Lennox SL280UHV, SL280UH070V36A, SL280UH090V36B, SL280UH090V48B, SL280UH090V60C Installation Instructions Manual

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Page 1

06/11

*2P0611*

506763−01

*P506763-01*

 2011 Lennox Industries Inc.

Dallas, Texas, USA

UPFLOW

HORIZONTAL LEFT HORIZONTAL RIGHT

AIR FLOW

AIR FLOWAIR FLOW

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.

INSTALLATION INSTRUCTIONS SL280UHV

DAVE LENNOX SIGNATURE

COLLECTION GAS FURNACE UPFLOW / HORIZONTAL AIR DISCHARGE

506763−01 06/2011 Supersedes 03/2011

THIS MANUAL MUST BE LEFT WITH THE

HOMEOWNER FOR FUTURE REFERENCE

This 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.

NOTICE

A thermostat is not included and must be ordered separately.

 The Lennox icomfort Touch

thermostat must be

used in communicating applications.

 In non−communicating applications, the Lennox

ComfortSense

7000 thermostat may be used, as

well as other non−communicating thermostats.

In all cases, setup is critical to ensure proper system operation.

Field wiring for both communicating and non−communicating applications is illustrated in diagrams, which begin on Page 27.

Table of Contents

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

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

SL280UHV Gas Furnace 4. . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

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

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

Venting 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas Piping 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Integrated Control Settings 36. . . . . . . . . . . . . . . . . . . . . . .

Blower Performance Data 39. . . . . . . . . . . . . . . . . . . . . . . .

Unit Start−Up 51. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas Pressure Adjustment 52. . . . . . . . . . . . . . . . . . . . . . . .

Proper Combustion 52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

High Altitude 53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Other Unit Adjustments 54. . . . . . . . . . . . . . . . . . . . . . . . . .

Heating Sequence of Operation 54. . . . . . . . . . . . . . . . . . .

Service 56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Planned Service 59. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Repair Parts List 59. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Integrated Control Diagnostic Codes 60. . . . . . . . . . . . . . .

Program Unit Capacity/Size Mode 67. . . . . . . . . . . . . . . . .

Troubleshooting 68. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Litho U.S.A.

Page 2

Unit Dimensions − inches (mm)

NOTE − 60C and 60D units that require air volumes over 1800 cfm

(850 L/s) must have one of the following:

1. Return air from single side transition will accommodate 20 x 25 x1 in. (508 x 635 x 25) cleanable air filter. (Required to maintain proper air velocity)

2. Single side return air with optional RAB Return Air Base.

3. Return air from bottom and one side.

4. Return air from both sides.

5. Return air from bottom.

See blower performance tables for additional information

Flue outlet may be horizontal but furnace must be

vented vertically

Optional external side return air filter kit cannot be used

with the optional RAB Return Air Base.

AIR FLOW

(19)

3/4

(19)

Bottom Return

Air Opening

FRONT VIEW

9/16 (14)

3/4

(838)

(406)

14−3/4

(375)

OPTIONAL

EXTERNAL

SIDE RETURN

AIR FILTER KIT

(Either Side)

5/8

(16)

FLUE OUTLET

(Top)

SUPPLY AIR

OPENING

TOP VIEW

OPTIONAL

EXTERNAL

SIDE RETURN

AIR FILTER KIT

(Either Side)

23−3/4

(603)

(635)

(584)

GAS PIPING INLET

(Either Side)

Side Return Air Opening (Either Side)

Bottom Return

ELECTRICAL INLET

(Either Side)

27−3/4

(705)

19−7/16

(494)

23−1/2

(597)

1−1/2

(38)

9−1/8 (232) Right

8−5/8 (219) Left

5−3/8 (137) Right

1−15/16 (49)

(356)

9/16

(14)

3 (76) Right

FLUE OUTLET

(Either Side)

3−1/4 (83)

3−1/4

(83)

SIDE VIEW

3−1/8 (79)

1−1/2 (38) Front Panel

7 (178) Left

2−3/4 (70) Left

Model No.

A B C D

in. mm, in. mm in. mm in. mm

SL280UH070V36A 14−1/2 368 13−3/8 340 13 330 4−3/4 121

SL280UH090V36B SL280UH090V48B

17−1/2 446 16−3/8 416 16 406 6−1/4 159

SL280UH090V60C SL280UH110V60C

21 533 19−7/8 504 19 1/2 495 8 203

SL280UH135V60D 24−1/2 622 23−3/8 546 23 584 9−3/4 248

Page 3

Parts Arrangement

FIGURE 1

HEAT EXCHANGER

CABINET

COMBUSTION AIR INDUCER

BLOWER

ASSEMBLY

BURNER BOX

INNER BLOWER ACCESS PANEL

ACCESS PANEL

SIGHT GLASS

COMBUSTION AIR INDUCER

PRESSURE SWITCH

GAS VALVE

CONTROL BOX

(Includes two−stage integrated control,

transformer and circuit breaker)

ROLLOUT SWITCH

Page 4

SL280UHV Gas Furnace

The SL280UHV gas furnace is equipped with a two−stage, variable speed integrated control. the control is compatible with: Communicating thermostats − icomfort Touch

. Non−comunicating thermostats − ComfortSense or other conventional thermostats. Control systems − Harmony III Zone Control System (non−communicating). Each SL280UHV unit is shipped ready for installation in the upflow or horizontal position (left or right). The furnace is shipped with the bottom panel in place. The bottom panel must be removed if the unit is to be installed in a horizontal application. The panel may also be removed in upflow applications.

Shipping and Packing List

Package 1 of 1 contains

1 − Assembled SL280UHV 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 − Suspension Kit (for horizontal installations) 1 − Propane/LP changeover kit 1 − Return air base 1 − High altitude kit 1 − Side filter kit

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

Safety Information

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.

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.

Certifications

SL280UHV units are CSA International certified to ANSI Z21.47.

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 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 figures 7 and 11. 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.

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.

Page 5

Temperature Rise

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

This SL280UHV 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. See figure 1. 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. See figure 1.

FIGURE 1

Gas Unit

Heating Unit Installed Upstream of Cooling Unit

Gas Unit

Dampers

(open during heating operation only)

Dampers

(open during cooling operation only)

Heating Unit Installed Parallell to Air Handler Unit

Air Handler Unit

Evaporator

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 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 SL280UHV furnace may be installed in alcoves, closets, attics, basements, garages, and utility rooms in the upflow or horizontal position.

This furnace is not designed for installation in mobile homes, recreational vehicles, or outdoors.

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

Use of Furnace as Construction Heater

Lennox does not recommend the use of SL280UHV 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.

SL280UHV 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 comple-

tion.

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

furnace rating plate.

 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.

 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, 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 SL280UHV furnace:

Page 6

 Place the furnace as close to the center of the air dis-

tribution system as possible. The furnace should also be located close to the chimney or vent termination point.

 Do not install the furnace where drafts might blow direct-

ly 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 insu-

lated space, keep insulation away from the furnace.

NOTE − The Commonwealth of Massachusetts stipulates these additional requirements:

D Gas furnaces shall be installed by a licensed plumb-

er or fitter only.

D The gas cock must be T handle" type. D When a furnace is installed in an attic, the passage-

way to and service area surrounding the equipment shall be floored.

WARNING

Product contains fiberglass wool.

Disturbing the insulation in this product during installation, maintenance, or repair will expose you to fiberglass wool. Breathing this may cause lung cancer. (Fiberglass wool is known to the State of California to cause cancer.)

Fiberglass wool may also cause respiratory, skin, and eye irritation.

To reduce exposure to this substance or for further information, consult material safety data sheets available from address shown below, or contact your supervisor.

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

Combustion, Dilution & Ventilation Air

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 SL280UHV 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). 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.

CAUTION

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

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

All gas-fired appliances require air for the combustion process. If sufficient combustion air is not available, the furnace or other 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 fireplaces, 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.

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

Page 7

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 combined input rating of all appliances installed in that space. This definition includes furnace closets or small equipment rooms.

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

EQUIPMENT IN CONFINED

SPACE ALL AIR FROM INSIDE

CHIMNEY

OR GAS

VENT

FURNACE

WATER

HEATER

OPENINGS

(To Adjacent

Room)

NOTE − Each opening shall have a free area of at least one square inch (645 mm

) per 1,000 Btu (.29 kW) per hour of the total input rating of all equipment in the enclosure, but not less than 100 square inches (64516 mm

AIR FLOW

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 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 2.

Air from Outside

If air from outside is brought in for combustion and ventilation, the confined space must have two permanent openings. One opening shall be within 12 inches (305 mm) of the top of the enclosure and one opening within 12 inches (305 mm) of the bottom. These openings must communicate directly or by ducts with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors or indirectly through vertical ducts. Each opening shall have a minimum free area of 1 square inch (645 mm

) per 4,000 Btu (1.17

kW) per hour of total input rating of all equipment in the enclosure. See figures 3 and 4. 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 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 8

EQUIPMENT IN CONFINED SPACE

ALL AIR FROM OUTSIDE

(Inlet Air from Crawlspace 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 (645 mm

) per 4,000 Btu (1.17 kW) per hour of the total input rating of all equipment in the enclosure.

VENTILATION LOUVERS

(Each end of attic)

OUTLET

AIR

WATER

HEATER

INLET

AIR

CHIMNEY OR

GAS VENT

FURNACE

VENTILATION

LOUVERS

(For unheated crawl space)

AIR FLOW

FIGURE 3

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 (645 mm

) per 4,000 Btu (1.17 kW) per hour of the total input rating of all equipment in the enclosure.

CHIMNEY

OR GAS

VENT

WATER

HEATER

OUTLET

AIR

VENTILATION LOUVERS

(Each end of attic)

INLET AIR

(Ends 12 in.

above bottom)

FURNACE

AIR FLOW

FIGURE 4

EQUIPMENT IN

CONFINED SPACE

ALL AIR FROM

OUTSIDE

OUTLET AIR

INLET AIR

WATER

HEATER

CHIMNEY

OR GAS

VENT

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

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

) per 4,000 Btu (1.17 kW) per hour of the total input rating of all other equipment in the enclosure.

FURNACE

AIR FLOW

FIGURE 5

Page 9

Setting Equipment

WARNING

Do not install the furnace on its front or its back. 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.

The SL280UHV gas furnace can be installed as shipped in either the upflow position or the horizontal position.

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 hp blower motors are equipped with three flexible legs and one rigid leg. See figure 6. 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 removed, the rig-

id leg will not touch the blower housing.

FIGURE 6

RIGID LEG

remove shipping bolt and washer

SL280UHV07036A and

SL280UHV09036B WITH 1/2 HP

BLOWER MOTOR

Upflow Applications

Allow for clearances to combustible materials as indicated on the unit nameplate. Minimum clearances for closet or alcove installations are shown in figure 7.

Upflow Application Installation Clearances

Top

Bottom

Left Side

Right Side

AIR FLOW

Type of Vent

Connector

Type C Type B1

Top 1 in. (25 mm) 1 in. (25 mm)

*Front 2−1/4 in. (57 mm)** 2−1/4 in. (57 mm)

Back 0 0

Sides 0† 0

Vent 6 in. (152 mm) 1 in. (25 mm)

Floor 0‡ 0‡

*Front clearance in alcove installation must be 24 in. (610 mm). Maintain a minimum of 24 in. (610 mm) for front service access. ** 3−1/4 in. if single wall vent pipe is used. ‡For installation on a combustible floor, do not install the furnace directly on carpeting, tile or other combustible materials other than wood flooring. †Left side requires 3 inches if a single wall vent is used on 14−1/2 inch cabinets, or 2 in. if a single wall vent is used on 17−1/2 in. cabinets.

FIGURE 7

Page 10

Return Air −− Upflow Applications

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.

NOTE −

60C and 60D units that require air volumes over 1800

cfm (850 L/s) must have one of the following:

1 − Return air from single side with transition which will

accommodate 20 x 25 x 1 in. (508 x 635 x 25 mm) cleanable air filter. (Required to maintain proper air velocity.) See figure 8.

2 − Return air from single side with optional RAB Return

Air Base. See figure 9.

3 − Return air from bottom and

one side.

4 − Return air from both sides.

5 − Return air from bottom.

Refer to Engineering Handbook for additional information.

FIGURE 8

Return Air

Plenum

Transition

20” X 25” X 1”

(508mm X635mm X 25mm)

Cleanable Filter

AIR FLOW

Single Side Return Air

(with transition and filter)

Optional Return Air Base

(Upflow Applications Only −− For use with A, B, C and D cabinets)

FIGURE 9

NOTE− Optional Side Return Air Filter Kits are not for use with Optional 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 or more of air (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.

OPTIONAL

RETURN AIR BASE

FURNACE

FRONT

AIR FLOW

14−1/2” (368) A Width (65W75)

17−1/2” (446) B Width (50W98)

21”− (533) C Width (50W99)

24−1/2”− (622) D Width (51W00)

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)

IF BASE

IS USED

WITHOUT

IAQ CABINET,

A SINGLE

RETURN AIR

PLENUM

MUST

COVER BOTH

UNIT AND

RETURN

AIR BASE

OPENINGS

INDOOR AIR

Page 11

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 10.

Removing the Bottom Panel

FIGURE 10

Screw

Bottom Panel

Bottom Cap

Hori

zontal Application

Installation Clearances

Top

Bottom

Left End

Right End

AIR FLOW

Vent Connector

Type

Type C Type B1

Top 0 0

*Front 2−1/4 in. (57 mm)** 2−14 in. (57 mm)

Back 0 0

Ends 2 in. (51 mm) 2 in. (51 mm)

Vent 6 in. (152 mm) 1 in. (25 mm)

Floor 0‡ 0‡

FIGURE 11

Horizontal Applications

The SL280UHV furnace can be installed in horizontal applications. Order kit number 51W10 (or use equivalent) from Lennox.

Allow for clearances to combustible materials as indicated on the unit nameplate. Minimum clearances for closet or alcove installations are shown in figure 11.

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 12, or install the furnace on a platform, as shown in figure 13.

Typical Horizontal Application

Unit Suspended in Attic or Crawlspace

FIGURE 12

Bracket

Bottom Cap

Metal Strap

3/16 inch

Air Flow

NOTE − Heavy−gauge perforated 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.

NOTE − When the furnace is installed on a platform in a crawlspace, it must be elevated enough to avoid water damage and to allow the evaporator coil to drain.

Return Air −− Horizontal Applications

Return air must be brought in through the end of a furnace installed in a horizontal application. The furnace is equipped with a removable bottom panel to facilitate installation. See figure 10.

Page 12

Horizontal Application

Unit Installed on Platform

FIGURE 13

clearances.

GAS

ENTRY

VENT

PIPE

See the unit nameplate for

Line contact is permissible

SERVICE PLATFORM

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.

