Lennox SL280UH090V36B, SL280DF070V36A, SL280UH070V36A, SL280UH090V48B, SL280UH090V60C Unit Information

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Page 1

Corp. 1117-L4

Service Literature

Revised 06-2016

icomfort® ENABLED SL280DFV SERIES UNITS

SL280DFV series units are 80% efficiency gas furnaces

used for downflow applications only, manufactured with

Lennox Duralok heat exchangers formed of aluminized

steel. Units are available in heating capacities of 66,000 to

110,000 Btuh and cooling applications up to 5 tons. Refer to

Engineering Handbook for proper sizing.

Units are factory equipped for use with natural gas. Kits are

available for conversion to LPG operation. SL280DFV mod

el units are equipped with the icomfort

two-stage variable speed integrated control. All units use a

redundant gas valve to assure safety shut-off as required by

CSA.

All specifications in this manual are subject to change. Pro

cedures outlined in this manual are presented as a recom

mendation only and do not supersede or replace local or

state codes. In the absence of local or state codes, the

guidelines and procedures outlined in this manual (except

where noted) are recommendations only and do not consti

tute code.

TABLE OF CONTENTS

Specifications Page 2.............................

Parts Identification Page 3.........................

I Unit Components Page 4........................

II Installation Page 29............................

III Start Up Page 29..............................

IV Heating System Service Checks Page 31.........

V Typical Operating Characteristics Page 34.........

VI Maintenance Page 34..........................

enabled SureLight

SL280DFV

WARNING

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

WARNING

Electric shock hazard. Can cause injury or death. Before attempting to perform any service or maintenance, turn the electrical power to unit OFF at discon nect switch(es). Unit may have multiple power supplies.

VII Wiring and Sequence of Operation Page 38......

VIII Program Unit Capacity Size Mode Page 42......

IX Field Wiring and Jumper Settings Page 43........

X Troubleshooting Flow Chart Page 47..............

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CAUTION

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

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SPECIFICATIONS

Gas Heating Performance

High Fire

Temperature rise range - °F 35-65 35-65 35-65 35-65

Gas Manifold Pressure (in. w.g.)

Nat. Gas / LPG/Propane

Low Fire

Temperature rise range - °F 25-55 25-55 25-55 25-55

Gas Manifold Pressure (in. w.g.)

Nat. Gas / LPG/Propane

High static - in. w.g. Heating 0.8 0.8 0.8 0.8

Connections

Flue connection - in. round 4 4 4 4

in.

Indoor

Wheel nominal diameter x width - in. 10 x 8 11 x 9 11 x 10 11 x 10

Blower

Tons of add-on cooling 2 - 3 3 - 4 3.5 - 5 3.5 - 5

Air Volume Range - cfm 589 - 1514 830 - 1996 899 - 2273 882 - 2120

Electrical Data

Blower motor full load amps 7.7 12.8 12.8 12.8

Maximum overcurrent protection 15 20 20 20

Shipping Data lbs. - 1 package 130 153 164 173

NOTE - Filters and provisions for mounting are not furnished and must be eld provided.

Annual Fuel Utilization Efciency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized

furnaces.

Model No. SL280DF070V36A SL280DF090V48B SL280DF090V60C SL280DF110V60C

AFUE 80% 80% 80% 80%

Input - Btuh 66,000 88,000 88,000 110,000

Output - Btuh 52,000 69,000 70,000 87,000

3.5 / 10.0 3.5 / 10.0 3.5 / 10.0 3.5 / 10.0

Input - Btuh 43,000 57,000 57,000 72,000

Output - Btuh 35,000 46,000 46,000 59,000

1.7 / 4.9 1.7 / 4.9 1.7 / 4.9 1.7 / 4.9

Cooling 1.0 1.0 1.0 1.0

Gas pipe size IPS 1/2 1/2 1/2 1/2

Motor output - hp 1/2 1 1 1

Voltage 120 volts - 60 hertz - 1 phase

OPTIONAL ACCESSORIES - MUST BE ORDERED EXTRA

“A” Width

Models

CABINET ACCESSORIES

Downow Combustible Flooring Base 11M59 11M60 11M61

CONTROLS

ComfortSense® 7000 Thermostat Y0349 Y0349 Y0349

Remote Outdoor Sensor (for dual fuel and Humiidtrol

) X2658 X2658 X2658

DOWNFLOW FILTER KITS

Downow Filter Kit 51W06 51W07 51W08

No. and Size of lter - in. (1) 20 x 16 x 1 (2) 20 x 20 x 1 (2) 20 x 20 x 1

NIGHT SERVICE KITS

Night Service Kit 16S36 16S36 16S36

Safety Service Kit 89W19

“B” Width

Models

“C” Width

Models

89W19 89W19

GAS HEAT ACCESSORIES

Models

Natural Gas to

LPG/Propane Kit

all 11K51 11K46

LPG/Propane to

Natural Gas Kit

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FLUE CHASE

CONTROL BOX

(Includes two-stage integrated control,

transformer and circuit breaker)

INTERNAL FLUE PIPE ASSEMBLY

PARTS IDENTIFICATION

BLOWER ASSEMBLY

GASKET

SECONDARY LIMIT

DOOR INTERLOCK SWITCH

ROLLOUT SWITCH

INNER BLOWER ACCESS PANEL

ACCESS PANEL

PRIMARY LIMIT LOCATION

HEAT EXCHANGER

COMBUSTION AIR INDUCER

PRESSURE SWITCHES

COMBUSTION AIR INDUCER

GAS VALVE

BURNER BOX ASSEMBLY

FIGURE 1

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I-UNIT COMPONENTS

Unit components are shown in figure 1. The gas valve, combustion air inducer and burners can be accessed by re moving the access panel. Electrical components are in the control box (figure 2) found in the blower section.

CIRCUIT BREAKER CB8

PRESS TO RESET

FIGURE 3

CAUTION

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

A- Control Box

1. Control Transformer (T1)

A transformer located in the control box provides power to the low voltage section of the unit. Transformers on all models are rated 40VA with a 120V primary and a 24V sec ondary.

2. Door Interlock Switch (S51)

An interlock switch rated 14A at 125VAC is wired in series with line voltage. When the indoor blower access panel is removed the unit will shut down.

CONTROL BOX SL280DFV

Transformer

Interlock Switch

WARNING

Shock hazard. Disconnect power before servicing. Integrated

control is not field repairable.

If control is inoperable, simply replace entire con trol.

Can cause injury or death. Unsafe operation will result if repair is attempted.

4. SureLight Integrated Control (A92)

Units are equipped with the icomfort enabled Sur

eLight control is used with the icomfort Wi-Fi of a communicating comfort system. The control can also operate with a non-communicating conventional single or two-stage thermostat. The system consists of a ignition / blower control (figures 4 and 5) with control pin designa tions in tables 1, 2 and 3 and ignitor (figure 13). The control and ignitor work in combination to ensure furnace ignition and ignitor durability. The control provides gas ignition, safety checks and indoor blower control with two-stage gas heating. The furnace combustion air inducer, gas valve and indoor blower are controlled in response to various system inputs such as thermostat signal, pressure and limit switch signal and flame signal. The control features a seven-seg ment LED display, indicating furnace status (including in door blower) and error codes. The LED flashes in single digits. For example using table 5 under LIMIT CODE, an “E” followed by “2” followed by “5” followed by “0”, the limit switch circuit is open. The control also has two unpowered (dry) 1/4” contacts for a humidifier and a 120 volt accessory terminal. Both rated at (1) one amp each.

two-stage, variable speed integrated control. This

thermostat as part

Circuit Breaker

SureLight

Integrated Control

FIGURE 2

3. Circuit Breaker (CB8)

A 24V circuit breaker is also located in the control box. The switch provides overcurrent protection to the trans former (T1). The breaker is rated 3A at 32V. If the current exceeds this limit the breaker will trip and all unit opera tion will shutdown. The breaker can be manually reset by pressing the button on the face. See figure 3.

