© 2022 Lennox Industries Inc.

Dallas, Texas USA

INSTALLATION

INSTRUCTIONS

ML180DFE

MERIT ® SERIES GAS FURNACE

DOWNFLOW DISCHARGE AIR

506734-03

03/2022

Supersedes 08/2019

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.

WARNING

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

CAUTION

As with any mechanical equipment, contact with sharp sheet metal edges can result in personal injury. Take care while handling this equipment and wear gloves and protective clothing.

DOWNFLOW

AIR FLOW

Contents

Unit Dimensions - inches (mm) ......................................2

ML180DFE Gas Furnace................................................3

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

Safety .............................................................................3

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

General ...........................................................................4

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

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

Filters ............................................................................10

Duct System ................................................................. 11

Venting ......................................................................... 11

Gas Piping ....................................................................17

Electrical .......................................................................19

Integrated Control .........................................................22

Unit Start-Up .................................................................24

Gas Pressure Measurement.........................................25

Proper Combustion.......................................................25

High Altitude .................................................................25

Other Unit Adjustments.................................................26

Service..........................................................................28

Repair Parts List ...........................................................30

Start-Up and Performance Checklist ............................31

Blower Data ..................................................................33

Page 1

Unit Dimensions - inches (mm)

FLUE OUTLET

(Top)

3-1/8

(79)

D

9/16

(14)

B

19-7/16

(494)

9/16

(14)

TOP VIEW

27-3/4

(705)

19-7/16

(494)

9/16

(14)

9/16

(14)

A

B

AIR FLOW

9/16

(14)

3/4 (19)

Front Panel

3/4

(19)

C

Supply

Air

FRONT VIEW

ML180DFE

Model

045E36A

070E36A

070E36B

090E48B

110E60C in

14-1/2

17-1/2

21

A mm

368

446

533

33

(838)

5-3/8 (137) Right

2-3/16 (56) Left

6-5/8 (168) Right

7-1/8 (181) Left

3/4

(19) in

13-3/8

16-3/8

19-7/8

B mm

340

416

504

ELECTRICAL INLET

(Either Side)

GAS PIPING INLET

(Either Side)

19-1/4

(489)

SIDE VIEW in

13

16

19-1/2

C mm

330

406

495

Supply

Air

3/4

(19) in

4-3/4

6-1/4

8

D mm

121

159

203

Page 2

ML180DFE Gas Furnace

The ML180DFE gas furnace is shipped ready for installation in the downflow position fueled by natural gas. A conversion kit (ordered separately) is required for use in

LP/ Propane gas applications.

Shipping and Packing List

Package 1 of 1 contains

1 - Assembled ML180DFE unit

1 - Bag assembly containing the following:

2 - Screws

1 - Snap bushing

1 - Snap plug

1 - Wire tie

1 -Vent warning label

1 - Owner’s manual and warranty card

The following items may be ordered separately:

1 - Thermostat

1 - LP/Propane changeover kit

1 - Combustible flooring base

1 - High altitude kit

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

Safety Information

Danger of explosion.

DANGER

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.

WARNING

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

CAUTION

As with any mechanical equipment, contact with sharp sheet metal edges can result in personal injury. Take care while handling this equipment and wear gloves and protective clothing.

Certifications

ML180DFE units are CSA International certified.

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). The National Fuel Gas Code is available from the following address:

American National Standards Institute, Inc.

11 West 42nd Street

New York, NY 10036

Clearances

Adequate clearance must be made around the air openings into the vestibule area. In order to ensure proper unit operation, combustion and ventilation air supply must be provided according to the current National Fuel Gas

Code. Vent installations must be consistent with the National Fuel Gas Code venting tables (in this instruction) and applicable provisions of local building codes.

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

Installed Locations

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.

NOTE - Furnace must be adjusted to obtain a temperature rise within the range(s) specified on the unit nameplate.

Failure to do so may cause erratic limit operation and may also result in premature heat exchanger failure.

This ML180DFE 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 units, it shall be installed in parallel with, or on the upstream side of, cooling units to avoid condensation in the heating compartment.

With a parallel flow arrangement, a damper (or other means to control the flow of air) must adequately prevent chilled air from entering the furnace (see figure 1). 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.

Page 3

GAS UNIT

Dampers

(open during heating operation only)

AIR HANDLER

Dampers

(open during cooling operation only)

Figure 1

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

NOTE - This furnace is designed for a minimum continu ous 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 ML180DFE furnace may be installed in alcoves, closets, attics, basements, garages, and utility rooms in the downflow position.

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

Use of Furnace as Construction Heater

Lennox does not recommend the use of ML180DFE 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.

ML180DFE units may be used for heating of buildings or structures under construction, if the following conditions are met:

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

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

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

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

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

• Air filters must be replaced upon construction com pletion.

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

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

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

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

General

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

In addition to the requirements outlined previously, the following general recommendations must be considered when installing a ML180DFE furnace:

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

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

• Do not block the furnace combustion air openings 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.

NOTE - The Commonwealth of Massachusetts stipulates these additional requirements:

• Gas furnaces shall be installed by a licensed plumber or fitter only.

• The gas cock must be “T handle” type.

• When a furnace is installed in an attic, the passageway to and service area surrounding the equipment shall be floored.

Page 4

Combustion, Dilution & Ventilation Air

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

In the absence of local codes concerning air for combustion and ventilation, use the guidelines and procedures in this section to install ML180DFE furnaces to ensure effi cient and safe operation. You must consider combustion air needs and requirements for exhaust vents. A portion of this information has been reprinted with permission from the National Fuel Gas Code (ANSI-Z223.1). 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.

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 appliances 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 fire places, exhaust fans, or clothes dryers are used at the same time as the furnace, much more air is necessary 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.

CAUTION

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

Permanent wave solutions

Chlorinated waxes and cleaners

Chlorine base swimming pool chemicals

Water softening chemicals

De-icing salts or chemicals

Carbon tetrachloride

Halogen type refrigerants

Cleaning solvents (such as perchloroethylene)

Printing inks, paint removers, varnishes, etc.

Hydrochloric acid

Cements and glues

Antistatic fabric softeners for clothes dryers

Masonry acid washing materials

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

Unconfined Space

An unconfined space is an area such as a basement or large equipment room with a volume greater than 50 cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the combined input rating of all appliances installed in that space.

This space also includes adjacent rooms which are not separated by a door. Though an area may appear to be unconfined, it might be necessary to bring in outdoor air for combustion if the structure does not provide enough air by infiltration. If the furnace is located in a building of tight construction with weather stripping and caulking around the windows and doors, follow the procedures in the air from outside section.

Confined Space

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

Page 5

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.

CHIMNEY

OR GAS

VENT

FURNACE

AIR FLOW

EQUIPMENT IN CONFINED

SPACE ALL AIR FROM INSIDE

OPENINGS

(To Adjacent

Room)

NOTE - Each opening shall have a free area of at least one square inch (645 mm 2 ing of all equipment in the enclosure, but not less than 100 square inches (64516 mm 2 ).

Figure 2

Air from Inside

If the confined space that houses the furnace adjoins a space categorized as unconfined, air can be brought in by providing two permanent openings between the two spaces.

Each opening must have a minimum free area of 1 square inch (645 mm2) per 1,000 Btu (.29 kW) per hour of total input rating of all gas-fired equipment in the confined space.

Each opening must be at least 100 square inches (64516 mm2). One opening shall be within 12 inches (305 mm) of the top of the enclosure and one opening within 12 inches

(305 mm) of the bottom. See figure 2.

Air from Outside

If air from outside is brought in for combustion and ventilation, the confined space must have two permanent open ings. One opening shall be within 12 inches (305 mm) of the top of the enclosure and one opening within 12 inches

(305 mm) of the bottom. These openings must communicate directly or by ducts with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors or indirectly through vertical ducts. Each opening shall have a minimum free area of 1 square inch (645 mm2) per 4,000

Btu (1.17kW) per hour of total input rating of all equipment in the enclosure. See figures 3 and 4. When communi cating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch

(645 mm2) per 2,000 Btu (.56 kW) per total input rating of all equipment in the enclosure. See figure 5.

