Lennox ML195UH045XP24B, ML195UH090XP36C, ML195UH045XP36B, ML195UH070XP36B, ML195UH090XP48C Installation Instructions Manual

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Page 1

07/11

*2P0711*

506723−01

*P506723-01*

E 2011 Lennox Industries Inc.

Dallas, Texas, USA

AIR FLOW

UPFLOW

AIR FLOW

HORIZONTAL RIGHT

HORIZONTAL LEFT

INSTALLATION INSTRUCTIONS ML195UH

MERIT

SERIES GAS FURNACE

UPFLOW / HORIZONTAL AIR DISCHARGE

506723−01 07/2011 Supersedes 506533−01

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ML195UH Parts Arrangement 3. . . . . . . . . . . . . . . . . . . . .

ML195UH Gas Furnace 4. . . . . . . . . . . . . . . . . . . . . . . . . .

Shipping and Packing List 4. . . . . . . . . . . . . . . . . . . . . . . .

Safety Information 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Use of Furnace as a Construction Heater 5. . . . . . . . . . .

General 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Combustion, Dilution, Ventilation Air 6. . . . . . . . . . . . . . .

Setting Equipment 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

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

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

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

Gas Pressure Measurement 42. . . . . . . . . . . . . . . . . . . . . .

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

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

Other Unit Adjustments 44. . . . . . . . . . . . . . . . . . . . . . . . . .

Blower Motor Performance 45. . . . . . . . . . . . . . . . . . . . . . .

Service 47. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Planned Service 49. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Integrated Control Diagnostic Codes 49. . . . . . . . . . . . . . .

Troubleshooting 50. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Repair Parts List 53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Start Up Checklist 54. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Litho U.S.A.

Page 2

ML195UH Unit Dimensions − inches (mm)

6−9/16 (167)

Left

9 (229)

Right

(584)

(19)

3/4

(19)

Bottom Return

Air Opening

GAS PIPING INLET

(Either Side)

Side Return Air Opening (Either Side)

Bottom Return

Air Opening

EXHAUST AIR

OUTLET

ELECTRICAL

INLET

(Either Side)

SUPPLY AIR

OPENING

FRONT VIEW

SIDE VIEW

TOP VIEW

9/16 (14)

3/4

27−3/4

(705)

19−7/16

(494)

23−1/2

(597)

1−1/2

(38)

6−1/2 (165) (Either Side)

(838)

3−3/8

(86)

1−15/16 (49)

(356)

9/16

(14)

12−5/8 (321) (Either Side)

OPTIONAL

SIDE RETURN

AIR FILTER KIT

(Either Side)

(406)

14−3/4

(375)

OPTIONAL

SIDE RETURN

AIR FILTER KIT

(Either Side)

5/8

(16)

3−1/4

(83)

23−3/4

(603)

(635)

1 (25)

Front Panel

COMBUSTION

AIR INTAKE

2 (51) (Either Side)

2 (51)

CONDENSATE TRAP CONNECTION (Either Side)

2−7/8

(73)

AIR FLOW

Optional External Side Return Air Filter Kit is not for use

with the optional Return Air Base.

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

one side return air.

See Blower Performance

tables for additional information.

NOTE − 60C size units that require air volumes

1800 cfm or over (850 L/s) must have one of the following

mm in.

ABCD

in. mm in. mm in. mm

17−1/2 446 16−3/8 416 16 406 7−5/8 194

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

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

ML195UH045XP24B ML195UH045XP36B ML195UH070XP36B

ML195UH090XP36C ML195UH090XP48C ML195UH110XP48C ML195UH110XP60C

ML195UH135XP60D

ML195UH Model

Page 3

ML195UH Parts Arrangement

ML195UH PARTS IDENTIFICATION

FIGURE 1

TOP CAP

CABINET

BURNER BOX

ASSEMBLY

SIGHT

GLASS

DuralokPlus

HEAT EXCHANGER

ASSEMBLY

CONTROL BOX

(includes integrated control, transformer and interlock switch)

COMBUSTION AIR

INDUCER

BLOWER

ACCESS

DOOR

BURNER ACCESS

PANEL

COMBUSTION

AIR PRESSURE

SWITCH

PRIMARY LIMIT

GAS VALVE

BLOWER

ASSEMBLY

FLEXIBLE NO−HUB EXHAUST COLLAR

MANIFOLD

COLD END

HEADER BOX

BAG ASSEMBLIES

(shipping location)

Page 4

ML195UH Gas Furnace

The ML195UH Category IV gas furnace is shipped ready for installation in the upflow or horizontal position. The furnace is shipped with the bottom panel in place. The bottom panel must be removed if the unit is to be installed in horizontal or upflow applications with bottom return air.

The ML195UH 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 applications. 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 and flue gases are discharged outdoors. See figure 2 for applications involving roof termination.

FIGURE 2

DIRECT VENT INSTALLATION NON−DIRECT VENT

INSTALLATION

EXHAUST OUTLET

ML195UH

COMBUSTION

AIR INTAKE INSIDE

OF HOUSE

EXHAUST OUTLET

COMBUSTION AIR INTAKE OUTSIDE OF HOUSE

ML195UH

Shipping and Packing List

Package 1 of 1 contains

1 − Assembled ML195UH 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

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

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.

ML195UH 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:

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.

Page 5

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 10. Accessibility and service clearances must take precedence over fire protection 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 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 ML195UH furnace must be installed so that its electrical 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 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

Gas Unit

Heating Unit Installed Upstream of Cooling Coil

Gas Unit

Dampers

(open during heating operation only)

Dampers

(open during cooling operation only)

Heating Unit Installed Parallel to Air Handler Unit

Air Handler Unit

Cooling Coil

AIR FLOWAIR FLOW

AIR FLOW AIR FLOW

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 ML195UH furnace may be installed in alcoves, closets, attics, basements, garages, crawl spaces and utility rooms in the upflow or horizontal position.

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

Use of Furnace as Construction Heater

Lennox does not recommend the use of ML195UH 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.

ML195UH 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.

Page 6

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

maintained during construction.

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 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.

D The furnace heat exchanger, components, duct system,

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.

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 ML195UH 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 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

ML195UH 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

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

Combustion, Dilution & Ventilation Air

If the ML195UH 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 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 practices make it necessary to bring in air from outside for combustion. Take into account that exhaust fans, appliance vents, chimneys, and fireplaces force additional air that could be used for combustion out of the house. Unless outside air is brought into the house for combus-

Page 7

tion, 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 ML195UH furnaces to ensure efficient and safe operation. You must consider combustion air needs and requirements for exhaust vents and gas piping. A portion of this information has been reprinted with permission from the National Fuel Gas Code (ANSI− Z223.1/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)

ML195UH

Page 8

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).

FIGURE 5

EQUIPMENT IN CONFINED SPACE − ALL AIR FROM OUTSIDE

(Inlet Air from Crawl Space and Outlet Air to 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

INLET

AIR

VENTILATION

LOUVERS

(For unheated

crawl space)

FURNACE

ROOF TERMINATED

EXHAUST PIPE

VENTILATION LOUVERS

(Each end of attic)

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

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 6. 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 7.

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.

FIGURE 6

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)

FURNACE

FIGURE 7

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)

FURNACE

Page 9

Shipping Bolt Removal

Units with 1/2 hp blower motor are equipped with 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 8. 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 8

RIGID LEG

(Remove shipping bolt

and washer)

ML195UH090P48C ML195UH110P48C

with 1/2 HP Blower Motor

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 ML195UH gas furnace can be installed as shipped in the upflow position. Refer to figure 10 for clearances. 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 9.

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

FIGURE 9

SETTING EQUIPMENT

UPFLOW APPLICATION

HORIZONTAL APPLICATION

FRONT VIEW

SIDE VIEW

FRONT VIEW

END VIEW

UNIT

FRONT

AIR FLOW

UNIT

FRONT

1/2"

max.

1/2"

max.

AIR FLOW

SIDE VIEW

UNIT

FRONT

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

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.

Installation Clearances

Top

Bottom (Floor)

Left Side

Right Side

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 furnace

directly on carpeting, tile or other combustible materials other than wood flooring.

FIGURE 10

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.