Electronic Ignition

At the beginning of the heat cycle the integrated control monitors the first stage and second stage combustion air inducer prove switch. The control will not begin the heating cycle if the first stage prove switch is closed (by-passed). Likewise the integrated control will not begin the second stage heating cycle if the second stage prove switch is closed, and will remain in first stage heat. However, if the second stage prove switch closes during the first stage heat pre-purge, the control will allow second stage heat. Once the first stage prove switch is determined to be open,

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the combustion air inducer is energized on low (first stage) heat speed. When the differential in the prove switch is great enough, the prove switch closes and a 15-second pre-purge begins.

NOTE - During abnormal conditions such as low supply voltage or low outdoor temperatures and the low fire pres sure 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

After the 15-second pre-purge period, the SureLight ignitor warms up for 20 seconds after which the gas valve opens for a 4-second trial for ignition. The ignitor energizes during the trial until flame is sensed. If ignition is not proved during the 4-second period, the control will try four more times with an inter purge and warm-up time between trials of 35 sec onds. After a total of five trials for ignition (including the ini tial trial), the control goes into Watchguard-Flame Failure mode. After a 60-minute reset period, the control will begin the ignition sequence again.

Two Stage Operation / Thermostat Selection DIP Switch

The control can be utilized in two modes: SINGLE-STAGE thermostat or TWO-STAGE thermostat. The thermostat selection is made using a DIP switch and must be posi tioned for the particular application. DIP switch 1, labeled T”STAT HEAT STAGE is factory-set in the OFF position for use with a two-stage thermostat. Move the DIP switch to ON for use with a single stage thermostat. While in the single-stage thermostat mode (single DIP switch setting), the burners will always fire on first-stage heat. The combustion air inducer will operate on low speed and indoor blower will operate on low heat speed. After a factory default 10 minute recognition period, the unit will switch to second stage heat. While in the two-stage ther mostat mode (two DIP switch setting) the burners will fire on first-stage heat. The combustion air inducer will operate on low speed and indoor blower will operate on low heat speed. The unit will switch to second-stage heat on call from the indoor thermostat. If there is a simultaneous call for first and second stage heat, the unit will fire an first stage heat and switch to second stage heat after 30 seconds of operation. See Sequence of Operation flow charts in the back of this manual for more detail.

TABLE 1

SureLight

Control 5 Pin Terminal Designation

PIN # Function

1 Ignitor

2 Combustion Air Inducer High Speed

3 Combustion Air Inducer Low Speed

4 Combustion Air Inducer Neutral

5 Ignitor Neutral

TABLE 2

SureLight

Control 12 Pin Terminal Designation

PIN # Function

1 Gas Valve High Fire

2 Second Stage Prove Switch

3 Rollout In

4 Ground

5 24V Hot

6 Primary Limit In

7 Gas Valve Low Stage

8 Gas Valve Common

9 24V Neutral

10 Ground

11 Rollout Switch Out

12 1st Stage Prove Switch

TABLE 3

SureLight

Control 6 Pin Terminal Designation

PIN # Function

1 Data Input From Motor

2 Common

3 Not Used

4 Data Output To Motor

5 5 Volt Bias Supply

6 Not Used

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HUM

LINE 1

7 SEGMENT LED

FLAME SENSE

DIAGNOSTIC

PUSH BUTTON

DIP SWITCHES

INTEGRATED CONTROL

ACC

HS/ CAI

INDOOR

BLOWER

CONNECTOR

NEUTRAL

OUTDOOR AIR

SENSOR

TERMINALS

DISCHARGE AIR

SENSOR

TERMINALS

TB83

COMMUNICATING

OUTDOOR

EQUIPMENT

I + I -CRI + I -

TB84

COMMUNICATING

INDOOR

THERMOSTAT

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 = 24VAC COMMON

RS-BUS INDOOR (TB84)

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

1/4” QUICK CONNECT TERMINALS

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

W1 W2 GY2Y1

NON-COMMUNICATINGNG

24V TERMINALS

12 PIN LOW

VOLTAGE

CONNECTOR

W915 Y1 TO Y2

2 STAGE COMPR

W951 R TO O HEAT PUMP

W914 R TO DS

DEHUM OR

RDHLODS

HARMONY

THERMOSTAT CONNECTIONS (TB1)

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

DH = DEHUMIDIFICATION OUTPUT COMMUNICATING

L = USE ONLY WITH A COMMUNICATING THERMOSTAT

AND A NON-COMMUNICATING OUTDOOR UNIT

REVERSING VALVE

THERMOSTAT ONLY

FIGURE 4

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THERMOSTAT SELECTION

TWO STAGE

THERMOSTAT

1−STAGE

THERMOSTAT

(TIMED STAGING)

−SEE SW #2

HEATING BLOWER−OFF DELAY

90 SECOND

HTG BLOWER

OFF DELAY

60 SECOND

HTG BLOWER

OFF DELAY

120 SECOND

HTG BLOWER

OFF DELAY

180 SECOND

HTG BLOWER

OFF DELAY

−BLOWER ON DELAY − 30 SEC. FIXED

HEATING MODE BLOWER SPEED

+ 24%

+ 18%

+ 12%

INCREASE AIR HTG CFM

+ 6%

FACTORY

DEFAULT

− 6%

− 12%

DECREASE AIR HTG CFM

− 18%

INTEGRATED CONTROL CONFIGURATION GUIDE

2ND STAGE HEAT ON DELAY

INDOOR EQUIPMENT

HEAT PUMP LINK

(JUMPERS R to O)

7 MIN

UPSTAGE

DELAY

12 MIN

UPSTAGE

DELAY

DIAGNOSTIC

PUSH BUTTON

FLAME SENSE

123456

S4S3

911

OUTDOOR

SENSOR

DISCHARGE

AIR SENSOR

I+ I−

RI+ I−CRI+ I− C

OUTDOOR EQUIPMENT

1−STG COMPRESSOR

W915

2 STAGE

COMPR

DO NOT CUT

2−STG COMPRESSOR

W915

2 STAGE

COMPR

CUT LINK

2−STAGE

COMPRESSOR LINK

(JUMPERS Y1 to Y2)

W915

CLG BLOWER SPEED ADJUSTMENT

HUM

W1W2 G Y2 Y1 C C DHL O DSR

HEAT PUMP UNIT

DEFAULT

ACC

W2GY2

ON−BOARD LINK

OPTION SELECTION

A/C UNIT

W951

HEAT PUMP

DO NOT CUT

W951

HEAT PUMP

CUT LINK

W951

+ 10%

− 10%

DIAGNOSTIC

LED

SureLight

HSI/CAI

IGN

CAI1

CAI2

P79

NO HARMONY ZONING

NO SIGNATURESTAT

W/ DS CONNECTION

110

4 7

CUT FOR

OPTION

SELECTION

W915

2 STAGE

COMPR

W951 HEAT

PUMP W914

DEHUM

HARMONY

DO NOT CUT

W914

DEHUM

HARMONY

HARMONY ZONING

SIGNATURESTAT W/

DS CONNECTION

CUT LINK

W914

DEHUM

HARMONY

DEHUMIDIFICATION−

HARMONY LINK

(JUMPERS R to DS)

W914

CONTINUOUS FAN MODE BLOWER SPEED

NEUTRALS

MEDIUM−LOW

SPEED

(38%)

MEDIUM−HIGH

SPEED

(70%)

LOW

SPEED

(28%)

HIGH SPEED (100%)

COOLING MODE BLOWER SPEED

HIGH

SPEED

MEDIUM−HIGH

SPEED

MEDIUM−LOW

SPEED

LOW

SPEED

COOLING MODE BLOWER RAMPING

OPTION A

OFF−50%−82%−

100%−50%−OFF

OPTION B

OFF−82%−100%−OFF

OPTION C

OFF−100%−100%−OFF

OPTION D

OFF−100%−OFF

−CUT ON−BOARD LINK (SOLDER TRACE) COMPLETELY THROUGH

BOTH LAYERS ON THE CONTROL BOARD

−LINKS CUT IN ERROR −INSTALL A JUMPER ON THE APPROPRIATE TERMINALS ON THE TERMINAL STRIP

−PROTECTIVE PLASTIC FILM ON DIP SWITCHES MAY BE REMOVED FOR EASE IN SETTING OF DIP SW.

