Lennox ML193UH User Manual

INSTALLATION

E 2013 Lennox Industries Inc.

Dallas, Texas, USA

INSTRUCTIONS ML193UH

MERIT UPFLOW / HORIZONTAL AIR DISCHARGE

507121-01 08/2013 Supersedes 06/2013

SERIES GAS FURNACE

Litho U.S.A.

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.

AIR FLOW

HORIZONTAL LEFT

UPFLOW

AIR FLOW

HORIZONTAL RIGHT

Table of Contents

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

ML193UH Gas Furnace 3..........................

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

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

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

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

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

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

Filters 13..........................................

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

Pipe and Fittings Specifications 13...................

Joint Cementing Procedure 15.......................

Venting Practices 16...............................

WARNING

Improper installation, adjustment, alteration, service or maintenance can cause property damage, person al injury or loss of life. Installation and service must be performed by a licensed professional HVAC in staller (or equivalent), service agency or the gas sup plier.

Vent Piping Guidelines 17...........................

Gas Piping 34.....................................

Electrical 37.......................................

Integrated Control 39...............................

Unit Start Up 40....................................

Gas Pressure Measurement 41......................

Proper Combustion 42..............................

High Altitude 42....................................

Testing For Combustion Air Non-Direct Vents 44.......

Other Unit Adjustments 45..........................

Twinning the ML193UH 45..........................

Service 46........................................

Repair Parts List 47................................

Start Up Checklist 48...............................

08/13

*2P0813*

Page 1

507121-01

*P507121-01*

ML193UH Unit Dimensions - inches (mm)

EXHAUST AIR

)

NOTE − 60C and 60D size units that require air volumes 1800 cfm or over (850 L/s) must have one of the following

1. Single side return air with transition, to accommodate 20 x 25 x 1 in. (508 x 635 x 25 mm) cleanable air

filter. Required to maintain proper air velocity.

2. Single side return air with optional Return Air Base

3. Bottom return air.

4. Return air from both sides.

5. Bottom and See Blower Performance

Optional External Side Return Air Filter Kit is not for use

one side return air.

tables for additional information.

with the optional Return Air Base.

3/4

(19)

AIR FLOW

Bottom Return

Air Opening

9/16 (14)

OPTIONAL

SIDE RETURN

AIR FILTER KIT

(Either Side)

3/4

(19)

FRONT VIEW

ML193UH Model No.

045XP24B 045XP36B 070XP24B 070XP36B

090XP36C 090XP48C 110XP48C 110XP60C

135XP60D

17−1/2 446 16−3/8 416 16 406 7−5/8

24−1/2 622 23−3/8 594 23 584 11−1/8 283

2 (51)

3−3/8

(86)

OUTLET

SUPPL Y AIR

OPENING

2−7/8

COMBUSTION

AIR INTAKE

OPTIONAL

SIDE RETURN

AIR FILTER KIT

(Either Side)

(73)

23−3/4

(603)

(635)

TOP VIEW

27−3/4

(705)

(Either Side)

CONDENSATE TRAP CONNECTION (Either Side)

6−1/2 (165) (Either Side)

(584)

Side Return Air Opening (Either Side)

23−1/2

(597)

Bottom Return

Air Opening

19−7/16

(494)

(356)

1−15/16 (49)

14−3/4

(375)

(406)

5/8

(16)

(838)

1 (25)

Front Panel

6−9/16 (167)

9 (229)

12−5/8 (321) (Either Side)

ELECTRICAL

INLET

(Either Side)

Left

Right

3−1/4

2 (51) (Either Side)

GAS PIPING INLET

(83)

SIDE VIEW

A B C D

in. mm in. mm in. mm in. mm

194

21 533 19−7/8 505 19−1/2 495 9−3/8 238

9/16

(14

1−1/

(38)

Page 2

ML193UH Gas Furnace

Shipping and Packing List

The ML193UH Category IV gas furnace is shipped ready for installation in the upflow or horizontal position. The fur nace is shipped with the bottom panel in place. The bottom panel must be removed if the unit is to be installed in hori zontal or upflow applications with bottom return air.