ML195UH 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.) require either a return air base or field−fabricated transition to accommodate an optional IAQ accessory taller than 14.5". See figure 11.

Side Return Air

(with transition and filter)

FIGURE 11

Return

Air

Plenum

Transition

20” X 25” X 1”

(508mmX635mmX 25mm)

Air Filter

1−1/2”

Page 11

FIGURE 12

Optional Return Air Base

(Upflow Applications Only)

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.

FRONT VIEW

Unit side return air

Opening

SIDE VIEW

3−1/4

(83)

23 (584)

Overall

(Maximum)

(584)

3/4

(19)

22−7/16

(570)

Overall

(Maximum)

SIDE RETURN

AIR OPENINGS

(Either Side)

5−5/8

(143)

Minimum

11 (279)

Maximum

14 (356)

(683)

26−7/8

7−1/4

(184)

FURNACE

FRONT

AIR FLOW

IF BASE

IS USED

WITHOUT

IAQ CABINET,

A SINGLE

RETURN AIR

PLENUM

MUST

COVER BOTH

UNIT AND

RETURN

AIR BASE

OPENINGS

INDOOR AIR

QUALITY CABINET

(PCO, Filter

Cabinet, etc.)

AIR BASE

OPTIONAL RETURN

CONDENSATE

TRAP

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

24−1/2 (622) D Width (51W00)

Removing the Bottom Panel

FIGURE 13

Screw

Bottom Panel

Bottom Cap

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 13.

Horizontal Applications

FIGURE 14

WARNING

Do not install the furnace on its front or back. See figure 14.

Front

Back

Page 12

The ML195UH furnace can be installed in horizontal applications with either right− or left−hand air discharge.

Refer to figure 15 for clearances in horizontal applications.

Horizontal Application

Installation Clearances

Left End Right End

Right−Hand Discharge

Left−Hand Discharge

Top

Bottom (Floor)**

Left End Right End

Air

Flow

Air

Flow

Air

Flow

Air

Flow

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 furnace directly on carpeting, tile or other combustible materials other than wood flooring.

FIGURE 15

Suspended Installation of Horizontal Unit

This furnace may be installed in either an attic or a crawlspace. Either suspend the furnace from roof rafters or floor joists, as shown in figure 16, or install the furnace on a platform, as shown in figure 17. 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 interfere with the plenum or exhaust piping installation.

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

FIGURE 16

HORIZONTAL SUSPENSION KIT

Bracket (typical)

Metal Strap

(typical)

Air

Flow

Internal Brace

(provided with kit)

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 15.

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 17. 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.

Page 13

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.

FIGURE 17

*Gas connector may be used for Canadian installation if acceptable by local authority having jurisdiction.

*GAS CONNECTION

RAISED

PLATFORM

SERVICE PLATFORM

INTAKE PIPE

EXHAUST PIPE

Return Air −− Horizontal Applications

Return air may be brought in only through the end of a furnace installed in the horizontal position. The furnace is equipped with a removable bottom panel to facilitate installation. See figure 13.

Filters

This unit is not equipped with a filter or rack. A field−provided high velocity rated filter is required for the unit to operate properly. Table 1 lists recommended filter sizes. A filter must be in place whenever the unit is operating.

TABLE 1

Furnace

Cabinet Width

Filter Size

Side Return Bottom Return

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)

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 0.8 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.

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.

Return air can be brought in through the bottom or either side of the furnace. 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 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 2 below for approved piping and fitting materials.

Page 14

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 2

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

IMPORTANT

ML195UH 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 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 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. When bonding the vent system to the furnace, use ULC S636 approved One−Step Transition Cement to bond the pipe to the flue collar, or to bond the 90° elbow or reducing 90° elbow to the flue collar. In addition, the first three feet of vent pipe from the furnace flue collar must be accessible for inspection.

Page 15

TABLE 3

OUTDOOR TERMINATION KITS USAGE

EL195

UNIT

VENT

PIPE

DIA.

(in.)

STANDARD CONCENTRIC

Outdoor Exhaust

Accelerator

(Dia. X

Length)

Outdoor Exhaust

Accelerator

(Dia. X

Length)

2" Wall Plate

Kit

3" Wall Plate

Kit

2" Wall

Ring Kit

FlushMount

Kit

1−1/2"

Concentric

Kit

Concentric

Kit

Concentric

Kit

1−1/2" X 12" 2" X 12"

22G44

or 30G28

44J40

or 81J20

15F74 51W11**

71M80

44W92

69M29

44W92

60L46

or 44W93

045

2 YES YES YES* YES YES YES

2−1/2 YES YES YES* YES YES YES

3 YES YES YES* YES YES YES

070

2 YES YES YES* YES YES YES

2−1/2 YES YES YES* YES YES YES

3 YES YES YES* YES YES YES

090

2 YES YES YES YES YES YES

2−1/2 YES YES YES YES YES YES

3 YES YES YES YES YES YES

110

2 YES YES YES YES YES YES

2−1/2 YES YES YES YES YES YES

3 YES YES YES YES YES YES

135 3 YES YES YES YES

*Requires field−provided and installed 1−1/2" exhaust accelerator. ** Kit 51W11 is provided with a 1−1/2" accelerator which must be used for all ML195UH−045, −070 and −090 installations.  Termination kits 44W92, 44W93, 30G28 and 81J20 approved for use in Canadian installations to meet CSAB149.  The 44W92 concentric kit is provided with a 1−1/2" accelerator which must be installed on the exhaust outlet when this kit is used with the ML195UH045P24B and

ML195UH070P36B

furnaces.

Joint Cementing Procedure

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

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.

NOTE − Check the inside of vent pipe thoroughly for any obstruction that may alter furnace operation.

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.

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

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.

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.

Page 16

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 18

* See table 2 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

insulation

(if required)

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 condensate collection trap and lines.

CHIMNEY

OR GAS

VENT

(Check sizing

for water

heater only)

FURNACE

(Replaced

by ML195)

WATER

HEATER

OPENINGS

(To Adjacent

Room)

If an ML195UH 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 19

REPLACING FURNACE THAT

WAS PART OF A COMMON

VENT SYSTEM

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.

Page 17

Vent Piping Guidelines

The ML195UH can be installed as either a Non−Direct Vent or a Direct Vent gas central furnace.

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

Intake and exhaust pipe sizing −− Size pipe according to

tables 4 and

5. Table 4 lists the minimum vent pipe lengths

permitted. Table 5 lists the maximum pipe lengths per- mitted.

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 6.

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.

NOTE − The exhaust collar on all models is sized to accommodate 2" Schedule 40 vent pipe. When vent pipe which is larger than 2" must be used in an upflow application, a transition must be applied at the exhaust collar in order to properly step to the larger diameter vent pipe. Contact the Application Department for more information concerning sizing of vent systems which include multiple pipe sizes.

FIGURE 20

Exhaust Pipe

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

NOTE − All horizontal runs of exhaust pipe must slope back to-

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

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

12” ma x

of straight pip

Exhaust Pipe

12” Min.

Horizontal

Gas Furnace

TABLE 4

MINIMUM VENT PIPE LENGTHS

ML195UH

MODEL

MIN. VENT LENGTH*

045, 070, 090, 110, 135

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.

Use the following steps to correctly size vent pipe diameter.

045, 070, 090, 110 or 135 btuh

Which termination?

Standard or Concentric? See table 3

Intake or exhaust

Which needs most elbows?

How many?

2", 2 1/2" or 3"

Desired pipe size?

Use table 5 to find max. intake or exhaust pipe length.

FIGURE 21

What is the altitude?

Furnace capacity?

IMPORTANT

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

Page 18

TABLE 5

Maximum Allowable 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.