When ducts are used, they shall be of the same cross-sectional area as the free area of the openings to which they connect. The minimum dimension of rectangular air ducts shall be no less than 3 inches (75 mm). In calculating free area, the blocking effect of louvers, grilles, or screens must be considered. If the design and free area of protective covering is not known for calculating the size opening required, it may be assumed that wood louvers will have

20 to 25 percent free area and metal louvers and grilles will have 60 to 75 percent free area. Louvers and grilles must be fixed in the open position or interlocked with the equipment so that they are opened automatically during equipment operation.

Page 6

EQUIPMENT IN CONFINED SPACE

ALL AIR FROM OUTSIDE

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

VENTILATION LOUVERS

(Each end of attic)

OUTLET

AIR FURNACE

VENTILATION

LOUVERS

(For unheated crawl space)

INLET

AIR

AIR FLOW

NOTE-The inlet and outlet air openings shall each have a free area of at least one square inch (645 mm 2 ) per 4,000 Btu (1.17 kW) per hour of the total input rating of all equipment in the enclosure.

Figure 3

CHIMNEY

OR GAS

VENT

FURNACE

EQUIPMENT IN CONFINED SPACE

ALL AIR FROM OUTSIDE

(All Air Through Ventilated Attic)

VENTILATION LOUVERS

(Each end of attic)

OUTLET

AIR

INLET AIR

(Ends 12 in.

above bottom)

WATER

HEATER

AIR FLOW

NOTE-The inlet and outlet air openings shall each have a free area of at least one square inch (645 mm 2 ) per 4,000 ment in the enclosure.

Figure 4

FURNACE

CHIMNEY

OR GAS

VENT

EQUIPMENT IN

CONFINED SPACE

ALL AIR FROM

OUTSIDE

OUTLET AIR

Page 7

INLET AIR

AIR FLOW

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

)

Figure 5

Downflow Installation

Downflow unit installs in three ways: on non-combustible flooring, on combustible flooring using a downflow com bustible flooring base, or on a reverse-flow cooling cabi net. Do not drag the unit across the floor.

Installation on Non-Combustible Flooring (Figure 6)

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

2 - Flange warm air plenum and lower the plenum into the opening.

3 - Set the unit over the plenum and seal the plenum to the unit.

4 - Ensure that the seal is adequate.

CAUTION

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

PROPERLY

SIZED FLOOR

OPENING

SUPPLY AIR PLENUM

DOWNFLOW

COMBUSTIBLE

FLOORING BASE

OPENING

SUPPLY AIR

PLENUM

Figure 6

TABLE 1

NON-COMBUSTIBLE FLOOR OPENING SIZE

Cabinet

Width

Front to Rear in mm

Side to Side in mm

A (14.5”)

B (17.5”) 19-3/4 502

13-1/4

16-3/4

337

413

C (21”) 19-3/4 502

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

Installation on Combustible Flooring (Figure 7)

1 - When unit is installed on a combustible floor, a downflow combustible flooring base must be installed between the furnace and the floor. The base must be ordered separately.

See table 2 for opening size to cut in floor.

Figure 7

TABLE 2

COMBUSTIBLE FLOOR OPENING SIZE

Cabinet

Width

Front to Rear in mm

Side to Side in mm

A (14.5”)

B (17.5”)

C (21”)

22 569

15-3/4

18-3/4

22-3/4

400

476

578

2 - After opening is cut, set combustible flooring base into opening.

3 - Check sealing strips on combustible flooring base to make sure they are properly glued and positioned.

4 - Lower supply air plenum into downflow combustible flooring base until plenum flanges seal against the strips.

NOTE - Be careful not to damage sealing strips.

Check for a tight seal.

5 - Set the furnace over the plenum.

6 - Ensure that the seal between the furnace and plenum is adequate.

Installation on Cooling Cabinet (Figure 8)

1 - Refer to reverse-flow coil installation instructions for correctly sized opening in floor and installation of cabinet.

NOTE - Downflow combustible flooring kit is not used

2 - When cooling cabinet is in place, set and secure the furnace according to the instructions that are provided with the cooling coil. Secure the furnace to the cabinet.

3 - Seal the cabinet and check for air leaks.

Page 8

PROPERLY

SIZED FLOOR

OPENING

COOLING COIL

PLENUM

Figure 8

Return Air Opening -- Downflow Units

.

The following steps should be taken when installing plenum:

1 - Bottom edge of plenum should be flanged with a hemmed edge (See figure 9)

PLENUM SECURE FROM

OUTSIDE CABINET

Side View

HEMMED EDGE

SEALING STRIP

(Field Provided)

CABINET SIDE PANEL

Figure 9

2 - Sealing strip should be used.

3 - In all cases, plenum should be secured to top flanges of furnace with sheet metal screws.

SIDE CABINET

PLENUM

HEMMED EDGE

Side View

FIBERGLASS

SEALING STRIP

(Field Provided)

CABINET SIDE

PANEL

Figure 10

4 - In closet installations, it may be impossible to install sheet metal screws from the outside. In this case, make plenum with a removable front and install screws from the inside (See figure 10).

5 - Make certain that an adequate seal is made.

Setting Equipment

WARNING

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

Install the ML180DFE gas furnace as shipped in the downflow position only. Do not install the furnace horizontally .

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, and installation and service clearances [24 inches (610 mm) at unit front]. The unit must be level.

NOTE - Units with 1/2 and 3/4 hp blower motors are equipped with three flexible legs and one rigid leg. See fig ure 11. 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). The bolt and washer must be removed before the furnace is placed into operation. After the bolt and washer have been re moved, the rigid leg will not touch the blower housing.

Units with 1/2 or 3/4 HP Blower Motor

RIGID LEG remove shipping bolt and washe

Figure 11

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.

Page 9

Horizontal

Front Back

Figure 12

Downflow Application

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

Downflow Application Installation Clearances

Top

Left Side Right Side

Bottom

Type of Vent

Connector

Type C Type B1

Top

*Front

Back

Sides

Vent

Floor

1 in. (25 mm)

2-1/4 in. (57 mm)**

0

0

†

6 in. (152 mm)

NC††

1 in. (25 mm)

2-1/4 in. (57 mm)

0

0

1 in. (25 mm)

NC††

*Front clearance in alcove installation must be 24 in. (610 mm).

Maintain a minimum of 24 in. (610 mm) for front service access.

** 4-1/2 in. if a single wall vent pipe is used.

inets, or 2 in. if a single wall vent is used on 17 - 1/2 in. cabinets.

††The furnace may be installed on a combustible wood floor if an optional additive base is installed between the furnace and the combustible floor.

CAUTION

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

WARNING

Improper installation of the furnace can result in personal injury or death. Combustion and flue products must never be allowed to enter the return air system or the living space. Use screws and joint tape to seal the return air system to the furnace.

In platform installations with bottom return air, the furnace should be sealed airtight to the return air plenum. A door must never be used as a portion of the return air duct system. The base must provide a stable support and an airtight seal to the furnace. Allow absolutely no sagging, cracks, gaps, etc.

The return and supply air duct systems must never be connected to or from other heating devices such as a fireplace or stove, etc. Fire, explosion, carbon monoxide poisoning, personal injury and/or property damage could result.

Filters

This unit is not equipped with a filter or rack. A field-pro vided high-velocity filter is required for the unit to operate properly. Table 3 lists recommended filter sizes. A filter must be in place any time the unit is operating.

Figure 13

Page 10

IMPORTANT

If a high efficiency filter is being installed as part of this system to ensure better indoor air quality, the filter must be properly sized. High efficiency filters have a higher static pressure drop than standard efficiency glass/foam filters. If the pressure drop is too great, system capacity and performance may be reduced.