* FACTORY DEFAULT

FIGURE 5

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TABLE 4

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..)

Diagnostic LED (Figure 4)

The seven-segment diagnostic LED displays operating status, target airflow, error codes and other information. The table beginning on Page 9 lists diagnostic LED codes.

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 any of the following:

Diagnostic Push Button (Figure 4)

The diagnostic push button is located adjacent to the seven-segment diagnostic LED. This button is used to en able 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.

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

lines “≡” are displayed

 10 minutes after entering the flame sense mode.

Program Unit Capacity/Size Mode

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 corre sponding to different variable speed furnace models for 3 seconds each. While the wanted character-model is dis played push button has to be released. Selected option will flash display for 10 seconds and during that time push but ton 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 field test mode and go into idle without changing programming the unit size.

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TABLE 5

Integrated Diagnostic Codes/Status of Equipment I.

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).

dF U E 105

E 110

E 111

E 112

E 113

E 114

E 115

E 116

E 117

E 120

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 dis played / Pause / Repeat Codes).

Heat pump stage (1 second ON, 0.5 second OFF) / % of input rate dis played / 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

Device communication problem - No other devices on RS BUS (Commu nication system).

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

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

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

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

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

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

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

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

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

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 miswired and/or loose connections between the stat, indoor unit and outdoor unit. Check for a high volt age source of noise close to the system. Fault clears after communication is restored.

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

normal operation 5 seconds after fault recovered.

System resumes normal operation 5 seconds after fault recovered.

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

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

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

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

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

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

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TABLE 5 Continued

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

E 124

Active communicating thermostat signal missing for more than 3 min utes.

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.).

E 126

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

E 131

Corrupted control parameters (Verify configuration of system). Communi cating only.

E 180

Outdoor air temperature sensor failure. Only shown if shorted or out-ofrange.

E 200

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

E 201

Indoor blower communication failure - Unable to communicate with blow er motor.

E 202

Indoor blower motor mis-match - Indoor motor horsepower does not match unit capacity. See Page 41.

E 203

Appliance capacity / size is NOT programmed. Invalid unit codes refer to configuration flow chart. See Page 41.

E 204

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

E 205

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

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 (sub net controller). Cleared after valid thermostat (sub net controller) message is received.

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.

control. Replace if problem prevents service and is persistent. Cleared 300 seconds after fault recov ered.

Reconfigure the system. Replace control if heating or cooling is not available. Only applicable in the communicating mode, not in startup. Exit from Com missioning and Execute 'Set Factory Default mode'. Control will still operate on default parameter set tings.

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), appropri ate 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 set ting and alarm, redo configuration and make sure that temperature sensor is marked as 'not installed' in Indoor Unit 'About' screen. When Indoor unit con trol is replaced, thermostat will 'tell' new control if temperature sensor is in system or not. Clears 30 seconds after fault recovered.

switch. Test furnace operation. Cleared after fault recovered.

Indoor blower communication failure (including pow er 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.

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 ther mostat from system while applying power and re programming.)

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

repaired.

correct, replace control.

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TABLE 5 Continued

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

E 206

E 207

E 223

E 224

E 225

E 226

E 227

E 228

E 229

E 240

E 241

E 250

E 252

E 270

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.

Hot surface ignitor sensed open - Refer to troubleshooting. SeePage 46. Measure resistance of hot surface ignitor. Replace if

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

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. Re sumes normal operation after fault is cleared

Low pressure switch failed closed - Refer to troubleshooting. See Page 46.

High pressure switch failed open - Refer to troubleshooting. See Page 46.

High pressure switch failed closed - Refer to troubleshooting. See Page 46.

Low pressure switch open during trial for ignition or run mode. Refer to troubleshooting. See Page 46.

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

Ignition on High Fire - Information Only Code is displayed if 1) low pressure switch fails to

Low flame current - Run mode - Refer to troubleshooting. See Page 46. Check micro-amperes of flame sensor using control

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

Limit switch circuit open - Refer to troubleshooting. See Page 46 Check for proper firing rate on furnace. Ensure

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

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

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 opera tion and restriction. Resumes normal operation after fault is cleared.

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

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 opera tion after fault is cleared.

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. Re sumes normal operation after fault is cleared.

Check vent system and pressure switch wiring con nections. Resumes normal operation after fault is cleared.

close, then furnace will switch to high speed inducer to close both low and high pressure switches, then furnace lights on high fire, or 2) if continuous fan is active, furnace lights on high fire for 60 seconds to improve heat exchanger warm up time.

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.

necessary. Alert clears when fault is recovered.

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.

Cleared when heat call is finished.

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

Page 11

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TABLE 5 Continued

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

E 271

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

E 272

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

E 273

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

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.

E 275

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

E 276

Watchguard calibration failure. Unable to perform pressure switch calibration.

E 290

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

E 291

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

E 292

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

E 294

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

E 295

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

E 310

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

E 311

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

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 opera tion and restriction. Clears when heat call finishes successfully.

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.

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

lockout. Clears when flame has been proven stable.

Check vent system and pressure switch wiring con nections. 1-hour soft lockout. Clears when calibra tion has finished successfully.

open or not within specifications. 1-hour soft lock out. Clears when flame has been proven stable.

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

Indoor blower motor unable to start (seized bear ing, stuck wheel, etc.). Replace motor or wheel if assembly does not operate or meet performance standards. 1-hour soft lockout. Clears after circula tor successfully starts.

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.

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

Compare outdoor sensor resistance to temperature/ resistance charts in installation instructions. Re place sensor if necessary. Cleared in Communicat ing mode: 30 seconds after fault recovered. In NonCommunicating mode: Cleared after the current heat call is completed.

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 re pair/add duct. 2-stage controls will reduce firing rate

stage. Clears when heat call finishes success

to 1 fully.

Page 12

Page 13

TABLE 5 Continued

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

E 312

E 313

E 331 E 334 E 347

E 348

E 349

E 370

E 400

E 401

E 402

E 403

E 404

E 405

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

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

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

Relay “Y1” stuck on interated control. Replace integrated control.

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

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

No 24 Volts between R & O on ”integrated control” with non communi cating outdoor unit (Dual fuel module required for heat pump applica tion).

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

LSOM - Compressor internal overload tripped. Thermostat demand Y1 is present; but, compres

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

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

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

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

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

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.

Check for proper configuring in installation instruc tions. Alarm is just a warning. The system will op erate, but might not meet efficiency and capacity parameters. Alarm will clear when commissioning is exited. Cleared after commissioning is com plete.

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.

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

Configuration link R to O needs to be restored. Replace link or hard-wire. Applicable in non com municating mode. Critical Alert.

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

sor 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.

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

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

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

Compressor rotor locked up due to run capacitor short, bearings are seized, excessive liquid refrig erant, etc. Clears the error after 4 consecutive nor mal run cycles or after power reset.

tion, open fuse, etc.) Clears the error after 1 nor mal compressor run cycle.

Page 13

Page 14

TABLE 5 Continued

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

E 406

E 407

E 408

E 409

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.