Standard Termination at Elevation 0 − 4500 ft

Number Of

90° Elbows

Used

2" Pipe 2−1/2" Pipe 3" Pipe

Model Model Model

045 070 090 110 135 045 070 090 110 135 045 070 090 110 135

1 81 66 44 24

n/a

115 115 93 58

n/a

138 137 118 118 114

2 76 61 39 19 110 110 88 53 133 132 11 3 11 3 109

3 71 56 34 14 105 105 83 48 128 127 108 108 104

4 66 51 29

n/a

100 100 78 43 123 122 103 103 99

5 61 46 24 95 95 73 38 118 117 98 98 94

6 56 41 19 90 90 68 33 113 112 93 93 89

7 51 36 14 85 85 63 28 108 107 88 88 84

8 46 31

n/a

80 80 58 23 103 102 83 83 79

9 41 26 75 75 53 18 98 97 78 78 74

10 36 21 70 70 48 13 93 92 73 73 69

Standard Termination Elevation 4500 − 10,000 ft

Number Of

90° Elbows

Used

2" Pipe 2−1/2" Pipe 3" Pipe

Model Model Model

045 070 090 110 135 045 070 090 110 135 045 070 090 110 135

1 81 66 44

n/a n/a

115 115 93 58

n/a

138 137 118 118 114

2 76 61 39 110 110 88 53 133 132 11 3 11 3 109

3 71 56 34 105 105 83 48 128 127 108 108 104

4 66 51 29 100 100 78 43 123 122 103 103 99

5 61 46 24 95 95 73 38 118 117 98 98 94

6 56 41 19 90 90 68 33 113 112 93 93 89

7 51 36 14 85 85 63 28 108 107 88 88 84

8 46 31

n/a

80 80 58 23 103 102 83 83 79

9 41 26 75 75 53 18 98 97 78 78 74

10 36 21 70 70 48 13 93 92 73 73 69

Page 19

TABLE 5 Continued

Maximum Allowable Vent Length in Feet

Concentric Termination at Elevation 0 − 4500 ft

Number Of 90° Elbows

Used

2" Pipe 2−1/2" Pipe 3" Pipe

Model Model Model

045 070 090 11 0 135 045 070 090 110 135 045 070 090 11 0 135

1 73 58 42 22

n/a

105 105 89 54

n/a

121 121 114 114 105

2 68 53 37 17 100 100 84 49 116 116 109 109 100

3 63 48 32 12 95 95 79 44 111 111 104 104 95

4 58 43 27

n/a

90 90 74 39 106 106 99 99 90

5 53 38 22 85 85 69 34 101 101 94 94 85

6 48 33 17 80 80 64 29 96 96 89 89 80

7 43 28 12 75 75 59 24 91 91 84 84 75

8 38 23

n/a

70 70 54 19 86 86 79 79 70

9 33 18 65 65 49 14 81 81 74 74 65

10 28 13 60 60 44 n/a 76 76 69 69 60

Concentric Termination Elevation 4501 − 10,000 ft

Number Of 90° Elbows

Used

2" Pipe 2−1/2" Pipe 3" Pipe

Model Model Model

045 070 090 11 0 135 045 070 090 110 135 045 070 090 11 0 135

1 73 58 42

n/a n/a

105 105 89 54

n/a

121 121 114 114 105

2 68 53 37 100 100 84 49 116 11 6 109 109 100

3 63 48 32 95 95 79 44 111 111 104 104 95

4 58 43 27 90 90 74 39 106 106 99 99 90

5 53 38 22 85 85 69 34 101 101 94 94 85

6 48 33 17 80 80 64 29 96 96 89 89 80

7 43 28 12 75 75 59 24 91 91 84 84 75

8 38 23

n/a

70 70 54 19 86 86 79 79 70

9 33 18 65 65 49 14 81 81 74 74 65

10 28 13 60 60 44 n/a 76 76 69 69 60

Page 20

FIGURE 22

TYPICAL EXHAUST AND INTAKE PIPE CONNECTIONS IN UPFLOW DIRECT OR

NON−DIRECT VENT APPLICATIONS

TRANSITION

2”

3”

2”

Pipe size determined in table 5

DO NOT transition

from smaller to larger

pipe in horizontal runs

of exhaust pipe.

2”

EXHAUST INTAKE

TRANSITION

3”

2”

EXHAUST INTAKE

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

FIGURE 23

2”

TRANSITION

2”

SIDE VIEW

2”

TYPICAL EXHAUST AND INTAKE PIPE CONNECTIONS IN HORIZONTAL DIRECT

OR NON−DIRECT VENT APPLICATIONS

(RIGHT HAND DISCHARGE SHOWN)

3”

2”

45°

MAX

45°

MAX

DO NOT transition

from smaller to larger

pipe in horizontal runs

of exhaust pipe.

EXHAUST

12" max.

2”

INTAKE

2”

TRANSITION

2”

3”

EXHAUST

INTAKE

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

Page 21

Intake Piping The ML195UH 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 and 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 transition solvent cement or a sheet metal screw

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

5 for pipe sizes.

FIGURE 24

TYPICAL AIR INTAKE PIPE CONNECTIONS

UPFLOW NON−DIRECT

VENT APPLICATIONS

INTAKE

DEBRIS

SCREEN

(Provided)

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

FIGURE 25

TYPICAL AIR INTAKE PIPE CONNECTIONS

HORIZONTAL NON−DIRECT VENT APPLICATIONS

(Horizontal Right−Hand Air Discharge Application Shown)

INTAKE

DEBRIS

SCREEN

(Provided)

NOTE − Debris screen may be positioned straight out (preferred) or with an elbow rotated to face down.

coupling

PVC pipe

Follow the next two steps when installing the unit in Non- Direct 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 or 25. 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 to either side in the upflow position, and either straight out or downward in the horizontal position.

The air intake piping must not terminate too close to the flooring or a platform. Ensure that the intake air inlet will not be obstructed by loose insulation or other items that may clog the debris screen.

2 − Use a sheet metal screw to secure the intake pipe to

the connector, if desired.

Page 22

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 ML195UH 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 ML195UH 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 26 or 27. 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 − If winter design temperature is below 32°F (0°C), exhaust piping should be insulated with 1/2" (13mm), Armaflex or equivalent when run through unheated space. Do not leave any surface area of exhaust pipe open to outside air; exterior 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.

NOTE − During extremely cold temperatures, below approximately 20°F (6.7°C), units with long runs of vent pipe through unconditioned space, even when insulated, may form ice in the exhaust termination that prevents the unit from operating properly. Longer run times of at least 5 minutes will alleviate most icing problems. Also, a heating cable may be installed on exhaust piping and termination to prevent freeze−ups. Heating cable installation kit is available from Lennox. See Condensate Piping section for part numbers.

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).

Page 23

FIGURE 26

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 24

FIGURE 27

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 (mm) for appliances

> 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 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"

* 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 (mm) for appliances

> 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 25

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.

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 28 through 39 show typical terminations.

1 − Exhaust and intake exits must be in same pressure

zone. Do not exit one through the roof and one on the side. Also, do not exit the intake on one side and the exhaust on another side of the house or structure.

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

28).

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 6.

TABLE 6

EXHAUST PIPE TERMINATION SIZE REDUCTION

ML195UH

MODEL

Exhaust Pipe Size

Termination

Pipe Size

*045 and 070

2" (51mm), 2−1/2" (64mm),

3" (76mm)

1−1/2" (38mm)

*090 2" (51mm)

110 2" (51mm)

135

3" (76mm)

2" (51mm)

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

FIGURE 28

UNCONDITIONED

ATTIC SPACE

1/2" (13mm) FOAM

INSULATION IN

UNCONDITIONED

SPACE

SIZE TERMINATION PIPE PER TABLE 6.

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)

FIGURE 29

FIELD−SUPPLIED WALL TERMINATION OR

(15F74) WALL RING TERMINATION KIT

See venting table 5 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 6

1/2" (13mm) ARMAFLEX

INSULATION IN UN-

CONDITIONED SPACE

STRAIGHT

APPPLICATION

* WALL

SUPPORT

1/2" (13mm) ARMAFLEX INSULATION

IN UNCONDITIONED SPACE

EXTENDED

APPLICATION

Page 26

FIGURE 30

FIELD−SUPPLIED WALL TERMINATION OR

(15F74) WALL RING TERMINATION KIT

With INTAKE ELBOW

See venting table 5 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 6

1/2" (13mm) ARMAFLEX

INSULATION IN UN-

CONDITIONED SPACE

STRAIGHT

APPPLICATION

* WALL

SUPPORT

1/2" (13mm) ARMAFLEX INSULATION

IN UNCONDITIONED SPACE

EXTENDED

APPLICATION

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 29 and 30.

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 29 and 30.