WARNING

The inner blower 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

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

TABLE 1

Furnace

Cabinet Width

Filter Size

Side Return Bottom Return

14−1/2" 16 X 25 X 1 (1) 14 X 25 X 1 (1) 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 (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.

NOTE − Do not operate the furnace in the heating mode with an external static pressure that exceeds 0.8 inches w.c. Higher external static pressures may cause erratic limit operation.

Supply Air Plenum

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

Return Air Plenum NOTE − Return air must not be drawn from a room

where this furnace, or any other gas−fueled appliance (i.e., water heater), or carbon monoxide− producing device (i.e., wood fireplace) is installed.

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

In upflow applications, the 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.

Page 13

Venting

A 4−inch diameter flue transition is factory-installed on the combustion air inducer outlet of all models. Figure 15

shows the combustion air inducer as shipped from the factory.

FIGURE 14

Mounting Screws Location

mounting screws

mounting screw

UPFlow Position

FIGURE 15

UPFLOW POSITION

Top Vent Discharge

FLOW

AIR

collector box

vent pipe

flue

transition

pressure

switch

make−up

box

IMPORTANT

The unit will not vent properly with the flue transition pointed down in the 6 o’clock position. The combustion air inducer may be rotated clockwise or counterclockwise by 90° to allow for top or side vent discharge in all applications. When the unit is installed, the flue transition must be in the 9 o’clock, 12 o’clock or 3 o’clock position.

If necessary reposition the combustion air inducer, pressure switch and or make up box as needed per the following steps and see figures 15 through 21.

1 − Remove the four mounting screws (figure 14) which

secure the combustion air inducer / pressure switch assembly to the orifice plate. Lift and rotate the assembly 90 degrees clockwise or counter clockwise to either the 3 o’clock position or to 9 o’clock position and re−secure with four screws. Gasket should be left in place.

2 − Use tin snips to cut preferred opening on the cabinet

for repositioning the flue outlet. Use the cut out piece as a cover plate to patch unused opening on cabinet.

UPFLOW POSITION

Left Side Vent Discharge

FIGURE 16

 Gas supply piping must be brought into the unit from the right

side in order to accommodate the flue pipe.

 Remove make−up box assembly (2 screws) and cut wire tie to

free make−up box wires. Re−install make−up box on other side of cabinet.

 Re−secure make−up box wires, either pulling excess wires

through the blower compartment and securing with supplied wire tie, or coil excess wire and secure to the gas manifold.

FLOW

AIR

make−up

box

pressure

switch

flue

transition

vent pipe

cover plate

collector box

UPFLOW POSITION

Right Side Vent Discharge

FIGURE 17

 Pressure switch tubing may be too long. Cut to

fit , then re−attach to barbed fitting on pressure switch. Tubing must not be allowed to sag.

FLOW

AIR

cover plate

flue transition

vent pipe

pressure switch

make−up

box

collector box

Page 14

Horizontal Position

FIGURE 18

HORIZONTAL LEFT POSITION

Top Vent Discharge

 Disconnect pressure switch hose from barbed fitting on the pres-

sure switch assembly. Remove pressure switch assembly (1 screw) and cut wire tie to free pressure switch wires. Re−install pressure switch on the other side of orifice plate and re−connect pressure switch hose.

 Re−secure pressure switch wires by either pulling excess wires

through the blower compartment and securing with supplied wire tie or coil excess wire and secure to the gas manifold.

pressure switch

vent pipe

flue

transition

cover plate

make−up box

collector box

FLOW

AIR

FIGURE 19

make−up box

collector box

flue transition

pressure switch

HORIZONTAL LEFT POSITION

Side Vent Discharge

 Disconnect pressure switch hose from barbed fitting on the

pressure switch assembly. Remove pressure switch assembly (1 screw) and cut wire tie to free pressure switch wires. Re− install pressure switch on the other side of orifice plate and re− connect pressure switch hose.

 Re−secure pressure switch wires by either pulling excess wires

through the blower compartment and securing with supplied wire tie, or coil excess wire and secure to the gas manifold.

FLOW

AIR

HORIZONTAL RIGHT POSITION

Top Vent Discharge

FIGURE 20

 Gas supply piping must be brought into the unit from the bottom

in order to accommodate the flue pipe.

 Remove make−up box assembly (2 screws) and cut wire tie to

free make−up box wires. Re−install make−up box on other side of cabinet.

 Re−secure make−up box wires by either pulling excess wires

through the blower compartment and securing with supplied wire tie, or coil excess wire and secure to the gas manifold.

FLOW

AIR

flue transition

vent pipe

pressure switch

cover plate

make−up box

collector box

HORIZONTAL RIGHT POSITION

Side Vent Discharge

FIGURE 21

FLOW

AIR

pressure switch

flue transition

collector box

make up box

Page 15

The SL280UHV series units are classified as fan−assisted Category I furnaces when vertically vented according to the latest edition of National Fuel Gas Code (NFPA 54 / ANSI Z223.1) in the USA. 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. The SL280UHV is not approved for use with horizontal venting..

NOTE − Use these instructions as a guide. They do not supersede local codes. This furnace must be vented according 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. See figure 22. 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.

FLUE TRANSITION

COLLAR

VENT CONNECTION

VENT PIPE

(min. 6" length)

“DISCONNECTED VENT”

WARNING

STICKER

FIGURE 22

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 figures 19, 21 and 22.

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

22.

Venting Using a Masonry Chimney

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

Masonry chimneys used to vent Category I central furnaces must be either tile-lined or lined with a listed metal lining system or dedicated gas vent. Unlined masonry chimneys are prohibited. See figures 23 and 24 for common venting.

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 encapsulated fiberglass sleeve recommended by the flexible vent pipe manufacturer. See figure 23.

FIGURE 23

Common Venting Using Metal−Lined Masonry Chimney

4 in. (102 mm)

minimum

MIN. LENGTH −− AS

SHORT AS PRACTICAL

MAX. LENGTH

−− SEE NOTE 1 BELOW.

SEALED

PERMANENTLY

SEALED FIREPLACE

OPENING

EXTERIOR

CHIMNEY WITH

METAL

LINER

VENT CONNECTOR

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

OTHER

APPLIANCE

FURNACE

5 ft. (1.5 m)

minimum

AIR FLOW

Page 16

FIGURE 24

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

MINIMUM LENGTH = AS SHORT AS PRACTICAL. FOR MAXIMUM LENGTH SEE NOTE TO LEFT

INTERIOR TILE−LINED MASONRY CHIMNEY

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

PERMANENTLY SEALED FIREPLACE OPENING

VENT

CONNECTOR

NOTE− Refer to provided venting tables for installations.

FURNACE

OTHER

APPLIANCE

AIR FLOW

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 drafthood

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 SL280UHV 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 considered to be exposed to the outdoors.

General Venting Requirements

Vent all SL280UHV furnaces according to these instructions:

1 − Vent diameter recommendations and maximum allow-

able 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 tile-lined

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

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

Page 17

6 − The entire length of single wall metal vent connector

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

7 − Single appliance venting configurations with zero lat-

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

8 − The common venting tables (5, 6, 7, and 8) were gen-

erated 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 2

Connector Diameter

inches (mm)

Maximum Horizontal

Connector Length feet (m)

3 (76) 4−1/2 (1.37)

4 (102) 6 (1.83)

5 (127) 7−1/2 (2.29)

6 (152) 9 (2.74)

7 (178) 10−1/2 (3.20)

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 ap-

pliances must be located in or pass through a crawlspace, attic 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 ceil-

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

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 regu-

lator or flue restrictor between the furnace and the chimney.

21 − When connecting this appliance to an existing dedi-

cated 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 18

TABLE 3

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

Serving a Single Category I Appliance

Height

(feet)

Lateral

(feet)

Vent and Connector Diameter − D (inches)

3 Inch 4 Inch 5 Inch 6 Inch

Appliance Input Rating in Thousands of Btu Per Hour

MIN MAX MIN MAX MIN MAX MIN MAX

0 0 78 0 152 0 251 0 375

2 13 51 18 97 27 157 32 232

4 21 49 30 94 39 153 50 227

6 25 46 36 91 47 149 59 223

0 0 84 0 165 0 276 0 415

2 12 57 16 109 25 178 28 263

5 23 53 32 103 42 171 53 255

8 28 49 39 98 51 164 64 247

0 0 88 0 175 0 295 0 447

2 12 61 17 118 23 194 26 289

5 23 57 32 113 41 187 52 280

10 30 51 41 104 54 176 67 267

0 0 94 0 191 0 327 0 502

2 11 69 15 136 20 226 22 339

5 22 65 30 130 39 219 49 330

10 29 59 40 121 51 206 64 315

15 35 53 48 112 61 195 76 301

0 0 97 0 202 0 349 0 540

2 10 75 14 149 18 250 20 377

5 21 71 29 143 38 242 47 367

10 28 64 38 133 50 229 62 351

15 34 58 46 124 59 217 73 337

20 48 52 55 116 69 206 84 322

0 0 100 0 213 0 374 0 587

2 9 81 13 166 14 283 18 432

5 21 77 28 160 36 275 45 421

10 27 70 37 150 48 262 59 405

15 33 64 44 141 57 249 70 389

20 56 58 53 132 66 237 80 374

30 NR NR 73 113 88 214 104 346

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).

Page 19

TABLE 4

Capacity of Type B Double−Wall Vents with Single−Wall Metal Connectors

Serving a Single Category I Appliance

Height

(feet)

Lateral

(feet)

Vent and Connector Diameter − D (inches)

3 Inch 4 Inch 5 Inch 6 Inch

Appliance Input Rating in Thousands of Btu Per Hour

MIN MAX MIN MAX MIN MAX MIN MAX

0 38 77 59 151 85 249 126 373

2 39 51 60 96 85 156 123 231

4 NR NR 74 92 102 152 146 225

6 NR NR 83 89 11 4 147 163 220

0 37 83 58 164 83 273 123 412

2 39 56 59 108 83 176 121 261

5 NR NR 77 102 107 168 151 252

8 NR NR 90 95 122 161 175 243

0 37 87 57 174 82 293 120 444

2 39 61 59 117 82 193 119 287

5 52 56 76 111 105 185 148 277

10 NR NR 97 100 132 171 188 261

0 36 93 56 190 80 325 116 499

2 38 69 57 136 80 225 115 337

5 51 63 75 128 102 216 144 326

10 NR NR 95 11 6 128 201 182 308

15 NR NR NR NR 158 186 220 290

0 35 96 54 200 78 346 114 537

2 37 74 56 148 78 248 113 375

5 50 68 73 140 100 239 141 363

10 NR NR 93 129 125 223 177 344

15 NR NR NR NR 155 208 216 325

20 NR NR NR NR 186 192 254 306

0 34 99 53 211 76 372 11 0 584

2 37 80 55 164 76 281 109 429

5 49 74 72 157 98 271 136 417

10 NR NR 91 144 122 255 171 397

15 NR NR 115 131 151 239 208 377

20 NR NR NR NR 181 223 246 357

30 NR NR NR NR NR NR NR NR

Page 20

TABLE 5

Vent Connector Capacity

Type B Double−Wall Vents with Type B Double−Wall Connectors

Serving Two or More Category I Appliances

Vent

Height

(feet)

Connector

Rise

(feet)

Vent and Connector Diameter − D (inches)

3 Inch 4 Inch 5 Inch 6 Inch

Appliance Input Rating in Thousands of Btu Per Hour

MIN MAX MIN MAX MIN MAX MIN MAX

1 22 37 35 66 46 106 58 164

2 23 41 37 75 48 121 60 183

3 24 44 38 81 49 132 62 199

1 22 40 35 72 49 114 64 176

2 23 44 36 80 51 128 66 195

3 24 47 37 87 53 139 67 210

1 22 43 34 78 49 123 65 189

2 23 47 36 86 51 136 67 206

3 24 50 37 92 52 146 69 220

1 21 50 33 89 47 142 64 220

2 22 53 35 96 49 153 66 235

3 24 55 36 102 51 163 68 248

1 21 54 33 99 46 157 62 246

2 22 57 34 105 48 167 64 259

3 23 60 35 110 50 176 66 271

1 20 62 31 113 45 181 60 288

2 21 64 33 118 47 190 62 299

3 22 66 34 123 48 198 64 309

TABLE 6

Common Vent Capacity

Type B Double−Wall Vents with Type B Double−Wall Connectors

Serving Two or More Category I Appliances

Vent

Height

(feet)

Common Vent Diameter − D (inches)

4 Inch 5 Inch 6 Inch 7 Inch

Appliance Input Rating in Thousands of Btu Per Hour

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

6 92 81 140 116 204 161 309 248

8 101 90 155 129 224 178 339 275

10 110 97 169 141 243 194 367 299

15 125 112 195 164 283 228 427 352

20 136 123 215 183 314 255 475 394

30 152 138 244 210 361 297 547 459

Page 21

TABLE 7

Vent Connector Capacity

Type B Double−Wall Vents with Single−Wall Metal Connectors

Serving Two or More Category I Appliances

Height

(feet)

Lateral

(feet)

Vent and Connector Diameter − D (inches)

3 Inch 4 Inch 5 Inch 6 Inch

Appliance Input Rating in Thousands of Btu Per Hour

MIN MAX MIN MAX MIN MAX MIN MAX

1 NR NR NR NR NR NR NR NR

2 NR NR NR NR NR NR 168 182

3 NR NR NR NR 121 131 175 198

1 NR NR NR NR NR NA NR NR

2 NR NR NR NR 125 126 184 193

3 NR NR NR NR 130 138 191 208

1 NR NR NR NR 119 121 182 186

2 NR NR 84 85 124 134 189 203

3 NR NR 89 91 129 144 197 217

1 NR NR 79 87 11 6 138 177 214

2 NR NR 83 94 121 150 185 230

3 NR NR 87 100 127 160 193 243

1 49 56 78 97 115 152 175 238

2 52 59 82 103 120 163 182 252

3 55 62 87 107 125 172 190 264

1 47 60 77 110 112 175 169 278

2 51 62 81 115 117 185 177 290

3 54 64 85 119 122 193 185 300

TABLE 8

Common Vent Capacity

Type B Double−Wall Vents with Single−Wall Metal Connectors

Serving Two or More Category I Appliances

Vent

Height

(feet)

Common Vent Diameter − D (inches)

4 Inch 5 Inch 6 Inch 7 Inch

Appliance Input Rating in Thousands of Btu Per Hour

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

6 NA 78 NA 113 200 158 304 244

8 NA 87 NA 126 218 173 331 269

10 NA 94 163 137 237 189 357 292

15 121 108 189 159 275 221 416 343

20 131 118 208 177 305 247 463 383

30 145 132 236 202 350 286 533 446

Page 22

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, 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 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 23

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.