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

Run current transformer. Clears the error after cur rent is sensed in RUN sensor, or 1 normal compres sor run cycle, or after power reset.

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

after 1 normal compressor run cycle or after power reset.

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.

DIP Switch Settings

NOTE - All icomfortt settings are set at the icomfort Wi-Fi thermostat. See icomfortt installation instruction. In icom fortt communication system all DIP switch and clippable link settings are ignored. For conventional thermostats pro ceed 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 twostage thermostat. If a single-stage thermostat is to be used, the DIP switch must be repositioned.

a - Select “OFF” for two-stage heating operation con

trolled by a two-stage heating thermostat (factory set ting);

b - Select “ON” for two-stage heating operation con

trolled by a single-stage heating thermostat. This set ting provides a timed delay before second-stage heat is initiated.

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

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

ual 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 set tings provide higher supply air temperatures.Table 6 pro vides the blower off timings that will result from different switch settings.

TABLE 6

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 posi tioned for high speed (4) indoor blower motor operation during the cooling mode. Table 7 provides the cooling mode blower speeds that will result from different switch settings. Switches 5 and 6 set the blower cfm for secondstage cool. The integrated control automatically ramps down to 70% of the second-stage cfm for first-stage cfm. Refer to blower tables for corresponding cfm values.

TABLE 7

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

Page 14

Page 15

-10% to better suit the application. Table 8 below provides blower speed adjustments that will result from different switch settings. Refer to blower tables for corresponding cfm values.

TABLE 8

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 dehumidification performance. Table 9 provides the cooling mode blower speed ramping options that will result from different switch settings. The cooling mode blower speed ramping options are detailed below.

NOTE - The off portion of the selected ramp profile also ap plies during heat pump operation in dual fuel applications.

TABLE 9

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

7 1/2 MIN 82% CFM

COMPRESSOR DEMAND

100% CFM

1/2 MIN 50% CFM

OFF

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

7 1/2 MIN

82%CFM

COMPRESSOR DEMAND

100% CFM

OFF

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

COMPRESSOR

DEMAND

100% CFM

45 SEC.

OFF

Ramping Option D

 Motor runs at 100% until demand is satisfied.

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

100% CFM

COMPRESSOR

DEMAND

OFFOFF

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

The switches are factory set to the OFF position which pro vides factory default heat speed. Refer to table 10 for switches 11, 12 and 13 that provided the corresponding in creases or decrease to both high and low heat demand.

TABLE 10

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

TABLE 11

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

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Page 16

BLOWER DATA

SL280DF070V36A BLOWER PERFORMANCE (less lter) 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% 1065 1170

+18% 1010 1115

+12% 960 1055

+6% 910 1000

Factory Default 860 945

–6% 805 885

–12% 755 830

–18% 705 775

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 745 870 1025 1075 1100 1240 1425 1515

Factory Default 665 780 925 985 1015 1115 1305 1380

– 590 690 815 865 900 1025 1170 1250

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 250 cfm. Lennox Harmony III™ Zone Control Applications - Minimum blower speed is 250 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

SL280DF070V36A BLOWER MOTOR WATTS (COOLING)

Cooling Speed

DIP Switch

Settings

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Motor Watts @ Various External Static Pressures - in. wg.

First Stage Second Stage

+ Setting

Low 46 63 83 96 115 128 144 170 181 138 162 177 212 229 247 270 288 320 342 363

Cooling

Speed

Med-low 66 81 104 127 144 160 175 195 219 185 210 238 266 293 317 349 374 399 432 448

Med-High 100 123 138 167 191 211 234 255 271 299 328 354 380 412 434 477 499 528 557 570

High 124 146 170 192 214 226 255 273 307 376 378 414 458 493 507 558 571 604 613 585

Factory Default

Low 38 57 64 85 98 107 133 147 158 104 125 144 166

Cooling

Speed

Med-low 49 72 87 96 122 135 160 176 197 141 167 184 216 237 256 288 304 326 356 383

Med-High 70 90 109 132 158 172 201 222 231 218 245 276 306 323 357 374 403 444 472 489

High 90 108 138 154 170 192 223 235 260 259 280 317 350 381 405 449 469 496 532 544

– Setting

Low 33 45 60 73 89 104 114 123 144 73 89 111 124 155 175 196 210 224 243 263

Cooling

Speed

Med-low 40 54 74 86 106 115 134 142 170 108 118 153 170 196 219 227 253 266 286 316

Med-High 52 74 85 107 128 149 161 181 201 156 181 208 222 253 284 305 333

High 64 82 98 129 139 157 183 197 214 176 198 228 267 283 317 355 382 396 425 450

192 212 230 261 267 295 315

356 374 398

Page 16

Page 17

BLOWER DATA

SL280DF090V48B BLOWER PERFORMANCE (less lter) 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 1500

+18% 1285 1415

+12% 1220 1350

+6% 1135 1285

Factory Default 1075 1200

–6% 1030 1110

–12% 960 1050

–18% 890 975

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 740 905 1040 1220 1085 1330 1545 1730

Factory Default 690 820 950 1110 990 1200 1400 1,595

– 610 745 855 1005 895 1075 1270 1460

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 380 cfm. Lennox Harmony III™ Zone Control Applications - Minimum blower speed is 380 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

SL280DF090V48B BLOWER MOTOR WATTS (COOLING)

Cooling Speed

DIP Switch

Settings

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Motor Watts @ Various External Static Pressures - in. wg.

First Stage Second Stage

+ Setting

Low 33 59 77 98 122 142 166 192 214 97 129 150 188 217 247 267 302 323 365 394

Cooling

Speed

Med-low 64 91 118 139 167 193 215 246 272 156 188 230 269 313 346 377 429 452 491 529

Med-High 92 119 150 174 209 240 261 292 319 281 304 361 413 455 473 528 552 607 637 673

High 136 174 200 236 264 305 342 376 399 442 470 538 566 603 636 691 730 775 814 838

Factory Default

Low 23 50 63 84 104 124 150 168 194 74 103 126 155

Cooling

Speed

Med-low 45 74 98 114 140 163 192 216 247 120 155 192 223 246 276 314 352 382 412 458

Med-High 62 93 122 143 173 195 232 260 290 206 236 285 324 369 401 437 483 514 551 590

High 112 142 168 202 220 253 282 306 346 323 336 400 445 489 523 558 595 643 660 689

– Setting

Low 17 38 56 72 88 11 5 132 150 170 51 78 106 129 155 178 207 229 259 289 311

Cooling

Speed

Med-low 31 54 76 97 11 7 142 165 187 209 92 122 147 178 217 244 264 289 322 361 385

Med-High 51 76 104 125 153 175 202 222 258 135 177 208 233 272 3 11 349 386

High 78 107 137 155 184 215 246 268 301 247 282 313 365 398 445 483 521 558 582 620

183 210 243 264 290 316 349

417 452 491

Page 17

Page 18

BLOWER DATA

SL280DF090V60C BLOWER PERFORMANCE (less lter) 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% 1540 1695

+18% 1465 1615

+12% 1390 1530

+6% 1320 1450

Factory Default 1245 1365

–6% 1170 1285

–12% 1095 1205

–18% 1020 1120

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1125 1250 1400 1590 1585 1770 2000 2275

Factory Default 1020 1135 1285 1445 1420 1610 1845 2,050

– 900 1005 1155 1280 1305 1395 1645 1875

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 450 cfm. Lennox Harmony III™ Zone Control Applications - Minimum blower speed is 450 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

SL280DF090V60C BLOWER MOTOR WATTS (COOLING)

Cooling Speed

DIP Switch

Settings

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Motor Watts @ Various External Static Pressures - in. wg.