The pressure drop may also cause the limit to trip more frequently during the winter and the indoor coil to freeze in the summer, resulting in an increase in the number of service calls.

Before using any filter with this system, check the specifications provided by the filter manufacturer against the data given in the appropriate Lennox Product

Specifications bulletin. Additional information is provided in Service and Application Note ACC002 (August 2000).

TABLE 3

Cabinet Width inches Air Filter Size inches

A - 14-1/2

B - 17-1/2

C - 21

14 x 25 x 1

16 x 25 x 1

20 x 25 x 1

Duct System

Use industry-approved standards (such as those published by Air Conditioning Contractors of America or American Society of Heating, Refrigerating and Air Conditioning Engineers) to size and install the supply and return air duct system. This will result in a quiet and low-static system that has uniform air distribution. Figure 14 shows proper duct installation.

NOTE - Do not operate the furnace in the heating mode with an external static pressure that exceeds 0.5 inches w.c. Higher external static pressures may cause erratic limit operation.

Ensure that you have made a seal between the supply air plenum and the furnace and between the furnace and the return air plenum.

Return Air Plenum

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 toxic gas might then be distributed throughout the house by the furnace duct system

Venting

A 4-inch diameter flue transition is factory-installed on all models. Modifying or removing the flue transition will cause the unit to operate unsafely and will void the unit certification. The vent connector does not require insulation.

The ML180DFE series units are classified as fan-assist ed Category I furnaces when vertically vented according to the latest edition of National Fuel Gas Code (NFPA 54

/ ANSI Z223.1). A fan-assisted Category I furnace is an appliance equipped with an integral mechanical means to either draw or force combustion products through the combustion chamber and/or heat exchanger.

NOTE - Use these instructions as a guide. They do not supersede local codes. This furnace must be vented ac cording to all local codes, these installation instructions, and the provided venting tables in these instructions

The venting tables in this manual were extracted from the

National Fuel Gas Code (NFPA 54 / ANSI Z223.1) and are provided as a guide for proper vent installation. Proper application, termination, construction and location of vents must conform to local codes having jurisdiction. In the absence of local codes, the NFGC serves as the defining document.

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

IMPORTANT

Once the venting system is installed, attach the

“Disconnected Vent” warning sticker to a visible area of the plenum near the vent pipe. The warning sticker is provided in the bag assembly. Order kit 66W04 for additional stickers.

WARNING

Asphyxiation hazard. The exhaust vent for this furnace must be securely connected to the furnace flue transition at all times.

Use self-drilling sheet metal screws or a mechanical fastener to firmly secure the vent pipe to the round collar of the flue transition. If self-drilling screws are used to attach the vent pipe, it is recommended that three be used. Drive one self-drilling screw through the front and one through each side of the vent pipe and collar. See figure 15.

Install the first vent connector elbow at a minimum of six inches (152 mm) from the furnace vent outlet.

Masonry chimneys used to vent Category I central furnaces must be either tile-lined or lined with a listed metal lining system or dedicated gas vent. Unlined masonry chimneys are prohibited. See figures 16 and 17 for common venting.

Page 11

Duct Installation

Down-Flow Unit

VENT CONNECTION

“DISCONNECTED VENT”

WARNING

STICKER

FLUE TRANSITION

COLLAR

Figure 15

SUPPLY

AIR

Figure 14

Common Venting Using Tile-Lined Interior Masonry Chimney and Combined Vent Connector

INTERIOR TILE-LINED

MASONRY CHIMNEY

NOTE- Refer to provided venting tables for installations.

NOTE - the chimney must be properly sized per provided venting tables or lined with listed metal lining system.

VENT

CONNECTOR

OTHER

APPLIANCE

PERMANENTLY

SEALED FIREPLACE

OPENING

AIR FLOW

FURNACE

Figure 16

Page 12

Venting Using a Masonry Chimney

The following additional requirements apply when a lined masonry chimney is used to vent this furnace.

A chimney with one or more sides exposed to the outside of the structure is considered to be an exterior chimney.

An exterior masonry chimney that is not tile-lined must be lined with B1 vent or a listed insulated flexible metal vent.

An exterior tile-lined chimney that is sealed and capped may be lined with a listed uninsulated flexible metal vent.

If the existing chimney will not accommodate a listed metal liner, either the chimney must be rebuilt to accommodate one of these liners or an alternate approved venting method must be found.

Insulation for the flexible vent pipe must be an encapsu lated fiberglass sleeve recommended by the flexible vent pipe manufacturer. See figure 17.

Common Venting Using Metal-Lined Masonry Chimney

SEALED

5 ft. (1.5 m) minimum

MAX. LENGTH

-- SEE NOTE 1

BELOW.

MIN. LENGTH -- AS

SHORT AS PRACTICAL

EXTERIOR

CHIMNEY WITH

METAL

LINER

4 in. (102 mm) minimum

VENT CONNECTOR

FURNACE

OTHER

APPLIANCE

PERMANENTLY

SEALED FIREPLACE

OPENING

AIR FLOW

NOTE 1 - Refer to the provided venting tables for installations. Refer to the capacity requirements shown in the provided venting tables.

Figure 17

DO NOT insulate the space between the liner and the chimney wall with puffed mica or any other loose granular insulating material

IMPORTANT

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

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

• The chimney is currently serving at least one draft hood equipped appliance

• The vent connectors and chimney are sized according to the provided venting tables.

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

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

When inspection reveals that an existing chimney is not safe for the intended purpose, it shall be rebuilt to conform to nationally recognized standards, lined or relined with suitable materials, or replaced with a gas vent or chimney suitable for venting ML180DFE series units. The chimney passageway must be checked periodically to ensure that it is clear and free of obstructions.

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

Never connect a Category I appliance to a chimney that is servicing a solid-fuel appliance. If a fireplace chimney flue is used to vent this appliance, the fireplace opening must be permanently sealed.

A type B or listed chimney lining system that passes through an unused masonry chimney flue is not consid ered to be exposed to the outdoors.

General Venting Requirements

Vent all ML180DFE furnaces according to these instructions:

Vent diameter recommendations and maximum allowable piping runs are found in the provided venting tables.

2 - In no case should the vent or vent connector diameter be less than the diameter specified in the provided venting tables.

3 - The minimum vent capacity determined by the sizing tables must be less than the low fire input rating and the maximum vent capacity must be greater than the high fire input rating.

4 - Single appliance vents - If the vertical vent or tilelined chimney has a larger diameter or flow area than the vent connector, use the vertical vent diameter to determine the minimum vent capacity and the vent connector diameter to determine the maximum vent capacity. The flow area of the vertical vent, however, shall not exceed 7 times the flow area of the listed appliance categorized vent area, drafthood outlet area or flue collar area unless designed according to approved engineering methods.

5 - Multiple appliance vents - The flow area of the largest section of vertical vent or chimney shall not exceed

7 times the smallest listed appliance categorized vent area, drafthood outlet area or flue collar area unless designed according to approved engineering methods.

6 - The entire length of single wall metal vent connector shall be readily accessible for inspection, cleaning, and replacement.

Page 13

7 - Single appliance venting configurations with zero lateral lengths (tables 5 and 6) are assumed to have no elbows in the vent system. For all other vent configurations, the vent system is assumed to have two 90° elbows. For each additional 90° elbow or equivalent (for example two 45° elbows equal one

90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10% (0.90 x maximum listed capacity).

8 - The common venting tables (6 and 7) were generated using a maximum horizontal vent connector length of

1-1/2 feet (.46 m) for each inch (25 mm) of connector diameter as follows:

TABLE 4

Connector Diameter inches (mm)

Maximum Horizontal

Connector Length feet (m)

3 (76)

4 (102)

4-1/2 (1.37)

6 (1.83)

5 (152)

6 (152)

7-1/2 (2.29)

9 (2.74)

7 (178) 10-1/2 (3.20)

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

10 - The vent pipe should be as short as possible with the least number of elbows and angles required to complete the job. Route the vent connector to the vent using the shortest possible route.