Gas Supply

1 − This unit is shipped standard for left or right side instal-

lation of gas piping (or top entry in horizontal applications). Connect the gas supply to the piping assembly.

2 − When connecting the gas supply piping, consider fac-

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

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

clothes chutes, gas vents or chimneys, 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 in 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 figures 35 and 36.

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.

IMPORTANT

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

TABLE 9

Gas Pipe Capacity − ft

/hr (m3/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)

175

(4.96)

120

(3.40)

(2.75)

(2.32)

(2.07)

(1.87)

(1.73)

(1.61)

(1.50)

(1.42)

3/4

(19.05)

.824

(20.930)

360

(10.19)

250

(7.08)

200

(5.66)

170

(4.81)

151

(4.28)

138

(3.91)

125

(3.54)

118

(3.34)

110

(3.11)

103

(2.92)

(25.4)

1.049

(26.645)

680

(919.25)

465

(13.17)

375

(10.62)

320

(9.06)

285

(8.07)

260

(7.36)

240

(6.80)

220

(6.23)

205

(5.80)

195

(5.52)

1−1/4

(31.75)

1.380

(35.052)

1400

(39.64)

950

(26.90)

770

(21.80)

660

(18.69)

580

(16.42)

530

(15.01)

490

(13.87)

460

(13.03)

430

(12.18)

400

(11.33)

1−1/2

(38.1)

1.610

(40.894)

2100

(59.46)

460

(41.34)

1180

(33.41)

990

(28.03)

900

(25.48)

810

(22.94)

750

(21.24)

690

(19.54)

650

(18.41)

620

(17.56)

(50.8)

2.067

(52.502)

3950

(111.85)

2750

(77.87)

2200

(62.30)

1900

(53.80)

1680

(47.57)

1520

(43.04)

1400

(39.64)

1300

(36.81)

1220

(34.55)

1150

(32.56)

2−1/2

(63.5)

2.469

(67.713)

6300

(178.39)

4350

(123.17)

3520

(99.67)

3000

(84.95

2650

(75.04)

2400

(67.96)

2250

(63.71)

2050

(58.05)

1950

(55.22)

1850

(52.38)

(76.2)

3.068

(77.927)

11000

(311.48)

7700

(218.03)

6250

(176.98)

5300

(150.07)

4750

(134.50)

4300

(121.76)

3900

(110.43)

3700

(104.77)

3450

(97.69)

3250

(92.03)

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

Page 24

GROUND

JOINT

UNION

AUTOMATIC

GAS VALVE

FIELD

PROVIDED

AND INSTALLED

GROUND

JOINT

UNION

Left Side Piping

(Standard)

Right Side Piping

(Alternate)

AUTOMATIC

GAS VALVE

DRIP LEG

MANUAL

MAIN SHUT−OFF

VALV E

(With 1/8 in. NPT

Plugged Tap Shown)

MANUAL

MAIN SHUT−OFF

VALV E

(With 1/8 in. NPT

Plugged Tap

Shown)

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

FIGURE 25

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 Applications

Possible Gas Piping Configurations

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

FIGURE 26

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.

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 by closing its individual manual shut-off valve and disconnecting from from the gas

supply system the 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.).

IMPORTANT

When testing pressure of gas lines, gas valve must be disconnected and isolated. See figure 27. 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

CAP

ISOLATE

GAS VALVE

FURNACE

FIGURE 27

1/8 NPT PLUG

Page 25

Electrical

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

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

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

INTERIOR MAKE−UP BOX INSTALLATION

FIGURE 28

BOX

Left side

INTERIOR MAKE−UP BOX INSTALLATION

FIGURE 29

BOX

Right Side

Refer to figure 33 for unit field wiring. See figures 30 and 31 for icomfort Touch

thermostat wiring in communicating applications. Table 11 shows DIP switch and on−board link settings for non−communicating thermostat applications. Typical wiring schematic is shown in figure 32.

1 − The power supply wiring must meet Class I restric-

tions. 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 shown in table

10.

TABLE 10

SL280UH Model

Maximum Over−Current

Protection (Amps)

070V36A, 09036B 15

090V48B, 090V60C, 110V60C,

135V60D

2 − Holes are on both sides of the furnace cabinet to facili-

tate wiring.

3 − Install a separate (properly sized) disconnect switch

near the furnace so that power can be turned off for servicing.

4 − Before connecting the thermostat or the power wiring,

check to make sure the wires will be long enough for servicing at a later date. Remove the blower access panel to check the length of the wire.

5 − Complete the wiring connections to the equipment.

Use the provided unit wiring diagram and the field wiring diagrams shown in table 11 and figure 33. Use 18−gauge wire or larger that is suitable for Class II rating for thermostat connections.

6 − 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 SL280UHV furnace contains electronic components that are polarity sensitive. Make sure that the furnace is wired correctly and is properly grounded.

7 − One line voltage ACC" 1/4" spade terminal is provided

on the furnace integrated control. Any electronic air cleaner or other accessory rated up to one amp can be connected to this terminal with the neutral leg of the circuit being connected to the one of the provided neutral terminals. See figure 34 for control configuration. This terminal is energized when the indoor blower is operating.

Page 26

8 − An unpowered, normally open (dry) set of contacts with

a 1/4" spade terminal HUM" are provided for humidifier connections and may be connected to 24V or 120V. Any humidifier rated up to one amp can be connected to these terminals. In 120V humidifier applications the neutral leg of the circuit can be connected to one of the provided neutral terminals. This terminal is energized in the heating mode.

9 − Install the room thermostat according to the instruc-

tions provided with the thermostat. See table 11 for field wiring connections in varying applications. If the furnace is being matched with a heat pump, refer to the instruction packaged with the dual fuel thermostat.

Thermostat Selection

CAUTION

Field wiring for both communicating and non−communicating applications is illustrated in diagrams, which begin on Page 27.

Non−Communicating

In non−communicating applications the SL280UHV is designed to operate in a SINGLE−STAGE mode or TWO− STAGE mode using a conventional thermostat.

For optimal performance in non−communicating applications, Lennox recommends use of a ComfortSense

7000 high quality electronic digital thermostat or any other with adjustable settings for 1st stage / 2nd stage on / off differentials and adjustable stage timers.

Lennox recommends the following two−stage thermostat settings: First heat stage differential set to 1/2 to 1 degree F; second heat stage differential set to 1/2 or 1 degree F; second heat stage upstage timer disabled, or set to maximum (1 hr minimum).

Communicating

In communicating applications the icomfort Touch® thermostat must be used. Refer to the instructions provided with the thermostat for installation, set−up and operation. In communicating system all unused thermostat wire in the wire bundle needs to be terminated inside and out. The extra wires can terminate on the ’C" terminal of the icomfort communication terminal strip. (RSBus). Using an additional wire come off "C" terminal and wire nut all the extra wires together. Termination on the outdoor control must match the indoor control.

Indoor Blower Speeds

Non−Communicating

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

blower will run continuously at a field selectable percentage of the second−stage cooling speed when there is no cooling or heating demand. The factory default setting is 38% of cool speed.

2 − When the SL280UHV is running in the heating mode,

the indoor blower will run on the heating speed designated by the positions of DIP switches 11, 12 and 13. First stage heating will run at 91% heat speed.

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

run on the cooling speed designated by the positions of DIP switches 5 and 6. First stage cooling will run at 70% cool speed.

Communicating

NOTE − When the SL280UHV is used with icomfort Touch

thermostat, proper indoor blower speed selec-

tions are made by the communicating thermostat.

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

blower will run at setting determined during system configuration.

2 − When there is a heating demand the fan will run on

heating speeds for firing rate.

3 − When there is a cooling demand, the fan will run on the

first stage and second stage cooling speed set using the icomfort Touch® thermostat in the installer setup mode. The factory default is based upon 400 CFM a ton.

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 (Range: 102 volts to

132 volts)

 The furnace operates at 60 Hz +

5% (Range: 57 Hz to

63 Hz)

 The furnace integrated control requires both correct

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

 Generator should have a wave form distortion of less

than 5% THD (total harmonic distortion)

Page 27

FIGURE 30

icomfort Touch

Thermostat with SL280UHV

and Non−Communicating Outdoor Unit

icomfort−

ENABLED

SL280UHV

FURNACE

icomfort Touch®

THERMOSTAT

NON−COMMUNICATING

OUTDOOR AIR

CONDITIONING UNIT −

1 OR 2 STAGE

icomfort Touch® Thermostat icomfort−Enabled SL280UHV Indoor Furnace Non−Communicating Outdoor Air Conditioner

OPTIONAL OUTDOOR

AIR SENSOR

OPTIONAL DISCHARGE AIR SENSOR

icomfort Touch® Thermostat with SL280UHV

and icomfort−ENABLED Outdoor Unit

icomfort Touch® Thermostat icomfort−Enabled SL280UHV Indoor Furnace icomfort−Enabled Outdoor Air Conditioner or Heat Pump

icomfort− ENABLED

SL280UHV

FURNACE

icomfort− ENABLED

OUTDOOR AIR CONDITIONING

OR HEAT PUMP UNIT

OPTIONAL OUTDOOR

AIR SENSOR

OPTIONAL DISCHARGE AIR SENSOR

CLIP ON−BOARD LINK W915 (Y1 TO Y2) FOR

TWO−STAGE OPERATION

icomfort Integrated Control

icomfort Touch

Outdoor Unit

NOTE − On communicating systems, extra wires must terminate on the "C" icomfort terminal strip (RSBus). Use an additional wire and come off "C" terminal and wire nut all the extra wires together. Termination on the outdoor control must match the indoor control.

icomfort Touch®

THERMOSTAT

Page 28

Optional Accessories for use with any icomfort Touch

System

FIGURE 31

NOTE: 24V UV LIGHT APPLICATIONS

In an icomfort by Lennox system, neither furnace nor air handler

transformer will have adequate VA to power 24V UV light applications. An additional transformer for UV light applications is required.

icomfort Touch

THERMOSTAT

Discharge Air

Sensor (Required

for even heat)

NOTE: icomfort Touch® THERMOSTAT SENSES HUMIDITY & CONTROLS HUM CONTACTS TO CYCLE HUMIDIFIER BASED ON DEMAND. NO OTHER CONTROL OR HUMIDISTAT REQUIRED.

OPTIONAL OUTDOOR AIR SENSOR FOR USE WITH HUMIDIFIER (IF NOT ALREADY IN THE SYSTEM FOR OTHER FUNCTIONS. BUILT INTO ALL icomfort by Lennox OUT- DOOR UNITS).

Maximum total length of all connections on the RSBus is limited to 1500ft.

Wire gauge of RSBus wire is 18.

RSBus

Rf WGhGsCf

HVAC EQUIP

DEHUMIDIFIER CONTROL

HVAC EQUIPMENT

STANDARD 1 OR 2

STAGE AC OR HP UNIT

*24V IN JUMPER

icomfort ENABLED SL280UHV FURNACE

icomfort Touch

THERMOSTAT

CONVENTIONAL NON−COMMUNICATING SYSTEM

COMMUNICATING SYSTEM

CS 7000 THERMOSTAT

*24V IN jumper not used in non− communicating configuration

24V HUMIDIFIER CONNECTIONS

120V CONNECTIONS

HEPA BYPASS FILTER X2680 HEPA INTERLOCK KIT

PASS INDOOR BLOWER MOTOR COMMON WIRE THROUGH CURRENT LOOP.

SEE HEPA INTERLOCK KIT FOR INSTALLATION DETAILS

icomfort ENABLED

SL280UHV FURNACE

LVCS VENTILATION CONTROL SYSTEM

SEE LVCS VENTILATION INSTRUCTIONS FOR DAMPER & SENSOR WIRING

icomfort ENABLED

SL280UHV FURNACE

icomfort 

ENABLED OUTDOOR

AIR CONDITIONING OR

HEAT PUMP UNIT

(POWER COMPANY INTERRUPTION SYSTEMS ARE WIRED SAME AS OVERFLOW SWITCH)

icomfort ENABLED

SL280UHV FURNACE

CUT R−DS W914

2 STAGE FURNACE

COMMUNICATING SYSTEM WIRING

NON−COMMUNICATING SYSTEM WIRING

HUM" CONTACT IS CLOSED ANYTIME HUMIDITY DEMAND IS PRESENT

Page 29

TABLE 11

SL280 Field Wiring Applications With Conventional Thermostat

Thermostat

DIP Switch Settings and On−Board Links (See figure 34)

Wiring Connections

DIP Switch 1

Thermostat

Heating

Stages

On Board Links Must Be Cut To Select

System Options

1 Heat / 1 Cool

NOTE − Use DIP switch 2 to set second−stage heat ON delay. OFF−7 minutes. ON−12 minutes.

DO NOT CUT ANY ON−BOARD LINKS

T’STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

1 Heat / 2 Cool

NOTE − Use DIP switch 2 to set second−stage heat ON delay. OFF−7 minutes. ON−12 minutes.

CUT ON−BOARD LINK

W915

2 STAGE

COMPR

T’STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

1 Heat / 2 Cool with t’stat with humidity control

NOTE − Use DIP switch 2 to set second−stage heat ON delay. OFF−7 minutes. ON−12 minutes.

CUT ON−BOARD LINK

W915

2 STAGE

COMPR

CUT ON−BOARD LINK

W914

DEHUM

HARMONY

T’STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

* Not required on all units.

Page 30

TABLE 11

SL280 Field Wiring Applications With Conventional Thermostat (Continued)

Thermostat

DIP Switch Settings and On−Board Links (See figure 34)

Wiring Connections

DIP Switch 1

Thermostat

Heating

Stages

On Board Links Must Be Cut To Select

System Options

2 Heat / 2 Cool OFF

CUT ON−BOARD LINK

W915

2 STAGE

COMPR

T’STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

2 Heat / 2 Cool with t’stat with humidity control

OFF

CUT ON−BOARD LINK

W915

2 STAGE

COMPR

CUT ON−BOARD LINK

W914

DEHUM

HARMONY

T’STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

2 Heat / 1 Cool with t’stat with humidity control

OFF

CUT ON−BOARD LINK

W914

DEHUM

HARMONY

T’STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

2 Heat / 1 Cool OFF

DO NOT CUT ANY ON−BOARD LINKS

T’STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

* Not required on all units.