First Stage Second Stage

+ Setting

Low 81 109 135 154 190 215 243 269 291 197 229 269 314 351 403 424 465 503 542 572

Cooling

Speed

Med-low 117 142 175 204 227 252 285 308 340 299 329 388 432 466 495 549 586 645 669 705

Med-High 143 183 208 247 283 312 352 385 423 451 501 521 587 633 664 705 765 794 848 879

High 209 246 291 329 370 402 447 490 525 689 720 783 826 890 938 995 1032 1072 1104 1131

Factory Default

Low 63 92 11 4 139 162 186 216 242 270 144 183 217 248

Cooling

Speed

Med-low 82 111 141 159 195 223 247 274 308 211 245 294 331 369 401 445 486 523 559 604

Med-High 121 148 181 2 11 241 279 304 331 356 331 366 411 468 497 546 588 629 664 707 748

High 155 194 216 260 296 334 363 393 434 481 535 574 604 655 714 762 816 851 877 942

– Setting

Low 53 76 101 121 139 166 184 209 238 117 149 180 203 235 269 294 327 349 387 421

Cooling

Speed

Med-low 68 94 120 137 166 193 219 239 266 154 187 219 258 291 319 365 386 424 458 492

Med-High 88 117 144 169 204 227 251 282 313 225 254 298 355 382 427 459 503

High 124 156 183 208 239 267 304 326 359 362 395 436 484 520 568 614 643 686 721 746

286 307 354 386 421 459 498

542 580 604

Page 18

Page 19

BLOWER DATA

SL280DF110V60C BLOWER PERFORMANCE (less lter) 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% 1645 1810

+18% 1565 1720

+12% 1485 1635

+6% 1405 1545

Factory Default 1325 1460

–6% 1245 1370

–12% 1170 1285

–18% 1090 1195

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1055 1230 1365 1525 1500 1755 1915 2120

Factory Default 975 1115 1250 1400 1360 1585 1770 1960

– 895 1005 1130 1245 1225 1405 1595 1760

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 450 cfm. Lennox Harmony III™ Zone Control Applications - Minimum blower speed is 450 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

SL280DF110V60C BLOWER MOTOR WATTS (COOLING)

Cooling Speed

DIP Switch

Settings

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Motor Watts @ Various External Static Pressures - in. wg.

First Stage Second Stage

+ Setting

Low 78 101 128 144 172 200 218 244 264 172 196 243 284 321 360 391 428 452 494 528

Cooling

Speed

Med-low 108 135 162 192 213 241 269 295 324 268 294 352 376 424 466 505 554 581 604 645

Med-High 146 180 203 238 271 305 334 358 396 373 424 459 504 529 575 641 680 712 747 810

High 181 219 254 291 327 365 401 436 479 510 557 596 660 725 763 815 869 922 962 993

Factory Default

Low 62 87 108 125 148 173 196 222 239 135 165 194 231

Cooling

Speed

Med-low 87 11 5 135 158 189 218 236 264 285 195 226 270 311 347 377 421 455 494 530 562

Med-High 11 4 140 173 201 224 250 283 312 339 290 335 358 401 450 497 528 565 611 640 677

High 148 186 207 246 282 307 354 375 410 395 438 484 525 559 608 659 7 11 745 776 826

– Setting

Low 47 67 94 108 128 140 172 193 212 106 134 161 191 214 238 259 295 322 349 379

Cooling

Speed

Med-low 67 91 114 134 151 180 206 226 247 147 181 210 245 280 312 347 376 404 445 476

Med-High 94 116 141 167 198 210 242 259 288 207 236 284 320 356 391 421 473

High 118 146 176 202 222 248 285 313 337 280 315 356 398 444 478 520 559 607 627 669

267 305 320 346 381 422 457

494 535 573

Page 19

Page 20

On-Board Links

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

damage. Refer to table 12 for operation sequence in ap plications including SL280DFV, a thermostat which fea tures humidity control and a single-speed outdoor unit. Table 13 gives the operation sequence in applications with a two-speed outdoor unit.

On-Board Link W951 Heat Pump (R to O)

WARNING

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

On-board link W951 is a clippable connection between ter minals 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 ener

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

On-board link W914, is a clippable connection between ter minals 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 Har mony III control will be blocked and also lead to control

gized 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 ter minals 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 cool ing only.

TABLE 12

SL280DFV, Non-Communicating Thermostat with Humidity Control Feature and Single-Stage Outdoor Unit

OPERATING SEQUENCE

System

Condition

NO CALL FOR DEHUMIDIFICATION

Normal Operation 1 On On On Acceptable

BASIC MODE (only active on a Y1 thermostat demand)

Normal Operation 1 On On On Acceptable

Dehumidification

Call

PRECISION MODE (operates independent of a Y1 thermostat demand)

Normal Operation 1 On On On Acceptable

Dehumidification call 2 On On On Demand

Dehumidification call

ONLY

ComfortSense

Step

Jumpers at indoor unit with a single stage outdoor unit With Condensing unit - Cut W914 (R to DS) on SureLight With Heat Pump - Cut W914 (R to DS) & W951 (R to O) on SureLight

7000 thermostat to use for this application - Y2081 4 heat / 2 cool

Thermostat Demand Relative Humidity

Y1 O G

2 On On On Demand

1 On On On Demand

SYSTEM DEMAND SYSTEM RESPONSE

Status D

*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.

VAC

Compres

sor

High 100%

High

High 100%

High

board

60%, 65%,

board

Blower

CFM

(COOL)

70%*

Comments

Compressor and indoor blower follow thermostat demand

ComfortSense mostat energizes Y1 and de-energizes D on a call for de-humidification

Dehumidification mode be gins when humidity is greater than set point

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

7000 ther

Page 20

Page 21

TABLE 13

SL280DFV, Non-Communicating Thermostat with Humidity Control Feature and Two-Stage Outdoor Unit

OPERATING

SEQUENCE

SYSTEM DEMAND SYSTEM RESPONSE

Thermostat Demand Relative Humidity

System

Condition

Ste

Y1 Y2 O G

W1W

Status D

NO CALL FOR DEHUMIDIFICATION

Normal Operation -

1 On On

2 On

O n

Acceptable

VAC

ROOM THERMOSTAT CALLS FOR FIRST STAGE COOLING

BASIC MODE (only active on a Y1 thermostat demand)

Normal Operation 1 On On

Dehumidification

Call

2 On

O n

Acceptable

Demand

VAC

PRECISION MODE (operates independent of a Y1 thermostat demand)

Normal Operation 1 On On

Dehumidification

call

Dehumidification

call ONLY

2 On

1 On

O n

Acceptable

Demand

VAC

ROOM THERMOSTAT CALLS FOR FIRST AND SECOND STAGE COOLING

BASIC MODE (only active on a Y1 thermostat demand)

Normal Operation 1 On

Dehumidification

Call

2 On

O n

Acceptable

Demand

VAC

PRECISION MODE (operates independent of a Y1 thermostat demand)

Normal Operation 1 On On

Dehumidification

call

Dehumidification

call ONLY

2 On

1 On

O n

Acceptable

Demand

VAC

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

Compres

sor

Low

High 100%

Low

High

Low

High

High 100%

High

Low

High

board

(COOL)

60%, 65%

60% 65%

control

Blower

CFM

70%*

70%**

70%*

70%**

70%*

70%**

Comments

Compressor and indoor blower follow thermo stat demand

ComfortSense

7000 thermostat energizes Y2 and de-energizes D on a call for de-humidi fication

Dehumidification mode begins when humidity is greater than set point

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

ComfortSense

7000 thermostat energizes Y2 and de-energizes D on a call for de-humidi fication

Dehumidification mode begins when humidity is greater than set point

ComfortSense

7000 thermostat will try to maintain room humidity setpoint by allowing the room space to maintain a cooler room thermo stat setpoint***

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 21

Page 22

B- Indoor Blower Motor

Supply Air Blower

blower wheel

blower motor

secondary

limit

power choke

A solid‐state controller is permanently attached to the motor. The controller is primarily an A.C. to D.C. con verter. Converted D.C. power is used to drive the motor. The controller contains a microprocessor which moni tors varying conditions inside the motor (such as motor workload).

