Lennox SL280DFV Installation Instructions Manual
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Lennox SL280DFV Installation Instructions Manual

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E 2011 Lennox Industries Inc.
Dallas, Texas, USA
CAUTION
As with any mechanical equipment, personal injury
can result from contact with sharp sheet metal
edges. Be careful when you handle this equipment.
This is a safety alert symbol and should never be ignored.
When you see this symbol on labels or in manuals, be alert
to the potential for personal injury or death.
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06/11
*2P0611*
DOWNFLOW
AIR FLOW

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INSTALLATION
INSTRUCTIONS
SL280DFV
DAVE LENNOX SIGNATURE
COLLECTION GAS FURNACE
DOWNFLOW AIR DISCHARGE
506710−01
06/2011
Supersedes 01/2011
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a licensed professional installer (or
equivalent), service agency or the gas supplier.
A thermostat is not included and must be ordered
separately.
D The Lennox icomfort Toucht thermostat must be
used in communicating applications.
D In non−communicating applications, the Lennox
ComfortSense
well as other non−communicating thermostats.
In all cases, setup is critical to ensure proper sys-
tem operation.
Field wiring for both communicating and non−com-
municating applications is illustrated in diagrams,
which begin on Page 23.
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WARNING
NOTICE
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7000 thermostat may be used, as
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Litho U.S.A.
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  • Page 1: Table Of Contents

    DOWNFLOW NOTICE AIR FLOW A thermostat is not included and must be ordered separately. D The Lennox icomfort Toucht thermostat must be used in communicating applications. D In non−communicating applications, the Lennox CAUTION ® ComfortSense 7000 thermostat may be used, as well as other non−communicating thermostats.

  • Page 2: Unit Dimensions

    Unit Dimensions − inches (mm) 3−1/8 9/16 (79) (14) RETURN AIR OPENING FLUE OUTLET 19−7/16 9/16 (Top) (494) (14) 9/16 (14) TOP VIEW 27−3/4 1−1/2 (38) (7705) Front Panel 9/16 19−7/16 9/16 (14) (494) (14) ELECTRICAL INLET (Either Side) (838) 5−3/8 (137) Right GAS PIPING INLET 2−1/8 (54) Left...

  • Page 3: Parts Arrangement

    Parts Arrangement BLOWER ASSEMBLY SECONDARY LIMIT GASKET FLUE CHASE CONTROL BOX (Includes two−stage integrated control, transformer and circuit breaker) INTERNAL FLUE PIPE ASSEMBLY DOOR INTERLOCK SWITCH PRIMARY LIMIT LOCATION ROLLOUT SWITCH HEAT EXCHANGER COMBUSTION AIR INDUCER PRESSURE SWITCHES COMBUSTION AIR INDUCER GAS VALVE INNER BLOWER ACCESS PANEL BURNER BOX ASSEMBLY...

  • Page 4: Sl280Dfv Gas Furnace

    Failure to do so may cause erratic limit operation should be installed in all LP applications. and may also result in premature heat exchanger failure. This SL280DFV furnace must be installed so that its electri- cal components are protected from water. WARNING...

  • Page 5: Use Of Furnace As A Construction Heater

    (see figure 1). If the SL280DFV units may be used for heating of buildings or damper is manually operated, it must be equipped to pre- structures under construction, if the following conditions vent operation of either the heating or the cooling unit, un- are met: less it is in the full HEAT or COOL setting.

  • Page 6: Combustion, Dilution & Ventilation Air

    SL280DFV furnaces to ensure effi- an unconfined or a confined space. cient and safe operation. You must consider combustion air Unconfined Space needs and requirements for exhaust vents.
  • Page 7 Confined Space Air from Inside If the confined space that houses the furnace adjoins a A confined space is an area with a volume less than 50 cu- space categorized as unconfined, air can be brought in by bic feet (1.42 m ) per 1,000 Btu (.29 kW) per hour of the providing two permanent openings between the two combined input rating of all appliances installed in that...
  • Page 8 EQUIPMENT IN CONFINED SPACE ALL AIR FROM OUTSIDE (Inlet Air from Crawlspace and Outlet Air to Ventilated Attic) CHIMNEY OR GAS VENT VENTILATION LOUVERS (Each end of attic) OUTLET WATER FURNACE HEATER INLET VENTILATION LOUVERS (For unheated crawl space) NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch (645 ) per 4,000 Btu (1.17 kW) per hour of the total input rating of all equipment in the enclosure.

