(S69) ROLLOUT SWITCH.

CHECK K13−1 CONTACT OPERATION AND

WIRING TO B6 (B15) COMBUSTION AIR

BLOWER?

CHECK SENSING TUBE FOR BLOCKAGE

AND S18 (S45) SWITCH FOR PROPER

OPERATION.

B6 (B15) COMBUSTION AIR BLOWER

PREPURGE FOR 30 SECS.

8 SEC TRIAL FOR IGNITION − START IGNITION

TRAIL, GV1 (GV3) GAS VALVE OPENS ON LOW

HEAT. IS FLAME SENSED WITHIN 8 SECS?

YES

K56 (K57) RELAY ENERGIZED. K25 CIRCUIT

BOARD ENERGIZED. SYSTEM BLOWERS ON

AFTER 45 SEC DELAY.

YES

FLAME SENSE OK?

YES

CONTINUED NEXT PAGE

NO

NO

Page 40

NO

NO

GV1 (GV3) GAS VALVE CLOSED, SPARK

OFF. INCREMENT TRAIL REGISTER.

(DURING RETRY PERIOD LED FLASHES

.5 SEC. ON AND 2.5 SEC. OFF. ARE THE

THREE TRIALS COMPLETE?

YES

LOCKOUT OCCURS. TO RESET A3 (A12)

IGNITION CONTROL MOVE THERMOSTAT

SWITCH FROM HEAT TO OFF TO HEAT.

CHECK BELT.

CHECK RELAYS.

HEATING SEQUENCE OF OPERATION WITH TWO-STAGE THERMOSTAT CONTINUED

NORMAL HEATING MODE

IS THE S10 (S99) HIGH LIMIT CLOSED?

YES

HAS ROOM AIR TEMPERATURE CONTINUED

TO DROP BELOW THE THERMOSTAT"S

W2 SET POINT?

YES

POWER FROM W2

ENERGIZES K19 RELAY

SECOND-STAGE OF GV1 (GV3)

GAS VALVE ENERGIZED (HIGH HEAT)

AFTER APPROXIMATELY 3 SEC.

IS W2 DEMAND SATISFIED?

NO

NO

IS W1 DEMAND SATISFIED?

YES

A3 (A12) LED OFF

FIRST-STAGE OF GV1 (GV3)

GAS VALVE CLOSES.

B6 (B15) COMBUSTION

AIR BLOWER OFF.

ABNORMAL HEATING MODE

DETERMINE WHY AUTOMATIC-RESET

S10 (S99) HIGH LIMIT OPEN. K20, (K123), K36

RELAYS MAINTAIN BLOWER OPERATION.

YES

CLOSE SECOND-STAGE OF

GV1 (GV3) GAS VALVE AFTER

APPROXIMATELY 3 SEC. AND THEN

RETURN TO LOW HEAT OPERATION.

NOTE − IF ECONOMIZER INSTALLED, ECONOMIZER OPERATES WHEN BLOWER POWERED.

1 − ON NORMAL OPERATION WITH THERMOSTAT CALLING FOR HEAT.
2 − 0.5 SEC ON AND 2.5 SECS OFF IN IGNITION RETRY PERIOD.
3 − OFF NO POWER OR DETECTED FAULT.

B3 SYSTEM BLOWERS OFF

AFTER 150 SEC DELAY.

LED CODES

Page 41

HEATING SEQUENCE OF OPERATION WITH SINGLE-STAGE THERMOSTAT

NOTE − THIS FURNACE FUNCTIONS WITH TWO INDEPENDENTLY CONTROLLED HEAT SECTIONS.

THE GRAY BOXES INDICATE COMPONENTS WHICH EFFECT BOTH HEAT SECTIONS SIMULTANEOUSLY.

NORMAL HEATING MODE

POWER ON

THERMOSTAT CALLS FOR HEAT

(W1 ENERGIZED)

K13 AND K19 RELAY ENERIZED.

(W1 AND W2 OF FURNACE

TERMINAL STRIP JUMPERED.)

A3 (A12) IGNITION CONTROL LED ON.

IS THE S10 (S99) HIGH LIMIT CLOSED?

YES

IS THE S47 (S69) ROLLOUT SWITCH CLOSED?

YES

IS THE B6 (B15) COMBUSTION

AIR BLOWER ON?

YES

IS THE S18 (S45) COMBUSTION AIR

BLOWER PROVING SWITCH CLOSED?

YES

NO

NO

NO

NO

ABNORMAL HEATING MODE

DETERMINE WHY AUTOMATIC-RESET

S10 (S99) HIGH LIMIT OPEN.