BLOWER MOTOR COMPONENTS

STATOR

(WINDINGS)

BEARING

1. Disconnect Power, 2. Remove internal flue pipe and chase

To Remove Blower From Unit:

3. Remove Control Box 4. Remove Bolts. 5. Unplug Motor Wires From Control Board. Then Slide Out Front of Unit.

FIGURE 6

WARNING

During blower operation, the ECM motor emits ener gy that may interfere with pacemaker operation. In terference is reduced by both the sheet metal cabinet and distance.

The motor communicates with the integrated control via a

2-way serial connection. The motor receives all necessary

functional parameters from the integrated control and does

not rely on a factory program like traditional variable speed

motors. SL280DFV units use a three‐phase, electronically

controlled D.C. brushless motor (controller converts single

phase a.c. to three phase D.C.), with a permanent‐magnet‐

type rotor (figure 7). Because this motor has a permanent

magnet rotor it does not need brushes like conventional D.C.

motors.

The stator windings are split into three poles which are electri

cally connected to the controller. This arrangement a l l o w s

motor windings to turn on and off in sequence by the con

troller.

IMPORTANT

Earlier ECM motors used on other Lennox furnace models are not interchangeable with motors used on the SL280DF furnace line.

ROTOR

FIGURE 7

The controller uses sensing devices to sense what position the rotor is in at any given time. By sensing the position of the rotor and then switching the motor windings on and off in se quence, the rotor shaft turns the blower.

All SL280DFV blower motors use single phase power. An external run capacitor is not used. The motor uses permanently lubricated ball‐type bearings.

Internal Operation

The motor is controlled via serial communication between the integrated control on the furnace and the controller at tached to the motor shell. The messages sent back and forth between the two controls serve to communicate rota tional direction, demand, motor size, current draw, torque, and rpm, among other variables.

Motor rpm is continually adjusted internally to maintain constant static pressure against the blower wheel. The control ler monitors the static work load on the motor and motor amp‐ draw to determine the amount of rpm adjustment. Blower rpm may be adjusted any amount in order to maintain a constant cfm as shown in Blower Ratings Tables. The cfm remains rel atively stable over a broad range of static pressure. Since the blower constantly adjusts rpm to maintain a specified cfm, mo tor rpm is not rated. Hence, the terms “cool speed”, “heat speed ” or “speed tap” in this manual, on the unit wiring dia gram and on blower B3, refer to blower cfm regardless of mo tor rpm.

Initial Power Up

When line voltage is applied to B3, there will be a large inrush of power lasting less than 1/4 second. This inrush charges a bank of DC filter capacitors inside the controller. If the discon nect switch is bounced when the disconnect is closed, the dis connect contacts may become welded. Try not to bounce the disconnect switch when applying power to the unit.

Page 22

Page 23

Motor Start‐Up

When B3 begins start‐up, the motor gently vibrates back and forth for a moment. This is normal. During this time the elec tronic controller is determining the exact position of the rotor. Once the motor begins turning, the controller slowly eases the motor up to speed (this is called “soft‐start”). The motor may take as long as 10‐15 seconds to reach full speed. If the motor does not reach 200 rpm within 13 seconds, the motor shuts down. Then the motor will immediately attempt a re start. The shutdown feature provides protection in case of a frozen bearing or blocked blower wheel. The motor may at tempt to start eight times. If the motor does not start after the eighth try, the controller locks out. Reset controller by momen tarily turning off power to unit.

The DC filter capacitors inside the controller are connected electrically to the motor supply wires. The capacitors take approximately 5 minutes to discharge when the disconnect is opened. For this reason it is necessary to wait at least 5 minutes after turning off power to the unit before attempt ing to service motor.

DANGER

Disconnect power from unit and wait at least five minutes to allow capacitors to discharge before at tempting to service motor. Failure to wait may cause personal injury or death.

Troubleshooting Motor Operation

To verify motor operation see steps below:

1- Remove J48 (5 pin power plug) from P48 on the mo tor.

2- With the power on at the furnace and door switch de pressed, use a test meter to verify 120V between pins 4 and 5 on J48.

3- Reconnect J48 to P48 on the motor.

4- Remove J49 (4 pin low voltage connector) from P49 on the motor.

5- Using test jumpers, apply 24V to pins 3 and 4 on P49 on the motor.

Note: Do not apply 24V to pins 2 and 4 on P49. Doing so will cause permanent damage to the motor.

6- Motor should run at 75%.

7- Test is complete. Remove jumpers and reconnect plugs.

Another option is to use the TECMate PRO motor tester with the 16 to 4 pin adaptor. The use of the TECMate PRO isolates the motor from the integrated control. Follow the instructions provided with the kit. If the motor runs do not replace.

Power Choke (L13)

A choke coil is used on SL280DFV 4 and 5 ton units equipped with 1 hp motors. The choke is located on the blower housing and is used to suppress transient current spikes.

Page 23

Page 24

BLOWER B3 HARNESS CONNECTORS

SHAFT

MOTOR with INTEGRATED

CONTROLLER

J48 5 Pin

J49 4 Pin

J49 4 Pin Control Connector

J48 5 Pin Line Voltage Connector

P48 5 Pin

P49 4 Pin

BLOWER B3 HARNESS CONNECTORS

P48 5 Pin

P49 4 Pin

SHAFT

MOTOR with INTEGRATED

CONTROLLER

P48 5 Pin

P49 4 Pin

FIGURE 8

J48 Connector installed on motor

P49 4 Pin

120v

J48 Connector

240v

Page 24

24v Transformer

J49 Connector

FIGURE 9

Page 25

Troubleshooting Motor Windings

Ensure that motor windings are not damaged by perform

ing the following tests:

NOTE - If your ohm meter is not an auto-ranging type, set it

to the highest ohm scale (100k ohms or greater) before

performing tests.

TABLE 14

Ohm Meter Range

TEST A

Measure the resistance between each of the three motor leads (3-pin plug) and the unpainted part of the end shield.

If the winding resistance to ground is <100k ohms, replace the motor and control module. If the resistance to ground is >100k, the motor windings are fine. Proceed to Test B.

Test A

Scale

200k

20k

200 two hundred ohm 0-200

Measurement Range

in words ohms

two megohm -- two million ohms

two hundred kilohm

-- two hundred thou sand ohms

twenty kilohm -twenty thousand ohms

two kilohm -- two thousand ohms

0-2,000,000

0-200,000

0-20,000

0-2,000

FIGURE 11

TEST B

Use an ohmmeter to measure the motor phase-to-phase resistance by checking these combinations of the the 3-pin motor plug. For the purpose of this test, start at either end of the connector as lead 1.

1 - The lead-to-lead resistance across any two leads

should be less than 20 ohms.

2 - Each lead-to-lead resistance should be the same.

If the measured resistance is greater than 20 ohms, re place the motor and control module.

Test B

FIGURE 10

FIGURE 12

Page 25

Page 26

C- Heating Components

1. Ignitor

The SureLight

ignitor is made of durable silicon nitride. Ig nitor longevity is enhanced by controlling voltage to the ig nitor. The integrated control provides a regulated 120 volts to the ignitor for a consistent ignition and long ignitor life. Ohm value should be 39 to 70. See figure 13 for ignitor location and figure 14 for ignitor check out.

NOTE - The SL280DFV(X) furnace contains electronic components that are polarity sensitive. Make sure that the furnace is wired correctly and is properly grounded.