Page 31

TABLE 11

SL280 Field Wiring Applications With Conventional Thermostat (Continued)

Thermostat

DIP Switch Settings and On−Board Links (figure 34)

Wiring Connections

DIP Switch 1

Thermostat

Heating

Stages

On Board Links Must Be Cut To Select

System Options

Dual Fuel Single Stage Heat Pump

ComfortSense 7000 L7724U thermostat w/ dual fuel capabilities Capable of 2 stage gas heat control

OFF

CUT ON−BOARD LINK

W951 HEAT

PUMP

L7724U T’STAT

FURNACE

TERM. STRIP

HEAT PUMP

67M41*

outdoor

sensor

Dual Fuel Two Stage Heat Pump

ComfortSense 7000 L7724U thermostat w/ dual fuel capabilities Capable of 2 stage gas heat control

OFF

CUT ON−BOARD LINK

W951 HEAT

PUMP

CUT ON−BOARD LINK

W915

2 STAGE

COMPR

FURNACE

TERM. STRIP

HEAT PUMP

out blue

67M41*

outdoor sensor

L7724U T’STAT

* Connect W1 to W1 ONLY if using defrost tempering kit 67M41

NOTE − Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the SL280 integrated control.

Page 32

TABLE 11

SL280 Field Wiring Applications With Conventional Thermostat (Continued)

Thermostat

DIP Switch Settings and On−Board Links (figure 34)

Wiring Connections

DIP Switch 1

Thermostat

Heating

Stages

On Board Links Must Be Cut To Select

System Options

Dual Fuel Single Stage Heat Pump

ComfortSense 7000 L7724U thermostat w/ dual fuel capabilities Capable of 2 stage gas heat control w/dehumidification control

OFF

CUT ON−BOARD LINK

W951 HEAT

PUMP

CUT ON−BOARD LINK

W914

DEHUM

HARMONY

L7724U T’STAT

FURNACE

TERM. STRIP

HEAT PUMP

67M41*

outdoor

sensor

Dual Fuel Two Stage Heat Pump

ComfortSense 7000 L7724U thermostat w/ dual fuel capabilities Capable of 2 stage gas heat control w/dehumidification

OFF

CUT ON−BOARD LINK

W914

DEHUM

HARMONY

CUT ON−BOARD LINK

W951 HEAT

PUMP

CUT ON−BOARD LINK

W915

2 STAGE

COMPR

L7724U T’STAT

FURNACE

TERM. STRIP

HEAT PUMP

67M41*

outdoor

sensor

out blue

* Connect W1 to W1 ONLY if using defrost tempering kit 67M41

NOTE − Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the SL280 integrated control.

Page 33

SL280UHV Schematic Wiring Diagram

FIGURE 32

Page 34

TYPICAL SL280UHV FIELD WIRING DIAGRAM

FIGURE 33

FIELD INSTALLED CLASS II 24V

FIELD INSTALLED LINE VOLTAGE

Page 35

Integrated Control

FIGURE 34

THERMOSTAT CONNECTIONS (TB1)

1/4" QUICK CONNECT TERMINALS

RS−BUS LINK (TB82, future use)

I+ = DATA HIGH CONNECTION I − = DATA LOW CONNECTION

RS−BUS OUTDOOR (TB83)

R = 24VAC I + = DATA HIGH CONNECTION I − = DATA LOW CONNECTION C = 24VAXC COMMON

RS−BUS INDOOR (TB84)

R = 24VAC I + = DATA HIGH CONNECTION I − = DATA LOW CONNECTION C = 24VAXC COMMON

FLAME SENSE

DIP SWITCHES

OUTDOOR AIR

SENSOR

TERMINALS

DISCHARGE AIR

SENSOR

TERMINALS

INDOOR

BLOWER

CONNECTOR

NEUTRAL

DIAGNOSTIC

PUSH BUTTON

TB83

COMMUNICATING

OUTDOOR

EQUIPMENT

TB84

COMMUNICATING

INDOOR

THERMOSTAT

DS = DEHUMIDIFICATION SIGNAL W2 = HEAT DEMAND FROM 2ND STAGE T/STAT

W1 = HEAT DEMAND FROM 1ST STAGE T/STAT R = CLASS 2 VOLTAGE TO THERMOSTAT

G = MANUAL FAN FROM T’STAT

C = THERMOSTAT SIGNAL GROUND CONNECTED TO TRANSFORMER GRD (TR) & CHASIS GROUND (GRD)

Y1 = THERMOSTAT 1ST STAGE COOL SIGNAL

Y2 = THERMOSTAT 2ND STAGE COOL SIGNAL

O = THERMOSTAT SIGNAL TO HEAT PUMP

REVERSING VALVE

L = USE ONLY WITH A COMMUNICATING THERMOSTAT

AND A NON−COMMUNICATING OUTDOOR UNIT

DH = DEHUMIDIFICATION OUTPUT COMMUNICATING

THERMOSTAT ONLY

HUM = UNPOWERED NORMALLY OPEN (DRY) CONTACTS

XMFR = 120 VAC OUTPUT TO TRANSFORMER

LI = 120 VAC INPUT TO CONTROL

ACC = 120 VAC OUTPUT TO OPTIONAL ACCESSORY

NEUTRALS = 120 VAC NEUTRAL

W915 Y1 TO Y2

2 STAGE COMPR

W951 R TO O HEAT PUMP

W914 R TO DS

DEHUM OR

HARMONY

W1 W2 GY2Y1

RDHLODS

I + I −CRI + I −

7 SEGMENT LED

ACC

LINE 1

HUM

12 PIN LOW

VOLTAGE

CONNECTOR

NON−COMMUNICATINGNG

24V TERMINALS

HS/ CAI

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

Page 36

Integrated Control DIP Switch Settings − Conventional Thermostat (non−communicating)

SL280UHV units are equipped with a two−stage, variable speed integrated control. This control manages ignition timing, heating mode fan off delays and indoor blower speeds based on selections made using the control dip switches and jumpers. The control includes an internal watchguard feature which automatically resets the ignition control when it has been locked out. After one hour of continuous thermostat demand for heat, the watchguard will break and remake thermostat demand to the furnace and automatically reset the control to relight the furnace.

Note: All icomfort settings are set at the icomfort Touch

thermostat. See icomfort installation instruction. In icomfort communication system all DIP switch and clippable link settings are ignored. For conventional thermostats proceed with DIP switch and clippable link settings as outlined in the following.

Heating Operation DIP Switch Settings Switch 1 −− Thermostat Selection −− This unit may be used

with either a single−stage or two−stage thermostat. The thermostat selection is made using a DIP switch which must be properly positioned for the particular application. The DIP switch is factory−positioned for use with a two− stage thermostat. If a single−stage thermostat is to be used, the DIP switch must be repositioned.

Select OFF" for two−stage heating operation con-

trolled by a two−stage heating thermostat (factory setting);

b − Select ON" for two−stage heating operation con-

trolled by a single−stage heating thermostat. This setting provides a timed delay before second−stage heat is initiated.

Switch 2 −− Second Stage Delay (Used with Single− Stage Thermostat Only) −− This switch is used to deter-

mine the second stage on delay when a single−stage thermostat is being used. The switch is factory−set in the OFF position, which provides a 7−minute delay before second− stage heat is initiated. If the switch is toggled to the ON position, it will provide a 12−minute delay before second− stage heat is initiated. This switch is only activated when the thermostat selector jumper is positioned for SINGLE− stage thermostat use.

Switches 3 and 4 −− Blower−Off Delay −− The blower−on delay of 30 seconds is not adjustable. The blower−off delay (time that the blower operates after the heating demand has been satisfied) can be adjusted by moving switches 3 and 4 on the integrated control. The unit is shipped from the factory with a blower−off delay of 90 seconds. The blower off delay affects comfort and is adjustable to satisfy individual applications. Adjust the blower off delay to achieve a supply air temperature between 90° and 110°F at the exact moment that the blower is de−energized. Longer off delay

settings provide lower supply air temperatures; shorter settings provide higher supply air temperatures.Table 12 provides the blower off timings that will result from different switch settings.

TABLE 12

Blower Off Delay Switch Settings

Blower Off Delay

(Seconds)

Switch 3 Switch 4

60 On Off

90 (Factory) Off Off

120 Off On 180 On On

Indoor Blower Operation DIP Switch Settings Switches 5 and 6 −− Cooling Mode Blower Speed −− The

unit is shipped from the factory with the dip switches positioned for high speed (4) indoor blower motor operation during the cooling mode. Table 13 provides the cooling mode blower speeds that will result from different switch settings. Switches 5 and 6 set the blower cfm for second− stage cool. The integrated control automatically ramps down to 70% of the second−stage cfm for first−stage cfm. Refer to tables for corresponding cfm values.

TABLE 13

Cooling Mode Blower Speeds

Speed

Switch 5 Switch 6

Low On On

Medium Low Off On

Medium High On Off

High (Factory) Off Off

Switches 7 and 8 −− Cooling Blower Speed Adjustment

−− The unit is shipped from the factory with the dip switches

positioned for NORMAL (no) adjustment. The dip switches may be positioned to adjust the blower speed by +10% or

−10% to better suit the application. Table 14 below provides blower speed adjustments that will result from different switch settings. Refer to tables for corresponding cfm values.

TABLE 14

Cooling Blower Speed Adjustment

Adjustment

Switch 7 Switch 8

+10% (approx.) On Off Factory Default Off Off

−10% (approx.) Off On

Switches 9 and 10 −− Cooling Mode Blower Speed Ramping −− Blower speed ramping may be used to en-

hance dehumidification performance. The switches are factory set at option A which has the greatest effect on de− humidification performance. Table 15 provides the cooling mode blower speed ramping options that will result from different switch settings. The cooling mode blower speed ramping options are detailed on the next page.

NOTE − The off portion of the selected ramp profile also applies during heat pump operation in dual fuel applications.

Page 37

TABLE 15

Cooling Mode Blower Speed Ramping

Ramping Option

Switch 9 Switch 10

A (Factory) Off Off

B Off On C On Off D On On

Ramping Option A (Factory Selection)

 Motor runs at 50% for 30 seconds.  Motor then runs at 82% for approximately 7−1/2 minu-

tes.

 If demand has not been satisfied after 7−1/2 minutes,

motor runs at 100% until demand is satisfied.

 Once demand is met, motor runs at 50% for 30 sec-

onds then ramps down to stop.

OFF

1/2 MIN 50% CFM

COMPRESSOR DEMAND

7 1/2 MIN 82% CFM

100% CFM

1/2 MIN 50% CFM

Ramping Option B

 Motor runs at 82% for approximately 7−1/2 minutes. If

demand has not been satisfied after 7−1/2 minutes, motor runs at 100% until demand is satisfied.

 Once demand is met, motor ramps down to stop.

OFF

82%CFM

100% CFM

COMPRESSOR DEMAND

7 1/2 MIN

Ramping Option C

 Motor runs at 100% until demand is satisfied.

 Once demand is met, motor runs at 100% for 45 sec-

onds then ramps down to stop.

OFF

100% CFM

45 SEC.

COMPRESSOR

DEMAND

Ramping Option D

 Motor runs at 100% until demand is satisfied.

 Once demand is met, motor ramps down to stop.

OFFOFF

100% CFM

COMPRESSOR

DEMAND

Switches 11, 12 and 13 −− Heating Mode Blower Speed −−

The switches are factory set to the OFF position which provides factory default heat speed. Refer to table 16 for switches 11, 12 and 13 that provided the corresponding increases or decrease to both high and low heat demand.

TABLE 16

Heating Mode Blower Speeds

Heat Speed

Switch

Switch12Switch

Increase 24% On On On

Increase 18% On On Off

Increase 12% On Off On

Increase 6% On Off Off

Factory Default Off Off Off

Decrease 6% Off Off On

Decrease 12% Off On Off

Decrease18% Off On On

Switches 14 and 15 −− Continuous Blower Speed −−

Table 17 provides continuous blower speed adjustments that will result from different switch settings.

TABLE 17

Continuous Blower Speed

Continuous

Blower Speed

Switch 14 Switch 15

28% of High Cool Speed Off On

38% of High Cool Speed

(Factory)

Off Off

70% of High Cool Speed On Off

100% of High Cool Speed On On

Page 38

On−Board Links

Note: In icomfort systems with a conventional outdoor unit (non−communicating), the on−board clippable links must be set to properly configure the system.

WARNING

Carefully review all configuration information provided. Failure to properly set DIP switches, jumpers and on−board links can result in improper operation!

On−Board Link W914 Dehum or Harmony (R to DS)

On−board link W914, is a clippable connection between terminals R and DS on the integrated control. W914 must be cut when the furnace is installed with either the Harmony III zone control or a thermostat which features humidity control. If the link is left intact the PMW signal from the Harmony III control will be blocked and also lead to control damage. Refer to table 18 for operation sequence in applications including SL280UHV, a thermostat which features humidity control and a single−speed outdoor unit. Table 19 gives the operation sequence in applications with a two−speed outdoor unit.

On−Board Link W951 Heat Pump (R to O)

On−board link W951 is a clippable connection between terminals R and O on the integrated control. W951 must be cut when the furnace is installed in applications which include a heat pump unit and a thermostat which features dual fuel use. If the link is left intact, terminal O" will remain energized eliminating the HEAT MODE in the heat pump.

On−Board Link W915 2 Stage Compr (Y1 to Y2)

On−board link W915 is a clippable connection between terminals Y1 and Y2 on the integrated control. W915 must be cut if two−stage cooling will be used. If the Y1 to Y2 link is not cut the outdoor unit will operate in second−stage cooling only.

Diagnostic LED (Figure 34)

The seven−segment diagnostic LED displays operating status, target airflow, error codes and other information. The table beginning on Page 60 lists diagnostic LED codes.

Diagnostic Push Button (Figure 34)

The diagnostic push button is located adjacent to the seven−segment diagnostic LED. This button is used to enable the Error Code Recall E" mode and the Flame Signal F" mode. Press the button and hold it to cycle through a menu of options. Every five seconds a new menu item will be displayed. When the button is released, the displayed item will be selected. Once all items in the menu have been displayed, the menu resumes from the beginning until the button is released.

Error Code Recall Mode

Select "E" from the menu to access the most recent 10 error codes. Select c" from the Error Code Recall menu to clear all error codes. Button must be pressed a second time while c" is flashing to confirm command to delete codes. Press the button until a solid ≡" is displayed to exit the Error Code Recall mode.

Flame Signal Mode

Select "F" from the menu to access the flame signal mode. The integrated control will display the flame current on 7 segment LED in in micro amps (uA).

Flame signal mode is exited after the following:

 Power is reset  Pressing and holding push button until 3 horizontal

lines ≡" are displayed

 10 minutes of entering the flame sense mode.