  • Page 9: Downflow Installation

    Installation on Non−Combustible Flooring (Figure 6) 1 − Cut floor opening keeping in mind clearances listed on SL280DFV UNIT unit rating plate. Also keep in mind gas supply connec- tions, electrical supply, flue and air intake connections and sufficient installation and servicing clearances.

  • Page 10: Setting Equipment

    PROPERLY death. PLENUM SIZED FLOOR OPENING Install the SL280DFV gas furnace as shipped in the downflow position only. Do not install the furnace hori- zontally. Select a location that allows for the required clearances FIGURE 8 that are listed on the unit nameplate. Also consider gas Return Air Opening −−...

  • Page 11: Filters

    Horizontal Front Back FIGURE 12 Downflow Application WARNING Allow for clearances to combustible materials as indi- cated on the unit nameplate. Minimum clearances for Improper installation of the furnace can result in per- closet or alcove installations are shown in figure 13. sonal injury or death.

  • Page 12: Duct System

    The vent connector does not require insula- tion. Use self−drilling sheet metal screws or a mechanical fas- The SL280DFV series units are classified as fan−assisted tener to firmly secure the vent pipe to the round collar of the Category I furnaces when vertically vented according to flue transition.
  • Page 13 OTHER suitable materials, or replaced with a gas vent or chimney APPLIANCE suitable for venting SL280DFV series units. The chimney PERMANENTLY SEALED FIREPLACE passageway must be checked periodically to ensure that it OPENING is clear and free of obstructions.
  • Page 14 9 (2.74) General Venting Requirements 7 (178) 10−1/2 (3.20) Vent all SL280DFV furnaces according to these instruc- 9 − If the common vertical vent is offset, the maximum tions: common vent capacity listed in the common venting 1 − Vent diameter recommendations and maximum allow-...
  • Page 15 18 − The common vent diameter must always be at least as 21 − When connecting this appliance to an existing dedi- large as the largest vent connector diameter. cated or common venting system, you must inspect the 19 − In no case, shall the vent connector be sized more than venting system’s general condition and look for signs two consecutive table size diameters over the size of of corrosion.
  • Page 16 TABLE 6 Capacity of Type B Double−Wall Vents with Single−Wall Metal Connectors Serving a Single Category I Appliance Vent and Connector Diameter − D (inches) Height Lateral 3 Inch 4 Inch 5 Inch 6 Inch Appliance Input Rating in Thousands of Btu Per Hour (feet) (feet) NOTE −...
  • Page 17 TABLE 7 Vent Connector Capacity Type B Double−Wall Vents with Type B Double−Wall Connectors Serving Two or More Category I Appliances Vent and Connector Diameter − D (inches) Vent Connector 3 Inch 4 Inch 5 Inch 6 Inch Height Rise Appliance Input Rating in Thousands of Btu Per Hour (feet) (feet)
  • Page 18 TABLE 9 Vent Connector Capacity Type B Double−Wall Vents with Single−Wall Metal Connectors Serving Two or More Category I Appliances Vent and Connector Diameter − D (inches) Height Lateral 3 Inch 4 Inch 5 Inch 6 Inch Appliance Input Rating in Thousands of Btu Per Hour (feet) (feet) NOTE −...