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 29 and 30. In addition, close coupled wall termination kits must be extended for use in this application. See figures 37 and 38. When exhaust and intake piping must be run up an outside wall, the exhaust piping must be terminated with pipe sized per table 6.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 34.

2" EXTENSION FOR 2" PVC PIPE 1" EXTENSION FOR 3" PVC PIPE

FIGURE 31

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 27

FIGURE 32

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

1 1/2" (38mm) accelerator

provided on 71M80 & 44W92

kits for ML195UH045P24B,

070P24B & 070P36B

12” (305mm)

INTAKE

AIR

EXHAUST

VENT

12" (305mm) Min.

above grade or

average snow

accumulation.

FIGURE 33

DIRECT VENT CONCENTRIC WALL TERMINATION

71M80, 69M29 or 60L46 (US)

41W92 or 41W93 (Canada)

INTAKE

AIR

INTAKE

AIR

INTAKE

AIR

OUTSIDE

WALL

GRADE

CLAMP

(Not Furnished)

FIELD−PROVIDED

REDUCER MAY BE REQUIRED

TO ADAPT LARGER VENT

PIPE SIZE TO TERMINATION

EXHAUST

VENT

1−1/2" (38mm) accelerator

provided on 71M80 & 44W92

kits for ML195UH045P24B,

070P24B & 070P36B

EXHAUST

VENT

FIGURE 34

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 accumulation.

optional intake elbow

FIGURE 35

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 6.

FIELD−

PROVIDED

REDUCER MAY

BE REQUIRED

TO ADAPT

LARGER VENT

PIPE SIZE TO

TERMINATION

FIGURE 36

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 6.

FIELD−

PROVIDED

REDUCER MAY

BE REQUIRED

TO ADAPT

LARGER VENT

PIPE SIZE TO

TERMINATION

Page 28

FIGURE 37

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

FIGURE 38

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

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

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

Page 29

ML195UH 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 39

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 6.

Minimum 12" (305MM)

above chimney top

plate or average snow

accumulation

8" − 12"

(203mm − 305mm)

3"−8"

(76mm−203mm)

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 40 through 43 show typical terminations.

1 − Exhaust piping must terminate straight out or up as

shown. The termination pipe must be sized as listed in table 6.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 41.

FIGURE 40

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 6.

1/2" (13mm) FOAM

INSULATION

FIGURE 41

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 6.

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 42. When exhaust piping must be run up an outside wall, any reduction in exhaust pipe size must be done after the final elbow.

FIGURE 42

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 TERMINATION

PIPE PER

TABLE 6.

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

EXTENDED OR (15F74) WALL TERMINATION VENT PIPE

EXTENDED

6" (152mm)

Max

Page 30

FIGURE 43

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 6.

ML195UH 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 in upflow applications. In horizontal applications, the condensate trap must extend below the unit. An 8" service clearance is required for the condensate trap. Refer to figures 44 and 45 for condensate trap locations. Figure 51 shows trap assembly using 1/2" PVC or 3/4" PVC.

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.

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 44)

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 51.

FIGURE 44

CONDENSATE TRAP AND PLUG LOCATIONS

(Unit shown in upflow position)

NOTE − In upflow applications where side return air filter is installed on same side as the condensate trap, filter rack must be installed beyond condensate trap or trap must be re−located to avoid interference.

Trap

(same on

right side)

Plug

(same on left side)

1−1/2 in.

4 − Install drain trap using appropriate PVC fittings, glue

all joints. Glue the provided drain trap as shown in figure 51. Route the condensate line to an open drain.

Condensate line must maintain a 1/4" downward slope from the furnace to the drain.

5 − Figures 46 and 47 show 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 48, 49 and 50. Upflow furnace (figure 46) − In upflow furnace applications the field provided vent must be a minimum 1" to a maximum 2" length above the condensate drain outlet connection. Any length above 2" may result in a flooded heat exchanger if the combined primary drain line were to become restricted. Horizontal furnace (figure 50) − In horizontal furnace applications the field provided vent must be a minimum 4" to a maximum 5" length above the condensate drain outlet connection. Any length above 5" may result in a flooded heat exchanger if the combined primary drain line were to become restricted.

6 − If unit will be started immediately upon completion of

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

Page 31

CAUTION

Do not use copper tubing or existing copper conden- sate lines for drain line.

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. Heating 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 45

CONDENSATE TRAP LOCATIONS

(Unit shown in upflow position with remote trap)

*5’ max.

To Drain

PVC Pipe Only

Field Provided Vent

Min. 1" Above Condensate

Drain Connection

1" Min.

Trap Can Be Installed a

Maximum 5’ From Furnace

*Piping from furnace must slope down a minimum of 1/4" per ft. toward trap.

2" Max.

FIGURE 46

Field−Provided Vent

(1" min. to 2" Max. above

ondensate drain connection)

Drain

Condensate trap and evaporator coil drain separately as

shown.

Condensate

Drain Connection

ML195UH With Evaporator Coil Using A Separate Drain

FIGURE 47

Condensate Drain

Connection

Field−Provided Vent

(4" min. to 5" Max. above

condensate drain connection)

*Piping from furnace and evaporator coil must slope down a minimum of 1/4" per ft. toward trap.

5’ max.

PVC Pipe Only

4”min

5”max

Evaporator

Coil

Drain Pan

ML195UH with Evaporatoir Coil Using a Separate Drain

(Unit shown in horizontal left−hand discharge position)

Page 32

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 48

Condensate Trap With Optional Overflow Switch

Field−Provided Vent

(Upflow/Furnace 1" Min. to 2" Max.

Horizontal Furnace 4" Min. to 5" Max. above

condensate drain connection)

Furnace Condensate

Drain Connection

From Evaporator Coil

To Drain

Optional

Overflow Switch

FIGURE 49

ML195UH with Evaporator Coil Using a Common Drain

Field−Provided Vent

(1" min. to 2" Max. above

condensate drain connection)

Evaporator

Drain Line

Vent Required

Condensate

Drain Connection

FIGURE 50

Condensate Drain

Connection

ML195UH with Evaporator Coil Using a Common Drain

(Unit shown in horizontal left−hand discharge position)

Field−Provided Vent

(4" min. to 5" Max. above

condensate drain connection)

*Piping from furnace and evaporator coil must slope down a minimum of 1/4" per ft. toward trap.

5’ max.

PVC Pipe Only

4”min

5”max

Evaporator

Coil

Drain Pan

Page 33

FIGURE 51

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 34

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 53. Move Bellows grommet to side which gas line enters. Ensure opposite gas line hole is plugged with supplied plug.

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 7 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 53 and

54.

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 61.

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.

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

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 52

MANUAL MAIN SHUT−OFF

VALVE WILL NOT HOLD

NORMAL TEST PRESSURE

FURNACE

ISOLATE

GAS VALVE

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

CAP

IMPORTANT

When testing pressure of gas lines, gas valve must be disconnected and isolated. See figure 52. 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 35

GROUND

JOINT

UNION

FIELD

PROVIDED

AND INSTALLED

Left Side Piping

(Standard)

DRIP LEG

MANUAL

MAIN SHUT−OFF

VALV E

Right Side Piping

(Alternate)

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

Bellows Grommet

PlugPlug

GROUND

JOINT

UNION

DRIP LEG

MANUAL

MAIN SHUT−OFF

VALV E

Gas Valve

Bellows Grommet

FIGURE 53

Horizontal Applications

Possible Gas Piping Configurations

GROUND

JOINT

UNION

DRIP LEG

MANUAL

MAIN SHUT−OFF

VALV E

GROUND

JOINT

UNION

DRIP LEG

MANUAL

MAIN SHUT−OFF

VALV E

GROUND

JOINT UNION

DRIP LEG

MANUAL

MAIN SHUT−OFF

VALV E

Horizontal Application

Left−Side Air Discharge

Horizontal Application

Right−Side Air Discharge

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

FIELD

PROVIDED

AND INSTALLED

Bellows Grommet

Plug

Gas Valve

FIGURE 54

Page 36

TABLE 7

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 of gas per hour (kilo liters of gas per hour) and based on 0.60 specific gravity gas.

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.