2. Flame Sensor

A flame sensor is located on the left side of the burner sup port. See figure 13. The sensor is tip protrudes into the flame envelope of the left-most burner. The sensor can be removed for service without removing any part of the burn ers. During operation, flame is sensed by current passed through the flame and sensing electrode. The SureLight control allows the gas valve to remain open as long as flame signal is sensed. To check flame sense signal use the push-button found on the integrated control and go to Field Test Mode. The menu will display the flame signal. See table 15 for flame signal.

TABLE 15

Flame Signal in Microamps

Normal

Low Drop Out

2.6 or greater 2.5 or less 1.1

3. Gas Valve

The valve (figure 16 or 17) is internally redundant to assure safety shut-off. If the gas valve must be replaced, the same type valve must be used.

24VAC terminals and gas control knob are located on the valve. A wire harness connects the terminals from the gas valve to the electronic ignition control. 24V applied to the termi nals energizes the valve.

Inlet and outlet pressure taps are located on the valve. A regu lator adjustment screw is located on the valve.

LPG change over kits are available from Lennox. Kits include burner orifices and a gas valve.

4. Flame Rollout Switches (S47)

Flame rollout switch is a high temperature limit located on top of the burner box, one on each side.- See figure 13. The limit is a N.C. SPST manual‐reset limit connected in series with the secondary limit S21. When S47 senses rollout, the

circuit breaks and the ignition control immediately stops ignition and closes the gas valve. Rollout can be caused by

a blocked heat exchanger, flue or lack of combustion air. The switch is factory set to trip (open) at 210°F and cannot be

adjusted. The switch can be manually reset. To manually re set a tripped switch, push the reset button located on the con trol.

5. Burners

All units use inshot burners. Burners are factory set and re

quire no adjustment. Always operate the unit with the burner box front panel in place. Each burner uses an orifice (see table 20 for orifice size) that is precisely matched to the burn

er input. Burners can be removed as a one piece assembly for service. If burner assembly has been removed, it is critical

to align center of each burner to the center of the clamshell when re-installing. See more detail in Section VI- MAINTE

NANCE sub-section E- Heat Exchanger and Burners.

6. Primary Limit Control (S10)

The primary limit (S10) is located in the heating vestibule pan el. When excess heat is sensed in the heat exchanger, the limit will open. If the limit is open, the furnace control energizes

the supply air blower and closes the gas valve. The limit auto matically resets when unit temperature returns to normal. The

switch must reset within three minutes or the SureLight control will go into Watch guard for one hour. The switch is factory set and cannot be adjusted. The switch may have a different

set point for each unit model number. See Lennox Repair Parts Handbook if limit switch must be replaced,

7. Secondary Limit Controls (S21)

The secondary limit (S21) is located in the blower compart

ment. See figure 6. When excess heat is sensed in the blower compartment, the limit will open. If the limit is open, the furnace

control energizes the supply air blower and closes the gas valve. The limit automatically resets when unit temperature re turns to normal. The switch must reset within three minutes or

the SureLight control will go into Watch guard for one hour. The switch is factory set and cannot be adjusted.

Page 26

Page 27

Rollout Switch

(alternate location)

Rollout Switch

Sensor

SL280DFV HEATING COMPONENTS

Ignitor

Burners

Gas Valve and Manifold Assembly

Sight Glass

FIGURE 13

Page 27

Page 28

l B

Multi−Meter (set to ohms)

SL280DF Ignitor Check Out

Test 1

Remove 5-pin plug from control

Check ohms reading across terminals 1and 5

Ohm value should be between 39 - 70.

Multi−Meter (set to ohms)

Test 2

Seperate the 2-pin jack plug near the manifold

and check resistance of the ignitor. If the reading

is correct, then then there is a problem with the

wiring between the jack plug and control. If the

reading is not correct the issue is the ignitor.

Test 2

Integrated Control Board

Detail

Integrated Contro

Detail

Multi−Meter (set to VAC)

Integrated Control Board

Detail

Test 3

Insert meter probes into the terminals 1 and 5. (Use small

diameter probes in order to not damage plug). Check voltage

during 20 second warm up period. Voltage should read 120

10%. If voltage is above these values, check for correct

volts +

supply voltage to furnace.

FIGURE 14

Page 28

Page 29

8. Combustion Air Inducer (B6)

All units use a two-stage combustion air inducer to move air through the burners and heat exchanger during heating op eration. The blower uses a 120VAC motor. The motor oper ates during all heating operation and is controlled by fur nace / blower control A92. The inducer also operates for 15 seconds before burner ignition (pre‐purge) and for 5 sec onds after the gas valve closes (post‐purge). The inducer operates on low speed during first-stage heat, then switches to high speed for second stage heat.

sure) and opens the circuit to the furnace control and gas valve. A bleed port on the switch allows relatively dry air in the vestibule to purge switch tubing, to prevent condensate build up.

NOTE - The switch is factory set and is not field adjust able. It is a safety shut‐down control in the furnace and must not be by-passed for any reason. If switch is closed or by-passed, the control will not initiate ignition at start up.

NOTE - Each furnace model uses a unique CAI. Refer to Lennox Repair Parts listing for correct inducer for re placement.

A pressure switch connected to the combustion air inducer orifice plate is used to prove inducer operation. The combus tion air inducer orifice will be different for each model. See table 16 for orifice sizes. The switch monitors air pressure in the inducer housing. During normal operation, the pressure in the housing is negative. If pressure becomes less negative (signifying an obstruction) the proving switch opens. When the proving switch opens, the furnace control (A92) immedi ately closes the gas valve to prevent burner operation.

TABLE 16

SL280DFV Unit

C.A.I. Orifice Size

-070 1.375

-090 1.625

-110 1.844

9. Combustion Air Inducer Pressure Switch (S18)

S18 is a dual combustion air pressure switch (first and sec ond stage) located on the combustion air inducer orifice bracket. The switch is connected to the combustion air in ducer housing by means of a flexible silicone hose. It moni tors negative air pressure in the combustion air inducer housing.

The switches are a single‐pole single‐throw proving switch electrically connected to the furnace control. The purpose of the switch is to prevent burner operation if the combustion air inducer is not operating or if the flue becomes obstructed.

On heat demand (first or second stage) the switch senses that the combustion air inducer is operating. It closes a cir cuit to the furnace control when pressure inside the com bustion air inducer decreases to a certain set point. Set points vary depending on unit size. See table 17. The pressure sensed by the switch is negative relative to atmo spheric pressure. If the flue becomes obstructed during op eration, the switch senses a loss of negative pressure (pressure becomes more equal with atmospheric pres

COMBUSTION AIR PRESSURE SWITCH

Ta p

Bracket

High Fire

Switch

Low Fire

Switch

FIGURE 15

TABLE 17

SL280DFV Unit

-070 0.55 0.20

-090 0.55 0.20

-110 0.60 0.25

Set Point High

Heat

Set Point Low Heat

II-PLACEMENT AND INSTALLATION

Make sure unit is installed in accordance with installation instructions and applicable codes.

III-START‐UP

A-Preliminary and Seasonal Checks

1 - Inspect electrical wiring, both field and factory installed

for loose connections. Tighten as required.

2 - Check voltage at disconnect switch. Voltage must be

within range listed on the nameplate. If not, consult the power company and have voltage condition corrected before starting unit.

B-Heating Start‐Up

WARNING

Shock and burn hazard.

SL280DFV units are equipped with a hot surface ignition system. Do not attempt to light manually.

1 - STOP! Read the safety information at the beginning of

this section.

2 - Set the thermostat to the lowest setting.

Page 29

Page 30

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 - Turn switch on gas valve to OFF. Do not force. See

figure 16 or 17.