  • Page 19: Gas Piping

    Removal of the Furnace from Common Vent 7 − If a venting problem is found during any of the preced- ing tests, the common venting system must be modi- In the event that an existing furnace is removed from a fied to correct the problem.
  • Page 20 TABLE 11 Gas Pipe Capacity − ft /hr (m /hr) Nominal Length of Pipe − feet (m) Internal Iron Pipe Diameter Size inches inches (mm) (3.048) (6.096) (9.144) (12.192) (15.240) (18.288) (21.336) (24.384) (27.432) (30.480) (mm) .622 (12.7) (17.799) (4.96) (3.40) (2.75) (2.32)

  • Page 21: Electrical

    Leak Check Refer to figure 24 for unit field wiring. See figures 21 and 22 ® for icomfort Touch thermostat wiring in communicating After gas piping is completed, carefully check all piping applications. Table 13 shows DIP switch and on−board link connections (factory−...
  • Page 22 38% of cool speed. er connections and may be connected to 24V or 120V. 2 − When the SL280DFV is running in the heating mode, Any humidifier rated up to one amp can be connected the indoor blower will run on the heating speed desig- to these terminals.
  • Page 23 Non−Communicating Outdoor Unit and icomfortt−ENABLED Outdoor Unit ® ® icomfort Touch Thermostat icomfort Touch Thermostat icomfortt−Enabled SL280DFV Indoor Furnace icomfortt−Enabled SL280DFV Indoor Furnace Non−Communicating Outdoor Air Conditioner icomfortt−Enabled Outdoor Air Conditioner or Heat Pump icomfortt− ENABLED icomfortt− SL280DFV ENABLED...
  • Page 24 HUMIDITY DEMAND MIDIFIER (IF NOT ALREADY IN THE SYSTEM FOR OTHER IS PRESENT FUNCTIONS. BUILT INTO ALL icomfort by Lennoxt OUT- DOOR UNITS). icomfortt ENABLED 24V HUMIDIFIER CONNECTIONS SL280DFV FURNACE Discharge Air Sensor (Required for even heat) CS 7000 THERMOSTAT ®...
  • Page 25 TABLE 13 SL280 Field Wiring Applications With Conventional Thermostat DIP Switch Settings and On−Board Links (See figure 25) DIP Switch 1 On Board Links Must Be Cut To Select Thermostat Thermostat Wiring Connections System Options Heating Stages 1 Heat / 1 Cool FURNACE OUTDOOR T’STAT...
  • Page 26 TABLE 13 SL280 Field Wiring Applications With Conventional Thermostat (Continued) DIP Switch Settings and On−Board Links (See figure 25) DIP Switch 1 On Board Links Must Be Cut To Select Thermostat Thermostat Wiring Connections System Options Heating Stages 2 Heat / 2 Cool FURNACE OUTDOOR T’STAT...
  • Page 27 TABLE 13 SL280 Field Wiring Applications With Conventional Thermostat (Continued) DIP Switch Settings and On−Board Links (figure 25) DIP Switch 1 Thermostat On Board Links Must Be Cut To Select Wiring Connections Thermostat Heating System Options Stages Dual Fuel FURNACE HEAT PUMP L7724U TERM.
  • Page 28 TABLE 13 SL280 Field Wiring Applications With Conventional Thermostat (Continued) DIP Switch Settings and On−Board Links (figure 25) DIP Switch 1 Thermostat On Board Links Must Be Cut To Select Wiring Connections Thermostat Heating System Options Stages Dual Fuel FURNACE HEAT PUMP L7724U TERM.
  • Page 29 SL280DFV Schematic Wiring Diagram FIGURE 23 Page 29...
  • Page 30 TYPICAL SL280DFV FIELD WIRING DIAGRAM FIELD INSTALLED CLASS II 24V FIELD INSTALLED LINE VOLTAGE FIGURE 24 Page 30...

  • Page 31: Integrated Control

    Integrated Control HS/ CAI LINE 1 NEUTRAL 7 SEGMENT LED FLAME SENSE INDOOR BLOWER DIAGNOSTIC CONNECTOR PUSH BUTTON DIP SWITCHES 12 PIN LOW OUTDOOR AIR VOLTAGE SENSOR CONNECTOR TERMINALS DISCHARGE AIR W915 Y1 TO Y2 SENSOR 2 STAGE COMPR TERMINALS W951 R TO O HEAT PUMP TB83...