The ML193UH can be installed as either a Direct Vent or a Non-Direct Vent gas central furnace.

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

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.

DIRECT VENT INSTALLATION NON-DIRECT VENT

EXHAUST OUTLET

COMBUSTION

AIR INTAKE OUTSIDE

OF HOUSE

INSTALLATION

EXHAUST

OUTLET

COMBUSTION

AIR INTAKE

INSIDE

OF HOUSE

Package 1 of 1 contains

1 - Assembled ML193UH 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 debris screen

1 - 3/4” Threaded street elbow 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 1 - Return air base kit 1 - Horizontal suspension kit

Safety Information

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 in staller (or equivalent), service agency or the gas sup plier.

FIGURE 1

NON-DIRECT VENT

INSTALLATION

EXHAUST OUTLET

COMBUSTION

AIR INTAKE INSIDE

VENTILATED

ATTIC SPACE

FIGURE 2

NON-DIRECT VENT

INSTALLATION

EXHAUST OUTLET

COMBUSTION

AIR INTAKE INSIDE

VENTILATED

CRAWL SPACE

CAUTION

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

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.

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

ML193UH 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

Page 3

Gas Code is available from the following address:

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.

Installation Locations

This furnace is CSA International certified for installation clearances to combustible material as listed on the unit nameplate and in the table in figure 12. Accessibility and service clearances must take precedence over fire protec tion clearances.

NOTE - For installation on combustible floors, the furnace shall not be installed directly on carpeting, tile, or other combustible material other than wood flooring.

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 at mosphere, the furnace must be installed according to rec ommended good practice requirements and current Na tional 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. Fail ure to do so may cause erratic limit operation and prema ture heat exchanger failure.

This ML193UH furnace must be installed so that its electri cal components are protected from water.

Installed in Combination with a Cooling Coil

When this furnace is used with cooling coils (figure 3), it shall be installed in parallel with, or on the upstream side of, cooling coils to avoid condensation in the heating compart ment. 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 manu ally 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 ad dress:

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.

Heating Unit Installed Parallell to Air Handler Unit

Dampers

(open during heating operation only)

Gas Unit

AIR FLOWAIR FLOW

Air Handler Unit

Dampers

(open during cooling operation only)

Heating Unit Installed Upstream of Cooling Coil

AIR FLOW AIR FLOW

Cooling Coil

Gas Unit

FIGURE 3

NOTE - This furnace is designed for a minimum continuous return air temperature of 60°F (16°C) or an intermittent op eration 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 ML193UH furnace may be installed in alcoves, clos ets, attics, basements, garages, crawl spaces and utility rooms in the upflow or horizontal position.

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

Use of Furnace as Construction Heater

Lennox does not recommend the use of ML193UH units as a construction heater during any phase of construction. Very low return air temperatures, harmful vapors and op eration of the unit with clogged or misplaced filters will dam age the unit.

ML193UH units may be used for heating of buildings or structures under construction, if the following conditions are met:

D The vent system must be permanently installed per

these installation instructions.

D A room thermostat must control the furnace. The use of

fixed jumpers that will provide continuous heating is not allowed.

D The return air duct must be provided and sealed to the

furnace.

D Return air temperature range between 60°F (16°C) and

80°F (27°C) must be maintained.

D Air filters must be installed in the system and must be

maintained during construction.

Page 4

D Air filters must be replaced upon construction comple

tion.

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

furnace rating plate.

D One hundred percent (100%) outdoor air must be pro

vided for combustion air requirements during construc tion. 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.

D The furnace heat exchanger, components, duct sys

tem, air filters and evaporator coils must be thoroughly cleaned following final construction clean-up.

D All furnace operating conditions (including ignition, in

put rate, temperature rise and venting) must be verified according to these installation instructions.

