Lennox MERIT ML193DF, ML195DF MERIT Installation Instructions Manual

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Page 1

06/12

*2P0612*

507011−01

*P507011-01*

 2012 Lennox Industries Inc.

Dallas, Texas, USA

AIR FLOW

DOWNFLOW

INSTALLATION INSTRUCTIONS ML193DF

MERIT

SERIES GAS FURNACE

DOWNFLOW AIR DISCHARGE

507011−01 06/2012 Supersedes 506475−01

THIS MANUAL MUST BE LEFT WITH THE

HOMEOWNER FOR FUTURE REFERENCE

This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in manuals, be alert to the potential for personal injury or death.

CAUTION

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

WARNING

Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Installation and service must be performed by a licensed professional installer (or equivalent), service agency or the gas supplier.

Table of Contents

Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ML193DF Gas Furnace 3. . . . . . . . . . . . . . . . . . . . . . . . . .

Shipping and Packing List 3. . . . . . . . . . . . . . . . . . . . . . . .

Safety Information 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Use of Furnace as a Construction Heater 4. . . . . . . . . . .

General 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Combustion, Dilution and Ventilation Air 5. . . . . . . . . . . .

Setting Equipment 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Filters 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Duct System 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pipe and Fittings Specifications 12. . . . . . . . . . . . . . . . . . .

Joint Cementing Procedure 14. . . . . . . . . . . . . . . . . . . . . . .

Venting Practices 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vent Piping Guidelines 15. . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas Piping 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unit Start Up 37. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas Pressure Measurement 38. . . . . . . . . . . . . . . . . . . . . .

Proper Combustion 39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

High Altitude 39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Testing Non Direct Appliances for Proper Air 40. . . . . . . .

Other Unit Adjustments 41. . . . . . . . . . . . . . . . . . . . . . . . . .

Twinning the ML193DF Furnace 42. . . . . . . . . . . . . . . . . .

Service 43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Repair Parts List 44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Start Up Checklist 45. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Litho U.S.A.

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ML193DF Unit Dimensions − inches (mm)

AIR

EXHAUST AIR

OUTLET

COMBUSTION

AIR INTAKE

FLOW

2−1/16 (52)

GAS PIPING INLET

(Either Side)

ELECTRICAL INLET

(Either Side)

RETURN AIR

OPENING

FRONT VIEW SIDE VIEW

TOP VIEW

3/4

(19)

27−3/4

19−1/4

(489)

9−1/8 (232) Right 6−9/16 (167) Left

2 (51)

Either Side

(838)

3/4

(19)

Supply

Air

Supply

Air

9/16

(14)

9/16

(14)

9/16

(14)

9/16 (14)

19−7/16

(494)

3/4

(19)

CONDENSATE

TRAP CONNECTION

(127)

6−1/2 (165) Either Side

2−1/4

(57)

(Either Side)

1 (25)

Front Panel

(705)

ML193DF

Model No.

A B C

in. mm in. mm in. mm

045XP36B

070XP6B

17−1/2 446 16−3/8 416 16 406

090XP48C 110XP60C

21 533 19−7/8 504 19−1/2 495

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ML193DF Gas Furnace

The ML193DF Category IV gas furnace is shipped ready for installation in the downflow position.

The furnace is equipped for installation in natural gas applications. A conversion kit (ordered separately) is required for use in propane/LP gas applications.

The ML193DF can be installed as a Direct Vent or Non− Direct Vent gas central furnace.

NOTE − In Direct Vent installations, combustion air is taken from outdoors and flue gases are discharged outdoors. In Non−Direct Vent installations, combustion air is taken from indoors or ventilated attic or crawlspace and flue gases are discharged outdoors. See figures 1 and 2 for applications involving roof termination.

FIGURE 1

DIRECT VENT INSTALLATION NON−DIRECT VENT

INSTALLATION

EXHAUST

OUTLET

COMBUSTION

AIR INTAKE OUTSIDE

OF HOUSE

COMBUSTION

AIR INTAKE

INSIDE

OF HOUSE

EXHAUST OUTLET

FIGURE 2

NON−DIRECT VENT

INSTALLATION

NON−DIRECT VENT

INSTALLATION

COMBUSTION

AIR INTAKE INSIDE

VENTILATED

CRAWL SPACE

COMBUSTION

AIR INTAKE INSIDE

VENTILATED

ATTIC SPACE

EXHAUST OUTLET

Shipping and Packing List

Package 1 of 1 contains

1 − Assembled ML193DF unit 1 − Bag assembly containing the following:

1 − Snap bushing 1 − Snap plug 1 − Wire tie 1 − Condensate trap 1 − Condensate trap cap 1 − Condensate trap clamp 1 − 2" diameter Air intake screen 1 − 1/2" Threaded street elbow

DANGER

Danger of explosion.

There are circumstances in which odorant used with LP/propane gas can lose its scent. In case of a leak, LP/propane gas will settle close to the floor and may be difficult to smell. An LP/propane leak detector should be installed in all LP applications.

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

The following items may also be ordered separately: 1 − Thermostat 1 − Propane/LP changeover kit

Safety Information

WARNING

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.

ML193DF units are CSA International certified to ANSI Z21.47 and CSA 2.3 standards.

Building Codes

In the USA, installation of gas furnaces must conform with local building codes. In the absence of local codes, units must be installed according to the current National Fuel Gas Code (ANSI-Z223.1/NFPA 54). The National Fuel Gas Code is available from the following address:

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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 Natural Gas and Propane Installation Codes, local plumbing or waste water codes and other applicable local codes.

In order to ensure proper unit operation in non−direct vent applications, combustion and ventilation air supply must be provided according to the current National Fuel Gas Code or CSA-B149 standard.

Locations and Clearances

This furnace is CSA International certified for installation clearances to combustible material as listed on the unit nameplate and in the table in figure 13. Accessibility and service clearances must take precedence over fire protection clearances.

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 standards.

NOTE − Furnace must be adjusted to obtain a temperature rise within the range specified on the unit nameplate. Failure to do so may cause erratic limit operation and premature heat exchanger failure.

This ML193DF furnace must be installed so that its electrical components are protected from water.

Installation in Combination with a Cooling Coil

When this furnace is used with cooling units (figure 3), 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, this 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.

FIGURE 3

Heating Unit Installed Parallell to Air Handler Unit

AIR HANDLER

GAS UNIT

Dampers

(open during cooling

operation only)

Dampers

(open during heating

operation only)

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.

The ML193DF furnace may be installed in alcoves, closets, attics, basements, garages, utility rooms and crawl spaces.

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

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

Use of Furnace as Construction Heater

Lennox does not recommend the use of ML193DF units as a construction heater 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.

ML193DF units may be used for heating of buildings or structures under construction, if the following conditions are met:

• The vent system must be permanently installed per these installation instructions.

• A room thermostat must control the furnace. The use of fixed jumpers that will provide continuous heating is not allowed.

• The return air duct must be provided and sealed to the furnace.

• Return air temperature range between 60°F (16°C) and 80°F (27°C) must be maintained.

• Air filters must be installed in the system and must be maintained during construction.

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• Air filters must be replaced upon construction completion.

• The input rate and temperature rise must be set per the furnace rating plate.

• One hundred percent (100%) outdoor air must be provided for combustion air requirements during construction. Temporary ducting may supply outdoor air to the furnace. Do not connect duct directly to the furnace. Size the temporary duct following these instructions in section for Combustion, Dilution and Ventilation Air in a confined space with air from outside.

• The furnace heat exchanger, components, duct system, air filters and evaporator coils must be thoroughly cleaned following final construction clean−up.

• All furnace operating conditions (including ignition, input rate, temperature rise and venting) must be verified according to these installation instructions.

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 outlined previously, the following general recommendations must be considered when installing a ML193DF furnace:

• Place the furnace 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.

• When the furnace is installed in non−direct vent applications, do not install the furnace where drafts might blow directly into it. This could cause improper combustion and unsafe operation.

• When the furnace is installed in non−direct vent applications, do not block the furnace combustion air opening with clothing, boxes, doors, etc. 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.

• When the furnace is installed in an unconditioned space, consider provisions required to prevent freezing of condensate drain system.

CAUTION

ML193DF unit should not be installed in areas normally subject to freezing temperatures.

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

Combustion, Dilution & Ventilation Air

If the ML193DF is installed as a Non−Direct Vent Furnace, follow the guidelines in this section.

NOTE − In Non−Direct Vent installations, combustion air is taken from indoors or ventilated attic or crawlspace and flue gases are discharged out−doors.

WARNING

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

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, ap-

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pliance 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 combus− tion and ventilation, use the guidelines and procedures in this section to install ML193DF furnaces to ensure efficient and safe operation. You must consider combustion air needs and requirements for exhaust vents and gas pip−ing. A portion of this information has been reprinted with permission from the National Fuel Gas Code (ANSI− Z223.1/NFPA 54). 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 CSA B149 installation codes.

CAUTION

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

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 m

) 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 m

) per 1,000 Btu (.29 kW) per hour of the com− bined 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 mm

) 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 mm

). 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 4.

FIGURE 4

EQUIPMENT IN CONFINED SPACE − ALL AIR FROM INSIDE

OPENINGS

(To Adjacent

Unconfined

Space)

NOTE − Each opening shall have a free area of at least one square inch per 1,000 Btu (645mm

per .29kW) per hour of the total input

rating of all equipment in the enclosure, but not less than 100 square inches (64516mm.

2).

ROOF TERMINATED

EXHAUST PIPE

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

Page 7

Air from Outside

If air from outside is brought in for combustion and ventilation, the confined space shall be provided with two permanent openings. One opening shall be within 12" (305mm) of the top of the enclosure and one within 12" (305mm) 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 per 4,000 Btu (645mm

per 1.17kW) per hour of total input rating of all equipment in the enclosure. When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch per 2,000 Btu (645mm

per .59kW) per total input rating of all equipment in the enclosure (See figure 5). It is also permissible to bring in air for combustion from a ventilated attic (figure 6) or ventilated crawl space (figure 7).

FIGURE 5

EQUIPMENT IN CONFINED SPACE − ALL AIR FROM OUTSIDE

(Inlet Air from Crawl Space and Outlet Air to Outised)

NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm

per 1.17kW) per

hour of the total input rating of all equipment in the enclosure.

OUTLET

AIR

INLET

AIR

VENTILATION

LOUVERS

(For unheated

crawl space)

ROOF TERMINATED

EXHAUST PIPE

VENTILATION LOUVERS

(Each end of attic)

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

FIGURE 6

EQUIPMENT IN CONFINED SPACE

(Inlet Air from Ventilated Attic and Outlet Air to Outside)

NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm

per 1.17kW) per

hour of the total input rating of all equipment in the enclosure.

Ventilation Louvers

Inlet Air

(Minimum

12 in.(305mm) Above

attic floor)

Roof Terminated

Exhaust Pipe

Furnace

*Intake Debris

Screen

(Provided)

* See table 8 for maximum vent lengths

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 mm

) per 4,000 Btu (1.17 kW) per hour of total input rating of all equipment in the enclosure. See figures 5 and 8. When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch (645 mm

) per 2,000 Btu (.56 kW) per total input rating of all

equipment in the enclosure. See figure 9.

FIGURE 7

NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm

per 1.17kW) per

hour of the total input rating of all equipment in the enclosure.

EQUIPMENT IN CONFINED SPACE

(Inlet Air from Ventilated Crawlspace and Outlet Air to Outside)

Roof Terminated

Exhaust Pipe

Furnace

Ventilation

Louvers

(Crawl space)

*Intake Debris Screen Provided)

Inlet Air

(Minimum

12 in.(305mm)

Above crawl

space floor)

Coupling or 3 in. to 2 in.

Transition

(Field Provided)

* See table 8 for maximum vent lengths

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.

Page 8

FIGURE 8

EQUIPMENT IN CONFINED SPACE − ALL AIR FROM OUTSIDE

(All Air Through Ventilated Attic)

NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm

per 1.17kW) per

hour of the total input rating of all equipment in the enclosure.

OUTLET

AIR

VENTILATION LOUVERS

(Each end of attic)

INLET AIR

(Ends 12" above

bottom)

ROOF TERMINATED

EXHAUST PIPE

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

FIGURE 9

EQUIPMENT IN CONFINED SPACE −

ALL AIR FROM OUTSIDE

OUTLET AIR

INLET AIR

NOTE−Each air duct opening shall have a free area of at least one square inch per 2,000 Btu (645mm

per .59kW) 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 1 square inch per 4,000 Btu (645mm

per 1.17kW) per

hour of the total input rating of all other equipment in the enclosure.

ROOF TERMINATED

EXHAUST PIPE

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

Shipping Bolt Removal

NOTE − The ML193DF09048C is equipped with a 1/2 hp blower motor which has three flexible legs and one rigid leg. The rigid leg is equipped with a shipping bolt and a flat white plastic washer (rather than the rubber mounting grommet used with a flexible mounting leg). See figure 10.

The bolt and washer must be removed before the furnace is placed into operation. After the bolt and washer

have been removed, the rigid leg will not touch the blower housing.