BLOWER DATA

SL280UH070V36A BLOWER PERFORMANCE (less lter)

BOTTOM RETURN AIR

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1045 1145

+18% 985 1080

+12% 940 1035

+6% 880 960

Factory Default 850 925

–6% 785 875

–12% 745 815

–18% 680 745

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 781 819 872 981 1045 1139 1219 1372

Factory Default 695 734 797 883 943 1005 111 4 1260

– 645 674 720 815 847 922 991 1144

SINGLE SIDE RETURN AIR

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

Heating Speed

DIP Switch

Settings

+24% 1050 1165

+18% 1000 1110

+12% 940 1040

+6% 895 975

Factory Default 820 935

–6% 775 855

–12% 735 805

–18% 685 750

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 764 802 886 977 1035 1122 1248 1360

Factory Default 704 725 793 899 949 1029 1135 1257

– 642 680 717 812 874 933 1021 1133

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position. Continuous Fan Only speed is selectable at 28%, 38%, 70% and 100% of the selected second stage cooling speed - minimum 500 cfm. Lennox Harmony III™ Zone Control Applications - Minimum blower speed is 425 cfm.

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

HEATING

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

Page 39

BLOWER DATA

SL280UH090V36B BLOWER PERFORMANCE (less lter)

BOTTOM RETURN AIR

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1300 1420

+18% 1250 1335

+12% 1185 1285

+6% 1145 1240

Factory Default 1070 1170

–6% 1015 1100

–12% 970 1035

–18% 880 980

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 616 755 846 980 1018 1197 1291 1399

Factory Default 571 698 767 886 909 1083 1197 1284

– 489 627 681 812 834 968 1081 1179

SINGLE SIDE RETURN AIR

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

Heating Speed

DIP Switch

Settings

+24% 1305 1425

+18% 1250 1350

+12% 1195 1290

+6% 1135 1230

Factory Default 1070 1165

–6% 995 1100

–12% 935 1030

–18% 870 960

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 611 731 830 971 995 1160 1274 1376

Factory Default 575 674 748 870 889 1075 1160 1270

– 519 604 691 786 808 952 1056 1147

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

HEATING

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

Page 40

BLOWER DATA

SL280UH090V48B BLOWER PERFORMANCE (less lter)

BOTTOM RETURN AIR

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1280 1410

+18% 1220 1340

+12% 1155 1270

+6% 1095 1205

Factory Default 1035 1135

–6% 970 1070

–12% 910 1000

–18% 845 930

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 670 890 1040 1210 1030 1335 1550 1755

Factory Default 605 815 965 1090 940 1205 1405 1,600

– 525 690 850 985 795 1060 1260 1435

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

SINGLE SIDE RETURN AIR

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

Settings

+24% 1280 1410

+18% 1220 1340

+12% 1155 1270

+6% 1095 1205

Factory Default 1035 1135

–6% 970 1070

–12% 910 1000

–18% 845 930

COOLING

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

+ 640 900 1015 1175 1005 1295 1500 1670

Factory Default 570 780 930 1040 895 1160 1345 1500

– 530 700 810 955 795 1050 1210 1405

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

Page 41

BLOWER DATA

SL280UH090V48B BLOWER PERFORMANCE (less lter)

SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1295 1425

+18% 1235 1355

+12% 1170 1290

+6% 111 0 1220

Factory Default 1045 1150

–6% 980 1080

–12% 920 1010

–18% 855 945

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 660 905 1030 1175 985 1290 1495 1675

Factory Default 600 760 930 1045 905 1125 1345 1525

– 535 700 850 970 815 1040 1225 1385

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

Page 42

BLOWER DATA

SL280UH090V60C BLOWER PERFORMANCE (less lter)

BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1420 1565

+18% 1355 1490

+12% 1285 1415

+6% 1215 1335

Factory Default 1145 1260

–6% 1080 1185

–12% 1010 111 0

–18% 940 1035

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1110 1205 1420 1680 1575 1740 2000 2305

Factory Default 1005 1100 1280 1545 1440 1595 1820 2125

– 890 1015 1125 1380 1295 1450 1610 1930

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

SINGLE SIDE RETURN AIR

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

Settings

+24% 1360 1500

+18% 1295 1425

+12% 1230 1355

+6% 1165 1280

Factory Default 1100 1210

–6% 1030 1135

–12% 965 1065

–18% 900 990

COOLING

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

+ 1050 1165 1335 1620 1515 1680 1915 2225

Factory Default 955 1060 1215 1480 1390 1545 1735 2060

– 840 945 1090 1290 1220 1385 1580 1825

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

Page 43

BLOWER DATA

SL280UH090V60C BLOWER PERFORMANCE (less lter)

SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1360 1495

+18% 1290 1420

+12% 1225 1350

+6% 1160 1275

Factory Default 1095 1205

–6% 1030 1130

–12% 965 1060

–18% 900 990

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1050 1190 1380 1615 1515 1715 1930 2240

Factory Default 970 1090 1245 1485 1380 1560 1755 2070

– 880 985 1095 1285 1215 1400 1580 1830

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

Page 44

BLOWER DATA

SL280UH110V60C BLOWER PERFORMANCE (less lter)

BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1690 1855

+18% 1605 1765

+12% 1525 1675

+6% 1445 1585

Factory Default 1360 1495

–6% 1280 1405

–12% 1200 1315

–18% 1115 1230

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1060 1220 1330 1565 1535 1710 1910 2210

Factory Default 970 1075 1180 1430 1400 1565 1715 2015

– 875 980 1070 1255 1260 1400 1560 1815

SINGLE SIDE RETURN AIR

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

Heating Speed

DIP Switch

Settings

+24% 1640 1805

+18% 1560 1715

+12% 1480 1630

+6% 1400 1545

Factory Default 1325 1455

–6% 1245 1370

–12% 1165 1280

–18% 1085 1195

Cooling Speed

DIP Switch

Settings

+ 1020 1160 1285 1550 1505 1690 1855 2125

Factory Default 940 1050 1155 1400 1375 1525 1685 1935

– 835 945 1020 1250 1235 1380 1505 1730

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

HEATING

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

Low Medium-Low Medium-High

High Low Medium-Low Medium-High2 High

Page 45

BLOWER DATA

SL280UH110V60C BLOWER PERFORMANCE (less lter)

SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1635 1800

+18% 1555 1710

+12% 1475 1625

+6% 1395 1535

Factory Default 1320 1450

–6% 1240 1365

–12% 1160 1275

–18% 1080 1190

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1085 1160 1270 1490 1595 1660 1840 2115

Factory Default 1010 1040 1160 1375 1470 1535 1655 1940

– 900 955 1025 1205 1315 1365 1510 1735

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

Page 46

BLOWER DATA

SL280UH135V60D BLOWER PERFORMANCE (less lter)

BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1875 2065

+18% 1785 1965

+12% 1695 1865

+6% 1605 1765

Factory Default 1515 1665

–6% 1425 1565

–12% 1330 1465

–18% 1240 1365

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1025 1120 1325 1650 1500 1600 1840 2235

Factory Default 965 1015 1180 1490 1420 1510 1700 2110

– 875 930 1060 1350 1225 1320 1505 1840

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

SINGLE SIDE RETURN AIR

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

Settings

+24% 1850 2035

+18% 1760 1935

+12% 1670 1835

+6% 1580 1740

Factory Default 1490 1640

–6% 1400 1540

–12% 1310 1445

–18% 1225 1345

COOLING

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

+ 1030 1105 1305 1635 1525 1600 1840 2255

Factory Default 960 1005 1175 1480 1355 1435 1635 2035

– 845 925 1050 1340 1240 1315 1520 1850

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

Page 47

BLOWER DATA

SL280UH135V60D BLOWER PERFORMANCE (less lter)

SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE

0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1840 2025

+18% 1750 1925

+12% 1660 1830

+6% 1575 1730

Factory Default 1485 1630

–6% 1395 1535

–12% 1305 1435

–18% 1215 1340

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1035 1105 1285 1610 1530 1610 1825 2240

Factory Default 955 1005 1145 1430 1365 1450 1650 2040

– 860 935 1050 1295 1225 1310 1515 1850

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specic DIP Switch

Settings.

Factory default setting.

NOTES - The effect of static pressure is included in air volumes shown.

First stage HEAT is approximately 91% of the same second stage HEAT.

First Stage Heating Speed - cfm Second Stage Heating Speed - cfm

COOLING

First Stage Cooling Speed - cfm Second Stage Cooling Speed - cfm

High Low Medium-Low Medium-High2 High

Page 48

Page 49

TABLE 18

OPERATING SEQUENCE

SL280UHV, Non−Communicating Thermostat with Humidity Control Feature and Single−Speed Outdoor Unit

OPERATING

SEQUENCE

SYSTEM DEMAND SYSTEM RESPONSE

System

Condition

Step

Thermostat Demand Relative Humidity

Compres-

sor

Blower

CFM

(COOL)

Comments

Y1 O G

Status D

NO CALL FOR DEHUMIDIFICATION

Normal Operation 1 On On On Acceptable

VAC

High 100%

Compressor and indoor blower follow thermostat demand

BASIC MODE (only active on a Y1 thermostat demand)

Normal Operation 1 On On On Acceptable

VAC

High 100%

ComfortSense® 7000 thermostat energizes Y1 and de−energizes D on a call for de−humidification

Dehumidification

Call

2 On On On Demand

VAC

High 70%*

PRECISION MODE (operates independent of a Y1 thermostat demand)

Normal Operation 1 On On On Acceptable

VAC

High 100%

Dehumidification mode begins when humidity is greater than set point

Dehumidification

call

2 On On On Demand

VAC

High 70%*

Dehumidification

call ONLY

1 On On On Demand

VAC

High 70%*

ComfortSense

7000

thermostat

will try to

maintain room humidity setpoint by allowing the room space to maintain a cooler room thermostat setpoint**

Jumpers at indoor unit with a single stage outdoor unit With Condensing unit − Cut W914 (R to DS) on SureLight

control

With Heat Pump − Cut W914 (R to DS) & W951 (R to O) on SureLight

control

Dave Lennox ComfortSense® 7000 thermostat to use for this application − Y2081 4 heat / 2 cool *Dehumidification blower speed is 70% of COOL speed for all units . **In Precision mode, ComfortSense

7000 thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room setting.

Page 50

TABLE 19

OPERATING SEQUENCE

SL280UHV, Non−Communicating Thermostat with Humidity Control Feature and Two−Speed Outdoor Unit

OPERATING

SEQUENCE

SYSTEM DEMAND SYSTEM RESPONSE

System

Condition

Ste

Thermostat Demand Relative Humidity

Compressor

Blower

CFM

(COOL)

Comments

Y1 Y2 O G

W1W

Status D

NO CALL FOR DEHUMIDIFICATION

Normal Opera-

tion − Y1

1 On On On Acceptable

VAC

Low 70%*

Compressor and indoor blower follow thermostat demand

Normal Opera-

tion − Y2

2 On On On On Acceptable

VAC

High 100%

ROOM THERMOSTAT CALLS FOR FIRST STAGE COOLING

BASIC MODE (only active on a Y1 thermostat demand)

Normal Opera-

tion

1 On On On Acceptable

VAC

Low 70%*

ComfortSense

7000 thermostat energizes Y2 and de−energizes D on a call for de−humidification

Dehumidification

Call

2 On On On On Demand

VAC

High 70%**

PRECISION MODE (operates independent of a Y1 thermostat demand)

Normal Opera-

tion

1 On On On Acceptable

VAC

Low 70%*

Dehumidification mode begins when humidity is greater than set point

Dehumidification

call

2 On On On On Demand

VAC

High 70%**

Dehumidification

call ONLY

1 On On On On Demand

VAC

High 70%**

ComfortSense® 7000 thermostat will try to maintain room humidity setpoint by allowing the room space to maintain a cooler room thermostat setpoint***

ROOM THERMOSTAT CALLS FOR FIRST AND SECOND STAGE COOLING

BASIC MODE (only active on a Y1 thermostat demand)

Normal Opera-

tion

1 On On On On Acceptable

VAC

High 100%

ComfortSense® 7000 thermostat energizes Y2 and de−energizes D on a call for de−humidification

Dehumidification

Call

2 On On On On Demand

VAC

High 70%**

PRECISION MODE (operates independent of a Y1 thermostat demand)

Normal Opera-

tion

1 On On On Acceptable

VAC

Low 70%*

Dehumidification mode begins when humidity is greater than set point

Dehumidification

call

2 On On On On Demand

VAC

High 70%**

Dehumidification

call ONLY

1 On On On On Demand

VAC

High 70%**

ComfortSense® 7000 thermostat will try to maintain room humidity setpoint by allowing the room space to maintain a cooler room thermostat setpoint***

Jumpers at indoor unit with a two stage outdoor unit Cut factory jumper from Y1 to Y2 or cut W915 (Y1 to Y2) With Condensing unit − Cut W914 (R to DS) on SureLight

control

With Heat Pump − Cut W914 (R to DS) & W951 (R to O) on SureLight

control

Dave Lennox ComfortSense® 7000 thermostat to use for this application − Y2081 4 heat / 2 cool *Normal operation first stage cooling blower speed is 70% COOL speed. **Dehumidification blower speed is, reduced to 70% of COOL. ***In Precision mode, ComfortSense

7000 thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room setting.

Page 51

Unit Start−Up

FOR YOUR SAFETY READ BEFORE LIGHTING

WARNING

Do not use this furnace if any part has been underwater. Immediately call a licensed professional service technician (or equivalent) to inspect the furnace and to replace any part of the control system and any gas control which has been under water.

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.

WARNING

During blower operation, the ECM motor emits energy that may interfere with pacemaker operation. Interference is reduced by both the sheet metal cabinet and distance.

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 SL280UHV unit will be 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:

SL280UHV 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 (Figures 35 and 36)

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 position. Do not force.

See figure 35 or 36.

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.

GAS VALVE SHOWN IN ON POSITION

INLET PRESSURE POST

HIGH FIRE ADJUSTMENT

SCREW

(under cap)

MANIFOLD

PRESSURE TAP

WHITE RODGERS GAS VALVE

FIGURE 35

GAS VALVE SHOWN IN ON POSITION

MANIFOLD

PRESSURE

TAP O N

SIDE

HIGH FIRE

ADJUSTING SCREW

(under cap)

INLET PRESSURE TAP

ON SIDE

HONEYWELL GAS VALVE

FIGURE 36

8 − Move gas valve switch to ON position. Do not force.

See figure 35 or 36.

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.

Page 52

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 position. Do not force.

See figure 35 or 36.

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 in-

spection.

Gas Pressure Adjustment

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 20 below. If manifold pressure matches table 22 and rate is incorrect, check gas orifices for proper size and restriction. Remove temporary gas meter if installed.

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

TABLE 20

GAS METER CLOCKING CHART

SL280

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

−70 55 11 0 136 272

−90 41 82 102 204

−110 33 66 82 164

−135 27 54 68 136

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

Supply Line Pressure

White Rodgers Gas Valve

An inlet post located on the gas valve provides access to the supply pressure. See figure 35. Back out the 3/32 hex screw one turn, connect a piece of 5/16 tubing and connect to a manometer to measure supply pressure. See table 22 for supply line pressure.