• The “A” coil drain pan is high quality engineering poly mer with a maximum service temperature of 500° F. However, adequate space must be provided between the drain pan and the furnace heat exchanger. At least 2” space is required for sectionalized heat exchanger and and 4” for drum-type or oil-fired furnace exchanger. Closer spacing may damage the drain pan and cause leaking.

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 fol lowing general recommendations must be considered when installing a ML193UH furnace:

• Place the furnace as close to the center of the air dis tribution system as possible. The furnace should also be located close to the vent termination point.

• When the furnace is installed in non-direct vent applica tions, 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 applica tions, 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 insu lated 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

ML193UH unit should not be installed in areas nor mally 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 Cal ifornia 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

WARNING

Insufficient combustion air can cause headaches, nausea, dizziness or asphyxiation. It will also cause excess water in the heat exchanger resulting in rust ing 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 com bustion 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

Combustion, Dilution & Ventilation Air

If the ML193UH is installed as a Non-Direct Vent Fur nace, 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.

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 prac tices make it necessary to bring in air from outside for com bustion. Take into account that exhaust fans, appliance vents, chimneys, and fireplaces force additional air that could be used for combustion out of the house. Unless out side air is brought into the house for combustion, negative pressure (outside pressure is greater than inside pressure)

Page 5

will build to the point that a downdraft can occur in the fur nace vent pipe or chimney. As a result, combustion gases enter the living space creating a potentially dangerous situ ation.

In the absence of local codes concerning air for combustion and ventilation, use the guidelines and procedures in this section to install ML193UH furnaces to ensure efficient and safe operation. You must consider combustion air needs and requirements for exhaust vents and gas piping. A portion of this information has been reprinted with per mission from the National Fuel Gas Code (ANSIZ223.1/NFPA 54). This reprinted material is not the com plete and official position of the ANSI on the referenced subject, which is represented only by the standard in its en tirety.

In Canada, refer to the CSA B149 installation codes.

CAUTION

Do not install the furnace in a corrosive or contami nated atmosphere. Meet all combustion and ventila tion air requirements, as well as all local codes.

All gas‐fired appliances require air for the combustion pro cess. If sufficient combustion air is not available, the fur nace or other appliance will operate inefficiently and un safely. Enough air must be provided to meet the needs of all fuel-burning appliances and appliances such as ex haust fans which force air out of the house. When fire places, exhaust fans, or clothes dryers are used at the same time as the furnace, much more air is required to en sure proper combustion and to prevent a downdraft. Insuf ficient air causes incomplete combustion which can result in carbon monoxide.

In addition to providing combustion air, fresh outdoor air di lutes contaminants in the indoor air. These contaminants may include bleaches, adhesives, detergents, solvents and other contaminants which can corrode furnace compo nents.

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 cu bic 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 con taining 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 ei ther 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.

EQUIPMENT IN CONFINED SPACE - ALL AIR FROM INSIDE

ROOF TERMINATED

EXHAUST PIPE

The requirements for providing air for combustion and ven tilation 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 com bined 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 un confined, it might be necessary to bring in outdoor air for combustion if the structure does not provide enough air by

OPENINGS

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

NOTE - Each opening shall have a free area of at least one square inch per 1,000 Btu (645mm all equipment in the enclosure, but not less than 100 square inches (64516mm.

2).

ML193UH

per .29kW) per hour of the total input rating of

(To Adjacent

Unconfined

Space)

FIGURE 4

Page 6

Air from Outside

If air from outside is brought in for combustion and ventila tion, the confined space shall be provided with two perma nent 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 verti cal 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 rat ing 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).