11 - A vent connector shall be supported without any dips or sags and shall slope a minimum of 1/4 inch

(6.4 mm) per linear foot (305 mm) of connector, back toward the appliance.

12 - Vent connectors shall be firmly attached to the furnace flue collar by self-drilling screws or other approved means, except vent connectors of listed type B vent material which shall be assembled according to the manufacturer’s instructions. Joints between sections of single wall connector piping shall be fastened by screws or other approved means.

13 - When the vent connector used for Category I appliances must be located in or pass through a crawlspace or other areas which may be cold, that portion of the vent connector shall be constructed of listed double-wall type B vent material or material having equivalent insulation qualities.

14 - All venting pipe passing through floors, walls, and ceilings must be installed with the listed clearance to combustible materials and be fire stopped according to local codes. In absence of local codes, refer to NFGC (Z223.1).

15 - No portion of the venting system can extend into, or pass through any circulation air duct or plenum.

16 - Vent connectors serving Category I appliances shall not be connected to any portion of mechanical draft systems operating under positive pressure such as

Category III or IV venting systems.

17 - If vent connectors are combined prior to entering the common vent, the maximum common vent capacity listed in the common venting tables must be reduced by 10%, the equivalent of one 90° elbow

(0.90 x maximum common vent capacity).

18 - The common vent diameter must always be at least as large as the largest vent connector diameter.

19 - In no case, shall the vent connector be sized more than two consecutive table size diameters over the size of the draft hood outlet or flue collar outlet.

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

21 - When connecting this appliance to an existing dedicated or common venting system, you must inspect the venting system’s general condition and look for signs of corrosion. The existing vent pipe size must conform to these instructions and the provided venting tables. If the existing venting system does not meet these requirements, it must be resized.

Page 14

Height

H

(feet)

Lateral

L

(feet)

TABLE 5

Capacity of Type B Double-Wall Vents with Type B Double-Wall Connectors

Serving a Single Category I Appliance

Vent and Connector Diameter - D (inches)

0

11

22

29

35

23

28

0

12

23

30

Min

0

13

21

25

0

12

0

3 inch

94

69

65

59

53

53

49

88

61

57

51

Max

78

51

49

46

84

57

97

0

15

30

40

48

32

39

0

17

32

41

4 inch 5 inch

Appliance Input Rating in Thousands of Btu Per Hour

Min Max Min Max

0

18

30

36

0

16

152

97

94

91

165

109

0

27

39

47

0

25

251

157

153

149

276

178

103

98

175

118

113

104

191

136

130

121

112

42

51

0

23

41

54

0

20

39

51

61

327

226

219

206

195

171

164

295

194

187

176

0 202 0 349

6 inch

6

8

10

15

0

2

5

8

5

10

4

6

0

2

0

2

5

10

0

2

15

0

0

22

49

64

76

53

64

0

26

52

67

Min

0

32

50

59

0

28

0

2 10 75 14 149 18 250 20 377

20

30

5

10

15

2

5

20

30

10

15

20

0

21

28

34

48

0

9

21

27

33

56

NA

71

64

58

52

100

81

77

70

64

58

NA

29

38

46

55

0

13

28

37

44

53

73

143

133

124

116

213

166

160

150

141

132

113

38

50

59

69

0

14

36

48

57

66

88

242

229

217

206

374

283

275

262

249

237

214

47

62

73

84

0

18

45

59

70

80

104

367

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

10 percent (0.90 x maximum listed capacity).

351

337

322

587

432

421

405

389

374

346

502

339

330

315

301

255

247

447

289

280

267

Max

375

232

227

223

415

263

540

Page 15

Height

H

(feet)

6

8

10

15

20

30

TABLE 6

Vent Connector Capacity

Type B Double-Wall Vents with Type B Double-Wall Connectors Serving Two or More Category I Appliances

Vent and Connector Diameter - D (inches)

Lateral

L

(feet)

Min

3 inch

Max

4 inch 5 inch

Appliance Input Rating in Thousands of Btu Per Hour

Min Max Min Max Min

6 inch

2

3

1

2

1

2

3

1

3

1

2

3

23

24

22

23

22

23

24

22

24

21

22

24

44

47

43

47

37

41

44

40

50

50

53

55

36

37

34

36

35

37

38

35

37

33

35

36

80

87

78

86

66

75

81

72

92

89

96

102

51

53

49

51

46

48

49

49

52

47

49

51

128

139

123

136

106

121

132

114

146

142

153

163

66

67

65

67

58

60

62

64

69

64

66

68

2

3

3

1

1

2

21

2

23

20

21

22

54

57

60

62

64

66

33

34

35

31

33

34

99

105

110

113

118

123

46

48

50

45

47

48

157

167

176

181

190

198

62

64

66

60

62

64

246

259

271

288

299

309

220

220

235

248

195

210

189

206

Max

164

183

199

176

Vent

Height

H

(feet)

6

8

10

15

20

30

TABLE 7

Common Vent Capacity

Type B Double-Wall Vents with Type B Double-Wall Connectors Serving Two or More Category I Appliances

Vent and Connector Diameter - D (inches)

4 inch 7 inch

FAN + FAN

92

FAN + NAT

81

5 inch 7 inch

Appliance Input Rating in Thousands of Btu Per Hour

FAN + FAN

140

FAN + NAT

116

FAN + FAN

204

FAN + NAT

161

FAN + FAN

309

FAN + NAT

248

101

110

125

136

152

90

97

112

123

138

155

169

195

215

244

129

141

164

183

210

224

243

283

314

361

178

194

228

255

297

339

367

427

475

547

275

299

352

394

459

Page 16

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 system.

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.

Close all building doors and windows and all doors between the space in which the appliances remaining connected to the common venting system are located and other spaces of the building. Turn on clothes dryers and any appliances not connected to the common venting system. Turn on any exhaust fans, such as range hoods and bathroom 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, or smoke from a cigarette, cigar, or pipe.

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 preceding 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.

Gas Piping

Gas supply piping should not allow more than 0.5”W.C. drop in pressure between gas meter and unit. Supply gas pipe must not be smaller than unit gas connection.

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 over torque (800 in-lbs) or under torque (350 inlbs) when attaching the gas piping to the gas valve.

1 - This unit is shipped standard for left or right side installation of gas piping. Connect the gas supply piping into the gas valve. The maximum torque is 800 in lbs and minimum torque is 350 in lbs when attaching the gas piping to the gas valve.

2 - When connecting the gas supply piping, consider factors such as length of run, number of fittings, and furnace rating to avoid excessive pressure drop. Table 8 lists recommended pipe sizes for typical applications.

3 - The gas piping must not run in or through air ducts, clothes chutes, gas vents or chimneys, dumb waiters, or elevator shafts.

4 - The piping should be sloped 1/4 inch (6.4 mm) per 15 feet (4.57 m) upward toward the meter from the furnace.

The piping must be supported at proper intervals [every 8 to 10 feet (2.44 to 3.01 m)] with suitable hangers or straps.

Install a drip leg inside vertical pipe runs to the unit.

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 23.

6 - In some localities, codes may require the installation of a manual main shut-off valve and union (furnished by the installer) external to the unit. The union must be of the ground joint type.

CAUTION

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

NOTE - If emergency shutoff is necessary, shut off the main manual gas valve and disconnect main power to the furnace. The installer should properly label these devices.