FIGURE 10

RIGID LEG

remove shipping bolt and washer

ML193DF09048C BLOWER MOTOR

Installation − Setting Equipment

WARNING

Do not install the furnace on its front, back or in the horizontal position. See figure 12. Do not connect the return air ducts to the back of the furnace. Doing so will adversely affect the operation of the safety control devices, which could result in personal injury or death.

Select a location that allows for the required clearances that are listed on the unit nameplate. Also consider gas supply connections, electrical supply, vent connection, condensate trap and drain connections, and installation and service clearances [24 inches (610 mm) at unit front]. The unit must be level from side to side. Unit may

be positioned from level to 1/2" toward the front to aid in draining.

See figure 11.

Page 9

Allow for clearances to combustible materials as indicated on the unit nameplate. Minimum clearances for closet or alcove installations are shown in figure 13.

WARNING

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

FIGURE 11

SETTING EQUIPMENT

FRONT VIEW SIDE VIEW

AIR FLOW

1/2"

max.

AIR FLOW

SIDE VIEW

Unit must be level side−to−side. Unit may be positioned from level to 1/2" toward the front to aid in draining.

FIGURE 12

Front

NOTE − Do not install the furnace on its front, back or in the horizontal position

Back

Horizontal

Page 10

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 air in the living space. Use sheet metal screws and joint tape to seal return air system to furnace. In platform installations with furnace return, 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. For no reason should return and supply air duct systems ever 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.

The unit may be installed three ways in downflow applications: on non−combustible flooring, on combustible flooring using an additive base, or on a reverse−flow cooling coil cabinet. Do not drag the unit across the floor in the

downflow position. Floor and furnace flange damage will result. Refer to figure 13 for clearances in downflow applica-

tions.

Downflow Application Installation Clearances

Top

Bottom

Left Side Right Side

Top 0

*Front 0

Back 0

Sides 0†

Vent 0

Floor NC‡

*Front clearance in alcove installation must be 24 in. (610 mm). Maintain a minimum of 24 in. (610 mm) for front service access. †Allow proper clearances to accommodate condensate trap and vent pipe installation. ‡The furnace may be installed on a combustible wood floor if an optional additive base is installed between the furnace and the combustible floor.

FIGURE 13

Installation on Non−Combustible Flooring Figure 14

1 − Cut floor opening keeping in mind clearances listed on

unit rating plate. Also keep in mind gas supply connections, electrical supply, flue and air intake connections and sufficient installation and servicing clearances. See table 1 for correct floor opening size.

2 − Flange warm air plenum and lower the plenum into the

opening.

3 − Set the unit over the plenum and seal the plenum to

the unit.

4 − Ensure that the seal is adequate.

TABLE 1

NON−COMBUSTIBLE FLOOR OPENING SIZE

Cabinet Width

Front to Rear Side to Side

in. mm in. mm

B Cabinet (17.5") 19 − 3/4 502 16 − 5/8 422

C Cabinet (21") 19 − 3/4 502 20−1/8 511

NOTE − Floor opening dimensions listed are 1/4 inch (6 mm) larger than the unit opening. See dimension drawing on page 2.

FIGURE 14

SUPPLY AIR

PLENUM

PROPERLY

SIZED FLOOR

OPENING

FURNACE

Installation on Combustible Flooring Figure 15

1 − When unit is installed on a combustible floor, a down-

flow combustible flooring base must be installed between the furnace and the floor. The base must be ordered separately. See table 2 for opening size to cut in floor.

CAUTION

The furnace and combustible flooring base shall not be installed directly on carpeting, tile, or other combustible material other than wood flooring.

Page 11

TABLE 2

COMBUSTIBLE FLOORING BASE OPENING SIZE

Cabinet

Width

Catalog Number

Front to Rear Side to Side

in. mm in. mm

B Cabinet

(17.5")

11M60

22 559 18 − 3/4 476

C Cabinet

(21")

11M61

22 559 22 − 3/4 578

FIGURE 15

FURNACE

SUPPLY AIR

PLENUM

COMBUSTIBLE FLOORING BASE

PROPERLY

SIZED FLOOR

OPENING

2 − After opening is cut, set the combustible flooring base

into opening.

3 − Check fiberglass strips on the combustible flooring

base to make sure they are properly glued and positioned.

4 − Lower supply air plenum into the combustible flooring

base until plenum flanges seal against fiberglass strips.

NOTE − Be careful not to damage fiberglass strips. Check for a tight seal.

5 − Set the furnace over the plenum.

6 − Ensure that the seal between the furnace and plenum

is adequate.

Installation on Cooling Coil Cabinet Figure 16

NOTE − Downflow combustible flooring kit is not used..

1 − Refer to reverse−flow coil installation instructions for

correctly sized opening in floor and installation of cabinet.

2 − When cooling cabinet is in place, set and secure the

furnace according to the instructions that are provided with the cooling coil. Secure the furnace to the cabinet.

3 − Seal the cabinet and check for air leaks.

FIGURE 16

COOLING COIL

PLENUM

PROPERLY

SIZED FLOOR

OPENING

FURNACE

Return Air Opening −− Downflow Units

Return air may be brought in only through the top opening of a furnace installed in the downflow position. The following steps should be taken when installing plenum:

1 − Bottom edge of plenum should be flanged with a

hemmed edge (See figure 17 or 18).

2 − Sealing strips should be used to ensure an airtight seal

between the cabinet and the plenum.

3 − In all cases, plenum should be secured to top of fur-

nace using sheet metal screws.

4 − Make certain that an adequate seal is made.

FIGURE 17

SECURE FROM

OUTSIDE CABINET

PLENUM

(Field Provided)

SEALING STRIP (Field Provided)

Side View

CABINET

SIDE PANEL

SECURE FROM

INSIDE CABINET

PLENUM

(Field Provided)

SEALING STRIP (Field Provided)

Side View

CABINET

SIDE PANEL

FIGURE 18

Page 12

Filters

This unit is not equipped with a filter or rack. A field−provided filter is required for the unit to operate properly. Table 3 lists recommended filter size. A filter must be in place whenever the unit is operating.

TABLE 3

Furnace

Cabinet Width

Filter Size

16 x 25 x 1 (1)

17−1/2"

21"

Duct System

Use industry-approved standards to size and install the supply and return air duct system. Refer to ACCA Manual D. This will result in a quiet and low-static system that has uniform air distribution.

NOTE − This furnace is not certified for operation in heating mode (indoor blower operating at selected heating speed) with an external static pressure which exceeds 0.5 inches w.c. Operation at these conditions may result in improper limit operation.

Supply Air Plenum

If the furnace is installed without a cooling coil, a removable access panel should be installed in the supply air duct. The access panel should be large enough to permit inspection of the heat exchanger. 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.

Return Air Plenum

NOTE − Return air must not be drawn from a room where this furnace, or any other gas−fueled appliance (i.e., water heater), or carbon monoxide−producing device (i.e., wood fireplace) 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 raw gas or toxic fumes might then be distributed throughout the house by the furnace duct system.

Use fiberglass sealing strips, caulking, or equivalent sealing method between the plenum and the furnace cabinet to ensure a tight seal. If a filter is installed, size the return air duct to fit the filter frame.

Pipe & Fittings Specifications

All pipe, fittings, primer and solvent cement must conform with American National Standard Institute and the American Society for Testing and Materials (ANSI/ASTM) standards. The solvent shall be free flowing and contain no lumps, undissolved particles or any foreign matter that adversely affects the joint strength or chemical resistance of the cement. The cement shall show no gelation, stratification, or separation that cannot be removed by stirring. Refer to the table 4 below for approved piping and fitting materials.

CAUTION

Solvent cements for plastic pipe are flammable liquids and should be kept away from all sources of ignition. Do not use excessive amounts of solvent cement when making joints. Good ventilation should be maintained to reduce fire hazard and to minimize breathing of solvent vapors. Avoid contact of cement with skin and eyes.

TABLE 4

PIPING AND FITTINGS SPECIFICATIONS

Schedule 40 PVC (Pipe) D1785 Schedule 40 PVC (Cellular Core Pipe) F891

Schedule 40 PVC (Fittings) D2466

Schedule 40 CPVC (Pipe) F441

Schedule 40 CPVC (Fittings) F438

SDR−21 PVC or SDR−26 PVC (Pipe) D2241

SDR−21 CPVC or SDR−26 CPVC (Pipe) F442

Schedule 40 ABS Cellular Core DWV (Pipe) F628

Schedule 40 ABS (Pipe) D1527

Schedule 40 ABS (Fittings) D2468

ABS−DWV (Drain Waste & Vent) (Pipe & Fittings)

D2661

PVC−DWV (Drain Waste & Vent) Pipe & Fittings)

D2665

PRIMER & SOLVENT CEMENT

ASTM

SPECIFICATION

PVC & CPVC Primer F656 PVC Solvent Cement D2564

CPVC Solvent Cement F493

ABS Solvent Cement D2235

PVC/CPVC/ABS All Purpose Cement For Fittings & Pipe of the same material

D2564, D2235, F493

ABS to PVC or CPVC Transition Solvent Cement

D3138

CANADA PIPE & FITTING & SOLVENT

CEMENT

MARKING

PVC & CPVC Pipe and Fittings

ULCS636

PVC & CPVC Solvent Cement

ABS to PVC or CPVC Transition Cement

Page 13

IMPORTANT

ML193DF exhaust and intake connections are made of PVC. Use PVC primer and solvent cement when using PVC vent pipe. When using ABS vent pipe, use transitional solvent cement to make connections to the PVC fittings in the unit.

Use PVC primer and solvent cement or ABS solvent cement meeting ASTM specifications, refer to Table 4. As an alternate, use all purpose cement, to bond ABS, PVC, or CPVC pipe when using fittings and pipe made of the same materials. Use transition solvent cement when bonding ABS to either PVC or CPVC.

Low temperature solvent cement is recommended during cooler weather. Metal or plastic strapping may be used for vent pipe hangers. Uniformly apply a liberal coat of PVC primer for PVC or use a clean dry cloth for ABS to clean inside socket surface of fitting and male end of pipe to depth of fitting socket.

Canadian Applications Only − Pipe, fittings, primer and solvent cement used to vent (exhaust) this appliance must be certified to ULC S636 and supplied by a single manufacturer as part of an approved vent (exhaust) system. In addition, the first three feet of vent pipe from the furnace flue collar must be accessible for inspection.

TABLE 5

OUTDOOR TERMINATION USAGE

Input Size

Vent Pipe

Dia. in.

STANDARD CONCENTRIC

FlushMount

Kit

Wall Kit Wall Ring Kit

Field

Fabricated

1−1/2 inch 2 inch 3 inch

2 inch 3 inch 2 inch

51W11

22G44 (US)

30G28 (CA)

44J40

(US)

81J20 (CA)

15F74

71M80

(US)

44W92

(CA)

69M29

(US)

44W92

(CA)

60L46 (US)

44W93 (CA)

045

YES YES

YES

2−1/2

YES YES

YES

YES YES

YES

070

YES YES

YES

2−1/2

YES YES

YES

YES YES

YES

090

YES YES YES

2−1/2

YES YES YES

110

2 YES YES YES

YES YES YES

2−1/2 YES YES

YES YES YES

3 YES YES

YES YES YES

NOTE − Standard Terminations do not include any vent pipe or elbows external to the structure. Any vent pipe or elbows external to the structure must be included in total vent length calculations. See vent length tables.

Requires field−provided outdoor 1−1/2" exhaust accelerator.

Concentric kits 71M80 and 44W92 include 1−1/2" outdoor accelerator, when used with 045 and 070 input models.

Flush mount kit 51W11 includes 1−1/2 in. outdoor exhaust accelerator, required when used with 045, 070 and 090 input models.

Termination kits 30G28, 44W92, 4493 and 81J20 are certified to ULC S636 for use in Canada only.

See table 10 for vent accelerator requirements.

Page 14

Joint Cementing Procedure

All cementing of joints should be done according to the specifications outlined in ASTM D 2855.

NOTE − A sheet metal screw may be used to secure the intake pipe to the connector, if desired. Use a drill or self tapping screw to make a pilot hole.

DANGER

DANGER OF EXPLOSION!

Fumes from PVC glue may ignite during system check. Allow fumes to dissipate for at least 5 minutes before placing unit into operation.

1 − Measure and cut vent pipe to desired length.

2 − Debur and chamfer end of pipe, removing any ridges

or rough edges. If end is not chamfered, edge of pipe may remove cement from fitting socket and result in a leaking joint.

3 − Clean and dry surfaces to be joined.

4 − Test fit joint and mark depth of fitting on outside of pipe.

5 − Uniformly apply a liberal coat of PVC primer for PVC or

use a clean dry cloth for ABS to clean inside socket surface of fitting and male end of pipe to depth of fitting socket.

6 − Promptly apply solvent cement to end of pipe and in-

side socket surface of fitting. Cement should be applied lightly but uniformly to inside of socket. Take care to keep excess cement out of socket. Apply second coat to end of pipe.

NOTE − Time is critical at this stage. Do not allow primer to dry before applying cement.