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

Roof T erminated

Exhaust Pipe

Ventilation

Louvers

(Crawl space)

EQUIPMENT IN CONFINED SPACE

Inlet Air

(Minimum

Furnace

12 in.(305mm)

Above crawl

space floor)

EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE

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

VENTILATION LOUVERS

OUTLET

AIR

(Each end of attic)

VENTILATION

LOUVERS

(For unheated

crawl space)

per 1.17kW) per

ROOF TERMINATED

EXHAUST PIPE

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

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

FURNACE

INLET

AIR

FIGURE 5

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

Roof T erminated

Exhaust Pipe

EQUIPMENT IN CONFINED SPACE

Ventilation Louvers

12 in.(305mm) Abov

*Intake Debris

Screen

(Provided)

Furnace

Inlet Air

(Minimum attic floor)

* See table 6 for maximum vent lengths

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

per 1.17kW) per

FIGURE 6

Coupling or 3 in. to 2 in.

Transition

(Field Provided)

*Intake Debris Screen Provided)

* See table 6 for maximum vent lengths

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

per 1.17kW) per

FIGURE 7

If air from outside is brought in for combustion and ventila tion, the confined space must have two permanent open ings. 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 di rectly or by ducts with the outdoors or spaces (crawl or at tic) 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 en closure. 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.

When ducts are used, they shall be of the same cross-sec tional 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 cov ering is not known for calculating the size opening required, it may be assumed that wood louvers will have 20 to 25 per cent 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 opera tion.

Page 7

EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE

ROOF TERMINATED

EXHAUST PIPE

(All Air Through Ventilated Attic)

VENTILATION LOUVERS

(Each end of attic)

OUTLET

AIR

leg). See figure 10. The bolt and washer must be re moved before the furnace is placed into operation. Af ter the bolt and washer have been removed, the rigid leg will not touch the blower housing.

ML193UH090P48C

and ML193UH110P48C

with 1/2 HP Blower Motor

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

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

FURNACE

INLET AIR

(Ends 12” above

bottom)

per 1.17kW) per hour

FIGURE 8

EQUIPMENT IN CONFINED SPACE -

ALL AIR FROM OUTSIDE

ROOF TERMINATED

EXHAUST PIPE

OUTLET AIR

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

NOTE-Each air duct opening shall have a free area of at least one square inch per 2,000 Btu (645mm input rating of all equipment in the enclosure. If the equipment room is located against an outside wall and the air openings communi cate directly with the outdoors, each opening shall have a free area of at least 1 square inch per 4,000 Btu (645mm hour of the total input rating of all other equipment in the enclosure.

FURNACE

INLET AIR

per .59kW) per hour of the total

per 1.17kW) per

FIGURE 9

Shipping Bolt Removal

Units with 1/2 hp blower motor are equipped with three flex ible 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

RIGID LEG

(Remove shipping bolt

and washer)

FIGURE 10

Installation - Setting Equipment

WARNING

Do not connect the return air duct 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.

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.

Upflow Applications

The ML193UH gas furnace can be installed as shipped in the upflow position. Refer to figure 12 for clearances. Se lect a location that allows for the required clearances that are listed on the unit nameplate. Also consider gas supply connections, electrical supply, vent connection, conden sate trap and drain connections, and installation and ser vice 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.

Allow for clearances to combustible materials as indicated on the unit nameplate.

Page 8

SETTING EQUIPMENT

UPFLOW APPLICA

TION

UNIT

FRONT

SIDE VIEW

AIR FLOW

FRONT VIEW

UNIT

FRONT

AIR FLOW

SIDE VIEW

1/2”

max.

HORIZONTAL APPLICATION

UNIT

FRONT

FRONT VIEW

AIR FLOW

END VIEW

1/2”

max.

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

FIGURE 11

Page 9

WARNING

Improper installation of the furnace can result in per sonal 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 fur nace should be sealed airtight to the return air ple num. 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. Al low absolutely no sagging, cracks, gaps, etc. For no reason should return and supply air duct sys tems ever be connected to or from other heating de vices such as a fireplace or stove, etc. Fire, explo sion, carbon monoxide poisoning, personal injury and/or property damage could result.

Installation Clearances

Top

Left Side

Right Side

Return Air Guidelines

Return air can be brought in through the bottom or either side of the furnace installed in an upflow application. If the furnace is installed on a platform with bottom return, make an airtight seal between the bottom of the furnace and the platform to ensure that the furnace operates properly and safely. The furnace is equipped with a removable bottom panel to facilitate installation.