Page 37

Electrical

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

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

INTERIOR MAKE−UP BOX INSTALLATION

FIGURE 55

MAKE−UP

BOX

Left side

INTERIOR MAKE−UP BOX INSTALLATION

FIGURE 56

MAKE−UP

BOX

Right Side

remove and relocate

plug to unused

opening on left side

The unit is equipped with a field make−up box. The make− up box may be moved to the right side of the furnace to facilitate installation. Seal unused openings on left side with plugs removed from right side. Secure the excess wire to the existing harness to protect it from damage.

Refer to figure 58 for field wiring and figure 59 for 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.

Before connecting the thermostat check to make sure the wires will be long enough for servicing at a later date. Make sure that thermostat wire is long enough to facilitate future removal of blower for service.

Complete the wiring connections to the equipment. Use the provided unit wiring diagram and the field wiring diagram shown in figure 58. 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 ML195UH 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 60 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 60 for integrated control configuration. This terminal is energized in the heating mode when the combustion air inducer is operating. 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.

Page 38

Thermostat Furnace Condensing

Unit

ML195UH and CONDENSING UNIT

THERMOSTAT DESIGNATIONS

(Refer to specific thermostat and outdoor unit.)

COMMON

POWER

HEAT

INDOOR BLOWER

COOLING

FIGURE 57

CONDENSING

UNIT

CONDENSING

UNIT COMMON

*CONDENSING

UNIT

*NOTE − R" REQUIRED ON SOME OUTDOOR UNITS

Install the room thermostat according to the instruc-

tions 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 ML195UH 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:

D The furnace requires 120 volts +

10% (Range: 108

volts to 132 volts).

D The furnace operates at 60 Hz +

5% (Range: 57 Hz to

63 Hz).

D 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.

D Generator should have a wave form distortion of less

than 5% THD (total harmonic distortion).

TYPICAL ML195UH FIELD WIRING DIAGRAM

FIGURE 58

IGNITOR

*NOTE − R" REQUIRED ON SOME OUTDOOR UNITS

Page 39

TYPICAL ML195UH WIRING DIAGRAM

FIGURE 59

Page 40

FIGURE 60

INTEGRATED CONTROL

(Automatic Hot Surface Ignition System)

TERMINAL DESIGNATIONS

HUM LINE XFMR EAC COOL HEAT PARK FLAME NEUTRALS

Humidifier (120VAC) Input (120VAC) Transformer (120VAC) Electronic Air Cleaner (120VAC) Blower − Cooling Speed (120VAC) Blower − Heating Speed (120VAC) Dead terminals to park alternate spd taps Flame sensor Neutral terminals (120VAC)

3 AMP, 32 VAC FUSE

BLOWER OFF

DELAY JUMPER

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.

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.

CAUTION

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

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 ML195UH is equipped with a gas control switch (lever). Use only your hand to move switch. Never use tools. If the 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:

ML195UH 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.

Page 41

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 al-

low 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 61)

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 61. 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 61.

MANIFOLD

PRESSURE

OUTLET

GAS VALVE SHOWN IN ON POSITION

INLET

PRESSURE

PORT

MANIFOLD

PRESSURE

ADJUSTMENT

SCREW

FIGURE 61

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.

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

Turning Off Gas to Unit" and call your service technician 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.

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.

Page 42

Gas Pressure Adjustment

Gas Flow (Approximate)

TABLE 8

GAS METER CLOCKING CHART

ML195

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 11 0 136 272

−090 41 82 102 204

−110 33 66 82 164

−135 27 54 68 136

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

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 8 below. If manifold pressure matches table 9 and rate is incorrect, check gas orifices for proper size and restriction. Remove temporary gas meter if installed.

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

Supply Pressure Measurement

When testing supply gas pressure, use the 1/8" N.P.T. plugged tap or pressure post located on the gas valve to facilitate test gauge connection. See figure 61. Check gas line pressure with unit firing at maximum rate. Low pressure may result in erratic operation or underfire. High pressure can result in permanent damage to gas valve or overfire.

On multiple unit installations, each unit should be checked separately, with and without units operating. Supply pressure must fall within range listed in table 9.

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, observe 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

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.

TABLE 9

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

Unit Fuel

Manifold

Pressure

Line Pressure

All Nat. Gas 3.5 4.5 − 10.5

All L.P. Gas 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.

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.

TABLE 10

ML195

Unit

CO2%

For Nat

CO2%

For L.P.

−045

7.2 − 8.2 8.6 − 9.6

−070

−090

−110

The maximum carbon monoxide reading should not exceed 50 ppm.

High Altitude Information

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

Units installed at altitude of 4501 − 10,000 feet (1373 to 3048m) require a pressure switch change which can be ordered separately. Table 11 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.

Page 43

TABLE 11

Conversion Kit and Pressure Switch Requirements at Varying Altitudes

ML195

Unit

Natural to

LP/Propane

High Altitude

Natural Burner

Orifice Kit

High Altitude

LP/Propane Burner

Orifice Kit

High Altitude Pressure Switch

0 − 7500 ft

(0 − 2286m)

7501 − 10,000 ft

(2286 − 3038m)

7501 − 10,000 ft (2286 − 3038m)

4501 − 7500 ft

(1373 − 2286m)

7501 −10,000 ft

(2286 − 3048m)

−045

*69W73 73W37 *68W68

No Change 80W60

−070 80W66 80W59

−090 80W65 80W59

−110 80W66 80W59

−135 80W65 80W59

* 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).

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

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 ML195UH gas furnace has been started, the following test should be conducted to ensure proper venting and sufficient combustion air has been provided to the ML195UH as well as to other gas-fired appliances which are separately vented.

If a ML195UH 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 44

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 90 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 62.

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). Correct voltage is 120VAC +

10%

3 − Check amp−draw on the blower motor with blower ac-

cess panel in place. 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 62

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 Blower performance data beginning on the next page.

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.

Electronic Ignition

The integrated control has an added feature of an internal Watchguard control. The feature serves as an automatic reset device for integrated control lockout caused by ignition failure. This type of lockout is usually due to low gas line pressure. After one hour of continuous thermostat demand for heat, the Watchguard will break and remake thermostat demand to the furnace and automatically reset the integrated control to begin the ignition sequence.

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 45

BLOWER DATA

ML195UH045XP24B PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 1140 455 920 365 765 295 710 265

0.10 1135 445 900 360 765 290 690 255

0.20 1125 430 895 350 755 285 680 255

0.30 1090 415 870 340 725 280 660 250

0.40 1065 405 870 325 715 270 635 245

0.50 1020 390 825 315 675 260 605 235

0.60 945 365 780 300 640 250 555 225

0.70 910 350 740 295 585 240 505 220

0.80 790 325 670 275 510 225 455 205

0.90 735 310 575 255 460 220 390 195

ML195UH045XP36B PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 1605 700 1370 590 1160 475 1010 400

0.10 1600 680 1355 565 1155 465 1015 390

0.20 1550 645 1330 540 1150 445 1000 380

0.30 1480 620 1295 520 1140 430 975 365

0.40 1425 590 1280 490 1105 415 975 345

0.50 1355 565 1190 460 1085 395 940 335

0.60 1320 545 1165 435 1030 380 900 315

0.70 1225 500 1110 425 980 355 855 310

0.80 1135 480 1050 395 920 330 780 280

0.90 1025 445 950 360 795 295 700 255

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Medium-

High

Medium-

High

Medium-Low Low

ML195UH090XP36C PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 1630 715 1345 590 1090 475 885 385

0.10 1615 700 1320 580 1070 465 890 380

0.20 1580 675 1305 570 1070 455 890 370

0.30 1525 620 1295 535 1060 435 890 360

0.40 1480 615 1275 515 1055 430 885 350

0.50 1415 565 1220 485 1030 410 860 330

0.60 1350 535 1175 450 1005 390 835 310

0.70 1260 505 1115 415 955 360 785 290

0.80 1190 480 1010 380 880 325 740 285

0.90 1060 435 930 360 795 295 655 250

ML195UH090XP48C PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 2140 880 1895 780 1590 645 1350 550