Page 17

Nominal

Iron Pipe

Size Inches

(mm)

1/2

(12.7)

3/4

(19.05)

1

(25.4)

1-1/4

(31.75)

1-1/2

(38.1)

2

(50.8)

2-1/2

(63.5)

3

(76.2)

Internal

Diameter inches

(mm)

.622

(17.799)

.824

(20.930)

1.049

(26.645)

1.380

(35.052)

1.610

(40.894)

2.067

(52.502)

2.469

(67.713)

3.068

(77.927)

10

(3.048)

172

(4.87)

360

(10.19)

678

(19.19)

1350

(38.22)

2090

(59.18)

4020

(113.83)

6400

(181.22)

11300

(319.98)

20

(6.096)

118

(3.34)

247

(7.000)

466

(13.19)

957

(27.09)

1430

(40.49)

2760

(78.15)

4400

(124.59)

7780

(220.30)

TABLE 8

Gas Pipe Capacity - ft3/hr (m3/hr)

Length of Pipe - feet (m)

30

(9,144)

95

(2.69)

199

(5.63)

374

(10.59)

768

(22.25)

1150

(32.56)

2220

(62.86)

3530

(99.95)

6250

(176.98)

40

(12,192)

81

(2.29)

170

(4.81)

320

(9.06)

657

(18.60)

985

(27.89)

1900

(53.80)

3020

(85.51)

5350

(151.49)

50

(15.240)

72

(2.03)

151

(4.23)

284

(8.04)

583

(16.50)

873

(24.72)

1680

(47.57)

2680

(75.88)

4740

(134.22)

60

(18.288)

65

(1.84)

137

(3.87)

257

(7.27)

528

(14.95)

791

(22.39)

1520

(43.04)

2480

(70.22)

4290

(121.47)

70

(21.336)

60

(1.69)

126

(3.56)

237

(6.71)

486

(13.76)

728

(20.61)

1400

(39.64)

2230

(63.14)

3950

(111.85)

80

(24.384)

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

56

(1.58)

117

(3.31)

220

(6.23)

452

(12.79)

677

(19.17)

1300

(36.81)

2080

(58.89)

3670

(103.92)

90

(27.432)

635

(17.98)

1220

(34.55)

1950

(55.22)

3450

(97.69)

52

(1.47)

110

(3.11)

207

(5.86)

424

(12.00)

100

(30,480)

50

(1.42)

104

(2.94)

195

(5.52)

400

(11.33)

600

(17.00)

1160

(32.844)

1840

(52.10)

3260

(92.31)

MANUAL

MAIN SHUT-OFF

VALVE

MANUAL

MAIN SHUT-OFF

VALVE

Left Side Piping

(Standard)

AUTOMATIC

GAS VALVE

(with manual shut-off valve)

GROUND

JOINT

UNION

DRIP LEG

AUTOMATIC

GAS VALVE

(with manual shut-off valve)

FIELD

PROVIDED

AND INSTALLED

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

Figure 18

GROUND

JOINT

UNION

DRIP LEG

Right Side Piping

(Alternate)

Page 18

Leak Check

After gas piping is completed, carefully check all field-in stalled piping connections for gas leaks. Use a commercially available leak detecting solution specifically manu factured for leak detection. Never use an open flame to test for gas leaks.

NOTE - If emergency shutoff is necessary, shut off the main manual gas valve and disconnect the main power to the furnace. The installer should properly label these devices.

CAUTION

Some soaps used for leak detection are corrosive to certain metals. Carefully rinse piping thoroughly after leak test has been completed. Do not use matches, candles, flame or other sources of ignition to check for gas leaks.

.

The furnace must be isolated from the gas supply sys tem by closing the individual manual shut-off valve during any gas supply system at pressures greater than or equal to ½ psig. (3.48 kPa, 14 inches w.c.). This furnace and its components are designed, manufactured and inde pendently certified to comply with all applicable ANSI/CSA standards. A leak check of the furnace and its components is not required.

IMPORTANT

When testing pressure of gas lines, gas valve must be disconnected and isolated. See figure 19. Gas valves can be damaged if subjected to pressures greater than

1/2 psig (3.48 kPa, 14 inches w.c.).

MANUAL MAIN

SHUT-OFF VALVE

WILL NOT HOLD

NORMAL TEST

PRESSURE

1/8 NPT PLUG

CAP

ISOLATE

GAS VALVE

FURNACE

Figure 19

Electrical

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

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

WARNING

Fire Hazard. Use of aluminum wire with this product may result in a fire, causing property damage, severe injury or death. Use copper wire only with this product.

CAUTION

Failure to use properly sized wiring and circuit breaker may result in property damage. Size wiring and circuit breaker(s) per Product Specifications bulletin (EHB) and unit rating plate.

The unit is equipped with a field make-up box on the left hand side of the cabinet. The make-up box may be moved to the right side (figure20) of the furnace to facilitate instal lation. If the make-up box is moved to the right hand side, clip the wire ties that bundle the wires together. Secure the excess wire to the existing harness to protect it from damage.

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.

INTERIOR MAKE-UP BOX INSTALLATION

(Right Side)

MAKE-UP

BOX

Cut the two wire ties to extend power wires for right side only

Figure 20

Refer to figure 21 for schematic wiring diagram, trouble shooting and field wiring.

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 re oval of blower for service.

Complete the wiring connections to the equipment. Use the provided unit wiring diagram and the field wiring dia gram shown in figure 21. Use 18-gauge wire or larger that is suitable for Class II rating for thermostat connections.

Page 19

WARNING

Electric Shock Hazard. Can cause injury or death. Unit must be properly grounded in accordance with national and local codes.

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). A green ground wire is provided in the field make-up box.

NOTE - The ML180DFE furnace contains electronic components that are polarity sensitive. Make sure that the furnace is wired correctly and is properly grounded.

Accessory Terminals See page 22 and 23 for ignition control and diagnostic code tables.

One line voltage “EAC” 1/4” spade terminal is provided on the furnace integrated control. 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. This terminal is energized in the heating mode when the combustion air inducer is operating. Any humidifier rated up to one amp can be con nected 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 relayOne

24V ”H” 1/4” spade terminal is provided on the furnace integrated control. The terminal is energized in the heating mode when the combustion air inducer is operating and the pressure switch is closed. Any humidifier rated up to

0.5 amp can be connected to this terminal with the ground leg of the circuit connected to ground or the ”C” terminal.

Generator Use - Voltage Requirements

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

• The furnace requires 120 volts + 10% (Range: 108 volts to 132 volts).

• The furnace operates at 60 Hz + 5% (Range: 57 Hz to 63 Hz).

• The furnace integrated control requires both proper polarity and proper ground. Both polarity and proper grounding should be checked before attempting to operate the furnace on either permanent or temporary power.

• Generator should have a wave form distortion of less than 5% total harmonic distortion.

Thermostat

Install the room thermostat according to the instructions provided with the thermostat. See figure 21 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 fan speed when there is no cooling or heating demand. See TABLE

14 for allowable continuous circulation speeds.

2 - When the ML180DFE 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.

Page 20

ML180DFE Schematic Wiring Diagram

Figure 21

Page 21

IGNITION CONTROL 103217-03

RED LED RECALL BUTTON

BLOWER OFF DELAY

120V HUM

LINE

XFMR

CIRC

EAC

1/4” QUICK CONNECT TERMINALS

POWER FOR HUMIDIFIER (120 VAC

INCOMING POWER LINE (120 VAC)

TRANSFORMER PRIMARY (120 VAC)

INDOOR BLOWER MOTOR (120 VAC)

ELECTRONIC AIR CLEANER (120 VAC)

HUM24 POWER FOR HUMIDIFIER (24 VAC)

NEUTRALS (5) NEUTRAL

COOL

HEAT

FAN

PARK (3)

FS

24 COM

3/16” QUICK CONNECT TERMINALS

COOL SPEED FROM INDOOR BLOWER

MOTOR (24 VAC)

HEAT SPEED FROM INDOOR BLOWER

MOTOR (24 VAC)

CONTINUOUS FAN SPEED FROM

INDOOR BLOWER MOTOR (24 VAC)

TERMINALS FOR UNUSED MOTOR

SPEED TAPS

FLAME SENSOR ELECTRODE (120 VAC)

COMMON (24 VAC)

Figure 22

Integrated Control 103217-03 Diagnostic Codes

RED LED

Flash Code 2

Off

Diagnostic Codes / Status of Furnace

No power to control or board fault detected

Heartbeat 1

Continuous Rapid Flash

1

2

3

4

5

6

7

10

11

12

13

8

9

Note - 1

Note - 2

Note - 3

Normal Operation - Idle, Continuous Fan, Cool

Call For Heat / Burner Operation

Reverse Line Voltage Polarity

Improper Earth Ground

Burner failed to light, or lost flame during heat demand

Low Flame Signal - check flame sensor

Watchguard - burner failed to light, exceeded maximum number of retries or recycles.