Markings are provided on both sides of the furnace cabinet for installations that require side return air. Cut the furnace cabinet at the maximum dimensions shown on page 2.

Refer to Engineering Handbook for additional information.

ML193UH applications which include side return air and a condensate trap installed on the same side of the cabinet (trap can be installed remotely within 5 ft.) re quire either a return air base or field-fabricated transi tion to accommodate an optional IAQ accessory taller than 14.5”. See figure 13.

Side Return Air

(with transition and filter)

Bottom (Floor)

Top/Plenum 1 in. (25 mm)

*Front 0

Back 0

Sides 0†

Vent 0

Floor 0‡

*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. ‡For installations on a combustible floor, do not install the fur

nace directly on carpeting, tile or other combustible materials oth er than wood flooring.

FIGURE 12

1−1/2”

Transition

FIGURE 13

20” X 25” X 1”

(508mmX635mmX25mm)

Air Filter

Return

Air

Plenum

Page 10

)

CONDENSATE

TRAP

Optional Return Air Base

(Upflow Applications Only)

FURNACE

FRONT

23 (584)

Overall

(Maximum)

Unit side return air

Opening

5−5/8 (143)

SIDE RETURN

AIR OPENINGS

(Either Side)

26−7/8

(683)

SIDE VIEW

(584)

Minimum

11 (279)

Maximum

14 (356)

22−7/16

(570)

Overall

(Maximum

3/4

(19)

AIR FLOW

17−1/2 (446) B Width (50W98) 21 (533) C Width (50W99)

24−1/2 (622) D Width (51W00)

INDOOR AIR

QUALITY CABINET

(PCO, Filter

Cabinet, etc.)

OPTIONAL RETURN AIR BASE

IF BASE

IS USED

WITHOUT

IAQ CABINET,

A SINGLE

RETURN AIR

PLENUM

MUST

COVER BOTH

UNIT AND

RETURN

AIR BASE

OPENINGS

3−1/4

(83)

7−1/4

(184)

FRONT VIEW

NOTE- Optional side return air filter kits are not for use with return air base.

Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet. Minimum unit side return air opening dimensions for units requiring 1800 cfm of air and over (W x H): 23 x 11 in. (584 x 279 mm). The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown. Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return air opening. The size of the opening must not extend beyond the markings on the furnace cabinet.

To minimize pressure drop, the largest opening height possible (up to 14 inches) is preferred.

FIGURE 14

Removing the Bottom Panel

Remove the two screws that secure the bottom cap to the furnace. Pivot the bottom cap down to release the bottom panel. Once the bottom panel has been removed, reinstall the bottom cap. See figure 15.

Horizontal Applications

Screw

Bottom Panel

FIGURE 15

Bottom Cap

Page 11

WARNING

Do not install the furnace on its front or back. See figure 16.

Front

FIGURE 16

Back

The ML193UH furnace can be installed in horizontal ap plications with either right- or left-hand air discharge.

Refer to figure 17 for clearances in horizontal applications.

Horizontal Application

Installation Clearances

HORIZONTAL SUSPENSION KIT

Metal Strap

(typical)

Internal Brace

(provided with kit)

Right-Hand Discharge

Left End Right End

Air

Flow

Bottom (Floor)**

Left-Hand Discharge

Top

Left End Right End

Air

Flow

Bottom (Floor)**

Top 0

Front* 0

Back 0

Ends 0

Vent 0

Floor 0‡

*Front clearance in alcove installation must be 24 in. (610 mm). Maintain a minimum of 24 in. (610 mm) for front service access. **An 8” service clearance must be maintained below the unit to provide for servicing of the condensate trap. ‡For installations on a combustible floor, do not install the fur nace directly on carpeting, tile or other combustible materials oth er than wood flooring.