  • Page 32: Integrated Control Settings

    14 pro- vides the blower off timings that will result from different SL280DFV units are equipped with a two−stage, variable speed integrated control. This control manages ignition switch settings. timing, heating mode fan off delays and indoor blower...
  • Page 33 NOTE − The off portion of the selected ramp profile also ap- Ramping Option D S Motor runs at 100% until demand is satisfied. plies during heat pump operation in dual fuel applications. TABLE 17 S Once demand is met, motor ramps down to stop. Cooling Mode Blower Speed Ramping Ramping Option Switch 9...
  • Page 34 Refer to table 20 for operation sequence in ap- all error codes. Button must be pressed a second time plications including SL280DFV, a thermostat which fea- while c" is flashing to confirm command to delete codes. tures humidity control and a single−speed outdoor unit.

  • Page 35: Blower Performance Data

    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. SL280DF090V48B BLOWER PERFORMANCE (less filter) 0 through 0.8 in.
  • Page 36 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 480 cfm. SL280DF110V60C BLOWER PERFORMANCE (less filter) 0 through 0.8 in.
  • Page 37 TABLE 20 SL280DFV, Non−Communicating Thermostat with Humidity Control Feature and Single−Speed Outdoor Unit OPERATING SYSTEM DEMAND SYSTEM RESPONSE SEQUENCE Thermostat Demand Relative Humidity Blower System Step Compressor Comments Condition Status (COOL) NO CALL FOR DEHUMIDIFICATION Compressor and indoor Normal Operation...
  • Page 38 TABLE 21 SL280DFV, Non−Communicating Thermostat with Humidity Control Feature and Two−Speed Outdoor Unit OPERATING SYSTEM DEMAND SYSTEM RESPONSE SEQUENCE Thermostat Demand Relative Humidity Blower System Step Compressor Comments Condition Status (COOL) NO CALL FOR DEHUMIDIFICATION Normal Operation − Acceptable 70%*...

  • Page 39: Unit Start−Up

    (under cap) heavier than air and will settle on the floor. The gas valve on the SL280DFV unit will be equipped with either a gas control switch. Use only your hand to move the control switch. Never use tools. If the switch will not turn or if the switch will not move by hand, do not try to repair it.

  • Page 40: Gas Pressure Adjustment

    NOTE − Pressure test adapter kit (10L34) is available from 11 − Is the rollout switch tripped? If the switch is tripped call Lennox to facilitate manifold pressure measurement. the service technician to inspect the unit. 1 − Connect test gauge to manifold pressure post (figure Gas Pressure Adjustment 26) or tap (figure 27) on gas valve.

  • Page 41: High Altitude

    High Altitude IMPORTANT The manifold pressure, gas orifice and pressure switch For safety, shut unit off and remove manometer as may require adjustment or replacement to ensure proper soon as an accurate reading has been obtained. operation at higher altitudes. Tables 24 through 27 shows Take care to replace pressure tap plug.

  • Page 42: Other Unit Adjustments

    The two−stage, variable speed integrated control used in low−fire heating speed and the high−fire (second SL280DFV units has an added feature of an internal Watch- stage) gas valve is de−energized. The low−fire (first guard control. The feature serves as an automatic reset de- stage) gas valve continues operation.
  • Page 43 Applications Using A Single−Stage Thermostat 4 − After the 20−second warm−up period has ended, the gas See figure 29 for ignition control sequence valve is energized on low fire (first stage) and ignition oc- curs. At the same time, the control module sends a sig- B −...

  • Page 44: Service

    If so, remove five screws from the left side or right side of cabinet. All SL280DFV filters are installed external to the unit. Fil- See figure 31. ters should be inspected monthly. Clean or replace the fil- ters when necessary to ensure that the furnace operates 10−...
  • Page 45 SL280DFV BURNER, COMBUSTION AIR INDUCER ASSEMBLY & HEAT EXCHANGER REMOVAL gasket orifice plate orifice plate gasket gasket flue chase internal flue pipe internal flue pipe combustion air inducer combustion air inducer rollout switch ignitor burner box assembly burner box assembly...
  • Page 46 12− To clean the combustion air inducer visually inspect and 22− Repeat steps 21 and 23 until no leaks are detected. using a wire brush clean where necessary. Use com- 23− Replace access panel. pressed air to clean off debris and any rust. 13−...