Honeywell Gas Valve

A threaded plug on the inlet side of the gas valve provides access to the supply pressure tap. Remove the threaded plug, install a field−provided barbed fitting and connect a manometer to measure supply pressure. See table 22 for supply line pressure. Replace the threaded plug after measurements have been taken.

Manifold Pressure

NOTE − Pressure test adapter kit (10L34) is available from Lennox to facilitate manifold pressure measurement.

1 − Connect test gauge to manifold pressure post (figure

35) or tap (figure 36) on gas valve.

2 − Ignite unit on high fire and let run for 5 minutes to allow

for steady state conditions.

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

manifold pressure and compare to value given in table

22.

4 − If necessary, make adjustments. Figures 35 and 36

show location of high fire adjustment screw.

5 − If an adjustment is made on high fire, re−check man-

ifold pressure on low fire. Do not adjust low fire man- ifold pressure. If low fire manifold pressure is more than 1/2" above or below value specified in table 22, replace valve.

Proper Combustion

Furnace should operate minimum 15 minutes with correct manifold pressure and gas flow rate before checking combustion. Table 21 shows acceptable combustion for ALL SL280UHV models. The maximum carbon monoxide reading should not exceed 50 ppm.

TABLE 21

Firing Rate

CO2%

For Nat

CO2%

For L.P.

High Fire 6.8 − 7.4 7.5 − 9.0

Low Fire 4.2 − 5.7 5.0 − 6.0

Page 53

High Altitude

The manifold pressure, gas orifice and pressure switch may require adjustment or replacement to ensure proper operation at higher altitudes. Tables 22 through 25 shows manifold pressure, pressures switch and gas conversion kits at all altitudes.

IMPORTANT

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

TABLE 22

Manifold Pressure Settings

Unit

Input

Gas

Orifice Size

0 − 7500 ft.

Orifice Size

7501 −

10,000 ft.

Manifold

Pressure in.wg.

0−4500 ft.

Manifold

Pressure in.wg.

4501−7500 ft.

Manifold

Pressure in.wg.

7501 − 10,000 ft.

Supply Line

Pressure

in. w.g.

Low Fire

High

Fire

Low

Fire

High

Fire

Low Fire

High

Fire

Min Max

070

Natural .063 .055 1.7 3.5 1.6 3.4 1.7 3.5 4.5 13.0

LP/propane

.039 .037 4.9 10.0 4.9 10.0 4.9 10.0 11.0 13.0

090

Natural .063 .055 1.7 3.5 1.5 3.2 1.7 3.5 4.5 13.0

LP/propane

.039 .037 4.9 10.0 4.9 10.0 4.9 10.0 11.0 13.0

110

Natural .063 .055 1.7 3.5 1.5 3.2 1.7 3.5 4.5 13.0

LP/propane

.039 .037 4.9 10.0 4.9 10.0 4.9 10.0 11.0 13.0

135

Natural .063 .055 1.7 3.5 1.6 2.8 1.7 3.5 4.5 13.0

LP/propane

.039 .037 4.9 10.0 4.9 10.0 4.9 10.0 11.0 13.0

This is the only permissible derate for these units.

Natural gas high altitude orifice kit required.

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.

NOTE − Units may be installed at altitudes up to 4500 ft. above sea level without modifications.

TABLE 23

High Altitude Pressure Switch Kits

Unit

Input

High Altitude

Pressure Switch Kit

0 − 4500 ft. 4501 − 7500 ft. 7501 − 10,000 ft.

070 No Change No Change 73W35

090 No Change 69W56 73W35

110 No Change 69W56 73W35

135 No Change 73W33 73W34

TABLE 24

Honeywell Gas Valve Conversion Kits

Unit

Input

High Altitude

Natural Gas

Orifice Kit

Natural Gas to

LP/ Propane Kit

LP/Propane

Natural Gas

Kit

7501 −

10,000 ft.

0 − 7500 ft.

7501 −

10,000 ft.

0 − 7500 ft.

070 73W37 51W02 73W38 69W79

090 73W37 51W02 73W38 69W79

110 73W37 51W02 73W38 69W79

135 73W37 51W02 73W38 69W79

TABLE 25

White Rodgers Gas Valve Conversion Kits

Unit

Input

High Altitude

Natural Gas

Orifice Kit

Natural Gas to

LP/ Propane Kit

LP/Propane

Natural Gas

Kit

7501 −

10,000 ft.

0 − 7500 ft.

7501 −

10,000 ft.

0 − 7500 ft.

070 77W05 77W07 77W11 77W09

090 77W05 77W07 77W11 77W09

110 77W05 77W07 77W11 77W09

135 77W05 77W07 77W11 77W09

Page 54

Other Unit Adjustments

Primary and Secondary Limits

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.

Flame Rollout Switches (Two)

These manually reset switches are located on (or inside of) the burner box. If tripped, check for adequate combustion air before resetting.

Pressure Switches

The pressure switch assembly (includes two switches) is located in the heating compartment adjacent to the combustion air inducer. These switches check for proper combustion air inducer operation before allowing ignition trial. The switches are factory−set and require no adjustment.

Temperature Rise

Place the unit into operation with a second−stage heating demand. After supply and return air temperatures have stabilized, check the temperature rise. If necessary, adjust the heating blower speed to maintain the temperature rise within the range shown on the unit nameplate. Increase the blower speed to decrease the temperature rise. Decrease the blower speed to increase the temperature rise. Failure to properly adjust the temperature rise may cause erratic limit operation.

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.

NOTE − Do not secure the electrical conduit directly to the air ducts or structure.

Heating Sequence of Operation

Electronic Ignition

The two−stage, variable speed integrated control used in SL280UHV units has an added feature of an internal Watchguard control. The feature serves as an automatic reset device for ignition control lockout caused by ignition failure. After one hour of continuous thermostat demand for heat, the Watchguard will break and remake thermostat demand to the furnace and automatically reset the control to begin the ignition sequence.

NOTE − The ignition control thermostat selection DIP switch is factory−set in the TWO−STAGE" position.

Applications Using a Two−Stage Thermostat

See figure 37 for ignition control sequence

A − Heating Sequence −− Integrated Control Thermostat Selection DIP Switch 1 OFF in Two−Stage" Position (Factory Setting)

1 − On a call for heat, thermostat first−stage contacts close

sending a signal to the integrated control. The integrated control runs a self-diagnostic program and checks high temperature limit switches for normally closed contacts and pressure switches for normally open contacts. The combustion air inducer is energized at low speed.

2 − Once the control receives a signal that the low pres-

sure switch has closed, the combustion air inducer begins a 15−second pre−purge in low speed.

NOTE − If the low fire pressure switch does not close the combustion air inducer will switch to high fire. After a 15 second pre−purge the high fire pressure switch will close and the unit will begin operation on high fire. After 10 to 20 seconds of high fire operation the unit will switch to low fire..

3 − After the pre−purge is complete, a 20−second initial ig-

nitor warm−up period begins. The combustion air inducer continues to operate at low speed.

4 − After the 20−second warm−up period has ended, the gas

valve is energized on low fire (first stage) and ignition occurs. At the same time, the control module sends a signal to begin an indoor blower 30−second ON−delay. When the delay ends, the indoor blower motor is energized on the low fire heating speed, the HUM contacts close energizing the humidifier and 120V ACC terminal is energized. The furnace will continue this operation as long as the thermostat has a first−stage heating demand.

5 − If second−stage heat is required, the thermostat sec-

ond−stage heat contacts close and send a signal to the integrated control. The integrated control initiates a 30−second second−stage recognition delay.

6 − At the end of the recognition delay, the integrated con-

trol energizes the combustion air inducer at high speed. The control also checks the high fire (second stage) pressure switch to make sure it is closed. The high fire (second stage) gas valve is energized and the indoor blower motor is energized for operation at the high fire heating speed.

7 − When the demand for high fire (second stage) heat is

satisfied, the combustion air inducer is switched to the low−fire heating speed and the high−fire (second stage) gas valve is de−energized. The low−fire (first stage) gas valve continues operation. The indoor blower motor is switched to the low−fire heating speed.

8 − When the thermostat demand for low−fire (first stage)

heat is satisfied, the gas valve is de−energized and the field−selected indoor blower off delay begins. The combustion air inducer begins a 5−second post−purge period.

9 − When the combustion air post−purge period is com-

plete, the inducer, the HUM contacts as well as the 120V ACC terminals are de−energized. The indoor blower is de−energized at the end of the off delay.

Page 55

Applications Using A Single−Stage Thermostat

See figure 38 for ignition control sequence

B − Heating Sequence −− Integrated Control Thermostat Selection DIP Switch 1 ON in Single−Stage" Position

NOTE − In these applications, two−stage heat will be initiated by the integrated control if heating demand has not been satisfied after the field adjustable period (7 or 12 minutes).

1 − On a call for heat, thermostat first−stage contacts close

2 − Once the control receives a signal that the low pres-

sure switch has closed, the combustion air inducer begins a 15−second pre−purge in low speed.

3 − After the pre−purge is complete, a 20−second initial ig-

nitor warm−up period begins. The combustion air inducer continues to operate at low speed.

4 − After the 20−second warm−up period has ended, the gas

valve is energized on low fire (first stage) and ignition occurs. At the same time, the control module sends a signal to begin an indoor blower 30−second ON−delay. When the delay ends, the indoor blower motor is energized on the low fire heating speed and the HUM contacts are energized. The integrated control also initiates a second−stage on delay (factory−set at 7 minutes; adjustable to 12 minutes).

5 − If the heating demand continues beyond the second−

stage on delay, the integrated control energizes the combustion air inducer at high speed. The control also checks the high fire (second stage) pressure switch to make sure it is closed. The high fire (second stage) gas valve is energized and the indoor blower motor is energized for operation at the high fire heating speed.

6 − When the thermostat heating demand is satisfied, the

combustion air inducer begins a 5−second low speed post−purge. The field−selected indoor blower off delay begins. The indoor blower operates at the low−fire heating speed.

7 − When the combustion air post−purge period is com-

plete, the inducer, the HUM contacts as well as the 120V ACC terminals are de−energized. The indoor blower is de−energized at the end of the off delay.

1 stg heat demand

2 stg heat demand

OFF

low speed CAI

Pre−Purge

Ignitor Warm−up

30* second

blower

on" delay

Post

Purge

5 SEC80

ignitor

HEATING OPERATION WITH TWO−STAGE THERMOSTAT

low fire gas valve

indoor blower low heat

high speed CAI high fire gas valve

indoor blower high heat

Trial For Ignition

blower

off"

delay

RECOGNITION PERIOD

30 seconds

FIGURE 37

* Conventional thermostat 30 seconds, icomfort Touch® thermostat set for 30 adjustable 15 to 45 seconds.

heat demand

OFF

low speed CAI

Pre−Purge

Ignitor Warm−up

30* second

blower

on" delay

Post

Purge

5 SEC

ignitor

HEATING OPERATION WITH SINGLE STAGE THERMOSTAT

low fire gas valve

high speed CAI high fire gas valve

indoor blower high heat

Trial For Ignition

7 or 12 minutes after heating demand begins, furnace switches to high fire (depends on setting)

blower

off"

delay

FIGURE 38

indoor blower low heat

* Conventional thermostat 30 seconds, icomfort Touch

thermostat set for 30 adjustable 15 to 45 seconds.

Page 56

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, a qualified technician should check the system as follows:

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 SL280UHV filters are installed external to the unit. Filters should be inspected monthly. Clean or replace the filters when necessary to ensure that the furnace operates properly. Replacement filters must be rated for high velocity airflow. Table 1 lists recommended filter sizes.

Flue And Chimney

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

ness and to make sure there is no blockage.

2 − Check unit for proper draft.

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 inner blow-

er panel in place. Unit Nameplate__________Actual__________

Cleaning the Heat Exchanger and Burners

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

1 − Turn off both electrical and gas power supplies to fur-

nace.

2 − Remove flue pipe and top cap (some applications top

cap can remain) from the unit.

3 − Label the wires from gas valve, rollout switches, prima-

ry limit switch and make−up box then disconnect them.

4 − Remove the screws that secure the combustion air in-

ducer/pressure switch assembly to the collector box. Carefully remove the combustion air inducer to avoid damaging blower gasket. If gasket is damaged, it must be replaced to prevent leakage.

5 − Remove the collector box located behind the combus-

tion air inducer. Be careful with the collector box gasket. If the gasket is damaged, it must be replaced to prevent leakage.

6 − Disconnect gas supply piping. Remove the screw se-

curing the burner box cover and remove cover. Remove the four screws securing the burner manifold assembly to the vestibule panel and remove the assembly from the unit.

7 − Remove screws securing burner box and remove

burner box.

8 − NOX units only − Remove screw securing NOX insert.

Remove NOX insert. See figure 40.

Page 57

SL280UHV BURNER, COMBUSTION AIR INDUCER ASSEMBLY &

HEAT EXCHANGER REMOVAL

FIGURE 39

heat exchanger

gasket

collector box

orifice plate

flue transition

pressure switch

combustion air inducer

burners

burner box assembly

burner box cover plate

manifold and gas valve

gasket

retention rings

cross over

ignitor

rollout switch

sensor

9 − Remove screws from both sides, top and bottom of

vestibule panel.

10− Remove heat exchanger. It may be necessary to

spread cabinet side to allow more room. If so, remove five screws from the left side or right side of cabinet. See figure 41.

11− Back wash using steam. Begin from the burner opening

on each clam. Steam must not exceed 275°F.

12− 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 39 shows burner detail.

13− To clean the combustion air inducer visually inspect and

using a wire brush clean where necessary. Use compressed air to clean off debris and any rust.

14− Reinstall heat exchanger in vestibule. (Replace the

five screws in the cabinet from step 10 if removed).

15− NOX units only − replace NOX inserst.

16− Reinstall collector box and combustion air assembly.

Reinstall all screws to the collector box and combustion air inducer. Failure to replace all screws may cause leaks. Inspect gaskets for any damage and replace if necessary.

17− Reinstall burner box, manifold assembly and burner box

cover.

Page 58

SL280UHV NOX INSERTS

FIGURE 40

FIGURE 41

Remove 5 screws if necessary

(either side of cabinet)

18− Reconnect all wires.

19− Reconnect top cap and vent pipe to combustion air in-

ducer outlet.

20− Reconnect gas supply piping.

21− Turn on power and gas supply to unit.

22− Set thermostat and check for proper operation.

23− Check all piping connections, factory and field, for gas

leaks. Use a leak detecting solution or other preferred means.

CAUTION

24− If a leak is detected, shut gas and electricity off and

repair leak.

25− Repeat steps 24 and 26 until no leaks are detected.

26− Replace access panel.