0.10 2110 850 1880 760 1585 635 1360 545

0.20 2060 810 1840 725 1580 620 1360 520

0.30 1990 765 1805 690 1550 585 1365 500

0.40 1925 750 1755 655 1510 545 1330 470

0.50 1830 700 1675 610 1460 525 1285 450

0.60 1720 645 1610 575 1390 480 1230 415

0.70 1600 615 1520 535 1300 465 1165 390

0.80 1455 560 1410 500 1200 430 1035 365

0.90 1300 515 1305 465 1100 390 901 320

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Medium-

High

Medium-

High

Medium-Low Low

ML195UH070XP36B PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 1585 685 1340 585 1095 480 880 380

0.10 1560 665 1320 565 1085 470 885 375

0.20 1515 630 1300 540 1080 460 880 370

0.30 1465 590 1275 520 1065 440 890 360

0.40 1410 570 1235 490 1050 420 875 350

0.50 1345 540 1195 470 1020 400 840 335

0.60 1275 510 1140 440 975 365 830 315

0.70 1195 485 1090 410 930 355 780 290

0.80 1105 460 995 380 850 325 730 275

0.90 985 420 890 345 770 300 650 255

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Medium-

High

Medium-Low Low

Page 45

ML195UH110XP48C PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 2000 910 1675 765 1360 635 1185 525

0.10 1980 895 1650 745 1370 610 1180 505

0.20 1935 855 1600 710 1400 590 1170 485

0.30 1875 830 1560 680 1370 570 1160 490

0.40 1800 785 1490 655 1325 545 1120 455

0.50 1725 720 1400 610 1295 515 1080 435

0.60 1630 685 1335 585 1185 480 1030 410

0.70 1530 665 1290 525 1100 435 940 385

0.80 1410 610 1190 485 985 400 790 365

0.90 1245 560 1000 430 925 380 715 315

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Medium-

High

Medium-Low Low

Page 46

BLOWER DATA

ML195UH110XP60C PERFORMANCE (Less Filter)

Air Volume / Watts at Different Blower Speeds

External

Static

Pressure

in. w.g.

0.00 2485 1515 2090 1070 1835 865 1380 660 2400 1475 2100 1075 1755 870 1320 655

0.10 2460 1475 2075 1040 1810 835 1390 650 2370 1440 2090 1060 1735 850 1330 645

0.20 2405 1445 2040 995 1790 820 1405 650 2320 1405 2060 1050 1720 835 1340 650

0.30 2335 1375 1990 980 1760 790 1460 635 2235 1350 2040 1030 1725 825 1350 645

0.40 2215 1355 1935 940 1740 775 1410 630 2165 1330 1975 970 1700 815 1330 632

0.50 2185 1310 1865 895 1680 750 1410 625 2040

0.60 2060 1270 1805 870 1630 720 1405 610 1960 1260 1845 910 1635 770 1340 620

0.70 1945 1235 1700 840 1605 700 1380 590 1865 1215 1750 890 1575 730 1295 600

0.80 1845 1210 1605 810 1505 670 1305 570 1715 1175 1590 840 1505 710 1280 590

0.90 1730 1150 1570 790 1470 660 1250 540 1630 1135 1490 685 1460 685 1235 565

ML195UH135XP60D PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 2595 1515 2245 2015 1780 890 1365 700 2540 1500 2185 1095 1715 880 1350 700

0.10 2570 1490 2235 1095 1765 875 1370 665 2525 1480 2165 1085 1725 870 1335 675

0.20 2440 1465 2135 1075 1745 865 1395 660 2440 1445 2120 1090 1725 865 1345 675

0.30 2340 1405 2075 1060 1755 845 1365 660 2345 1400 2060 1060 1715 850 1345 670

0.40 2255 1370 1995 1005 1680 825 1370 660 2220 1345 1955 1015 1685 820 1370 660

0.50 2095 1320 1915 960 1650 805 1335 650 2100

0.60 1995 1270 1840 935 1595 775 1320 630 2005 1285 1780 945 1605 790 1285 635

0.70 1900 1225 1755 905 1540 755 1270 615 1845 1235 1700 910 1510 740 1225 610

0.80 1740 1180 1650 875 1430 725 1190 590 1745 1185 1645 880 1450 720 1175 595

0.90 1580 1140 1535 840 1350 695 1145 570 1655 1160 1545 840 1380 705 1135 575

Bottom Return Air, Side Return Air with Optional Return Air Base, Return Air from Both Sides or Return Air from Bottom and One Side.

High Medium-High Medium-Low Low High Medium-High Medium-Low Low

cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts

Air Volume / Watts at Different Blower Speeds Bottom Return Air, Side Return Air with Optional Return Air Base, Return Air from Both Sides or Return Air from Bottom and One Side.

High Medium-High Medium-Low Low High Medium-High Medium-Low Low

cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts

Single Side Return Air − Air volumes in bold require eld fabricated transition to accommodate 20 x 25 x 1 in. air lter in order to maintain proper air velocity.

1290 1920 945 1700 790 1325 620

Single Side Return Air − Air volumes in bold require eld fabricated transition to accommodate 20 x 25 x 1 in. air lter in order to maintain proper air velocity.

1310 1895 985 1620 805 1320 650

Page 46

Page 47

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 1 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 clean out cap.

Cleaning Heat Exchanger

If cleaning the heat exchanger becomes necessary, follow the below procedures and refer to figure 1 when disassembling unit. Use papers or protective covering in front of furnace while removing heat exchanger assembly.

1 − Turn off electrical and gas supplies to the furnace. 2 − Remove the burner access panel. 3 − Mark all gas valve wires and disconnect them from

valve. 4 − Remove gas supply line connected to gas valve. 5 − Remove sensor wire from flame sensor. Disconnect

2-pin plug from the ignitor. 6 − Disconnect wires from flame roll−out switches. 7 − Remove four burner assembly screws at the vestibule

panel and remove gas valve /manifold and burner box

as a single unit.

NOTE − If necessary, clean burners at this time. Follow

procedures outlined in Burner Cleaning section.

9 − Remove the clean−out cap on trap and drain. Replace

cap. 10 − Disconnect condensate drain line from the conden-

sate trap. Remove condensate trap (it may be neces-

sary to cut drain pipe). Remove the 1/2" NPT fitting

from the cold end header box. Disconnect drain tubes

from cold end header collector box. 11 − Disconnect condensate drain tubes from flue collar.

Remove screws that secures flue collar in place. Re-

move flue collar. It may be necessary to cut the exiting

exhaust pipe for removal of the fitting. 12 − Loosen two clamps from flexible no−hub exhaust col-

lar. 13 − Disconnect the 2-pin plug from the combustion air in-

ducer. Remove screws which secure combustion air

inducer to collector box. Remove combustion air in-

ducer assembly. Remove ground wire. 14 − Mark and disconnect all combustion air pressure tub-

ing from cold end header collector box. 15 − Mark and remove wires from pressure switch. Re-

move pressure switch. Keep tubing attached to pres-

sure switch. 16 − Remove electrical junction box from the side of the fur-

nace. 17 − Remove blower access panel. 18 − Mark and disconnect any remaining wiring to heating

compartment components. Disengage strain relief

bushing and pull wiring and bushing through the hole in

the blower deck. 19 − Remove the primary limit from the vestibule panel. 20 − Remove top cap screws to allow top cap to be tilted up-

ward to allow clearance for removing heat exchanger.

Page 48

21 − Remove two screws from the front cabinet flange at

the blower deck. Spread cabinet sides slightly to allow clearance for removal of heat exchanger.

22 − Remove screws along vestibule sides and bottom

which secure vestibule panel and heat exchanger assembly to cabinet. Remove two screws from blower rails which secure bottom heat exchanger flange. Remove heat exchanger from furnace cabinet.

23 − Back wash heat exchanger with soapy water solution

or steam. If steam is used it must be below 275°F

(135°C) .

24 − Thoroughly rinse and drain the heat exchanger. Soap

solutions can be corrosive. Take care to rinse entire assembly.

25 − Reinstall heat exchanger into cabinet making sure that

the rear baffle of the heat exchanger assembly is nested under the support located at the rear of the cabinet. Remove the indoor blower to view this area through the blower opening.

26 − Re-secure the supporting screws along the vestibule

sides.

27 − Reinstall blower assembly and reinstall two screws

through rails.