  • Page 47: Planned Service

    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: SL280DF070V36A. All service must be performed by a licensed professional installer (or equivalent), service agency, or gas supplier.

  • Page 48: Integrated Control Diagnostic Codes

    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"...
  • Page 49 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 (Commu- Equipment is unable to communicate. Indicates nication numerous message errors. In most cases errors are system).
  • Page 50 Integrated Control Diagnostic Codes (continued) E 131 Corrupted control parameters (Verify configuration of system). Communi- Reconfigure the system. Replace control if heating cating only. or cooling is not available. Only applicable in the communicating mode, not in startup. Exit from Com- missioning and Execute ’Set Factory Default mode’.
  • Page 51 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 in- ducer for correct operation and restriction.
  • Page 52 Integrated Control Diagnostic Codes (continued) E 272 Soft lockout − Exceeded maximum number of recycles. Last recycle due Check operation of low pressure switch to see if it is to the pressure switch opening. stuck closed on heat call. Check pressure (inches w.c.) of high pressure switch closing on heat call.
  • Page 53 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 Warning Only. Restricted airflow − Indoor blower is setting. running at a reduced CFM (Cutback Mode −...
  • Page 54 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 cur- rent is sensed in START sensor, or after power re- set. E 407 LSOM −...

  • Page 55: Program Unit Capacity/Size Mode

    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)

  • Page 56: Troubleshooting: Heating Sequence Of Operation

    Troubleshooting: Heating Sequence of Operation CALL FOR FIRST−STAGE HEAT CALL FOR 1ST STAGE HEAT (LOW FIRE) INDOOR BLOWER OFF AFTER HEAT FAN OFF DELAY (LOW HEAT SPEED) INDOOR LIMIT BLOWER OFF HIGH ERROR SWITCH WATCHGUARD − INDOOR AFTER HEAT FAN LIMIT SWITCH CODE CLOSED WITHIN 3...
  • Page 57 Troubleshooting: Heating Sequence of Operation (Continued) CALL FOR SECOND−STAGE HEAT CALL FOR 2ND STAGE HEAT (HIGH FIRE) SINGLE STAGE 2 STAGE THERMOSTAT THERMOSTAT 2ND STAGE RECOGNITION DELAY ON DELAY (30 SECONDS) EXPIRED? ONLY FOR 1ST EXPIRED? REQUEST FOR 2ND STAGE HEAT INDUCER SWITCHED TO HIGH SPEED HIGH...
  • Page 58 Troubleshooting: Heating Sequence of Operation (Continued) CALL FOR HEAT SATISFIED FIRST−STAGE HEAT SECOND−STAGE HEAT RUN MODE: 1ST OR 2ND STAGE CALL FOR HEAT. ALL INPUTS MONITORED (LIMIT, PRESSURE, CALL FOR HEAT/COOL, FLAME LEVEL) 2ND STAGE HEAT 2ND STAGE CALL FOR HEAT SATISFIED? DE−ENERGIZE 2ND STAGE GAS VALVE...
  • Page 59 Troubleshooting: Cooling Sequence of Operation (Continued) CALL FOR COOLING 1ST STAGE COOLING REQUEST RECEIVED WAIT FOR COMPRESSOR TIMED OFF DELAY TO EXPIRE ENERGIZE 1ST STAGE COOLING CONTACTOR (COMPRESSOR & FAN) INDOOR BLOWER 2 SECOND ON DELAY ENERGIZE INDOOR BLOWER (LOW COOLING MODE) MAINTAIN INDOOR BLOWER (LOW COOLING MODE)
  • Page 60 Troubleshooting: Continuous Fan Sequence of Operation CALL FOR FAN CALL FOR FAN INDOOR BLOWER ON CONTINUOUS FAN SPEED CALL FOR FAN MAINTAIN INDOOR REMOVED? BLOWER AT CONTINUOUS FAN REQUEST MAINTAIN INDOOR FOR COOLING GO TO CALL FOR COOLING BLOWER AT RECEIVED? CONTINUOUS FAN REQUEST...

This manual is also suitable for:

Sl280df070v36aSl280df090v48bSl280df090v60cSl280df110v60c

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