CHECK VENTING SYSTEM

OPERATION/BLOCKAGE BEFORE

RESETTING THE MANUALLY-RESET S47

(S69) ROLLOUT SWITCH.

CHECK K13−1 CONTACT OPERATION AND

WIRING TO B6 (B15) COMBUSTION AIR

BLOWER?

CHECK SENSING TUBE FOR BLOCKAGE

AND S18 (S45) SWITCH FOR PROPER

OPERATION.

B6 (B15) COMBUSTION AIR BLOWER

PREPURGE FOR 30 SECS.

8 SEC TRIAL FOR IGNITION − START IGNITION

TRAIL, GV1 (GV3) GAS VALVE OPENS ON LOW

HEAT AND AFTER A 3 SEC. DELAY OPENS ON

HIGH HEAT. IS FLAME SENSED WITHIN 8 SECS?

YES

K56 (K57) RELAY ENERGIZED. K25 CIRCUIT

BOARD ENERGIZED. SYSTEM BLOWERS ON

AFTER 45 SEC DELAY.

YES

FLAME SENSE OK?

YES

CONTINUED NEXT PAGE

Page 42

NO

NO

NO

NO

GV1 (GV3) GAS VALVE CLOSED, SPARK

OFF. INCREMENT TRAIL REGISTER.

(DURING RETRY PERIOD LED FLASHES

.5 SEC. ON AND 2.5 SEC. OFF. ARE THE

THREE TRIALS COMPLETE?

YES

LOCKOUT OCCURS. TO RESET A3 (A12) IGNITION

CONTROL MOVE THERMOSTAT SWITCH FROM

HEAT TO OFF TO HEAT.

CHECK BELT.

CHECK RELAYS.

HEATING SEQUENCE OF OPERATION WITH SINGLE-STAGE THERMOSTAT CONTINUED

NORMAL HEATING MODE

IS THE S10 (S99) HIGH LIMIT CLOSED?

YES

IS W1 DEMAND OF

THERMOSTAT SATISFIED?

YES

A3 (A12) LED OFF

SECOND-STAGE OF GV1 (GV3)

GAS VALVE CLOSES AFTER

APRROXIMATELY 3 SEC. AND

THEN FIRST-STAGE CLOSES.

B6 (B15) COMBUSTION

AIR BLOWER OFF.

B3 SYSTEM BLOWERS OFF

AFTER 150 SEC DELAY.

NO

ABNORMAL HEATING MODE

DETERMINE WHY AUTOMATIC-RESET

S10 (S99) HIGH LIMIT OPEN. K20, (K123), K36

RELAYS MAINTAIN BLOWER OPERATION.

NOTE − IF ECONOMIZER INSTALLED, ECONOMIZER OPERATES WHEN BLOWER POWERED.

LED CODES

1 − ON NORMAL OPERATION WITH THERMOSTAT CALLING FOR HEAT.
2 − 0.5 SEC ON AND 2.5 SECS OFF IN IGNITION RETRY PERIOD.
3 − OFF NO POWER OR DETECTED FAULT.

Page 43

COOLING SEQUENCE OF OPERATION

FOR TWO CONDENSING UNITS

THERMOSTAT CALLS FOR COOLING

(Y1 POWERED)

COOLING CONTACTOR OF FIRST-STAGE

CONDENSING UNIT CLOSES AND SYSTEM

BLOWERS START.

HAS ROOM AIR TEMPERATURE CONTINUED

TO RISE ABOVE THE THERMOSTAT"S

Y2 SET POINT?

YES

COOLING CONTACTOR OF SECOND-STAGE

CONDENSING UNIT CLOSES.

IS Y2 DEMAND SATISFIED?

YES

FOR A SINGLE CONDENSING UNIT

THERMOSTAT CALLS FOR COOLING

(Y1 POWERED)

COOLING CONTACTOR OF CONDENSING UNIT

CLOSES AND SYSTEM BLOWERS START.

IS Y1 DEMAND SATISFIED?

YES

COOLING UNIT CONTACTOR

OPENS AND B3 SYSTEM

BLOWERS OFF.

SECOND-STAGE COOLING

UNIT CONTACTOR OPENS

IS Y1 DEMAND SATISFIED?

YES

FIRST-STAGE COOLING UNIT

CONTACTOR OPENS AND B3

SYSTEM BLOWERS OFF.

MANUAL FAN OPERATION

MANUAL FAN SELECTION MADE AT THERMOSTAT.

THE BLOWERS RUN CONTINUOUSLY WITH OR

WITHOUT A CALL FOR HEATING OR COOLING.

Page 44