28 − Reinstall cabinet screws on front flange at blower

deck. 29 − Reinstall screws securing top cap. 30 − Reinstall the primary limit on the vestibule panel. 31 − Route heating component wiring through hole in blow-

er deck and reinsert strain relief bushing. 32 − Reinstall pressure switch and reconnect pressure

switch wiring. 33 − Carefully connect combustion air pressure switch

hosing from pressure switch to proper stubs on cold

end header collector box. 34 − Reinstall 1/2" NPT (if removed) in the cold end header

box. Reconnect drain tubing to collector box. 35 − Reinstall condensate trap pipe. Reconnect conden-

sate drain line to the condensate trap. 36 − Reinstall electrical junction box. 37− Reinstall the combustion air inducer and flexible no

hub connector. Reconnect the 2−pin plug to the wire

harness. 39 − Reconnect drain tubes between flue collar and cold

end header box. 40 − Secure burner assembly to vestibule panel using four

existing screws. Burners are self aligning to center

of clam shells.

41 − Reconnect gas supply line to gas valve. 42 − Reconnect flame roll−out switch wires. 43 − Reconnect sensor wire and reconnect 2−pin plug from

ignitor. 44 − Reconnect wires to gas valve. 45 − Replace the blower compartment access panel. 46 − Refer to instruction on verifying gas and electrical con-

nections when re−establishing supplies. 47 − 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. 48 − Replace heating compartment access panel.

Cleaning the Burner Assembly

1 − Turn off gas and electrical power to the furnace. Re-

move heating compartment access panel. 2 − Disconnect the gas supply line from the gas valve. 3 − Disconnect and label wires from gas valve. 4 − Disconnect ignitor wiring at 2 circuit plug. 5 − Disconnect and label wires from rollout switch. 6 − Disconnect and label flame sensor wire. 7 − Disconnect and label ground wire from burner/man-

ifold assembly. 8 − Remove four screws that secures burner/manifold as-

sembly to vestibule. Remove the assembly and make

note not to allow ignitor plate to dislodge from the as-

sembly. 9 − Gently clean the face of the burners using the soft

brush attachment on a vacuum cleaner. Visually in-

spect the inside of the burners and crossovers for any

blockage caused by foreign matter. Remove any

blockage 10 − Reinstall the burner/manifold assembly using the ex-

isting four screws. Burners are self aligning to cen-

ter of clam shells.

11 − Reconnect ground wire. 12 − Reconnect flame sensor wire. 13 − Reconnect rollout switch wires. 14 − Reconnect ignitor wires. 15 − Reconnect gas valve wires. 16 − Reconnect gas supply line to gas valve. 17 − Refer to instructions on verifying gas and electrical

connections when re−establishing supplies. 18 − Follow instructions to place furnace in operation. Run

furnace 5 minutes to ensure burners are clean and op-

erating correctly. 19 − Replace heating compartment access panel.

Page 49

Planned Service

A service technician should check the following items during an annual inspection. Power to the unit must be shut off for safety.

Fresh air grilles and louvers (on the unit and in the room where the furnace is installed) − Must be open and unobstructed to provide combustion air.

Burners − Must be inspected for rust, dirt, or signs of water.

Vent pipe − Must be inspected for signs of water, cracked,

damaged or sagging pipe, or disconnected joints.

Unit appearance − Must be inspected for rust, dirt, signs of water, burnt or damaged wires, or components.

Blower access door − Must be properly in place and provide a seal between the return air and the room where the furnace is installed.

Return air duct − Must be properly attached and provide an air seal to the unit.

Operating performance − Unit must be observed during operation to monitor proper performance of the unit and the vent system.

Combustion gases − Flue products must be analyzed and compared to the unit specifications.

Problems detected during the inspection may make it necessary to temporarily shut down the furnace until the items can be repaired or replaced.

Instruct the homeowners to pay attention to their furnace. Situations can arise between annual furnace in-

spections that may result in unsafe operation. For instance, items innocently stored next to the furnace may obstruct the combustion air supply. This could cause incomplete combustion and the production of carbon monoxide gas.

Ignition Control Board Diagnostic Codes

DIAGNOSTIC CODES

Make sure to Identify LED’S Correctly.

LED #1 (Red) LED #2 (Green) DESCRIPTION

SIMULTANEOUS

SLOW FLASH

SIMULTANEOUS

SLOW FLASH

Power on − Normal operation. Also signaled during cooling and continuous fan.

SIMULTANEOUS

FAST FLASH

SIMULTANEOUS

FAST FLASH

Normal operation − signaled when heating demand initiated at thermostat.

SLOW FLASH ON

Primary limit switch open. Limit must close within 3 minutes or unit goes into 1 hour Watchguard.

OFF SLOW FLASH

Pressure prove switch open. OR: Blocked inlet/exhaust vent; OR: Pressure switch closed prior to activation of combustion air inducer.

ALTERNATING

SLOW FLASH

ALTERNATING

SLOW FLASH

Watchguard 1 hour −− burners failed to ignite or lost flame 5 times during single heating demand.

SLOW FLASH OFF Flame sensed without gas valve energized.

ON SLOW FLASH Rollout switch open. OR: 12-pin connector improperly attached.

OFF

Circuit board failure or control wired incorrectly.

FAST FLASH SLOW FLASH Main power polarity reversed. Switch line and neutral.

SLOW FLASH FAST FLASH Low flame signal. Measures below 1.5 microamps. Replace flame sense rod.

ALTERNATING

FAST FLASH

ALTERNATING

FAST FLASH

Improper main ground. OR: Line voltage below 90 volts.

NOTE − Slow flash rate equals 1 Hz (one flash per second). Fast flash rate equals 3 Hz (three flashes per second). Minimum flame sense current = 0.5 microAmps.

Page 50

Troubleshooting: Heating Sequence of Operation

HEATING SEQUENCE OF OPERATION

NORMAL HEATING MODE

ABNORMAL HEATING MODE

CONTROL SELF−CHECK OKAY?

NORMAL OPERATION:

LED #1 −− SLOW FLASH LED #2 −− SLOW FLASH

YES

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER DELAY OFF.

LED #1 ON LED #2 ON

(RESET CONTROL BY TURNING MAIN POWER OFF.)

POLARITY REVERSED.

LED #1 −− FAST FLASH

LED #2 −− SLOW FLASH

POWER ON

IS POLARITY CORRECT?

ROLLOUT SWITCH CLOSED?

THERMOSTAT CALLS FOR HEAT:

LED #1 −− FAST FLASH LED #2 −− FAST FLASH

IS COMBUSTION AIR

PRESSURE SWITCH OPEN?

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.

INDOOR BLOWER ON.

LED #1 −− ON. LED #2 −− SLOW FLASH.

SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES

AND POWER IS RESET OR T’STAT IS INTERRUPTED

FOR MINIMUM OF 1 SECOND.

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.

INDOOR BLOWER ON HEATING SPEED.

LED #1 −− SLOW FLASH

LED #2 −− OFF

GAS VALVE OFF.

COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER OFF WITH DELAY.

LED #1 OFF

LED #2 SLOW FLASH

(Sequence holds until pressure switch

opens or thermostat resets control.)

YES

IS VOLTAGE

ABOVE 90 VOLTS?

LEDs SIGNAL FAST ALTERNATING FLASH.

CONTROL WILL NOT RESPOND TO A CALL FOR

HEATING UNTIL VOLTAGE RISES ABOVE 95 VOLTS.

IS COMBUSTION AIR INDUCER

ENERGIZED?

HAS COMBUSTION AIR PRESSURE

SWITCH CLOSED IN 2.5 MINUTES?

YES

PRESSURE SWITCH IS IN WATCHGUARD MODE.

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER OFF WITH DELAY.

LED #1 −− OFF. LED #2 −− SLOW FLASH.

IS 5-MINUTE RESET PERIOD COMPLETE?

PRIMARY AND SECONDARY LIMIT SWITCH.

CLOSED?

YES

CONTINUED NEXT PAGE

COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER ON

LED #1 SLOW FLASH RATE

LED #2 −− ON

YES

IS THERE A PROPER GROUND?

YES

IMPROPER GROUND. LED #1 −− ALTERNATING FAST FLASH LED #2 −− ALTERNATING FAST FLASH

YES

BURNER OFF?