Air

Flow

Air

Flow

FIGURE 17

Suspended Installation of Horizontal Unit

This furnace may be installed in either an attic or a crawl space. Either suspend the furnace from roof rafters or floor joists, as shown in figure 18, or install the furnace on a plat form, as shown in figure 19. A horizontal suspension kit (51W10) may be ordered from Lennox or use equivalent.

NOTE - Heavy-gauge sheet metal straps may be used to suspend the unit from roof rafters or ceiling joists. When straps are used to suspend the unit in this way, support must be provided for both the ends. The straps must not in terfere with the plenum or exhaust piping installation. Cool

ing coils and supply and return air plenums must be supported separately.

Bracket (typical)

Air

Flow

FIGURE 18

NOTE - When the furnace is installed on a platform or with the horizontal suspension kit in a crawlspace, it must be elevated enough to avoid water damage, accommodate drain trap and to allow the evaporator coil to drain.

Platform Installation of Horizontal Unit

1 - Select location for unit keeping in mind service and

other necessary clearances. See figure 17.

2 - Construct a raised wooden frame and cover frame

with a plywood sheet. If unit is installed above finished space, fabricate an auxiliary drain pan to be installed under unit. Set unit in drain pan as shown in figure 19. Leave 8 inches for service clearance below unit for condensate trap.

3 - Provide a service platform in front of unit. When instal

ling the unit in a crawl space, a proper support platform may be created using cement blocks.

4 - Route auxiliary drain line so that water draining from

this outlet will be easily noticed by the homeowner.

5 - If necessary, run the condensate line into a conden

sate pump to meet drain line slope requirements. The pump must be rated for use with condensing furnaces. Protect the condensate discharge line from the pump to the outside to avoid freezing.

6 - Continue with exhaust, condensate and intake piping

installation according to instructions.

Page 12

INTAKE PIPE

EXHAUST PIPE

SERVICE PLATFORM

*GAS CONNECTION

RAISED

PLATFORM

FIGURE 19

Return Air -- Horizontal Applications

Return air may be brought in only through the end of a fur nace installed in the horizontal position. The furnace is equipped with a removable bottom panel to facilitate instal lation. See figure 15.

Filters

This unit is not equipped with a filter or rack. A field-pro vided high velocity rated filter is required for the unit to oper ate properly. Table 1 lists recommended filter sizes. A filter must be in place whenever the unit is operating.

IMPORTANT

If a highefficiency filter is being installed as part of this system to ensure better indoor air quality, the fil ter must be properly sized. Highefficiency filters have a higher static pressure drop than standardef ficiency glass/foam filters. If the pressure drop is too great, system capacity and performance may be re duced. The pressure drop may also cause the limit to trip more frequently during the winter and the indoor coil to freeze in the summer, resulting in an increase in the number of service calls.

Before using any filter with this system, check the specifications provided by the filter manufacturer against the data given in the appropriate Lennox Product Specifications bulletin. Additional informa tion is provided in Service and Application Note ACC002 (August 2000).

TABLE 1

Furnace

Cabinet Width

17-1/2” 16 X 25 X 1 (1) 16 X 25 X 1 (1)

21” 16 X 25 X 1 (1) 20 X 25 X 1 (1)

24-1/2” 16 X 25 X 1 (2) 24 X 25 X 1 (1)

Side Return Bottom Return

Filter Size

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 al ways be in place when the furnace is operating and it must not allow leaks.

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 de vice (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 re verse flow of the flue gas may result in incomplete com bustion 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.

Return air can be brought in through the bottom or either side of the furnace (return air brought into either side fur nace allowed in upflow applications only). If a furnace with bottom return air is installed on a platform, make an airtight seal between the bottom of the furnace and the platform to ensure that the unit operates properly and safely. Use fi berglass sealing strips, caulking, or equivalent sealing method between the plenum and the furnace cabinet to en sure 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 Ameri can Society for Testing and Materials (ANSI/ASTM) stan dards. The solvent shall be free flowing and contain no lumps, undissolved particles or any foreign matter that ad versely affects the joint strength or chemical resistance of the cement. The cement shall show no gelation, stratifica tion, or separation that cannot be removed by stirring. Re fer to the table 2 below for approved piping and fitting ma terials.