7 − Immediately after applying last coat of cement to pipe,

and while both inside socket surface and end of pipe are wet with cement, forcefully insert end of pipe into socket until it bottoms out. Turn PVC pipe 1/4 turn during assembly (but not after pipe is fully inserted) to distribute cement evenly. DO NOT turn ABS or cellular core pipe.

NOTE − Assembly should be completed within 20 seconds after last application of cement. Hammer blows should not be used when inserting pipe.

8 − After assembly, wipe excess cement from pipe at end

of fitting socket. A properly made joint will show a bead around its entire perimeter. Any gaps may indicate an improper assembly due to insufficient solvent.

9 − Handle joints carefully until completely set.

Venting Practices

FIGURE 19

* See table 4 for allowable pipe.

Piping Suspension Guidelines

NOTE − Isolate piping at the point where it exits the outside wall or roof in order to prevent transmission of vibration to the structure.

SCHEDULE 40

PVC − 5’

all other pipe* − 3’

Wall

inside outside

24" maximum 3/4" minimum

Wall Thickness Guidelines

CHIMNEY

OR GAS

VENT

(Check sizing

for water

heater only)

FURNACE

(Replaced

by ML193)

WATER

HEATER

OPENINGS

(To Adjacent

Room)

If an ML193DF furnace replaces a furnace which was commonly vented with another gas appliance, the size of the existing vent pipe for that gas appliance must be checked. Without the heat of the original furnace flue products, the existing vent pipe is probably oversized for the single water heater or other appliance. The vent should be checked for proper draw with the remaining appliance.

FIGURE 20

REPLACING FURNACE THAT

WAS PART OF A COMMON

VENT SYSTEM

1 − In areas where piping penetrates joists or interior

walls, hole must be large enough to allow clearance on all sides of pipe through center of hole using a hanger.

Page 15

2 − When furnace is installed in a residence where unit is

shut down for an extended period of time, such as a vacation home, make provisions for draining condensate collection trap and lines.

Exhaust Piping (Figures 22 and 23)

Route piping to outside of structure. Continue with installation following instructions given in piping termination section.

CAUTION

Do not discharge exhaust into an existing stack or stack that also serves another gas appliance. If vertical discharge through an existing unused stack is required, insert PVC pipe inside the stack until the end is even with the top or outlet end of the metal stack.

CAUTION

The exhaust vent pipe operates under positive pressure and must be completely sealed to prevent leakage of combustion products into the living space.

Vent Piping Guidelines

The ML193DF can be installed as either a Non−Direct Vent or a Direct Vent gas central furnace.

Intake and exhaust pipe sizing −− Size pipe according to

tables 6 and 7. Count all elbows inside and outside the home. Table 6 lists the minimum vent pipe lengths permitted. Table 7 lists the maximum pipe lengths permitted.

TABLE 6

MINIMUM VENT PIPE LENGTHS

ML193DF

MODEL

MIN. VENT LENGTH*

045, 070, 090, 110

15 ft. or

5 ft plus 2 elbows or

10 ft plus 1 elbow

*Any approved termination may be added to the minimum length listed.

Regardless of the diameter of pipe used, the standard roof and wall terminations described in section Exhaust Piping Terminations should be used. Exhaust vent termination pipe is sized to optimize the velocity of the exhaust gas as it exits the termination. Refer to table 10.

In some applications which permit the use of several different sizes of vent pipe, a combination vent pipe may be used. Contact Lennox’ Application Department for assistance in sizing vent pipe in these applications.

IMPORTANT

Do not use screens or perforated metal in exhaust or intake terminations. Doing so will cause freeze−ups and may block the terminations.

Use the following steps to correctly size vent pipe diameter.

FIGURE 21

Piping Size Process

Which style termination

being used?

Standard or concentric?

See table 5.

Which needs

most elbows?

Intake or

exhaust?

How many elbows? Count all elbows inside and outside house.

Desired pipe size?

2", 2−1/2", 3"

Use table 7 or 8 to find max intake or exhaust pipe length. Includes all vent pipe and elbows inside and outside the house.

What is the altitude of the furnace installation?

What is the

furnace capacity?

045, 070, 090 or

110?

NOTE − It is acceptable to use any pipe size which fits within the guidelines allowed in table 7.

NOTE −

All horizontal runs of exhaust pipe must slope back

toward unit. A minimum of 1/4" (6mm) drop for each 12" (305mm) of horizontal run is mandatory for drainage.

NOTE − Exhaust pipe MUST be glued to furnace exhaust fittings.

NOTE − Exhaust piping should be checked carefully to make sure there are no sags or low spots.

Page 16

TABLE 7

Maximum Allowable Intake or Exhaust Vent Length in Feet

*Size intake and exhaust pipe length separately. Values in table are for Intake OR Exhaust, not combined total. Both Intake and Exhaust must be same pipe size. NOTE − Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.

Standard Termination at Elevation 0 − 10,000 ft.

Number

Of 90°

Elbows

Used

2" Pipe 2−1/2" Pipe 3" Pipe

Model Model Model

045 070 090 110 045 070 090 110 045 070 090 110

1 61 46 24

n/a

100 80 43

n/a

127 127 108 108

2 56 41 19 95 75 38 122 122 103 103

3 51 36 14 90 70 33 117 117 98 98

4 46 31

n/a

85 65 28 112 112 93 93

5 41 26 80 60 23 107 107 88 88

6 36 21 75 55 18 102 102 83 83

7 31 16 70 50 13 97 97 78 78

8 26 11 65 45

n/a

92 92 73 73

9 21

n/a

60 40 87 87 68 68

10 16 55 35 82 82 63 63

Concentric Termination Elevation 0 − 10,000 ft.

Number

Of 90°

Elbows

Used

2" Pipe 2−1/2" Pipe 3" Pipe

Model Model Model

045 070 090 110 045 070 090 110 045 070 090 110

1 53 38 22

n/a

90 70 39

n/a

111 111 104 104

2 48 33 17 85 65 34 106 106 99 99

3 43 28 12 80 60 29 101 101 94 94

4 38 23

n/a

75 55 24 96 96 89 89

5 33 18 70 50 19 91 91 84 84

6 28 13 65 45 14 86 86 79 79

7 23

n/a

60 40

n/a

81 81 74 74

8 18 55 35 76 76 69 69

9 13 50 30 71 71 64 64

10 n/a 45 25 66 66 59 59

TABLE 8

Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated

Attic or Crawl Space For Intake Air in Feet

NOTE − Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.

Standard Termination at Elevation 0 − 10,000 ft.

Number

Of 90°

Elbows

Used

2" Pipe 2−1/2" Pipe 3" Pipe

Model Model Model

045 070 090 110 045 070 090 110 045 070 090 110

1 51 36 14

n/a

85 65 28

n/a

107 107 88 88

2 46 31 9 80 60 23 102 102 83 83

3 41 26 4 75 55 18 97 97 78 78

4 36 21

n/a

70 50 13 92 92 73 73

5 31 16 65 45 8 87 87 68 68

6 26 11 60 40 3 82 82 63 63

7 21 6 55 35

n/a

77 77 58 58

8 16 1 50 30 72 72 53 53

9 11

n/a

45 25 67 67 48 48

10 6 40 20 62 62 43 43

Page 17

FIGURE 22

TYPICAL EXHAUST PIPE CONNECTIONS

TRANSITION

2”

3”

Pipe size determined in table 7.

2”

DO NOT transition from smaller

to larger pipe size in horizontal

runs of exhaust pipe.

TOP VIEW

EXHAUST

INTAKE

* When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible.

NOTE − Exhaust pipe and intake pipe must be the same diameter.

*2”

FIGURE 23

TYPICAL INTAKE PIPE CONNECTIONS

2”

TRANSITION

2”

3”

TRANSITION

3”

Pipe size determined in table 7.

2”

TOP VIEW

EXHAUST

INTAKE

* When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible.

NOTE − Intake pipe and exhaust pipe must be the same diameter.

*2”

Page 18

Intake Piping

The ML193DF furnace may be installed in either direct vent or non−direct vent applications. In non−direct vent

applications, when intake air will be drawn into the furnace from the surrounding space, the indoor air quality must be considered. Guidelines listed in Combustion, Dilution and Ventilation Air section must be followed.

Follow the next two steps when installing the unit in Direct Vent applications, where combustion air is taken from outdoors and flue gases are discharged outdoors. The

provided air intake screen must not be used in direct vent applications (outdoors).

1 − Use cement to secure the intake pipe to the inlet air

connector.

2 − Route piping to outside of structure. Continue with

installation following instructions given in general guide lines for piping terminations and intake and exhaust piping terminations for direct vent sections. Refer to table

7 for pipe sizes.

FIGURE 24

TYPICAL AIR INTAKE PIPE CONNECTIONS

NON−DIRECT VENT APPLICATIONS

AIR

INTAKE

SCREEN

(Provided)

NOTE − Air intake screen and elbow may be rotated, so that screen may be positioned to face forward or to either side.

Follow the next two steps when installing the unit in NonDirect Vent applications where combustion air is taken from indoors and flue gases are discharged outdoors.

1 − Use field−provided materials and the factory−provided

air intake screen to route the intake piping as shown in figure 24. Maintain a minimum clearance of 3" (76mm) around the air intake opening. The air intake opening (with the protective screen) should always be directed forward, or sideways.

2 − If intake air is drawn from a ventilated attic (figure 25)

or ventilated crawlspace (figure 26) the exhaust vent length must not exceed those listed in table 8. If 3" diameter pipe is used, reduce to 2" diameter pipe at the termination point to accommodate the debris screen.

3 − Use cement to secure the intake pipe to the connector,

if desired.

CAUTION

If this unit is being installed in an application with combustion air coming in from a space serviced by an exhaust fan, power exhaust fan, or other device which may create a negative pressure in the space, take care when sizing the inlet air opening. The inlet air opening must be sized to accommodate the maximum volume of exhausted air as well as the maximum volume of combustion air required for all gas appliances serviced by this space.

FIGURE 25

EQUIPMENT IN CONFINED SPACE

(Inlet Air from Ventilated Attic and Outlet Air to Outside)

NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm

per 1.17kW) per

hour of the total input rating of all equipment in the enclosure.

Ventilation Louvers

Inlet Air

(Minimum

12 in.(305mm) Above

attic floor)

Roof Terminated

Exhaust Pipe

Furnace

*Intake Debris

Screen

(Provided)

* See table 8 for maximum vent lengths

Page 19

FIGURE 26

NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm

per 1.17kW) per

hour of the total input rating of all equipment in the enclosure.

EQUIPMENT IN CONFINED SPACE

(Inlet Air from Ventilated Crawlspace and Outlet Air to Outside)

Roof Terminated

Exhaust Pipe

Furnace

Ventilation

Louvers

(Crawl space)

*Intake Debris Screen Provided)

Inlet Air

(Minimum

12 in.(305mm)

Above crawl

space floor)

Coupling or 3 in. to 2 in.

Transition

(Field Provided)

* See table 8 for maximum vent lengths

General Guidelines for Vent Terminations

In Non-Direct Vent applications, combustion air is taken from indoors and the flue gases are discharged to the outdoors. The ML193DF is then classified as a non-direct vent, Category IV gas furnace.

In Direct Vent applications, combustion air is taken from outdoors and the flue gases are discharged to the outdoors. The ML193DF is then classified as a direct vent, Category IV gas furnace.

In both Non-Direct Vent and 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

CSA−B149 Natural Gas and Propane Installation Codes in Canada for details.

Position termination according to location given in figure 27 or 28. In addition, position termination so it is free from any obstructions and 12" above the average snow accumulation.

At vent termination, 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 (1.8m) of a condensing unit because the condensate can damage the painted coating.

NOTE − See table 9 for maximum allowed exhaust pipe length without insulation in unconditioned space during winter design temperatures below 32°F (0°C). If required exhaust pipe should be insulated with 1/2" (13mm) Armaflex or equivalent. In extreme cold climate areas, 3/4" (19mm) Armaflex or equivalent may be necessary. Insulation on outside runs of exhaust pipe must be painted or wrapped to protect insulation from deterioration. Exhaust pipe insulation may not be necessary in some specific applications.

IMPORTANT

Do not use screens or perforated metal in exhaust terminations. Doing so will cause freeze−ups and may block the terminations.

IMPORTANT

For Canadian Installations Only: In accordance to CSA International B149 installation codes, the minimum allowed distance between the combustion air intake inlet and the exhaust outlet of other appliances shall not be less than 12 inches (305mm).

TABLE 9

Maximum Allowable Exhaust Vent Pipe Length Without Insulation In Unconditioned Space For

Winter Design Temperatures Single − Stage High Efficiency Furnace

Winter Design

Temperatures

°F (°C)

Vent Pipe

Diameter

Unit Input Size

045 070 090 110 135

32 to 21

(

0 to −6)

2 in. 26 44 44 24 N/A

2−1/2 in. 18 32 50 58 N/A

3 in. 14 26 38 55 60

20 to 1

(−7 to −17)

2 in 16 28 40 24 N/A

2−1/2 in. 12 20 30 44 N/A

3 in. 9 16 26 32 40

0 to −20

(−18 to −29)

2 in. 10 20 30 24 N/A

2−1/2 in. 8 14 20 32 N/A

3 in. 4 10 16 26 30

1Refer to 99% Minimum Design Temperature table provided in the current edition of the ASHRAE Fundamentals Handbook. NOTE − Maximum unisulated vent lengths listed cannot exceed the maximum allowable intake or exhaust vent length listed in table 7.