Not Used

Primary or Secondary Limit Open or Watchguard Mode - Limit Switch Open longer than 3 minutes

Rollout Switch Open

Pressure Switch failed to close or opened during heat demand

Watchguard - Pressure Switch opened 5 times during one heat demand

Pressure Switch stuck closed prior to activation of combustion air inducer

Flame Sensed without gas valve energized

Low Line Voltage

Notes

A ”Heartbeat” is indicated by a ”Slow Flash” - 1 sec on 1 sec off, repeating

Error codes are indicated by a “rapid flash” - the LED flashes X times at ½ second on ½ second off, remains off for 3 seconds then repeats.

Last 10 error codes are stored in memory including when power is shut off to the unit. - To recall, press and release button, most recent will be displayed first, LED off for 3 sec, then next error code is displayed, etc. To clear error codes, depress and hold button longer than 5 seconds.

Page 22

IGNITION CONTROL 107163-01

PARKS

COOL

Push Button

Error Recall

W C R G Y

Diagnostic LED

Heating Blower Off

Delay Selector Switch

Integrated Control 107163-01 Diagnostic Codes

RED LED

Flash Code

Off

On

Fast Heartbeat 3

Slow Heartbeat 1

1 Flash 2

2 Flashes 2

3 Flashes 2

4 Flashes 2

5 Flashes 2

6 Flashes 2

7 Flashes 2

8 Flashes 2

9 Flashes 2

10 Flashes 2

11 Flashes 2

12 Flashes 2

13 Flashes 2

Note - 1

Note - 2

Note - 3

Note - 4

Diagnostic Codes / Status of Furnace

No Power to Control or Board Fault Detected

Board Fault Detected

Call for Heat / Burner Operation

Normal Operation – Idle, Continuous Fan, or Cool

Reverse Line Voltage Polarity or Phasing of 120V power

Improper earth ground

Burner failed to light, or lost flame during heat demand

Low flame signal – check flame sensor

Watchguard – burner failed to light, exceeded maximum number of retries/recycles, 1 hour lockout

Not used

Primary or Secondary limit switch open or Watchguard mode – Limit Switch open longer than 3 minutes

Roll-out Switch Open

Pressure Switch failed to close or opened during heat demand, inducer on

Watchguard - Pressure switch opened 5 times during a single heating demand

Pressure switch stuck closed prior to activation of Combustion Air Inducer

Flame sensed without gas valve energized

Low line voltage

Notes

A slow heartbeat is indicated by 1s on / 1s off. It is used for idle, continuous fan and cool modes.

Error codes are indicated by a “rapid flash” - the LED flashes X times at ½ second on ½ second off, remains off for 3 seconds then repeats.

A fast heartbeat is indicated by 0.5s on / 0.5s off. It is only used during a heat call.

Last 10 error codes are stored in memory including when power is shut off to the unit.

- To recall, press, and release button, most recent will be displayed first, LED off for 3 sec, then next error code is displayed, etc. To clear error codes, depress and hold button longer than 5 seconds.

Page 23

Unit Start-Up

FOR YOUR SAFETY READ BEFORE LIGHTING

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

If overheating occurs or if gas supply fails to shut off, shut off the manual gas valve to the appliance before shutting off electrical supply..

CAUTION

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

BEFORE LIGHTING smell all around the appliance area for gas. Be sure to smell next to the floor because some gas is heavier than air and will settle on the floor.

The gas valve on the ML180DFE unit is equipped with a gas control switch. Use only your hand to move the switch.

Never use tools. If the switch will not turn or if the control switch will not move by hand, do not try to repair it.

Placing the furnace into operation:

ML180DFE units are equipped with an automatic ignition system. Do not attempt to manually light burners on these furnaces. 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 units with an automatic ignition system.

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 23)

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

5 - Remove the access panel.

6 - Move switch on gas valve to OFF. Do not force. See figure 23.

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 instructions. If you do not smell gas go to next step.

MANIFOLD

PRESSURE

ADJUSTMENT

SCREW

MANIFOLD

PRESSURE

OUTLET

PORT

INLET

PRESSURE

PORT GAS VALVE SHOWN IN ON POSITION

Figure 23

8 - Move switch on gas valve to ON. Do not force. See figure 23.

9 - Replace the access panel.

10- Turn on all electrical power 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- 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 access panel.

4 - Move switch on gas valve to OFF. Do not force.

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 circuit 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 lock out? If the unit locks out again, call the service technician to inspect the unit for blockages.

10 - Is pressure switch closed? Obstructed flue will cause unit to shut off at pressure switch. Check flue and outlet for blockages.

11 - Are flame rollout switches tripped? If flame rollout switches are tripped, call the service technician for inspection.

Page 24

Heating Sequence Of Operation

(follow steps below and see Figure 21)

1 - When thermostat calls for heat, combustion air blower starts.

Combustion air pressure switch proves blower operation. Switch is factory-set and requires no adjustment.

3 - After a 15-second prepurge, the hot surface ignitor energizes.

4 - After a 20-second ignitor warm-up period, the gas valve solenoid opens. A 4-second trial for ignition period 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 ignition 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 automatically repeat steps 1 through

6 after 60 minutes.

7 - To interrupt the 60-minute “WATCHGUARD” period, move thermostat from “Heat” to “OFF” then back to

“Heat.” Heating sequence then restarts at step 1.

Gas Pressure Adjustment

Gas Flow (Approximate)

TABLE 9

GAS METER CLOCKING CHART

ML80DFE

Unit

-045

-070

-090

-110

-135

1 cu ft

Dial

Seconds For One Revolution

Natural LP/Propane

2 cu ft

Dial

1 cu ft

Dial

2 cu ft

Dial

80

55

41

33

27

160

110

82

66

54

200

136

102

82

68

400

272

204

164

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 revolu tions of gas through the meter. (Two revolutions assures a more accurate time.) Divide by two and compare to time in table 10 below. If manifold pressure matches table 12 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

A threaded plug on the inlet side of the gas valve provides access to the supply pressure tap. Remove the threaded plug, install a field-provided barbed fitting and connect a manometer to measure supply pressure. Furnace should operate at least 5 minutes before checking supply pressure. See table 12 for proper supply pressure. Replace the threaded plug after measurements have been taken.

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 12.

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

Proper Combustion

Furnace should operate a minimum 15 minutes with correct manifold pressure and gas flow rate before checking combustion. Take combustion sample beyond the flue out let and compare to the tables below. The maximum carbon monoxide reading should not exceed 100 ppm.

TABLE 10

CO

2

% Nat CO

2

% LP ML180DFE Unit

-045

-070

-090

-110

6.8 - 7.4

7.5 - 9.0

High Altitude

The manifold pressure may require adjustment and combustion air pressure switch may need replacing to ensure proper combustion at higher altitudes. Refer to table 12 for manifold pressure and table 13 for pressure switch change and gas conversion kits.

WARNING

For safety, shut unit off and remove manometer as soon as an accurate reading has been obtained. Take care to replace pressure tap plug.

Page 25

Model

Input Size

045

070

090

110

Gas

Nat

LP/Propane

Nat

LP/Propane

Nat

LP/Propane

Nat

LP/Propane

TABLE 11

Manifold Pressure Settings at all Altitudes

0 - 4500 ft.