Page 59

Planned Service

The following items should be checked during an annual inspection. Power to the unit must be shut off for the service technician’s 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, 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 panel − 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.

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: SL280UH070V36A. All service must be

performed by a licensed professional installer (or equivalent), service agency, or gas supplier. Cabinet Parts

Upper access panel Blower panel Top cap

Control Panel Parts

Transformer Two−stage, variable speed integrated control Door interlock switch Circuit breaker

Blower Parts

Blower wheel Blower housing Motor Motor electronics Power choke (1 hp only) Motor mounting frame Motor capacitor Blower housing cutoff plate

Heating Parts

Flame Sensor

Heat exchanger assembly Gas manifold Two−speed combustion air inducer Two−stage gas valve Main burner cluster Main burner orifices Pressure switch Ignitor Primary limit control Flame rollout switch

Secondary limit

Page 60

Integrated Control Diagnostic Modes

Display Action (when button released)

No change (idle)* Remain in idle mode

Solid E" Enter diagnostic recall mode

Solid D" Discharge Air Installed

Solid F" Enter flame signal mode

Solid P" (variable speed only) Program unit capacity/size (Unit Code)**

* No change implies the display will continue to show whatever is currently being displayed for normal operation (blinking decimal, active error code, heat state, etc..)

** After the P" is selected (by releasing the push button) the integrated control will start flashing the P" on display for 90 seconds. If push button is pressed again and held during that time, the control will start to display characters corresponding to different variable speed furnace models for 3 seconds each. While the wanted character−model is displayed push button has to be released. Selected option will flash display for 10 seconds and during that time push button has to be pressed and held for 5 seconds. Once control accepts new setting it will store data in non−volatile memory and reset itself. If 10 seconds expires or push button is held less than 5 seconds, control will exit filed test mode and go in idle without programming the unit size.

Integrated Control Diagnostic Codes

Press the diagnostic push button and hold it to cycle through a menu of options. Every five seconds a new menu item will be displayed. Release the button when the desired mode is displayed. When a solid "P" is displayed, the furnace capacity / size is programmed. When the solid E" is displayed, the control enters the Diagnostic Recall (Alarm History). Diagnostic Recall mode menu options: No change (displaying error history) remains in Diagnostic Recall mode; solid  =

" exits Diagnostic Recall mode; and solid c" clears the error history. Must press button while flashing c" is displayed to clear error codes. When the solid F" is displayed, the control enters the Flame Signal Mode. The Flame Signal Mode is exited: with power cycle/reset, by pressing and holding the push button until 3 horizontal line are displayed =

, after 10 minutes of entering

flame signal mode.

Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover

Idle mode (Decimal blinks at 1 Hertz −− 0.5 second ON, 0.5 second OFF).

Cubic feet per minute (cfm) setting for indoor blower (1 second ON, 0.5 second OFF) / cfm setting for current mode displayed.

Cooling stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed / Pause / cfm setting displayed / Pause / Repeat codes).

Dehumidification mode (1 second ON) / 1 second OFF) / cfm setting displayed / Pause / Repeat Codes).

Heat pump stage (1 second ON, 0.5 second OFF) / % of input rate displayed / Pause / cfm setting / Pause / Repeat codes.

Gas Heat Stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed / Pause / cfm setting displayed / Pause / Repeat codes. Blinking during ignition.

Defrost mode.

Discharge Air Temperature

Page 61

Integrated Control Diagnostic Codes (continued)

Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover

E 105

Device communication problem − No other devices on RS BUS (Communication system).

Equipment is unable to communicate. Indicates numerous message errors. In most cases errors are related to electrical noise. Make sure high voltage power is separated from RSBus. Check for mis− wired and/or loose connections between the stat, indoor unit and outdoor unit. Check for a high voltage source of noise close to the system. Fault clears after communication is restored.

E 110

Low line voltage. Line Voltage Low (Voltage lower than nameplate

rating). Check power line voltage and correct. Alarm clears 5 seconds after fault recovered.

E 111

Line voltage polarity reversed. Reverse line power voltage wiring. System resumes

normal operation 5 seconds after fault recovered.

E 112

Ground not detected System shuts down. Provide proper earth ground.

System resumes normal operation 5 seconds after fault recovered.

E 113

High line voltage. Line Voltage High (Voltage higher than nameplate

rating). Provide power voltage within proper range. System resumes normal operation 5 seconds after fault recovered.

E 114

Line voltage frequency out−of−range. No 60 Hertz Power. Check voltage and line power

frequency. Correct voltage and frequency problems. System resumes normal operation 5 seconds after fault recovered.

E 115

Low 24V − Control will restart if the error recovers. 24−Volt Power Low (Range is 18 to 30 volts). Check

and correct voltage. Check for additional power−robbing equipment connected to system. May require installation of larger VA transformer to be installed in furnace / air handler. Clears after fault recovered.

E 116

High 24V. 24 Volt Power High (Range is 18 to 30 volts). Check

and correct voltage. Check for proper line voltage (120V, 240V, etc.) to equipment. Clears when control senses proper voltage.

E 117

Poor ground detected (Warning only) Provide proper grounding for unit. Check for proper

earth ground to the system. Warning only will clear 30 seconds after fault recovered.

E 120

Unresponsive device. Communication only. Usually caused by delay in outdoor unit responding

to indoor unit poling. Recycle power. Check all wiring connections. Cleared after unresponsive device responds to any inquiry.

E 124

Active communicating thermostat signal missing for more than 3 minutes.

Equipment lost communication with the thermostat. Check four wiring connections, ohm wires and cycle power at the thermostat. Alert stops all services and waits for heartbeat message from thermostat (subnet controller). Cleared after valid thermostat (subnet controller) message is received.

E 125

Control failed self−check, internal error, failed hardware. Will restart if error recovers. Integrated control not communicating. Covers hardware errors (flame sense circuit faults, pin shorts, etc.).

Hardware problem on the control. Cycle power on control. Replace if problem prevents service and is persistent. Critical alert. Cleared 300 seconds after fault recovered.

E 126

Control internal communication problem. Hardware problem on the control. Cycle power on

control. Replace if problem prevents service and is persistent. Cleared 300 seconds after fault recovered.

Page 62

Integrated Control Diagnostic Codes (continued)

E 131

Corrupted control parameters (Verify configuration of system). Communicating only.

Reconfigure the system. Replace control if heating or cooling is not available. Only applicable in the communicating mode, not in startup. Exit from Commissioning and Execute ’Set Factory Default mode’. Control will still operate on default parameter settings.

E 180

Outdoor air temperature sensor failure. Only shown if shorted or out−of− range.

Compare outdoor sensor resistance to temperature/ resistance charts in unit installation instructions. Replace sensor pack if necessary. At beginning of (any) configuration, furnace or air handler control will sense outdoor air and discharge air temperature sensor(s). If detected (reading in range), appropriate feature will be set as ’installed’ and that could be seen in ’About’ screen. In normal operation after control recognizes sensors, alarm will be sent if valid temperature reading is lost. To get rid of setting and alarm, redo configuration and make sure that temperature sensor is marked as ’not installed’ in Indoor Unit ’About’ screen. When Indoor unit control is replaced, thermostat will ’tell’ new control if temperature sensor is in system or not. Clears 30 seconds after fault recovered.

E 200

Hard lockout − Rollout circuit open or previously open. Correct cause of rollout trip, or replace flame rollout

switch. Test furnace operation. Cleared after fault recovered.

E 201

Indoor blower communication failure − Unable to communicate with blower motor.

Indoor blower communication failure (including power outage). Lost communication with indoor blower motor. Possible causes: motor not powered, loose wiring. Problem may be on control or motor side. Cleared after fault recovered.

E 202

Indoor blower motor mis−match − Indoor motor horsepower does not match unit capacity. See Page 67.

Incorrect appliance capacity code selected. Check for proper configuring under: Unit Size Codes for Furnace/Air Handler on configuration guide or in installation instructions. Cleared after the correct match is detected following a reset. (Remove thermostat from system while applying power and reprogramming.)

E 203

Appliance capacity / size is NOT programmed. Invalid unit codes refer to configuration flow chart. See Page 67.

No appliance capacity code selected. Check for proper configuring under: Unit Size Codes for Furnace on configuration guide or in installation instructions. Critical Alert. Cleared after valid unit code is read following a reset. (Remove thermostat from system while applying power and reprogramming.)

E 204

Gas valve mis−wired. Check gas valve operation and wiring. Clears when

repaired.

E 205

Gas valve control relay contact shorted. Check wiring on control and gas valve. If wiring is

correct, replace control.

E 206

Gas valve second−stage relay failure Furnace will operate on 1st stage for remainder of

the heating demand. Will clear after fault recovered. If unable to operate 2nd stage, replace control.

E 207

Hot surface ignitor sensed open − Refer to troubleshooting. See Page 68. Measure resistance of hot surface ignitor. Replace if

open or not within specified range found in IOM. Resumes normal operation after fault is cleared.

Page 63

Integrated Control Diagnostic Codes (continued)

Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover

E 223

Low pressure switch failed open. Check pressure (inches w.c.) of low pressure switch

closing on heat call. Measure operating pressure (inches w.c.). Inspect vent and combustion air inducer for correct operation and restriction. Resumes normal operation after fault is cleared

E 224

Low pressure switch failed closed − Refer to troubleshooting. See Page 68.

Check operation of low pressure switch to see if it is stuck closed on heat call longer than 150 seconds. Measure operating pressure (inches w.c.). Inspect vent and combustion air inducer for correct operation and restriction. Resumes normal operation after fault is cleared.

E 225

High pressure switch failed open − Refer to troubleshooting. See Page 68.

Check pressure (inches w.c.) of high pressure switch closing on heat call. Measure operating pressure (inches w.c.). Inspect vent and combustion air inducer for correct operation and restriction. Resumes normal operation after fault is cleared.

E 226

High pressure switch failed closed − Refer to troubleshooting. See Page 68.

Check operation of high pressure switch closing on heat call. Measure operating pressure (inches w.c.). Inspect vent and combustion air inducer for correct operation and restriction. Resumes normal operation after fault is cleared.

E 227

Low pressure switch open during trial for ignition or run mode. Refer to troubleshooting. See Page 68.

Check pressure (inches w.c.) of low pressure switch closing on heat call. Measure operating pressure (inches w.c.). Inspect vent and combustion air inducer for correct operation and restriction. Resumes normal operation after fault is cleared.

E 228

Combustion air inducer calibration failure Unable to perform pressure switch calibration.

Check vent system and pressure switch wiring connections. Resumes normal operation after fault is cleared.

E 229

Ignition on high fire IFC switched to high fire ignition because low fire

pressure switch did not close in allowed time. No action is needed.

E 240

Low flame current − Run mode − Refer to troubleshooting. See Page 68. Check micro−amperes of flame sensor using control

diagnostics or field−installed mode. Clean or replace sensor. Measure voltage of neutral to ground to ensure good unit ground. Alert clears after current heat call has been completed.

E 241

Flame sensed out of sequence − Flame still present. Shut off gas. Check for gas valve leak. Replace, if

necessary. Alert clears when fault is recovered.

E 250

Limit switch circuit open − Refer to troubleshooting. Check for proper firing rate on furnace. Ensure

there is no blockage in heater. Check for proper air flow. If limit not closed within 3 minutes, unit will go into 1−hour soft lockout. Resumes normal operation after fault is cleared.

E 252

Discharge air temperature too high (gas heat only). Check temperature rise, air flow and input rate.

Cleared when heat call is finished.

E 270

Soft lockout − Exceeded maximum number of retries. No flame current sensed.

Check for proper gas flow. Ensure that ignitor is lighting burner. Check flame sensor current. Clears when heat call finishes successfully.

E 271

Soft lockout − Exceeded maximum number of retries. Last retry failed due to the pressure switch opening.

Page 64

Integrated Control Diagnostic Codes (continued)

E 272

Soft lockout − Exceeded maximum number of recycles. Last recycle due to the pressure switch opening.

Check operation of low pressure switch to see if it is stuck closed on heat call. Check pressure (inches w.c.) of high pressure switch closing on heat call. Measure operating pressure (inches w.c.). Inspect vent and combustion air inducer for correct operation and restriction. Clears when heat call finishes successfully.

E 273

Soft lockout − Exceeded maximum number of recycles. Last recycle due to flame failure.

Check micro−amperes of flame sensor using control diagnostics or field−installed mode. Clean or replace sensor. Measure voltage of neutral to ground to ensure good unit ground. Clears when heat call finishes successfully.

E 274

Soft lockout − Exceeded maximum number of recycles. Last recycle failed due to the limit circuit opening or limit remained open longer than 3 minutes.

Shut down system. 1−hour soft lockout. Check firing rate and air flow. Check for blockage. Clears when heat call finishes successfully.

E 275

Soft lockout − Flame sensed out of sequence. Flame signal is gone. Shut off gas. Check for gas valve leak. 1−hour soft

lockout. Clears when flame has been proven stable.

E 276

Watchguard calibration failure. Unable to perform pressure switch calibration.

Check vent system and pressure switch wiring connections. 1−hour soft lockout. Clears when calibration has finished successfully.

E 290

Ignitor circuit fault − Failed ignitor or triggering circuitry. Measure resistance of hot surface ignitor. Replace if

open or not within specifications. 1−hour soft lockout. Clears when flame has been proven stable.

E 291

Heat air flow restricted below the minimum. Check for dirty filter and air flow restriction. Check

blower performance. 1−hour soft lockout. Cleared when heat call finishes successfully.

E 292

Indoor blower motor unable to start due to obstructed wheel, seized bearings.

Indoor blower motor unable to start (seized bearing, stuck wheel, etc.). Replace motor or wheel if assembly does not operate or meet performance standards. 1−hour soft lockout. Clears after circulator successfully starts.

E 294

Combustion air inducer over current. Check combustion blower bearings, wiring and

amps. Replace if does not operate or does not meet performance standards. Clears after inducer current is sensed to be in−range after the ignition following the soft lockout or reset.

E 295

Indoor blower motor temperature is too high. Indoor blower motor over temperature (motor

tripped on internal protector). Check motor bearings and amps. Replace if necessary. Cleared after blower demand is satisfied.

E 310

Discharge error temperature sensor failure. Only shown if shorted or out of range.

Compare outdoor sensor resistance to temperature/ resistance charts in installation instructions. Replace sensor if necessary. Cleared in Communicating mode: 30 seconds after fault recovered. In Non− Communicating mode: Cleared after the current heat call is completed.

E 311

Heat rate reduced to match indoor blower air flow. Warning Only. Furnace blower in cutback mode due

to restricted airflow. Reduce firing rate every 60 seconds to match available CFM. Check filter and duct system. To clear, replace filter if needed or repair/add duct. 2−stage controls will reduce firing rate to 1

stage. Clears when heat call finishes success-

fully.