Page 20

FIGURE 27

VENT TERMINATION CLEARANCES

FOR NON−DIRECT VENT INSTALLATIONS IN THE USA AND CANADA

INSIDE CORNER

DETAIL

VENT TERMINAL

AIR SUPPLY INLET

AREA WHERE TERMINAL IS NOT PERMITTED

Fixed

Closed

Operable

Fixed

Closed

Operable

A =

B =

C =

D =

E =

F =

G =

H =

I =

J =

K =

L =

M =

US Installations

Canadian Installations

12 inches (305mm) or 12 in. (305mm)

above average snow accumulation.

12 inches (305mm) or 12 in. (305mm)

above average snow accumulation.

Clearance above grade, veranda,

porch, deck or balcony

Clearance to window or

door that may be opened

4 feet (1.2 m) below or to side of opening;

1 foot (30cm) above opening

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

Clearance to permanently

closed window

Vertical clearance to ventilated soffit

located above the terminal within a

horizontal distance of 2 feet (610 mm)

from the center line of the terminal

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

Clearance to each side of center line ex-

tended above meter / regulator assembly

Clearance to service regulator

vent outlet

Clearance to non−mechanical air

supply inlet to building or the com-

bustion air inlet to any other ap-

pliance

Clearance to mechanical air sup-

ply inlet

Clearance above paved sidewalk or

paved driveway located on public property

Clearance under veranda, porch, deck or balcony

* 12"

* Equal to or greater than soffit depth.

* 3 feet (.9m)

* 12"

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

3 feet (.9m)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

3 feet (.9m) above if within 10 feet

(3m) horizontally

6 feet (1.8m)

7 feet (2.1m)

12 inches (305mm)

In accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code

In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code  A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

 Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor. Lennox recommends avoiding this location if possible.

4 feet (1.2 m) below or to side of opening;

1 foot (30 cm) above opening

7 feet (2.1m)

* Equal to or greater than soffit depth.

* No minimum to outside corner * No minimum to outside corner

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

*12 inches (305mm)

*For clearances not specified in ANSI Z223.1/NFPA 54 or CSA B149.1, clearance will be in accordance with local installation codes and the requirements of the gas supplier and these installation instructions."

Page 21

FIGURE 28

VENT TERMINATION CLEARANCES

FOR DIRECT VENT INSTALLATIONS IN THE USA AND CANADA

INSIDE CORNER

DETAIL

VENT TERMINAL

AIR SUPPLY INLET

AREA WHERE TERMINAL IS NOT PERMITTED

Fixed

Closed

Operable

Fixed

Closed

Operable

A =

B =

C =

D =

E =

F =

G =

H =

I =

J =

K =

L =

M =

US Installations

Canadian Installations

12 inches (305mm) or 12 in. (305mm)

above average snow accumulation.

12 inches (305mm) or 12 in. (305mm)

above average snow accumulation.

Clearance above grade, veranda,

porch, deck or balcony

Clearance to window or

door that may be opened

6 inches (152mm) for appliances <10,000

Btuh (3kw), 9 inches (228mm) for ap-

pliances > 10,000 Btuh (3kw) and <50,000

Btuh (15 kw), 12 inches (305mm) for ap-

pliances > 50,000 Btuh (15kw)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

Clearance to permanently

closed window

Vertical clearance to ventilated soffit

located above the terminal within a

horizontal distance of 2 feet (610mm)

from the center line of the terminal

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

Clearance to each side of center line extended above meter / regulator assembly

Clearance to service regulator

vent outlet

Clearance to non−mechanical air

supply inlet to building or the com-

bustion air inlet to any other ap-

pliance

Clearance to mechanical air sup-

ply inlet

Clearance above paved sidewalk or

paved driveway located on public property

Clearance under veranda, porch, deck or balcony

* 12"

* 7 feet (2.1m)

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

3 feet (.9m)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 9 inches (228mm) for ap-

pliances > 10,000 Btuh (3kw) and <50,000

Btuh (15 kw), 12 inches (305mm) for ap-

pliances > 50,000 Btuh (15kw)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

3 feet (.9m) above if within 10 feet

(3m) horizontally

6 feet (1.8m)

7 feet (2.1m)

12 inches (305mm)

In accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code

In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code

 A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

 Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor. Lennox recommends avoiding this location if possible.

* 12"

* Equal to or greater than soffit depth

* Equal to or greater than soffit depth* Equal to or greater than soffit depth

* Equal to or greater than soffit depth * Equal to or greater than soffit depth

* No minimum to outside corner

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

3 feet (.9m)

*12 inches (305mm)

Page 22

Details of Intake and Exhaust Piping Terminations for Direct Vent Installations

NOTE − In Direct Vent installations, combustion air is taken from outdoors and flue gases are discharged to outdoors.

NOTE − Flue gas may be slightly acidic and may adversely affect some building materials. If any vent termination is used and the flue gasses may impinge on the building material, a corrosion−resistant shield (minimum 24 inches square) should be used to protect the wall surface. If the optional tee is used, the protective shield is recommended. The shield should be constructed using wood, plastic, sheet metal or other suitable material. All seams, joints, cracks, etc. in the affected area should be sealed using an appropriate sealant. See figure 32.

Intake and exhaust pipes may be routed either horizontally through an outside wall or vertically through the roof. In attic or closet installations, vertical termination through the roof is preferred. Figures 31 through 43 show typical terminations.

1 − Intake and exhaust terminations are not required to be

in the same pressure zone. You may exit the intake on one side of the structure and the exhaust on another side (figure 29). You may exit the exhaust out the roof and the intake out the side of the structure (figure 30).

2 − Intake and exhaust pipes should be placed as close

together as possible at termination end (refer to illustrations). Maximum separation is 3" (76mm) on roof terminations and 6" (152mm) on side wall terminations.

3 − On roof terminations, the intake piping should termi-

nate straight down using two 90° elbows (See figure

31).

4 − Exhaust piping must terminate straight out or up as

shown. A reducer may be required on the exhaust piping at the point where it exits the structure to improve the velocity of exhaust away from the intake piping. See table 10.

TABLE 10

EXHAUST PIPE TERMINATION SIZE REDUCTION

ML193

MODEL

Termination

Pipe Size

*045 and *070

1−1/2" (38mm)

*090 2" (51mm)

110 2" (51mm)

*ML193DF−045, −070 and −090 units with the flush−mount termination must use the 1−1/2"accelerator supplied with the kit.

5 − On field−supplied terminations for side wall exit, ex-

haust piping may extend a maximum of 12 inches (305mm) for 2" PVC and 20 inches (508mm) for 3" (76mm) PVC beyond the outside wall. Intake piping should be as short as possible. See figures 33 and 34.

6 − On field supplied terminations, a minimum distance

between the end of the exhaust pipe and the end of the intake pipe without a termination elbow is 8" and a minimum distance of 6" with a termination elbow. See figures 33 and 34.

NOTE − Care must be taken to avoid recirculation of exhaust back into intake pipe.

FIGURE 29

Exhaust

Pipe

Furnace

Exiting Exhaust and Intake Vent

(no common pressure zone)

Inlet Air (Minimum 12 in. 305 MM) above

grade or snow

accumulation

FIGURE 30

Roof T

erminated

Exhaust Pipe

Furnace

Exiting Exhaust and Intake Vent

(no common pressure zone)

Inlet Air (Minimum 12 in. 305 MM) above

grade or snow

accumulation

FIGURE 31

UNCONDITIONED

ATTIC SPACE

1/2" (13mm) FOAM

INSULATION IN

UNCONDITIONED

SPACE

SIZE TERMINATION

PIPE PER TABLE 10.

3"(76mm) MAX.

12" (305mm) ABOVE

AVERAGE SNOW ACCUMULATION

3" (76mm) OR

2" (51mm) PVC

PROVIDE SUPPORT

FOR INTAKE AND

EXHAUST LINES

8" (203mm) MIN

Inches(mm)

DIRECT VENT ROOF TERMINATION KIT

(15F75 or 44J41)

7 − If intake and exhaust piping must be run up a side wall

to position above snow accumulation or other obstructions, piping must be supported every 24" (610mm) as shown in figures 33 and 34. In addition, close coupled wall termination kits must be extended for use in this application. See figures 41 and 42.

Page 23

When exhaust and intake piping must be run up an outside wall, the exhaust piping must be terminated with pipe sized per table 10.The intake piping may be equipped with a 90° elbow turndown. Using turndown will add 5 feet (1.5m) to the equivalent length of the pipe

8 − A multiple furnace installation may use a group of up to

four terminations assembled together horizontally, as shown in figure 37.

FIGURE 32

12"

2" (51mm)

Vent Pipe

3" (76mm)

Vent Pipe

A− Clearance above

grade or average snow

accumulation

B−Horizontal

separation between

intake and exhaust

C−Minimum from

end of exhaust to

inlet of intake

D−Exhaust pipe length

E−Wall support distance

from top of each pipe

(intake/exhaust)

12" (305MM) Min.

6" (152MM) Min.

24" (610 MM) Max

9" (227MM) Min.

12" (305MM) Min. 16" (405 MM) Max.

6" (152MM) Max.

6" (152MM) Min.

24" (610 MM) Max

9" (227MM) Min.

12" (305MM) Min. 20" (508MM) Max.

6" (152MM) Max.

TABLE 11

The exhaust termination tee should be connected to the 2" or 3" PVC flue pipe as shown in the illustration. Do

not use an accelerator in applications that include an exhaust termination tee. The accelerator is not required.

As required. Flue gas may be acidic and may adversely affect some building materials. If a side wall vent

termination is used and flue gases will impinge on the building materials, a corrosion−resistant shield (24 inches square) should be used to protect the wall surface. If optional tee is used, the protective shield is recommended. The shield should be constructed using wood, sheet metal or other suitable material. All seams, joints, cracks, etc. in affected area, should be sealed using an appropriate sealant.

Exhaust pipe 45° elbow can be rotated to the side away from the combustion air inlet to direct exhaust away

from adjacent property. The exhaust must never be directed toward the combustion air inlet.

Front View of

Intake and Exhaust

Intake

Exhaust

Intake

Exhaust

Page 24

FIGURE 33

FIELD FABRICATED WALL TERMINATION OR

(15F74) WALL RING TERMINATION KIT

See venting table 7 for maximum venting lengths with this arrangement.

* Use wall support every 24" (610 mm). Use two wall supports if extension is greater than 24" (610 mm) but less than 48" (1219 mm). NOTE − One wall support must be 6" (152 mm) from top of each pipe (intake and exhaust)

2" (51mm)

Vent Pipe

3" (76mm)

Vent Pipe

A−Minimum clearance

above grade or average

snow accumulation

B−Maximum horizontal separation between

intake and exhaust

C−Minimum from

end of exhaust to

inlet of intake

D−Maximum exhaust

pipe length

E−Maximum wall support

distance from top of each

pipe (intake/exhaust)

12" (305MM) 12" (305MM)

6" (152MM) 6" (152MM)

8" (203MM) 8" (203MM)

12" (305MM) 20" (508MM)

6" (152MM) 6" (152MM)

NOTE − FIELD PROVIDED

REDUCER MAY BE

REQUIRED TO ADAPT

LARGER VENT PIPE SIZE

TO TERMINATION

SIZE TERMINATION

PER TABLE 10

1/2" (13mm) ARMAFLEX

INSULATION IN UN-

CONDITIONED SPACE

STRAIGHT

APPPLICATION

* WALL

SUPPORT

1/2" (13mm) ARMAFLEX INSULATION

IN UNCONDITIONED SPACE

EXTENDED

APPLICATION

FIGURE 34

FIELD FABRICATED WALL TERMINATION OR

(15F74) WALL RING TERMINATION KIT

With INTAKE ELBOW

See venting table 7 for maximum venting lengths with this arrangement.

2" (51mm)

Vent Pipe

3" (76mm)

Vent Pipe

12" (305MM) 12" (305MM)

6" (152MM) 6" (152MM)

6" (152MM)

12" (305MM) 20" (508MM)

6" (152MM) 6" (152MM)

6" (152MM)

A−Minimum clearance

above grade or average

snow accumulation

B−Maximum horizontal separation between

intake and exhaust

C−Minimum from

end of exhaust to

inlet of intake

D−Maximum exhaust

pipe length

E−Maximum wall support

distance from top of each

pipe (intake/exhaust)

NOTE − FIELD PROVIDED

REDUCER MAY BE

REQUIRED TO ADAPT

LARGER VENT PIPE SIZE

TO TERMINATION

SIZE TERMINATION

PER TABLE 10

1/2" (13mm) ARMAFLEX

INSULATION IN UN-

CONDITIONED SPACE

STRAIGHT

APPPLICATION

* WALL

SUPPORT

1/2" (13mm) ARMAFLEX INSULATION

IN UNCONDITIONED SPACE

EXTENDED

APPLICATION

Page 25

FIGURE 35

DIRECT VENT CONCENTRIC ROOFTOP TERMINATION

71M80, 69M29 or 60L46 (US)

41W92 or 41W93 (Canada)

Minimum

Above Average

Snow

Accumulation

SHEET METAL STRAP

(Clamp and sheet metal strap must be field installed to support the weight of the termination kit.)