3.5

10.0

3.5

10.0

3.5

10.0

3.5

10.0

4501 - 7500 ft .

7501 - 10,000 ft.

3.5

10.0

3.3

10.0

3.3

10.0

3.3

10.0

3.5

10.0

3.5

10.0

3.5

10.0

3.5

10.0

Line Pressure in. wg.

Min Max

4.5

11.0

13.0

13.0

4.5

11.0

4.5

11.0

4.5

11.0

13.0

13.0

13.0

13.0

13.0

13.0

Model

Input Size

045

070

TABLE 12

Pressure Switch and Gas Conversion Kits at all Altitudes

High Altitude Pressure Switch Kit

No

Change No Change

High Altitude

Natural Gas

Burner Orifice Kit

Natural Gas to LP/Propane

Burner Orifice Kit

LP/Propane to Natural

Gas

Burner

Orifice Kit

0-4500 ft 4501-7500 ft 7501-10,000 ft 7501- 10,000 ft 0 - 7500 ft 7501- 10,000 ft 0 - 7500 ft

No Change

80W52

80W51 73W37 11K49 11K44 73W81

090

110 80W52

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.

Other Unit Adjustments

Fan Control

Primary and Secondary Limits Ignition Control 103217-03

The primary limit is located on the heating compartment vestibule panel. The secondary limits (if equipped) are located in the blower compartment, attached to the back side of the blower. These auto reset limits are factory-set and require no adjustment.

Pressure Switch

The pressure switch is located in the heating compartment adjacent to the combustion air inducer. The switch checks for proper combustion air inducer operation before allowing ignition trial. The switch is factory-set and requires no adjustment.

Temperature Rise

The heat fan-on time of 30 seconds is not adjustable. The heat fan-off delay (amount of time that the blower oper ates 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 delay setting of 90 seconds. The fan-off de lay 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 24.

Ignition Control 107163-01

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. See TABLE 13 for allowable heating speeds. Decrease the blower speed to increase the temperature rise. Failure to adjust the temperature rise may cause erratic limit operation.

The heat fan-on time of 30 seconds is not adjustable The heat fan-off delay (amount of time that the blower oper ates after the heat demand has been satisfied) may be adjusted by changing the two position dip switch on the integerated control, to one of four slections. Blower off de lay is factory set at 90 seconds. For other blower off delay settings, please refer to the following chart:

Page 26

60

90

120

180

Blower Delay Select

SW2-1

OFF

OFF

ON

ON

Factory Setting is 90

SW2-2

ON

HEAT FAN ‐ OFF TIME IN SECONDS

OFF

OFF

ON

NO JUMPER

To adjust fan-off timing, reposition jumper across pins to achieve desired setting.

60 Second off Time

90 Second off Time

120 Second off Time

180 Second off Time

60 90

120 180

60 90 60 90 60 90

Figure 24

Constant Torque Motor

ML180DFE units are equipped with a permanent magnetic indoor blower motor that provides constant torque. The motor has five speed taps all referenced to the same sig nal common. Each tap requires 24 volts to be energize.

Flame Rollout Switches

These manually reset switches are located on the burner box.

Input Voltage Requirements

The circuit is designed to be operated with AC voltage. A voltage of 12 to 33VAC is required to energize the motor.

Expected current draw will be less than 20mA.

Electrical

1 - Check all wiring for loose connections.

2 - Check for the correct voltage at the furnace operating).

Correct voltage is 120VAC + 10%

3 - Check amp-draw on the blower motor with blower access panel in place.

Motor Nameplate__________Actual__________

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 diagram 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.

Page 27

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.

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.

Annual Furnace Maintenance

At the beginning of each heating season, and to comply with the Lennox Limited Warranty, your system should be checked by a licensed professional technician (or equivalent) as follows:

1 - Check wiring for loose connections, voltage at indoor unit and amperage of indoor motor.

2- Check the condition of the belt and shaft bearings if applicable.

3- Inspect all gas pipe and connections for leaks.

4- Check the cleanliness of filters and change if necessary (monthly).

5- Check the condition and cleanliness of burners and heat exchanger and clean if necessary.

Check the cleanliness of blower assembly and clean the housing, blower wheel and blower motor if necessary. The blower motors are prelubricated for extended bearing life. No further lubrication is needed.

7- Inspect the combustion air inducer and clean if necessary.

8- Evaluate the heat exchanger integrity by inspecting the heat exchanger per the AHRI heat exchanger inspection procedure. This procedure can be viewed at www.ahrinet.org

9- Ensure sufficient combustion air is available to the furnace. Fresh air grilles and louvers (on the unit and in the room where the furnace is installed) must be properly sized, open and unobstructed to provide combustion air.

10- Inspect the furnace venting system to make sure it is in place, structurally sound, and without holes, corrosion, or blockage. Vent system must be free and clear of obstructions and must slope upward away from the furnace . Vent system should be installed per the National Fuel Gas Code

11- Inspect the furnace return air duct connection to ensure the duct is sealed to the furnace. Check for air leaks on supply and return ducts and seal where necessary.

12- Check the condition of the furnace cabinet insulation and repair if necessary.

13- Perform a complete combustion analysis during the furnace inspection to ensure proper combustion and operation. Consult Service Literature for proper combustion values.

Verify operation of CO detectors and replace batteries as required.

Perform a general system test. Turn on the furnace to check operating functions such as the start-up and shutoff operation.

1 - Check the operation of the ignition system, inspect and clean flame sensor. Check microamps before and after. Check controls and safety devices (gas valve, flame sensor, temperature limits). Consult

Service Manual for proper operating range. Thermal

Limits should be checked by restricting airflow and not disconnecting the indoor blower. For additional details, please see Service and Application Note

H049.

2 - Verify that system total static pressure and airflow settings are within specific operating parameters.

3 - Clock gas meter to ensure that the unit is operating at the specified firing rate. Check the supply pressure and the manifold pressure. On two-stage gas furnaces check the manifold pressure on high fire and low fire. If manifold pressure adjustment is necessary, consult the Service Literature for unit specific information on adjusting gas pressure.

Not all gas valves are adjustable. Verify correct temperature rise.

Page 28

Cleaning the Burners

NOTE - Use papers or protective covering in front of the furnace during cleaning.

1 - Turn off both electrical and gas power supplies to furnace.

2 - Remove access panel.

3 - Label the wires from gas valve and rollout switches then disconnect them.

4 - Mark and disconnect sensor wire from the sensor.

Disconnect plug from the ignitor at the burner box.

5 - Disconnect gas supply piping. Remove the four screws securing the burner manifold assembly to the vestibule panel and remove the assembly from the unit.

6 - Remove screws securing burner box and remove burner box.

7- To clean burners, run a vacuum cleaner with a soft brush attachment over the face of burners.

Visually inspect inside the burners and crossovers for any blockage caused by foreign matter. Remove any blockage. Figure 25 shows burner detail.

8 - Reinstall the burner box assembly using the existing four screws. Make sure that the burners line up in the center of the burner ports.

9 - Reconnect the sensor wire and reconnect the 2-pin plug to the ignitor wiring harness.

10 - Follow lighting instructions to light and operate furnace for 5 minutes to ensure that heat exchanger is clean and dry and that furnace is operating properly.

11 - Replace access panel.

CAUTION

Some soaps used for leak detection are corrosive to certain metals. Carefully rinse piping thoroughly after leak test has been completed. Do not use matches, candles, flame or other sources of ignition to check for gas leaks.

gasket flue chase rollout switch sensor ignitor

BURNER ASSEMBLY REMOVAL retention rings cross over

Figure 25

Page 29

Repair Parts List

The following repair parts are available through independent Lennox dealers. When ordering parts, include the complete furnace model number listed on the CSA International nameplate -- Example: ML180DF110E60C.