(Flame sensed without gas valve energized)

Page 51

Troubleshooting: Heating Sequence of Operation (Continued)

HEATING SEQUENCE CONTINUED

NORMAL HEATING MODE ABNORMAL HEATING MODE

FLAME RECTIFICATION CURRENT

CHECK. CAN FLAME BE PROVEN WITHIN

4 SECONDS AFTER GAS VALVE OPENS?

(0.5 microamps)

FLAME PRESENT?

INDOOR BLOWER ON

AFTER 30−SECOND DELAY

PRIMARY AND SECONDARY LIMIT

SWITCHES CLOSED?

COMBUSTION AIR PRESSURE

SWITCH CLOSED?

LOW FLAME SIGNAL

(Does not affect operation of control)

LED #1 −− SLOW FLASH

LED #2 −− FAST FLASH

GAS VALVE DE−ENERGIZED.

COMBUSTION AIR INDUCER DE−ENERGIZED.

INDOOR BLOWER ON UNTIL SWITCH CLOSES.

LED #1 −− SLOW FLASH. LED #2 −− ON.

IS LIMIT SWITCH CLOSED?

GAS VALVE DE−ENERGIZED.

COMBUSTION AIR INDUCER ON.

INDOOR BLOWER OFF WITH DELAY

LED #1 −− OFF. LED #2 −− SLOW FLASH.

HAS CAB SWITCH CLOSED IN 2.5 MINUTES?

15-SECOND COMBUSTION AIR INDUCER PREPURGE

INITIATED BY CLOSED PRESSURE SWITCH.

YES

IGNITOR WARM-UP −− 20 SECONDS.

YES

FLAME STABILIZATION PERIOD.

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.

INDOOR BLOWER OFF.

HAS CONTROL FAILED TO SENSE FLAME FOR

FIVE CONSECUTIVE TRIES DURING A SINGLE

HEAT DEMAND?

WATCHGUARD MODE. GAS VALVE OFF.

COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER OFF WITH DELAY

LEDs SIGNAL WATCHGUARD FAILURE CODE.

IS 60-MINUTE RESET PERIOD COMPLETE?

YES

4 SECONDS

YES

HAS CONTROL RESET IGNITION

SEQUENCE FOUR TIMES?

FLAME SIGNAL 1.5 MICROAMPS OR GREATER?

YES

ROLLOUT SWITCH CLOSED?

GAS VALVE POWER OFF.

COMBUSTION AIR INDUCER POWER ON.

INDOOR BLOWER ON

LED #1 −− ON. LED #2 −− SLOW FLASH.

SEQUENCE HOLDS UNTIL ROLLOUT SWITCH IS RESET

AND MAIN POWER IS INTERRUPTED OR

THERMOSTAT IS CYCLED OFF/ON FOR 1 SEC. MINIMUM.

YES

THERMOSTAT DEMAND SATISFIED.

LED #1 & #2 SIMULTANEOUS SLOW FLASHES.

COMB. AIR INDUCER CONTINUES 5-SECOND

POST PURGE AFTER T’STAT DEMAND IS SATISFIED.

INDOOR AIR BLOWER COMPLETES SELECTED OFF"

DELAY BEFORE SHUTTING OFF.

YES

5-MINUTE PRESSURE SWITCH

WATCHGUARD MODE.

YES

IS VOLTAGE ABOVE 90 VOLTS?

LEDS SIGNAL

ALTERNATING

FAST FLASH UNTIL

VOLTAGE IS ABOVE

95 VOLTS, THEN

RESTARTS HEATING

SEQUENCE.

YES

HAS PRIMARY / SECONDARY

LIMIT RESET TIME

EXCEEDED 3 MINUTES?

LIMIT SWITCH WATCHGUARD MODE. GAS VALVE, COMB. AIR INDUCER AND INDOOR BLOW-

ER OFF. LEDs SIGNAL LIMIT SWITCH OPEN UNTIL MAIN

POWER IS

INTERRUPTED OR

T’STAT IS CYCLED

OFF/ON FOR 1 SEC.

MINIMUM. 60−MINUTE

WATCHGUARD PE-

RIOD STARTS AT

TIME LIMIT CLOSES.

IS 60−MIN. PERIOD

COMPLETE?

YES

4-SECOND TRIAL FOR IGNITION.

GAS VALVE OPENS. IGNITOR ENERGIZED FOR

FIRST 3 SECONDS OF THE TRIAL.

HAS PRESSURE SWITCH OPENED 5

TIMES IN THE SAME HEAT DEMAND?

1 HR

PRESSURE

SWITCH

WATCHGUARD

MODE

Page 52

Troubleshooting: Cooling Sequence of Operation

COOLING SEQUENCE OF OPERATION

NORMAL COOLING MODE ABNORMAL COOLING MODE

IGNITION CONTROL MAIN POWER ON.

CONTROL SELF DIAGNOSTIC CHECK.

IS CONTROL OPERATING NORMALLY?

YES

SIGNAL POLARITY REVERSED AT LED. CONTROL

WILL CONTINUE TO CALL FOR COOLING IN THIS

CONDITION.

POWER ON

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER OFF WITH NORMAL DELAY.

SIGNAL CIRCUIT BOARD FAILURE AT LED.

INTERRUPT MAIN POWER TO RESET CONTROL.

YES

IS POLARITY CORRECT?

ROLLOUT SWITCH MONITORED CONTINUOUSLY.

IS ROLLOUT SWITCH CLOSED?

LED: SLOW FLASH RATE REMAINS UNCHANGED

THROUGHOUT COOLING CYCLE.

THERMOSTAT CALLS FOR COOLING.

COMPRESSOR CONTACTOR AND SYSTEM FAN

ENERGIZED WITH 2-SECOND DELAY

(COOLING SPEED). EAC TERM. ENERGIZED.

COMPRESSOR OFF.

THERMOSTAT OPENS.

SYSTEM FAN AND EAC TERM. OFF

WITH 45-SECOND DELAY.

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.

INDOOR BLOWER ON.

SIGNAL ROLL-OUT SWITCH OPEN AT LED.

SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES

AND MAIN POWER IS INTERRUPTED OR THERMOSTAT

IS CYCLED OFF/ON FOR 1 SEC. MINIMUM.

IS VOLTAGE

ABOVE 90 VOLTS?

LED SIGNALS LOW VOLTAGE. CONTROL WILL

CONTINUE TO CALL FOR COOLING

IN THIS CONDITION.

YES

IS THERE A PROPER GROUND?

YES

SIGNAL IMPROPER GROUND AT LED.

CONTROL WILL CONTINUE TO CALL FOR COOLING

IN THIS CONDITION.

Page 53

Troubleshooting: Continuous Fan Sequence of Operation

CONTINUOUS HEAT SPEED FAN SEQUENCE OF OPERATION

LED: SLOW FLASH RATE REMAINS

UNCHANGED THROUGHOUT SEQUENCE.

MANUAL FAN SELECTION MADE AT THERMOSTAT.

CONTROL (G) ENERGIZES SYSTEM FAN AT HEAT

SPEED. EAC TERMINAL IS ENERGIZED.

THERMOSTAT CALLS FOR HEAT (W).

THERMOSTAT CALLS FOR COOLING.

THERMOSTAT OPENS.

SYSTEM FAN SWITCHED TO COOL SPEED.

EAC TERM. REMAINS ON.

THERMOSTAT OPENS.

MANUAL FAN SELECTION MADE AT THERMOSTAT.

CONTROL (G) ENERGIZES SYSTEM FAN AT HEAT

SPEED. EAC TERM. ENERGIZED.

YES

HUM TERM. ENERGIZES

WITH COMB. AIR INDUCER.

SYSTEM FAN REMAINS ON

HEATING SPEED.

SYSTEM FAN REMAINS ON

HEATING SPEED.

HUM TERM. DE−ENERGIZES

WITH COMB. AIR INDUCER

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: ML195UH045XP24B−01. 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 54

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 55

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 56

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 inspection, the inspector observes carbon monoxide detectors and signage installed in accordance with the provisions 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 separate 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 system 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 ML195UH045XP24B, ML195UH090XP36C, ML195UH045XP36B, ML195UH070XP36B, ML195UH090XP48C Installation Instructions Manual

Specifications and Main Features

Frequently Asked Questions

User Manual