Page 65

Integrated Control Diagnostic Codes (continued)

Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover

E 312

Restricted air flow in cooling or continuous fan mode is lower than cfm setting.

Warning Only. Restricted airflow − Indoor blower is running at a reduced CFM (Cutback Mode − The variable speed motor has pre−set speed and torque limiters to protect the motor from damage caused by operating outside of design parameters (0 to 0.8" W.C.. total external static pressure). Check filter and duct system. To clear, replace filter if needed or repair/add duct. Cleared after the current service demand is satisfied.

E 313

Indoor or outdoor unit capacity mismatch. Communication only. Incorrect indoor/outdoor capacity code selected.

Check for proper configuring in installation instructions. Alarm is just a warning. The system will operate, but might not meet efficiency and capacity parameters. Alarm will clear when commissioning is exited. Cleared after commissioning is complete.

E 331

Global network connection − Communication link problem. For Future Use.

E 334

Relay Y1" stuck on interated control. Replace integrated control.

E 347

No 24 Volt output on Y1 of "integrated control" with non communicating outdoor unit.

Operation stopped. Y1 relay / Stage 1 failed. (Pilot relay contacts did not close or the relay coil did not energize; no input back to IFC chip). Critical Alert. Cleared after reset and Y1 input sensed.

E 348

No 24 Volt output on Y2 of "integrated control" with non?communicating outdoor unit.

Y2 relay / Stage 2 failed. (Pilot relay contacts did not close or the relay coil did not energize; no input back to IFC chip). Critical Alert. Cleared after reset and Y1 input sensed.

E 349

No 24 Volts between R & O on "integrated control" with non communicating outdoor unit (Dual fuel module required for heat pump application).

Configuration link R to O needs to be restored. Replace link or hard−wire. Applicable in non communicating mode. Critical Alert.

E 370

Interlock switch sensed open for 2 minutes. Control sees the loss of 24VAC for 2 minutes .Ter-

minate all services and wait for interlock switch to close. The alarm will clear when 24VAC is continuously sensed on DS terminal for a minimum of 10 seconds or on a power reset.

E 400

LSOM − Compressor internal overload tripped. Thermostat demand Y1 is present; but, compressor

is not running. Check power to outdoor unit. Clears the error after current is sensed in both RUN and START sensors for at least 2 seconds, or after service is removed, or after power reset.

E 401

LSOM Compressor long run cycle or low system pressure. Compressor ran more than 18 hours to satisfy a

single thermostat demand. Critical Alert. Clears the error after 30 consecutive normal run cycles or power reset. Also monitors low pressure switch trips.

E 402

LSOM − Outdoor unit system pressure trip. Discharge or suction pressure out−of−limits, or com-

pressor overloaded. Clears the error after 4 consecutive normal compressor run cycles.

E 403

LSOM − Compressor short−cycling. .(Running less than 4 minutes). Outdoor unit pressure trip

Compressor runs less than 3 minutes to satisfy a thermostat demand. Clears the error after 4 consecutive normal run cycles or power reset.

E 404

LSOM − Compressor rotor locked. Compressor short−cycling. (Running less than 4 minutes).

Compressor rotor locked up due to run capacitor short, bearings are seized, excessive liquid refrigerant, etc. Clears the error after 4 consecutive normal run cycles or after power reset.

E 405

LSOM − Compressor open circuit. Compressor circuit open (due to power disconnec-

tion, open fuse, etc.) Clears the error after 1 normal compressor run cycle.

Page 66

Integrated Control Diagnostic Codes (continued)

E 406

LSOM − Compressor open start circuit. Required amount of current is not passing through

Start current transformer. Clears the error after current is sensed in START sensor, or after power reset.

E 407

LSOM − Compressor open run circuit. Required amount of current is not passing through

Run current transformer. Clears the error after current is sensed in RUN sensor, or 1 normal compressor run cycle, or after power reset.

E 408

LSOM − Compressor contactor is welded. Compressor runs continuously. Clears the error

after 1 normal compressor run cycle or after power reset.

E 409

LSOM − Compressor low voltage. Secondary voltage is below 18VAC. After 10 min-

utes, operation is discontinued. Clears the code after voltage is higher than 20 VAC for 2 seconds or after power reset.

Page 67

Program Unit Capacity/Size Mode

Power−Up − Number displayed represents by integrated control unit size code (furnace model

and capacity). If three horizontal bars are displayed followed by continuous E203, furnace control does not recognize unit size code. Configure per the following:

Furnace control in IDLE mode

No heating, cooling or indoor fan

operation)

To enter Program Unit Capacity/Size: push and hold button next to 7−segment LED display until solid P" symbol appears. Release button.

Turn room thermostat to OFF

Solid P starts blinking on 7−Segment LED

Push and hold button. Integrated control will display unit size code number for each furnace model for three seconds.

When the correct unit size code is displayed, release button. Selected code will flash for 10−second period. During that period, press and hold push button for 5 seconds. Integrated control will store code in memory and will automatically exit Program Unit Capacity/Size Mode and reset. (If second period expires or push button is held less than five seconds, control will automatically exit Program Capacity/Size Mode and go into IDLE mode without storing unit size code. If this happens, programming function must be repeated).

Verify that the selected unit size code is correct and stored in non−volatile memory by cycling the 24 volt power to the furnace control. (At 24 volt power−up of the furnace control, the 7−segment LED will display a unit size code

. If three horizontal bars display, board does not recognize unit size code

. Programming

function must be repeated)

Yes

IMPORTANT: Field replacement controls may need to be manually configured to validate furnace unit size code.

FURNACE MODEL

SL280UH070V36A

SL280UH090V36B

SL280UH090V48B

SL280UH090V60C

SL280UH110V60C

SL280UH135V60D

UNIT SIZE

CODE

−

FINISHED

FURNACE MODEL

SL280DF070V36A

SL280DF090V48B

SL280DF090V60C

SL280DF110V60C

UNIT SIZE

CODE

Page 68

Troubleshooting: Heating Sequence of Operation

HIGH

LIMIT SWITCH

CLOSED?

LOW

PRESSURE

SWITCH

OPEN?

INDUCER ON

PRE−PURGE

(15 SECONDS)

1ST STAGE GAS

VALVE ENERGIZED

FLAME

SENSED WITHIN

4 SECONDS?

(LOW HEAT SPEED)

HEAT FAN OFF DELAY

(LOW HEAT SPEED)

AFTER HEAT FAN OFF DELAY (LOW

HEAT SPEED)

YES

ERROR

CODE

FLASHES

ON(LOW HEAT

SPEED)

CALL

FOR HEAT

ENDS?

ERROR CODE

FLASHES (AFTER

5 SECONDS)

5TH

UNSUCCESSFUL

TRIAL?

POSTPURGE (5 SECONDS)

INDUCER

OFF

YES

ROLLOUT

CIRCUITS CLOSED?

DE−ENERGIZE

GAS VALVE

ERROR

CODE

FLASHES

INDOOR BLOWER

ON (LOW HEAT

SPEED)

INDUCER ON

(HIGH SPEED)

LIMIT

SWITCH

CLOSED WITHIN 3

MINUTES?

CALL FOR

1ST STAGE HEAT

(LOW FIRE)

GAS VALVE

DE−ENERGIZED

H.S.I. OFF

H.S.I. ON

(20 SECONDS)

WATCHGUARD − ERROR CODE FLASHES

CALL FOR HEAT SATISFIED

IGNITION TRIAL

BEGINS (H.S.I. ON)

HEAT FAN ON DELAY

TIMER STARTED

INTERPURGE

(15 SECONDS)

H.S.I. OFF

INDUCER OFF

AFTER POST

PURGE

HARD LOCKOUT − ERROR CODE FLASHES

YES

LOW PRESSURE SWITCH OPENS

HARD LOCKOUT REQUIRES THERMOSTAT RESET OR CYCLING OF POWER TO RESET THE LOCKOUT.

IN CASE HIGH SPEED INDUCER IS RUNNING AT THE TIME THE GAS VALVE GETS ENERGIZED, 2ND STAGE GAS VALVE IS ENERGIZED INSTEAD OF 1ST STAGE. 20 SECONDS AFTER FLAME IS SENSED, INDUCER SWITCHES TO LOW SPEED, AND GAS VALVE SWITCHES TO 1ST STAGE.

LOW

PRESSURE SWITCH

CLOSED WITHIN 120

SECONDS?

LOW & HIGH

PRESSURE SWITCH

CLOSED WITHIN 30

SECONDS?

HIGH

PRESSURE

SWITCH

OPEN

BEFORE

INDUCER WAS

TURNED ON?

INDUCER TO

HIGH SPEED−

ERROR CODE

FLASHES

INDUCER OFF−

WAIT 5 MINUTES ERROR CODE

FLASHES

YES

INDOOR BLOWER OFF AFTER

INDOOR

BLOWER OFF INDOOR BLOWER

ROLLOUT

CIRCUIT CLOSES

(MANUAL

RE−SET)

LOW SPEED

INDOOR BLOWER OFF AFTER HEAT OFF DELAY

YES

INDOOR

BLOWER

ON?

WATCHGUARD − ERROR CODE FLASHES

INDOOR

BLOWER

ON?

INDOOR

BLOWER ON 30 SEC.

WATCHGUARD LOCKOUT AUTOMATICALLY RESETS AFTER ONE HOUR

CALL FOR FIRST−STAGE HEAT

INDOOR

BLOWER

OFF AFTER

HEAT FAN

OFF DELAY

Page 69

Troubleshooting: Heating Sequence of Operation (Continued)

WHEN USED WITH A SINGLE STAGE THERMOSTAT, SET SW1 TO THE ON POSITION IN DIP SWITCH S4.

IF THE HIGH FIRE PRESSURE SWITCH DOES NOT CLOSE WITHIN 5 ATTEMPTS, THE SYSTEM WILL OPERATE AT LOW FIRE FOR THE REMAINDER OF THE CALL FOR HEAT REQUEST.

2ND STAGE GAS VALVE

ENERGIZED

ONLY FOR 1ST REQUEST FOR

2ND STAGE HEAT

YES

CALL FOR HEAT SATISFIED

INDUCER SWITCHED

TO HIGH SPEED

SINGLE STAGE

THERMOSTAT

2 STAGE THERMOSTAT

INDUCER SWITCHED

TO LOW SPEED

5 MINUTE DELAY

(ERROR CODE FLASHES)

HIGH

PRESSURE SWITCH

CLOSED WITHIN 10

SECONDS?

2ND STAGE

ON DELAY

EXPIRED?

CALL FOR 2ND STAGE HEAT

(HIGH FIRE)

YES

CALL FOR SECOND−STAGE HEAT

RECOGNITION DELAY

(30 SECONDS)

EXPIRED?

INDOOR BLOWER ENERGIZED

ON HIGH HEAT SPEED

SYSTEM WILL ALWAYS LIGHT ON LOW FIIRE, EVEN IF 2ND STAGE HEAT IS IN PLACE.

Page 70

Troubleshooting: Heating Sequence of Operation (Continued)

2ND STAGE HEAT

RUN MODE: 1ST OR 2ND STAGE CALL FOR HEAT.

ALL INPUTS MONITORED (LIMIT, PRESSURE, CALL FOR HEAT/COOL, FLAME LEVEL)

2ND STAGE

CALL FOR HEAT

SATISFIED?

YES

DE−ENERGIZE 2ND STAGE

GAS VALVE

INDUCER SPEED SWITCHED

TO LOW SPEED

2 3

1ST STAGE HEAT

1ST STAGE

CALL FOR HEAT

SATISFIED?

YES

GAS VALVE

DE−ENERGIZED

INDUCER OFF AFTER

5 SECOND POST PURGE

CALL FOR HEAT SATISFIED

FIRST−STAGE HEAT SECOND−STAGE HEAT

INDOOR BLOWER SWITCHED

TO LOW HEAT SPEED

INDOOR BLOWER OFF

AFTER FIELD SELECTABLE

OFF DELAY

Page 71

Troubleshooting: Cooling Sequence of Operation (Continued)

1ST STAGE COOLING

REQUEST RECEIVED

ENERGIZE 1ST STAGE COOLING CONTACTOR (COMPRESSOR & FAN)

2ND STAGE

COOLING

REQUEST?

YES

1ST STAGE

COOLING REQUEST

STILL ACTIVE?

YES

ENERGIZE 2ND STAGE

COOLING CONTACTOR (COMPRESSOR & FAN)

DE−ENERGIZE 2ND

STAGE COOLING

CONTACTOR

(COMPRESSOR & FAN)

CONTROL WILL NOT RESPOND TO A 2ND STAGE COOLING REQUEST UNLESS A 1ST STAGE COOLING REQUEST IS ACTIVE.

AND SPEED RAMPING PROFILES. THE SPECIFIC PROFILE IS SELECTED USING THE

DE−ENERGIZE 1ST

STAGE COOLING

CONTACTOR

(COMPRESSOR & FAN)

2ND STAGE

COOLING REQUEST

STILL ACTIVE?

COOLING REQUEST

STILL ACTIVE?

CALL FOR COOLING

WAIT FOR COMPRESSOR TIMED

OFF DELAY TO EXPIRE

INDOOR BLOWER 2 SECOND ON DELAY

YES

1ST STAGE

DE−ENERGIZE INDOOR

BLOWER

INDOOR BLOWER LOW COOLING MODE AND HIGH COOLING MODE HAVE SPECIFIC ON, OFF

ENERGIZE INDOOR BLOWER

(LOW COOLING MODE)

ENERGIZE INDOOR BLOWER

(HIGH COOLING MODE)

MAINTAIN INDOOR BLOWER

(HIGH COOLING MODE)

ENERGIZE AND MAINTAIN

INDOOR BLOWER AT

(LOW COOLING MODE)

DIP SWITCHES ON THE CONROL.

MAINTAIN INDOOR

BLOWER

(LOW COOLING MODE)

Page 72

Troubleshooting: Continuous Fan Sequence of Operation

CALL FOR FAN

REMOVED?

YES

REQUEST FOR HEAT

RECEIVED?

REQUEST

FOR COOLING

RECEIVED?

GO TO CALL FOR 1ST STAGE HEAT

YES

GO TO CALL FOR COOLING

YES

CALL FOR FAN

INDOOR BLOWER ON

CONTINUOUS FAN

SPEED

MAINTAIN INDOOR

BLOWER AT

CONTINUOUS FAN

MAINTAIN INDOOR

BLOWER AT

CONTINUOUS FAN

INDOOR BLOWER OFF

DE−ENERGIZE INDOOR

BLOWER

Lennox SL280UHV, SL280UH070V36A, SL280UH090V36B, SL280UH090V48B, SL280UH090V60C Installation Instructions Manual

Specifications and Main Features

Frequently Asked Questions

User Manual