Page 13

CAUTION

Solvent cements for plastic pipe are flammable liq uids 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 ce ment with skin and eyes.

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)

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

PRIMER & SOLVENT CEMENT

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

ABS to PVC or CPVC Transition Solvent Cement

CANADA PIPE & FITTING & SOLVENT

CEMENT

PVC & CPVC Pipe and Fittings PVC & CPVC Solvent Cement

ABS to PVC or CPVC Transition Cement

TABLE 2

D2661

D2665

ASTM

SPECIFICATION

D2564, D2235, F493

D3138

MARKING

ULCS636

IMPORTANT

ML193UH 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 ce ment meeting ASTM specifications, refer to Table 2. 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 in side 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) sys tem. In addition, the first three feet of vent pipe from the fur nace flue collar must be accessible for inspection.

Page 14

Vent

Input Size

Pipe

Dia. in.

045

2-1/2

070

2-1/2

090

2-1/2

2 YES YES YES

110

2-1/2 YES YES

3 YES YES

135 3 YES

OUTDOOR TERMINATION USAGE*

TABLE 3

STANDARD CONCENTRIC

Flush Mount

Kit

2 inch 3 inch 2 inch

51W11

(US)

51W12

22G44 (US)

30G28 (CA)

(CA)

YES YES

YES YES YES

Wall Kit Wall Ring Kit

44J40

(US)

81J20 (CA)

YES

15F74

YES

1-1/2 inch 2 inch 3 inch

Field

Fabricated

YES

YES YES YES

YES YES

71M80

(US)

44W92

(CA)

YES

69M29

(US)

44W92

(CA)

60L46 (US)

44W93 (CA)

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.

* Kits must be properly installed according to kit instructions.

Requires field-provided outdoor 1-1/2” exhaust accelerator.

Concentric kits 71M80 and 44W92 include 1-1/2” outdoor accelerator, when uses with 045 and 070 input models.

Flush mount kits 51W11 and 51W12 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 8 for vent accelerator requirements.

4 - Test fit joint and mark depth of fitting on outside of

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 in take pipe to the connector, if desired. Use a drill or self tap ping screw to make a pilot hole.

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.

NOTE - Time is critical at this stage. Do not allow prim er to dry before applying cement.

DANGER

DANGER OF EXPLOSION!

Fumes from PVC glue may ignite during system check. Allow fumes to dissipate for at least 5 minutes

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

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

before placing unit into operation.

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

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.

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 dur ing assembly (but not after pipe is fully inserted) to dis tribute cement evenly. DO NOT turn ABS or cellular core pipe.

Page 15

NOTE - Assembly should be completed within 20 sec onds 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.

CHIMNEY

OR GAS

VENT

(Check sizing

for water

heater only)

FURNACE

(Replaced

by ML193)

REPLACING FURNACE THAT

WAS PART OF A COMMON

VENT SYSTEM

WATER

HEATER

Venting Practices

Piping Suspension Guidelines

SCHEDULE 40

PVC - 5'

all other pipe* - 3'

* See table 2 for allowable pipe.

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

Wall Thickness Guidelines

24” maximum 3/4” minimum

inside outside

Wall

OPENINGS

(To Adjacent

Room)

If an ML193UH furnace replaces a furnace which was commonly vented with another gas appliance, the size of the existing vent pipe for that gas ap pliance 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 21

Exhaust Piping (Figures 24 and 25)

Route piping to outside of structure. Continue with installa tion following instructions given in piping termination sec tion.

FIGURE 20

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.

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 conden sate collection trap and lines.

CAUTION

Do not discharge exhaust into an existing stack or stack that also serves another gas appliance. If verti cal discharge through an existing unused stack is re quired, 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 pres sure and must be completely sealed to prevent leak age of combustion products into the living space.

Page 16

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