All service must be performed by a licensed professional installer (or equivalent), service agency, or gas supplier.

Cabinet Parts

Heating access panel

Blower access panel

Top cap

Control Panel Parts

Transformer

Integrated control

Door interlock switch

Circuit breaker

Blower Parts

Blower wheel

Blower housing

Motor

Motor electronics

Power choke (1/2 and 3/4 hp only)

Motor mounting frame

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 switch

Secondary limit

Page 30

Start-Up & Performance Check List

2

UNIT SET UP

(typical)

Unit Model Number_______________

Serial Number___________________

2

Line Voltage

5

SUPPLY

AIR upflow furnace shown

1

1

Gas Supply Pressure

4

3

Filter

RETURN

AIR

1

GAS SUPPLY

Natural Gas LP/Propane Gas

Piping Connections Tight

Leak Tested

Supply Line Pressure “ W.C.________

2

VENT / EXHAUST PIPE

Secure to Unit

Elbows Secured to Pipe

Roof Flashing (water tight)

Vent Pipe Supported

3

4

DUCT SYSTEM

SUPPLY AIR DUCT

Sealed

Insulated (if necessary)

Registers Open and Unobstructed

RETURN DUCT

Sealed

Filter Installed and Clean

Grilles Unobstructed

INTEGRATED CONTROL

DIP Switches Set (if applicable)

Appropriate Links in Place (if applicable)

5 VOLTAGE CHECK

Supply Voltage _____

Electrical Connections Tight

Page 31

UNIT OPERATION

(typical)

Combustion CO

2

2

SUPPLY

AIR

Gas Manifold Pressure

1

7 Thermostat

6 upflow furnace shown

Filter

Temperatures

4

Blower Motor Amps

3

Duct Static

5

1

2

3

HEATING MODE

GAS MANIFOLD PRESSURE “W.C._____

COMBUSTION SAMPLE CO

2

%

______

CO PPM_______

INDOOR BLOWER AMPS______

3

COOLING MODE

INDOOR BLOWER AMPS______

4 TEMPERATURE DROP

Return Duct Temperature _________

Supply Duct Temperature _ _______

Temperature Drop = _________

4

5

TEMPERATURE RISE

Supply Duct Temperature ________

Return Duct Temperature _ _____

Temperature Rise = ________

5 TOTAL EXTERNAL STATIC (dry coil)

Supply External Static _______

Return External Static + ______

Total External Static = _______

TOTAL EXTERNAL STATIC (dry coil)

Supply External Static _______

Return External Static + ______

Total External Static = _______

6 DRAIN LINE

Leak Free

7 THERMOSTAT

Adjusted and Programmed

Operation Explained to Owner

Contractor's: Name_________________________Telephone_____________Checklist Completed____________________

Job Address_____-________________________________Technician's Name___________________________________

Page 32

BLOWER DATA

Model Number

ML180DF045E36A

ML180DF070E36B

ML180DF090E48B

ML180DF110E60C

Red

Not Allowed

Not Allowed

Allowed

Not Allowed

TABLE 13

Allowable Heating Speeds

Yellow

Allowed

Blue

Factory Setting

Model Numberww

All Models

Red

Factory Setting

TABLE 14

Allowable Circulation Speeds

Yellow

Not Allowed

Blue

Not Allowed

Brown

Allowed

Brown

Not Allowed

Black

Not Allowed

Black

Not Allowed

ML180DF045E36A PERFORMANCE (Less Filter)

External

Static

Pressure in. w.g.

cfm

High

(Black)

Watts

Air Volume / Watts at Various Blower Speeds

Medium-High cfm

(Brown)

Watts cfm

Medium

(Blue)

Watts

Medium-Low cfm

(Yellow)

Watts

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

1430

1400

1375

1335

1320

1275

1245

1215

1175

285

285

300

315

325

335

345

355

365

1215

1175

1145

1120

1075

1045

1000

970

925

180

185

200

210

220

230

235

245

255

1035

995

950

915

870

835

785

745

695

120

130

140

145

155

165

170

180

185

995

885

840

790

745

715

655

605

555

110

100

110

115

125

135

140

150

155 cfm

930

850

725

665

625

565

520

355

400

Low

(Red)

Watts

100

90

85

95

100

105

115

130

130

Page 33

BLOWER DATA

ML180DF070E36A PERFORMANCE (Less Filter)

External

Static

Pressure in. w.g.

cfm

High

(Black)

Watts

Air Volume / Watts at Various Blower Speeds

Medium-High cfm

(Brown)

Watts cfm

Medium

(Blue)

Watts

Medium-Low cfm

(Yellow)

Watts

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

- - -

1460

1420

1395

1375

1335

1285

1210

1140

- - -

348

360

371

380

378

374

356

333

- - -

1235

1195

1175

1150

1120

1075

1065

1020

- - -

221

233

245

247

259

260

274

276

- - -

1150

1115

1070

1045

1010

985

955

920

- - -

179

193

196

207

211

221

225

237

- - -

1110

1090

1055

1025

990

955

915

890

- - -

164

175

181

191

198

206

209

219 cfm

- - -

965

920

900

845

820

770

730

675

Low

(Red)

Watts

- - -

114

116

126

130

143

144

154

158

ML180DF070E36B PERFORMANCE (Less Filter)

External

Static

Pressure in. w.g.

cfm

High

(Black)

Watts

Air Volume / Watts at Various Blower Speeds

Medium-High cfm

(Brown)

Watts cfm

Medium

(Blue)

Watts

Medium-Low cfm

(Yellow)

Watts

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

1430

1400

1360

1310

1280

1250

1220

1165

290

295

310

325

335

350

355

365

1275

1230

1205

1155

1110

1060

1000

935

175

190

205

210

220

235

245

250

1190

1125

1085

1050

985

935

865

795

145

160

160

175

185

195

205

210

1155

1110

1055

1000

950

865

815

750

135

150

155

165

180

185

195

200 cfm

Low

(Red)

Watts

1005

900

845

790

705

645

590

480

95

100

115

115

130

135

140

145

Page 34

BLOWER DATA

ML180DF090E48B PERFORMANCE (Less Filter)

External

Static

Pressure in. w.g.

cfm

High

(Black)

Watts

Air Volume / Watts at Various Blower Speeds

Medium-High cfm

(Brown)

Watts cfm

Medium

(Blue)

Watts

Medium-Low cfm

(Yellow)

Watts

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

1750

1725

1695

1660

1615

1570

1545

N/A

N/A

385

390

405

415

430

450

465

N/A

N/A

1550

1495

1470

1425

1395

1360

1295

1265

1215

265

270

285

300

310

325

340

350

365

1430

1390

1340

1290

1250

1210

1165

1120

1080

205

220

235

240

255

265

280

295

305

1355

1320

1280

1225

1185

1145

1085

1040

1000

185

195

210

215

230

240

255

265

275 cfm

1195

1145

1105

1040

1005

945

865

810

755

Low

(Red)

Watts

130

140

145

160

170

180

185

200

210

ML180DF110E60C PERFORMANCE (Less Filter)

External

Static

Pressure in. w.g.

cfm

High

(Black)

Watts

Air Volume / Watts at Various Blower Speeds

Medium-High cfm

(Brown)

Watts cfm

Medium

(Blue)

Watts

Medium-Low cfm

(Yellow)

Watts

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

2410

2385

2325

2280

2235

2165

2125

2090

2035

625

630

650

675

690

710

735

740

760

2095

2100

2010

1940

1895

1845

1800

1755

1700

405

415

440

460

475

490

510

530

540

1875

1830

1760

1705

1635

1595

1545

1510

1460

295

310

330

340

365

380

390

405

425

1700

1610

1570

1500

1440

1380

1320

1285

1255

225

240

255

260

285

300

310

325

345 cfm

1635

1505

1375

1320

1265

1200

1170

1100

1030

Low

(Red)

Watts

180

190

195

210

225

235

250

260

275

Page 35