FLASHING

(Not Furnished)

CLAMP

FIELD−PROVIDED

REDUCER MAY BE REQUIRED

TO ADAPT LARGER VENT

PIPE SIZE TO TERMINATION

INTAKE

1−1/2" (38mm) accelerator provided on 71M80 & 44W92 kits for ML193DF045P36B− &

070P36B

12” (305mm)

12" (305mm) Min.

above grade or

average snow ac-

cumulation.

FIGURE 36

DIRECT VENT CONCENTRIC WALL TERMINATION

71M80, 69M29 or 60L46 (US)

41W92 or 41W93 (Canada)

INTAKE

AIR

EXHAUST

AIR

INTAKE

AIR

INTAKE

AIR

EXHAUST

AIR

OUTSIDE

WALL

GRADE

CLAMP

(Not Furnished)

FIELD−PROVIDED

REDUCER MAY BE

REQUIRED TO ADAPT

LARGER VENT PIPE

SIZE TO TERMINATION

1−1/2" (38mm) accelerator

provided on 71M80 &

44W92 kits for

ML193DF045P36B− &

070P36B

FIGURE 37

EXHAUST

VENT

INTAKE

AIR

5−1/2"

(140mm)

Front View

12"

(305mm)

(127mm)

18" MAX.

(457mm)

EXHAUST VENT

INTAKE

AIR

OPTIONAL VENT TERMINATION FOR MULTIPLE UNIT

INSTALLATION OF DIRECT VENT WALL TERMINATION KIT

(22G44, 44J40, 30G28 or 81J20)

Inches (mm)

Side View

12" (305mm) Min.

above grade or

average snow ac-

cumulation.

optional intake elbow

FIGURE 38

1/2" (13mm) Foam Insulation

in Unconditioned Space

EXHAUST VENT

INTAKE AIR

OUTSIDE WALL

EXHAUST VENT

INTAKE

AIR

Front View

Top View

DIRECT VENT WALL TERMINATION KIT

(30G28 or 81J20)

6 (152mm) MIN.

SIZE

TERMINATION

PIPE PER

TABLE 10.

FIELD−PROVIDED

REDUCER MAY

BE REQUIRED TO

ADAPT LARGER

VENT PIPE SIZE

TO TERMINATION

FIGURE 39

1/2" (13mm) Foam Insulation

in Unconditioned Space

EXHAUST VENT

INTAKE AIR

OUTSIDE WALL

EXHAUST VENT

INTAKE

AIR

Front View

Top View

DIRECT VENT WALL TERMINATION KIT

(22G44 or 44J40)

8" (206mm) MIN.

SIZE

TERMINATION

PIPE PER

TABLE 10.

FIELD−PROVIDED

REDUCER MAY

BE REQUIRED TO

ADAPT LARGER

VENT PIPE SIZE

TO TERMINATION

FIGURE 40

2" EXTENSION FOR 2" PVC PIPE1" EXTENSION FOR 3" PVC PIPE

1−1/2" ACCELERATOR

(all −45, −070 and −090 units)

FURNACE

EXHAUST

PIPE

FURNACE

INTAKE

PIPE

4’’

GLUE EXHAUST

END FLUSH INTO

TERMINATION

FLAT SIDE

FLUSH−MOUNT SIDE WALL TERMINATION

51W11

Page 26

FIGURE 41

12” (305 mm) Minimum

Above Grade or Average

Snow Accumulation

1/2” (13 mm)

FOAM INSULATION

(Field Furnished)

5” (127 mm)

5−1/2”

(140 mm)

EXHAUST

AIR

INTAKE

AIR

GRADE

12”

(305 mm)

INTAKE

AIR

EXHAUST

AIR

GRADE

12” (305 mm) Max. for 2” (51 mm) Dia. Exhaust 20” (508 mm) Max. for 3” (76 mm) Dia. Exhaust

WALL SUPPORT*

12” (305 mm) Max. for 2” (51 mm) Dia. Exhaust 20” (508 mm) Max. for 3” (76 mm) Dia. Exhaust

12” (305 mm) Minimum

Above Grade or Average

Snow Accumulation

WALL TERMINATION KITS (CLOSE−COUPLE)

EXTENDED VENT FOR GRADE CLEARANCE

2 inch (51 mm) 22G44 (US)

3 inch (76 mm) 44J40 (US)

6” (152 mm)

Maximum

8” (203 mm) Min. for 2” (51 mm) & 3” (76 mm) DIA. pipe

between the end of the exhaust pipe and intake pipe

8” (203 mm) Min.

*Use wall support every 24" (610). Use two supports if

extension is greater than 24" but less than 48".

FIELD−PROVIDED

REDUCER MAY BE REQUIRED TO ADAPT

LARGER VENT PIPE SIZE TO TERMINATION

If intake and exhause pipe is less than 12 in. (305 mm) above snow accumulation or other obstructions, field− fabricated piping must be installed.

FIGURE 42

12” (305 mm) Minimum

Above Grade or Average

Snow Accumulation

1/2” (13 mm)

FOAM INSULATION

(Field Furnished)

5” (127 mm)

5−1/2”

(140 mm)

EXHAUST

AIR

INTAKE

AIR

GRADE

12”

(305 mm)

INTAKE

AIR

EXHAUST

AIR

GRADE

WALL SUPPORT*

12” (305 mm) Minimum

Above Grade or Average

Snow Accumulation

WALL TERMINATION KITS (CLOSE−COUPLE)

EXTENDED VENT FOR GRADE CLEARANCE

2 inch (51 mm) 30G28 (WTK Canada) 3 inch (76 mm) 81J20 (WTK Canada)

See Installation Instructions for additional information.

6” (152 mm)

Maximum

12” (305 mm) Max. for 2” (51 mm) Dia. Exhaust 20” (508 mm) Max. for 3” (76 mm) Dia. Exhaust

6” (152 mm)

Minimum

6” (152 mm)

Minimum

*Use wall support every 24" (610). Use two supports if

extension is greater than 24" but less than 48".

FIELD−PROVIDED

REDUCER MAY BE REQUIRED TO ADAPT

LARGER VENT PIPE SIZE TO TERMINATION

If intake and exhause pipe is less than 12 in. (305 mm) above snow accumulation or other obstructions, field− fabricated piping must be installed.

Page 27

ML193DF DIRECT VENT APPLICATION

USING EXISTING CHIMNEY

NOTE − Do not discharge exhaust gases directly into any chimney or vent stack. If vertical discharge through an existing unused chimney or stack is required, insert piping inside chimney until the pipe open end is above top of chimney and terminate as illustrated. In any exterior portion of chimney, the exhaust vent must be insulated.

FIGURE 43

3" − 8" (76mm− 203mm)

3" − 8"

(76mm−

203mm)

STRAIGHT−CUT OR

ANGLE−CUT IN DIRECTION

OF ROOF SLOPE *

EXHAUST VENT

1/2" (13mm)

WEATHERPROOF

INSULATION

SHOULDER OF FITTINGS

PROVIDE SUPPORT

OF PIPE ON TOP PLATE

ALTERNATE

INTAKE PIPE

INSULATION (optional)

EXTERIOR

PORTION OF

CHIMNEY

INSULATE

TO FORM

SEAL

SHEET

METAL TOP

PLATE

*SIZE TERMINATION PIPE PER TABLE 10.

Minimum 12" (305MM)

above chimney top

plate or average snow

accumulation

8" − 12"

(203mm − 305mm)

Details of Exhaust Piping Terminations for Non-Direct Vent Applications

Exhaust pipes may be routed either horizontally through an outside wall or vertically through the roof. In attic or closet installations, vertical termination through the roof is preferred. Figures 44 through 47 show typical terminations.

1 − Exhaust piping must terminate straight out or up as

shown. The termination pipe must be sized as listed in table 10.The specified pipe size ensures proper velocity required to move the exhaust gases away from the building.

2 − On field supplied terminations for side wall exit, ex-

haust piping may extend a maximum of 12 inches (305mm) for 2" PVC and 20 inches (508mm) for 3" (76mm) PVC beyond the outside wall. See figure 45.

FIGURE 44

NON−DIRECT VENT ROOF TERMINATION KIT

(15F75 or 44J41)

UNCONDITIONED

ATTIC SPACE

3" (76mm) OR

2" (51mm) PVC

PROVIDE SUPPORT

FOR EXHAUST LINES

12" (305mm)

ABOVE AVE.

SNOW

ACCUMULATION

SIZE TERMINATION

PIPE PER TABLE

10.

1/2" (13mm) FOAM

INSULATION

FIGURE 45

1/2" (13mm) ARMAFLEX

INSULATION IN

UNCONDITIONED SPACE

PVC REDUCER

1/2" (13mm)

ARMAFLEX

INSULATION

NON−DIRECT VENT FIELD SUPPLIED WALL TERMINATION OR

(15F74) WALL TERMINATION KIT

SIZE TERMINATION

PIPE PER TABLE 10.

FIELD−PROVIDED

REDUCER MAY

BE REQUIRED TO

ADAPT LARGER

VENT PIPE SIZE

TO TERMINATION

12" MIN.

(305mm)

Above Grade or

average snow

accumulation

12" (305mm) MAX. for 2" (51mm) 20" (508mm) MAX. for 3" (76mm)

3 − If exhaust piping must be run up a side wall to position

above snow accumulation or other obstructions, piping must be supported every 24 inches (610mm) as shown in figure 46. When exhaust piping must be run up an outside wall, any reduction in exhaust pipe size must be done after the final elbow.

Page 28

FIGURE 46

12" (305mm)

ABOVE GRADE OR

AVERAGE SNOW

ACCUMULATION

UNCONDITIONED

SPACE

1/2" (13mm) FOAM

INSULATION

1/2" (13mm) FOAM

INSULATION IN

UNCONDITIONED

SPACE

*WALL SUPPORT

OUTSIDE WALL

SIZE TER-

MINATION

PIPE PER

TABLE 10.

FIELD−PROVIDED

REDUCER MAY BE

REQUIRED TO

ADAPT LARGER

VENT PIPE SIZE TO

TERMINATION

*Use wall support every 24" (610). Use

two supports if extension is greater

than 24" but less than 48".

12" (305mm) MAX. for 2" (51mm) 20" (508mm) MAX. for 3" (76mm)

NON−DIRECT VENT FIELD SUPPLIED WALL TERMINATION EX-

TENDED OR (15F74) WALL TERMINATION VENT PIPE EXTENDED

6" (152mm)

Max

FIGURE 47

3" − 8"

(76mm−

203mm)

3" − 8"

(76mm−

203mm)

STRAIGHT−CUT OR

ANGLE−CUT IN DIRECTION

OF ROOF SLOPE

EXHAUST VENT

1/2" (13mm)

WEATHERPROOF

INSULATION

SHOULDER OF FITTINGS

PROVIDE SUPPORT

OF PIPE ON TOP PLATE

EXTERIOR

PORTION OF

CHIMNEY

INSULATE

TO FORM

SEAL

SHEET

METAL TOP

PLATE

SIZE TERMINATION

PIPE PER TABLE 10.

ML193DF NON−DIRECT VENT APPLICATION

USING EXISTING CHIMNEY

Minimum 12" (305MM)

above chimney top

plate or average snow

accumulation

Condensate Piping

This unit is designed for either right- or left-side exit of condensate piping. Refer to figures 48 and 49 for condensate trap locations.

NOTE − If necessary the condensate trap may be installed up to 5´ away from the furnace. Use PVC pipe to connect trap to furnace condensate outlet. Piping from furnace must slope down a minimum of 1/4" per ft. toward trap.

FIGURE 48

CONDENSATE TRAP AND PLUG LOCATIONS

Trap

(same on

right side)

Plug

(same on left

side)

1−1/2 in.

1 − Determine which side condensate piping will exit the

unit, location of trap, field−provided fittings and length of PVC pipe required to reach available drain.

2 − Use a 3/8 allen wrench and remove plug (figure 48)

from the cold end header box at the appropriate location on the side of the unit. Install field−provided 1/2" NPT male fitting into cold end header box. Use teflon tape or appropriate pipe dope.

3 − Install the cap over the clean out opening at the base of

the trap. Secure with clamp. See figure 53.

4 − Install drain trap using appropriate PVC fittings, glue

all joints. Glue the provided drain trap as shown in figure 53. Route the condensate line to an open drain.

5 − Figure 50 shows the furnace and evaporator coil using

a separate drain. If necessary, the condensate line from the furnace and evaporator coil can drain together. See figures 51 and 52. The field provided vent must be a minimum 1" to a maximum 2" length above the condensate drain outlet connection.

NOTE − If necessary the condensate trap may be installed up to 5 feet away from the furnace. Piping from furnace must slope down a minimum of 1/4" per ft. toward trap.

NOTE − Vinyl tubing may be used for condensate drain. Tubing must be 1−1/4" OD X 1" ID and should be attached to the drain on the trap using a hose clamp.

Page 29

6 − If unit will be started immediately upon completion of

installation, prime trap per procedure outlined in Unit Start−Up section.

Condensate line must slope downward away from the trap to drain. If drain level is above condensate trap, condensate pump must be used. Condensate drain line should be routed within the conditioned space to avoid freezing of condensate and blockage of drain line. If this is not possible, a heat cable kit may be used on the condensate trap and line. Heat cable kit is available from Lennox in various lengths; 6 ft. (1.8m) − kit no. 26K68; 24 ft. (7.3m) − kit no. 26K69; and 50 ft. (15.2m) − kit no. 26K70.

FIGURE 49

CONDENSATE TRAP LOCATION

(shown with right side exit of condensation)

5’ max.

to drain

Field Provided Vent

1" Min. 2" Max. Above

Condensate Drain

1" min.

Trap can be installed a

maximum of 5 ft. from furnace.

(*PVC Only)

*Piping from furnace must slope down a

minimum of 1/4" per ft. toward trap.

2" max.

FIGURE 50

ML193DF with Evaporator Coil

Using a Separate Drain

Drain

Evaporator Drain

Line Vent Required

Field−Provided Vent

(1" Min. to 2" Max. above

condensate drain connection)

Condensate

Drain Connection

IMPORTANT

When combining the furnace and evaporator coil drains together, the A/C condensate drain outlet must be vented to relieve pressure in order for the furnace pressure switch to operate properly.

FIGURE 51

ML193DF with Evaporator Coil Using a Common Drain

Field−Provided Vent

(1" Min. to 2" Max. above

condensate drain connection)

Condensate

Drain Connection

Evaporator Drain

Line Vent Required

FIGURE 52

Condensate Trap With Optional Overflow Switch

Field−Provided Vent

1" Min. to 2" Max.

above condensate drain connection)

Furnace Condensate

Drain Connection

From Evaporator Coil

To Drain

Optional

Overflow Switch

CAUTION

Do not use copper tubing or existing copper condensate lines for drain line.

Page 30

FIGURE 53

TRAP / DRAIN ASSEMBLY USING 1/2" PVC OR 3/4" PVC

Adapter 1/2 inch slip X

1/2 inch mpt (Not Furnished)

Drain Trap

Assembly

(Furnished)

Vent

Drain Trap Clean Out

5 Feet

Maximum

Coupling 1/2 inch slip X slip

(Not Furnished)

90° Elbow 1/2 inch PVC

(Not Furnished)

1/2 inch PVC Pipe

(Not Furnished)

1/2 inch PVC Pipe

(Not Furnished)

Condensate Drain

Connection In Unit

(178)

Drain Assembly for 1/2 inch Drain Pipe

90° Elbow

3/4 inch PVC

(Not Furnished)

Coupling 3/4 inch slip X slip

(Not Furnished)

Drain

90° Elbow

3/4 inch PVC

(Not Furnished)

90° Street Elbow

1/2 inch PVC

Drain

90° Elbow

1/2 inch PVC

(Not Furnished)

1/2 inch PVC Pipe

(Not Furnished)

Drain Assembly for 3/4 inch Drain Pipe

90° Street Elbow

1/2 inch PVC

(Not Furnished)

Condensate Drain

Connection In Unit

Adapter 1/2 inch slip X

1/2 inch mpt (Not Furnished)

Condensate Drain Connection In Unit

Vent

Drain

Condensate Drain Connection In Unit

Drain Trap Assembly with 3/4 inch Piping

Vent

Drain

(Furnished)

Optional Condensate Drain Connection

Optional Drain Piping From Trap

Drain Trap Assembly

(Furnished)

Drain Trap Assembly with 1/2 inch Piping

Drain Trap Assembly with 3/4 inch Piping

1/2 inch

3/4 inch

1 (25 mm) Min. 2 (50 mm) Max. Above Top Of Condensate Drain Connection In Unit

Trap

Page 31

Gas Piping

CAUTION

If a flexible gas connector is required or allowed by the authority that has jurisdiction, black iron pipe shall be installed at the gas valve and extend outside the furnace cabinet. The flexible connector can then be added between the black iron pipe and the gas supply line.

WARNING

Do not exceed 600 in−lbs (50 ft−lbs) torque when attaching the gas piping to the gas valve.

1 − Gas piping may be routed into the unit through either

the left- or right-hand side. Supply piping enters into the gas valve from the side of the valve as shown in figure 55.

2 − When connecting gas supply, factors such as length of

run, number of fittings and furnace rating must be considered to avoid excessive pressure drop. Table 12 lists recommended pipe sizes for typical applications.

NOTE − Use two wrenches when connecting gas piping to avoid transferring torque to the manifold.

3 − Gas piping must not run in or through air ducts, clothes

chutes, chimneys or gas vents, dumb waiters or elevator shafts. Center gas line through piping hole. Gas line should not touch side of unit. See figures 55.

4 − Piping should be sloped 1/4 inch per 15 feet (6mm per

5.6m) upward toward the gas meter from the furnace. The piping must be supported at proper intervals, every 8 to 10 feet (2.44 to 3.05m), using suitable hangers or straps. Install a drip leg in vertical pipe runs to serve as a trap for sediment or condensate.

5 − A 1/8" N.P.T. plugged tap or pressure post is located

on the gas valve to facilitate test gauge connection. See figure 59.

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

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

IMPORTANT

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

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.

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 less than or equal to 1/2 psig (3.48 kPa, 14 inches w.c.).

FIGURE 54

MANUAL MAIN SHUT−OFF

VALVE WILL NOT HOLD

NORMAL TEST PRESSURE

CAP

FURNACE

ISOLATE

GAS VALVE

1/8" N.P.T. PLUGGED TAP

IMPORTANT

When testing pressure of gas lines, gas valve must be disconnected and isolated. See figure 54. Gas valves can be damaged if subjected to pressures greater than 1/2 psig (3.48 kPa).

WARNING

FIRE OR EXPLOSION HAZARD Failure to follow the safety warnings exactly could result in serious injury, death, or property damage. Never use an open flame to test for gas leaks. Check all connections using a commercially available soap solution made specifically for leak detection. Some soaps used for leak detection are corrosive to certain metals. Carefully rinse piping thoroughly after leak test has been completed.

Page 32

GROUND

JOINT

UNION

AUTOMATIC

GAS VALVE

(with manual

shut−off valve)

FIELD

PROVIDED

AND INSTALLED

GROUND

JOINT

UNION

Left Side Piping

(Standard)

Right Side Piping

(Alternate)

AUTOMATIC

GAS VALVE

(with manual

shut−off valve)

DRIP LEG

MANUAL

MAIN SHUT−OFF

VALV E

(With 1/8 in. NPT

Plugged Tap Shown)

MANUAL

MAIN SHUT−OFF

VALV E

(With 1/8 in. NPT

Plugged Tap

Shown)

NOTE − BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET

FIGURE 55

Bellows Grommet

Plug

TABLE 12

GAS PIPE CAPACITY − FT

/HR (kL/HR)

Nominal

Iron Pipe

Size

inches

(mm)

Internal

Diameter

inches

(mm)

Length of Pipe − feet (m)

(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)

100

(30.480)

1/2

(12.7)

.622

(17.799)

172

(4.87)

118

(3.34)

(2.69)

(2.29)

(2.03)

(1.84)

(1.69)

(1.58)

(1.47)

(1.42)

3/4

(19.05)

.824

(20.930)

360

(10.19)

247

(7.00)

199

(5.63)

170

(4.81)

151

(4.28)

137

(3.87)

126

(3.56)

117

(3.31)

110

(3.11)

104

(2.94)

(25.4)

1.049

(26.645)

678

(19.19)

466

(13.19)

374

(10.59)

320

(9.06)

284

(8.04)

257

(7.27)

237

(6.71)

220

(6.23)

207

(5.86)

195

(5.52)

1−1/4

(31.75)

1.380

(35.052)

1350

(38.22)

957

(27.09)

768

(22.25)

657

(18.60)

583

(16.50)

528

(14.95)

486

(13.76)

452

(12.79)

424

(12.00)

400

(11.33)

1−1/2

(38.1)

1.610

(40.894)

2090

(59.18)

1430

(40.49)

1150

(32.56)

985

(27.89)

873

(24.72)

791

(22.39)

728

(20.61)

677

(19.17)

635

(17.98)

600

(17.00)

(50.8)

2.067

(52.502)

4020

(113.83)

2760

(78.15)

2220

(62.86)

1900

(53.80)

1680

(47.57)

1520

(43.04)

1400

(39.64)

1300

(36.81)

1220

(34.55)

1160

(32.844)

2−1/2

(63.5)

2.469

(67.713)

6400

(181.22)

4400

(124.59)

3530

(99.95)

3020

(85.51)

2680

(75.88)

2480

(70.22)

2230

(63.14)

2080

(58.89)

1950

(55.22)

1840

(52.10)

(76.2)

3.068

(77.927)

11300

(319.98)

7780

(220.30)

6250

(176.98)

5350

(151.49)

4740

(134.22)

4290

(121.47)

3950

(111.85)

3670

(103.92)

3450

(97.69)

3260

(92.31)

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

Page 33

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.

Conduct the following test while each appliance is operating and the other appliances (which are not operating) remain connected to the common venting system. If the venting system has been installed improperly, you must correct the system as indicated in the general venting requirements section.

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:

1 − Seal any unused openings in the common venting sys-

tem.

2 − Inspect the venting system for proper size and horizontal

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

3 − Close all building doors and windows and all doors be-

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

4 − Follow the lighting instructions. Turn on the appliance

that is being inspected. Adjust the thermostat so that the appliance operates continuously.

5 − After the main burner has operated for 5 minutes, test

for leaks of flue gases at the draft hood relief opening. Use the flame of a match or candle.

6 − After determining that each appliance connected to the

common venting system is venting properly, (step 3) return all doors, widows, exhaust fans, fireplace dampers, and any other gas−burning appliances to their previous mode of operation.

7 − If a venting problem is found during any of the preced-

ing tests, the common venting system must be modified to correct the problem.

Resize the common venting system to the minimum vent pipe size determined by using the appropriate tables in Appendix G. (These are in the current standards of the National Fuel Gas Code ANSI Z223.1.

Electrical

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

Electrostatic discharge can affect electronic components. Take precautions to neutralize electrostatic charge by touching your hand and tools to metal prior to handling the control.

The unit is equipped with a field make−up box on the left hand side of the cabinet. A field−provided make−up box can be installed on the exterior of the right side of the furnace to facilitate installation. If the make−up box is moved to the right side, clip the wire ties that bundle the wires together and install on the outside of the cabinet. See figure 56. The excess wire must be pulled into the blower compartment. Secure the excess wire to the existing harness to protect it from damage.

FIGURE 56

MAKE−UP

BOX OUTSIDE CABINET

Right Side

EXTERIOR MAKE−UP BOX

(FIELD PROVIDED RIGHT SIDE)

Refer to figure 57 for field wiring, schematic wiring diagram and troubleshooting.

The power supply wiring must meet Class I restrictions. Protected by either a fuse or circuit breaker, select circuit protection and wire size according to unit nameplate.

NOTE − Unit nameplate states maximum current draw. Maximum Over−Current Protection allowed is 15 AMP.

Holes are on both sides of the furnace cabinet to facilitate wiring.

Install a separate (properly sized) disconnect switch near the furnace so that power can be turned off for servicing.

Page 34

Before connecting the thermostat or the power wiring, check to make sure the wires will be long enough for servicing at a later date. Remove the blower access panel to check the length of the wire.

Complete the wiring connections to the equipment. Use the provided unit wiring diagram and the field wiring diagram shown in figure 57. Use 18−gauge wire or larger that is suitable for Class II rating for thermostat connections.

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 and current Canadian Electric Code part 1 (CSA standard C22.1) for Canada. A green ground wire is provided in the field make−up box.

NOTE − The ML193DF furnace contains electronic components that are polarity sensitive. Make sure that the furnace is wired correctly and is properly grounded.

Accessory Terminals

One line voltage EAC" 1/4" spade terminal is provided on the furnace integrated control. See figure 58 for integrated control configuration. This terminal is energized when the indoor blower is operating. Any accessory rated up to one amp can be connected to this terminal with the neutral leg of the circuit being connected to one of the provided neutral terminals. If an accessory rated at greater than one amp is connected to this terminal, it is necessary to use an external relay.

One line voltage HUM" 1/4" spade terminal is provided on the furnace integrated control. See figure 58 for integrated control configuration. This terminal is energized in the heating mode when the combustion air inducer is operat-

ing. Any humidifier rated up to one amp can be connected to this terminal with the neutral leg of the circuit being connected to one of the provided neutral terminals. If a humidifier rated at greater than one amp is connected to this terminal, it is necessary to use an external relay relay.

Thermostat

Install the room thermostat according to the instructions provided with the thermostat. See figure 57 for thermostat designations. If the furnace is being matched with a heat pump, refer to the FM21 installation instruction or appropriate dual fuel thermostat instructions.

Indoor Blower Speeds

1 − When the thermostat is set to FAN ON," the indoor

blower will run continuously on the heating speed when there is no cooling or heating demand.

2 − When the ML193DF is running in the heating mode,

the indoor blower will run on the heating speed.

3 − When there is a cooling demand, the indoor blower will

run on the cooling speed.

Generator Use − Voltage Requirements

The following requirements must be kept in mind when specifying a generator for use with this equipment:

 The furnace requires 120 volts +

10% (Range: 108

volts to 132 volts)

 The furnace operates at 60 Hz +

5% (Range: 57 Hz to

63 Hz)

 The furnace integrated control requires both polarity

and proper ground. Both polarity and proper grounding should be checked before attempting to operate the furnace on either permanent or temporary power

 Generator should have a wave form distortion of less

than 5% THD (total harmonic distortion).

Page 35

TYPICAL ML193DF WIRING DIAGRAM

FIGURE 57

Page 36

FIGURE 58

INTEGRATED CONTROL

(Automatic Hot Surface Ignition System)

BLOWER OFF

DELAY JUMPER

PUSH BUTTON

LED

TWIN

TERMINAL DESIGNATIONS

HUM LINE XFMR EAC COOL HEAT PARK CONT NEUTRALS

Humidifier (120VAC) Input (120VAC) Transformer (120VAC) Indoor Air Qality Accessory Air Cleaner (120VAC) Blower − Cooling Speed (120VAC) Blower − Heating Speed (120VAC) Dead terminals to park alternate spd taps Continuous blower Neutral terminals (120VAC)

TWIN

Twinning Terminal (24VAC)

Integrated Control Diagnostic Codes

DIAGNOSTIC CODES

LED Status DESCRIPTION

LED Off

No power to control or control harware fault detected.

LED On Normal operation.

1 Flash

Flame present with gas vavle de−energized.

2 Flashes

Pressure switch closed with combustion air inducer de−energized.

3 Flashes

Pressure switch open with combustion air inducer energized.

4 Flashes Primary limit switch open.

5 Flashes Rollout switch open.

6 Flashes Pressure switch cycle lockout.

7 Flashes Lockout, burners fail to light.

8 Flashes

Lockout, buners lost flame too many times.

9 Flashes Line voltage polarity incorrect.

Note − This control is equipped with a push button switch for diagnostic code recall. The control stores the last 5 fault codes in non−volatile memory. The most recent fault code is flashed first, the oldest fault code is flashed last. There is a 2 second pause between codes. When the push button switch is pressed for less than 5 seconds, the control will flash the stored fault codes when the switch is released. The fault code history may be cleared by pressing the push button switch for more than 5 seconds.

Page 37

Unit Start−Up

FOR YOUR SAFETY READ BEFORE OPERATING

WARNING

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

CAUTION

Before attempting to perform any service or maintenance, turn the electrical power to unit OFF at disconnect switch.

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.

BEFORE LIGHTING the unit, smell all around the fur-

nace area for gas. Be sure to smell next to the floor because some gas is heavier than air and will settle on the floor.

The gas valve on the ML193DF is equipped with a gas control switch. Use only your hand to move switch. Never use tools. If the switch will not move by hand, do not try to repair it. Force or attempted repair may result in a fire or explosion.

Placing the furnace into operation:

ML193DF units are equipped with an automatic hot surface ignition system. Do not

attempt to manually light burners on this furnace. Each time the thermostat calls for heat, the burners will automatically light. The ignitor does not get hot when there is no call for heat on these units.

Priming Condensate Trap

The condensate trap should be primed with water prior to start−up to ensure proper condensate drainage. Either pour 10 fl. oz. (300 ml) of water into the trap, or follow these steps to prime the trap:

1 − Follow the lighting instructions to place the unit into op-

eration. 2 − Set the thermostat to initiate a heating demand. 3 − Allow the burners to fire for approximately 3 minutes. 4 − Adjust the thermostat to deactivate the heating de-

mand.

5 − Wait for the combustion air inducer to stop. Set the

thermostat to initiate a heating demand and again allow the burners to fire for approximately 3 minutes.

6 − Adjust the thermostat to deactivate the heating de-

mand and wait for the combustion air inducer to stop. At this point, the trap should be primed with sufficient water to ensure proper condensate drain operation.

WARNING

If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or death.

Gas Valve Operation (Figure 59)

1 − STOP! Read the safety information at the beginning of

this section. 2 − Set the thermostat to the lowest setting. 3 − Turn off all electrical power to the unit. 4 − This furnace is equipped with an ignition device which

automatically lights the burners. Do not try to light the

burners by hand. 5 − Remove the upper access panel. 6 − Move gas valve switch to OFF. See figure 59. 7 − Wait five minutes to clear out any gas. If you then smell

gas, STOP! Immediately call your gas supplier from a

neighbor’s phone. Follow the gas supplier’s instruc-

tions. If you do not smell gas go to next step. 8 − Move gas valve switch to ON. See figure 59. 9 − Replace the upper access panel.

10− Turn on all electrical power to to the unit.

11− Set the thermostat to desired setting.

NOTE − When unit is initially started, steps 1 through 11 may need to be repeated to purge air from gas line.

GAS VALVE SHOWN IN ON POSITION

MANIFOLD

PRESSURE

OUTLET

INLET

PRESSURE

PORT

MANIFOLD

PRESSURE

ADJUSTMENT

SCREW

FIGURE 59

12− If the appliance will not operate, follow the instructions

Turning Off Gas to Unit" and call your service techni-

cian or gas supplier.

Turning Off Gas to Unit

1 − Set the thermostat to the lowest setting. 2 − Turn off all electrical power to the unit if service is to be

performed. 3 − Remove the upper access panel. 4 − Move gas valve switch to OFF. 5 − Replace the upper access panel.

Page 38

Failure To Operate

If the 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? 4 − Is there a blown fuse or tripped breaker? 5 − Is the filter dirty or plugged? Dirty or plugged filters will

cause the limit control to shut the unit off. 6 − Is gas turned on at the meter? 7 − Is the manual main shut-off valve open? 8 − Is the internal manual shut-off valve open? 9 − Is the unit ignition system in lockout? If the unit locks out

again, inspect the unit for blockages.

Heating Sequence Of Operation

1 − When thermostat calls for heat, combustion air inducer

starts. 2 − Combustion air pressure switch proves blower opera-

tion. Switch is factory−set and requires no adjustment. 3 − After a 15−second prepurge, the hot surface ignitor en-

ergizes. 4 − After a 20−second ignitor warm−up period, the gas

valve solenoid opens. A 4−second Trial for Ignition peri-

od begins." 5 − Gas is ignited, flame sensor proves the flame, and the

combustion process continues. 6 − If flame is not detected after first ignition trial, the igni-

tion control will repeat steps 3 and 4 four more times

before locking out the gas valve (WATCHGUARD"

flame failure mode). The ignition control will then auto-

matically repeat steps 1 through 6 after 60 minutes.

To interrupt the 60−minute WATCHGUARD" period,

move thermostat from Heat" to OFF" then back to

Heat". Heating sequence then restarts at step 1.

Gas Pressure Adjustment

Gas Flow (Approximate)

TABLE 13

GAS METER CLOCKING CHART

ML193

Unit

Seconds for One Revolution

Natural LP

1 cu ft

Dial

2 cu ft

Dial

1 cu ft

Dial

2 cu ft

DIAL

−045 80 160 200 400

−070 55 110 136 272

−090 41 82 102 204

−110 33 66 82 164

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

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

Furnace should operate at least 5 minutes before checking gas flow. Determine time in seconds for two revolutions of gas through the meter. (Two revolutions assures a more accurate time). Divide by two and compare to time in table 13. If manifold pressure matches table 14 and rate is incorrect, check gas orifices for proper size and restriction. Remove temporary gas meter if installed.

Supply Pressure Measurement

A threaded plug on the inlet side of the gas valve provides access to the supply pressure tap. Remove the threaded plug, install a field−provided barbed fitting and connect a manometer to measure supply pressure. See table 14 for proper supply line pressure. Replace the threaded plug after measurements have been taken.

TABLE 14

Manifold and Supply Pressure (Outlet) inches w.c.

Fuel

Model

Input Sizes

Manifold

Pressure in.wg.

Supply

Pressure in.wg.

Min. Max.

Nat. Gas All sizes

3.5

4.5 10.0

L.P. Gas All sizes

10.0

11.0 13.0

NOTE − A natural to L.P. propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for the conversion procedure.

Manifold Pressure Measurement

1 − Remove the threaded plug from the outlet side of the

gas valve and install a field−provided barbed fitting. Connect to a manometer to measure manifold pressure.

2 − Start unit and allow 5 minutes for unit to reach steady

state.

3 − While waiting for the unit to stabilize, notice the flame.

Flame should be stable and should not lift from burner. Natural gas should burn blue.

4 − After allowing unit to stabilize for 5 minutes, record

manifold pressure and compare to value given in table

14.

NOTE − Shut unit off and remove manometer as soon as an accurate reading has been obtained. Take care to remove barbed fitting and replace threaded plug.

Page 39

Proper Combustion

Furnace should operate minimum 15 minutes with correct manifold pressure and gas flow rate before checking combustion. Take combustion sample beyond the flue outlet and compare to the tables below. The maximum carbon

monoxide reading should not exceed 50 ppm.

TABLE 15

ML193

Unit

CO2%

For Nat

CO2%

For L.P.

−045

7.2 − 7.9 8.6 − 9.3

−070

−090

−110

High Altitude Information

NOTE − In Canada, certification for installations at elevations over 4500 feet (1372 m) is the jurisdiction of local authorities.

ML193DF units require no manifold pressure adjustments for operation at altitudes up to 10,000 feet (3048 m) above sea level. Units installed at altitude of 4501 − 10,000 feet (1373 to 3048m) require a pressure switch change which can be ordered separately. Table 16 lists conversion kit and pressure switch requirements at varying altitudes. The combustion air pressure switch is factory−set and requires no adjustment.

NOTE − A natural to LP/propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for the conversion procedure.

TABLE 16

Conversion Kit and Pressure Switch Requirements at Varying Altitudes

ML193

Unit

Natural to

LP/Propane

High Altitude

Natural Burner

Orifice Kit

LP/Propane

to Natural

High Altitude

LP/Propane

Burner Orifice Kit

High Altitude Pressure

Switch

0 − 7500 ft

(0 − 2286m)

7501 − 10,000 ft

(2286 − 3038m)

0 − 7500 ft

(0 − 2286m)

7501 − 10,000 ft

(2286 − 3038m)

4501 − 7500

(1373 −

2286m)

7501 −10,000

(2286 −

3048m)

−045

*69W73 73W37 *73W81 *68W68 80W60 80W61

−070

−090

−110

* Conversion requires installation of a gas valve manifold spring which is provided with the gas conversion kit. Pressure switch is factory set. No adjustment necessary. All models use the factory−installed pressure switch from 0−4500 feet (0−1370 m).

Page 40

Testing of Non−Direct Vent Applications for Proper Venting and Sufficient Combustion Air

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 ML193DF gas furnace has been started, the following test should be conducted to ensure proper venting and sufficient combustion air has been provided to the ML193DF as well as to other gas-fired appliances which are separately vented.

If a ML193DF furnace replaces a Category I furnace which was commonly vented with another gas appliance, the size of the existing vent pipe for that gas appliance must be checked. Without the heat of the original furnace flue products, the existing vent pipe is probably oversized for the single water heater or other appliance. The vent should be checked for proper draw with the remaining appliance.

The test should be conducted while all appliances (both in operation and those not in operation) are connected to the venting system being tested. If the venting system has been installed improperly, or if provisions have not been made for sufficient amounts of combustion air, corrections must be made as outlined in the previous section.

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 lo-

cated 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 − Use the flame of match or candle to test for spillage of

flue gases at the draft hood relief opening after 5 min-

utes of main burner operation. 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 ap-

propriate 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 cur-

rent standard of the CSA−B149 Natural Gas and Pro-

pane Installation Codes 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.

Page 41

Other Unit Adjustments

Primary Limit

The primary limit is located on the heating compartment vestibule panel. This limit is factory set and requires no adjustment.

Flame Rollout Switches (Two)

These manually reset switches are located on the front of the burner box.

Pressure Switch

The pressure switch is located in the heating compartment on the cold end header box. This switch checks for proper combustion air inducer operation before allowing ignition trial. The switch is factory−set and must not be adjusted.

Temperature Rise

After the furnace has been started and supply and return air temperatures have been allowed to stabilize, check the temperature rise. If necessary, adjust the blower speed to maintain the temperature rise within the range shown on the unit nameplate. Increase the blower speed to decrease the temperature. Decrease the blower speed to increase the temperature rise. Failure to adjust the temperature rise may cause erratic limit operation.

Fan Control

The fan on time of 30 seconds is not adjustable. The fan off delay (amount of time that the blower operates after the heat demand has been satisfied) may be adjusted by changing the jumper position across the five pins on the integrated control. The unit is shipped with a factory fan off setting of 120 seconds. The fan off delay affects comfort and is adjustable to satisfy individual applications. Adjust the fan off delay to achieve a supply air temperature between 90° and 110°F at the moment that the blower is de− energized. Longer off delay settings provide lower return air temperatures; shorter settings provide higher return air temperatures. See figure 60.

Thermostat Heat Anticipation

Set the heat anticipator setting (if adjustable) according to the amp draw listed on the wiring diagram that is attached to the unit.

Electrical

1 − Check all wiring for loose connections. 2 − Check for the correct voltage at the furnace (furnace

operating).

3 − Check amp-draw on the blower motor.

Motor Nameplate__________Actual__________

HEAT FAN-OFF TIME IN SECONDS

To adjust fan−off timing, reposition jumper across pins to

achieve desired setting.

NO JUMPER

FIGURE 60

120

180

120

180

120

180

120

180

60 Second

off Time

90 Second

off Time

120 Second

off Time

180 Second

off Time

Blower Speeds

Follow the steps below to change the blower speeds.

1 − Turn off electrical power to furnace.

2 − Remove blower access panel.

3 − Disconnect existing speed tap at integrated control

speed terminal.

NOTE − Termination of any unused motor leads must be insulated.

4 − Place unused blower speed tap on integrated control

PARK" terminal or insulate.

5 − Refer to blower speed selection chart on unit wiring dia-

gram for desired heating or cooling speed. See Product Specifications bulletin for blower performance tables.

6 − Connect selected speed tap at integrated control

speed terminal.

7 − Resecure blower access panel.

8 − Turn on electrical power to furnace.

9 − Recheck temperature rise.

Exhaust and Air Intake Pipe

1 − Check exhaust and air intake connections for tightness

and to make sure there is no blockage.

2 − Is pressure switch closed? Obstructed exhaust pipe

will cause unit to shut off at pressure switch. Check termination for blockages.

3 − Obstructed pipe or termination may cause rollout

switches to open. Reset manual flame rollout switches on burner box assembly if necessary.

Page 42

Twinning the ML193DF

The control board in this furnace is equipped with a provision to "twin" (interconnect) two(2) adjacent furnaces with a common plenum such that they operate as one (1) large unit.

When twinned, the circulating blower speeds are synchronized between the furnaces. If either furnace has a need to run the blower, both furnaces will run the blower on the same speed. The cooling speed has highest priority, followed by heating speed and fan speed.

Field installation of twinning consists of connecting wires

between the "C" and "Twin" terminals of the two controls. The 24 VAC secondary of the two systems must be in phase. All thermostat connections are made to one control only. Figure 61 show wiring for two−stage and single stage thermostats.

The twinned furnace without thermostat connections is to have the call for heat supplied by an external 24VAC isolation relay to prevent its rollout switch from being bypassed by the other twinned furnace. The coil of the isolation relay connects from the thermostat "W" to 24 VAC common. The contacts of the relay connect "R" to "W" on the non−thermostat twin.

FIGURE 61

TWIN

TWIN 2

TWIN 1

ISOLATION RELAY

TWO−STAGE THERMOSTAT

Call For Cool

Call For Fan

Call For 1st Stage Heat

Call For 2nd

StageHeat

TWIN

TWIN 2

TWIN 1

ISOLATION RELAY

Call For Cool

Call For Fan

Call For Heat

SINGLE STAGE THERMOSTAT

FIELD WIRING FOR TWINNING

Page 43

Service

WARNING

ELECTRICAL SHOCK, FIRE,

OR EXPLOSION HAZARD.

Failure to follow safety warnings exactly could result in dangerous operation, serious injury, death or property damage. Improper servicing could result in dangerous operation, serious injury, death, or property damage. Before servicing, disconnect all electrical power to furnace. When servicing controls, label all wires prior to disconnecting. Take care to reconnect wires correctly. Verify proper operation after servicing.

At the beginning of each heating season, system should be checked as follows by a qualified service technician:

Blower

Check the blower wheel for debris and clean if necessary. The blower motors are prelubricated for extended bearing life. No further lubrication is needed.

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.

Filters

All air filters are installed external to the unit. Filters should be inspected monthly. Clean or replace the filters when necessary to ensure proper furnace operation. Table 3 lists recommended filter sizes.

Exhaust and air intake pipes

Check the exhaust and air intake pipes and all connections for tightness and to make sure there is no blockage.

NOTE − After any heavy snow, ice or frozen fog event the furnace vent pipes may become restricted. Always check the vent system and remove any snow or ice that may be obstructing the plastic intake or exhaust pipes.

Electrical

1 − Check all wiring for loose connections. 2 − Check for the correct voltage at the furnace (furnace

operating).

3 − Check amp−draw on the blower motor.

Motor Nameplate__________Actual__________

Winterizing and Condensate Trap Care

1 − Turn off power to the furnace.

2 − Have a shallow pan ready to empty condensate water.

3 − Remove the clean out cap from the condensate trap

and empty water. Inspect the trap then reinstall the drain plug.

Cleaning the Burner Assembly

1 − Turn off electrical and gas power supplies to furnace.

Remove upper and lower furnace access panels. 2 − Disconnect the 2−pin plug from the gas valve. 3 − Remove the burner box cover. 4 − Disconnect the gas supply line from the gas valve. Re-

move gas valve/manifold assembly. 5 − Mark and disconnect sensor wire from the sensor. Dis-

connect 2-pin plug from the ignitor at the burner box. 6 − Remove four screws which secure burner box assem-

bly to vest panel. Remove burner box from the unit. 7 − Use the soft brush attachment on a vacuum cleaner to

gently clean the face of the burners. Visually inspect

the inside of the burners and crossovers for any block-

age caused by foreign matter. Remove any blockage. 8 − Reconnect the sensor wire and reconnect the 2−pin

plug to the ignitor wiring harness. 9 − Reinstall the burner box assembly using the existing

four screws. Make sure that the burners line up in the

center of the burner ports. 10 − Reinstall the gas valve manifold assembly. Reconnect

the gas supply line to the gas valve. Reinstall the burn-

er box cover. 11 − Reconnect 2−pin plug to gas valve. 12 − Replace the blower compartment access panel. 13 − Refer to instruction on verifying gas and electrical con-

nections when re−establishing supplies. 14 − Follow lighting instructions to light and operate fur-

nace for 5 minutes to ensure that heat exchanger is

clean and dry and that furnace is operating properly. 15 − Replace heating compartment access panel.

Page 44

Repair Parts List

The following repair parts are available through Lennox dealers. When ordering parts, include the complete furnace model number listed on the CSA nameplate −− Example: ML193DF045XP36B. All service must be performed by a licensed

professional installer (or equivalent), service agency, or gas supplier.

Cabinet Parts

Upper access panel Blower access panel Top Cap

Control Panel Parts

Transformer Integrated control board Door interlock switch

Blower Parts

Blower wheel Motor Motor mounting frame Motor capacitor Blower housing cutoff plate

Heating Parts

Flame Sensor

Heat exchanger assembly Gas manifold Combustion air inducer Gas valve Main burner cluster Main burner orifices Pressure switch Ignitor Primary limit control Flame rollout switches

Page 45

Start−Up & Performance Check List

Gas Supply Pressure

SUPPLY

AIR

Line Voltage

GAS SUPPLY

Natural Gas

LP Propane Gas

Piping Connections Tight

Leak Tested

Supply Line Pressure W.C.________

INTAKE / EXHAUST PIPE

All Joints Primed and Glued

Terminations Installed Properly

Pipes Supported

Condensate Trap Primed / Line Sloped

Heat Cable Installed and Operable (if applicable)

Horizontal Pipes Sloped (if applicable)

UNIT SET UP

Flter

RETURN AIR

Furnace: Model Number_______________

Serial Number_________________

DUCT SYSTEM

SUPPLY AIR DUCT

Sealed

Insulated (if necessary)

RETURN DUCT

Sealed

Filter Installed and Clean

Grilles Unobstructed

VOLTAGE CHECK

Supply Voltage _____

Electrical Connections Tight

Page 46

Contractor’s: Name_________________________Telephone_____________Checklist Completed____________________

Job Address_____−________________________________Technician’s Name___________________________________

HEATING MODE

GAS MANIFOLD PRESSURE W.C._____

COMBUSTION SAMPLE CO

2%______

CO PPM_______

INDOOR BLOWER AMPS______

TEMPERATURE RISE

Supply Duct Temperature ________ Return Duct Temperature

_____

Temperature Rise = ________

TOTAL EXTERNAL STATIC

Supply External Static _______

Return External Static + ______

Total External Static = _______

CONDENSATE LINE

Leak Free

VENT PIPE

Leak Free

COOLING MODE

INDOOR BLOWER AMPS______

TEMPERATURE DROP

Return Duct Temperature _________ Supply Duct Temperature

_ _______

Temperature Drop = _________

DRAIN LINE

Leak Free

THERMOSTAT

Adjusted and Programmed

Explained Operation to Owner

SUPPLY

AIR

Blower Motor Amps

Duct Static

Thermostat

Gas Manifold Pressure

Temperatures

RETURN AIR

Combustion CO

UNIT OPERATION

TOTAL EXTERNAL STATIC (dry coil)

Supply External Static _______

Return External Static + ______

Total External Static = _______

Page 47

Requirements for Commonwealth of Massachusetts

Modifications to NFPA−54, Chapter 10

Revise NFPA−54 section 10.8.3 to add the following requirements:

For all side wall, horizontally vented, gas−fueled equipment installed in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above the finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisfied:

1 − INSTALLATION OF CARBON MONOXIDE DETEC-

TORS. At the time of installation of the side wall, horizontally vented, gas−fueled equipment, the installing plumber or gasfitter shall observe that a hard−wired carbon monoxide detector with an alarm and battery backup is installed on the floor level where the gas equipment is to be installed. In addition, the installing plumber or gasfitter shall observe that a battery−operated or hard−wired carbon monoxide detector with an alarm is installed on each additional level of the dwelling, building or structure served by the side wall, horizontally vented, gas−fueled equipment. It shall be the responsibility of the property owner to secure the services of qualified licensed professionals for the installation of hard−wired carbon monoxide detectors.

a − In the event that the side wall, horizontally vented,

gas−fueled equipment is installed in a crawl space or an attic, the hard−wired carbon monoxide detector with alarm and battery back−up may be installed on the next adjacent floor level.

b − In the event that the requirements of this subdivi-

sion cannot be met at the time of completion of installation, the owner shall have a period of thirty (30) days to comply with the above requirements; provided, however, that during said thirty (30) day period, a battery−operated carbon monoxide detector with an alarm shall be installed.

2 − APPROVED CARBON MONOXIDE DETECTORS.

Each carbon monoxide detector as required in accordance with the above provisions shall comply with NFPA 720 and be ANSI/UL 2034 listed and IAS certified.

3 − SIGNAGE. A metal or plastic identification plate shall

be permanently mounted to the exterior of the building at a minimum height of eight (8) feet above grade directly in line with the exhaust vent terminal for the horizontally vented, gas−fueled heating appliance or equipment. The sign shall read, in print size no less than one−half (1/2) inch in size, GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS."

4 − INSPECTION. The state or local gas inspector of the

side wall, horizontally vented, gas−fueled equipment

shall not approve the installation unless, upon inspec-

tion, the inspector observes carbon monoxide detec-

tors and signage installed in accordance with the pro-

visions of 248 CMR 5.08(2)(a) 1 through 4.

EXEMPTIONS: The following equipment is exempt from 24 CMR 5.08(2)(a) 1 through 4:

1 − The equipment listed in Chapter 10 entitled Equip-

ment Not Required to Be Vented" in the most current

edition of NFPA 54 as adopted by the Board; and

2 − Product Approved side wall, horizontally vented, gas−

fueled equipment installed in a room or structure sepa-

rate from the dwelling, building or structure used in

whole or in part for residential purposes.

MANUFACTURER REQUIREMENTS − GAS EQUIPMENT VENTING SYSTEM PROVIDED.

When the manufacturer of Product Approved side wall, horizontally vented, gas−fueled equipment provides a venting system design or venting system components with the equipment, the instructions provided by the manufacturer for installation of the equipment and the venting system shall include:

1 − Detailed instructions for the installation of the venting

system design or the venting system components:

and

2 − A complete parts list for the venting system design or

venting system.

MANUFACTURER REQUIREMENTS − GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED.

When the manufacturer of Product Approved side wall, horizontally vented, gas−fueled equipment does not provide the parts for venting the flue gases, but identifies special venting systems," the following requirements shall be satisfied by the manufacturer:

1 − The referenced special venting system" instructions

shall be included with the appliance or equipment

installation instructions; and

2 The special venting systems" shall be Product Ap-

proved by the Board, and the instructions for that sys-

tem shall include a parts list and detailed installation

instructions.

A copy of all installation instructions for all Product Approved side wall, horizontally vented, gas−fueled equipment, all venting instructions, all parts lists for venting instructions, and/or all venting design instructions shall remain with the appliance or equipment at the completion of the installation.

Lennox MERIT ML193DF, ML195DF MERIT Installation Instructions Manual

Specifications and Main Features

Frequently Asked Questions

User Manual