7 - Wait five minutes to clear out any gas. If you then smell

gas, STOP! Immediately call your gas supplier from a neighbor's phone. Follow the gas supplier's instruc tions. If you do not smell gas go to next step.

WHITE RODGERS GAS VALVE

INLET PRESSURE POST

GAS VALVE SHOWN IN ON POSITION

MANIFOLD

PRESSURE TAP

HIGH FIRE ADJUSTMENT

SCREW

(under cap)

FIGURE 16

HONEYWELL GAS VALVE

INLET PRESSURE TAP

ON SIDE

GAS VALVE SHOWN IN ON POSITION

HIGH FIRE ADJUSTING SCREW

(under cap)

MANIFOLD

PRESSURE

TAP ON

SIDE

FIGURE 17

8 - Turn switch on gas valve to ON. Do not force. See fig

ure 16 or 17.

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.

Turning Off Gas To Unit

1 - Set thermostat to lowest setting. 2 - Turn off all electrical power to unit if service is to be per

formed.

3 - Remove access panel. 4 - Turn switch on gas valve to OFF. Do not force. See fig

ure 16 or 17.

5 - Replace 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.

C-Safety or Emergency Shutdown

Turn off unit power. Close manual and main gas valves.

D-Extended Period Shutdown

Turn off thermostat or set to “UNOCCUPIED” mode. Close all gas valves (both internal and external to unit) to guaran tee no gas leak into combustion chamber. Turn off power to unit. All access panels and covers must be in place and se cured.

Page 30

Page 31

IV-HEATING SYSTEM SERVICE CHECKS

A-CSA Certification

All units are CSA design certified without modifications. Refer to the SL280DFV Installation Instruction.

B-Gas Piping

CAUTION

If a flexible gas connector is required or allowed by the authority that has jurisdiction, black iron pipe shall be installed at the gas valve and extend outside the furnace cabinet. The flexible connector can then be added between the black iron pipe and the gas supply line.

WARNING

Do not over torque (800 in-lbs) or under torque (350 in-lbs) when attaching the gas piping to the gas valve.

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

Compounds used on gas piping threaded joints should be resistant to action of liquefied petroleum gases.

C-Testing Gas Piping

IMPORTANT

sion on various metals used in gas piping. Use of a specialty Gas Leak Detector is strongly recommended. It is available through Lennox under part number 31B2001. See Corp. 8411-L10, for further details.

Do not use matches, candles, flame or any other source of ignition to check for gas leaks.

D-Testing Gas Supply Pressure

White Rodgers Gas Valve

An inlet post located on the gas valve provides access to the supply pressure. See figure 16. 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 20 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 20 for supply line pressure. Replace the threaded plug after mea surements have been taken.

E-Check Manifold Pressure

After line pressure has been checked and adjusted, check manifold pressure. Move pressure gauge to outlet pres sure tap located on unit gas valve (GV1). Checks of man ifold pressure are made as verification of proper regulator ad justment. Manifold pressure can be measured at any time the gas valve is open and is supplying gas to the unit. See table 20 for normal operating manifold pressure.

In case emergency shutdown is required, turn off the main shut‐off valve and disconnect the main power to unit. These controls should be properly labeled by the installer.

When pressure testing gas lines, the gas valve must be dis connected and isolated. Gas valves can be damaged if subjected to more than 0.5 psig (14” W.C.). See figure 18. If the pressure is equal to or less than 0.5psig (14”W.C.), use the manual shut-off valve before pressure testing to isolate furnace from gas supply.

GAS PIPING TEST PROCEDURE

MANUAL MAIN SHUT-OFF VALVE

WILL NOT HOLD TEST PRESSURE

IN EXCESS OF 0.5 PSIG (14”W.C.)

1/8 NPT PLUG

GAS VALVE

FIELD PROVIDED

LINE PRESSURE TAP

FIGURE 18

When checking piping connections for gas leaks, use pre ferred means. Kitchen detergents can cause harmful corro

CAP

IMPORTANT

For safety, connect a shut‐off valve between the manometer and the gas tap to permit shut off of gas pressure to the manometer.

The gas valve is factory set and should not require adjust ment. All gas valves are factory regulated.

Manifold Adjustment Procedure:

1 - Connect test gauge to manifold pressure post (figure

16) or tap (figure 17) 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

20.

4 - If necessary, make adjustments. Figures 16 and 17

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 20, replace valve.

6 - Shut unit off and remove manometer as soon as an ac

curate reading has been obtained. Take care to re place pressure tap plug.

7 - Start unit and perform leak check. Seal leaks if found.

Page 31

Page 32

F- Proper Gas Flow (Approximate)

Furnace should operate at least 5 minutes before check

ing gas flow. Determine time in seconds for two revolu

tions of gas through the meter. (Two revolutions assures a

more accurate time.) Divide by two and compare to time

in table 18 below. If manifold pressure matches table 20

and rate is incorrect, check gas orifices for proper size and

restriction.

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

TABLE 18

GAS METER CLOCKING CHART

Seconds for One Revolution

SL280DF

Unit

-045 80 160 200 400

-70 55 110 136 272

-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

Natural LP

1 cu ft

Dial

2 cu ft

Dial

1 cu ft

Dial

2 cu ft

DIAL

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.

G- Proper Combustion

Furnace should operate minimum 15 minutes with correct manifold pressure and gas flow rate before checking com bustion. See sections E- and F-. Take combustion sample beyond the flue outlet and compare to the table below. The maximum carbon monoxide reading should not exceed 100 ppm.

TABLE 19

Firing Rate

High Fire 6.0 - 7.4 6.9 - 8.4

Low Fire 4.8 - 6.0 5.7 - 7.0

The carbon monoxide reading should not exceed 100 ppm.

H-High Altitude

The manifold pressure, gas orifice and pressure switch may require adjustment or replacement to ensure proper operation at higher altitudes. See table 20 for manifold pressures, table 21 for pressure switch kits and table 23 or 22 for gas conversion kits.

CO2%

For Nat

CO2%

For L.P.

Page 32

Page 33

Table 20

Manifold Pressure Settings

Unit

Input

Gas

Orifice Size

0 - 7500 ft.

Orifice Size

7501 -

10,000 ft.

Manifold

Pressure in.wg.

0-4500 ft.

Low

Fire

High

Fire

Manifold

Pressure in.wg.

4501-7500 ft.

Low

Fire

High

Fire

Manifold

Pressure in.wg.

7501 - 10,000 ft.

Low

Fire

High

Fire

Supply Line

Min Max

Pressure

in. w.g.

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

070

LP/propane

.034 .032 4.9 10.0 4.9 10.0 4.9 10.0 11.0 13.0

Natural .063 .055 1.7 3.5 1.5 3.0 1.7 3.5 4.5 13.0

090

LP/propane

.034 .032 4.9 10.0 4.9 10.0 4.9 10.0 11.0 13.0

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

110

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.

LP/propane

.034 .032 4.9 10.0 4.9 10.0 4.9 10.0 11.0 13.0

TABLE 21

High Altitude Pressure Switch

Unit

Input

070 No Change No Change 73W36

090 No Change 69W56 73W36

110 No Change 69W56 73W35

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

High Altitude

Pressure Switch Kit

TABLE 22

Honeywell Gas Valve Conversion Kits

High Altitude

Natural Gas

Unit

Input

070 73W37 51W02 73W38 69W79

090 73W37 51W02 73W38 69W79

110 73W37 51W02 73W38 69W79

Orifice Kit

7501 -

10,000 ft.

Natural Gas to

LP/ Propane Kit

0 - 7500 ft.

7501 -

10,000 ft.

LP/Propane

Natural Gas

Kit

0 - 7500 ft.

TABLE 23

White Rodgers Gas Valve Conversion Kits

High Altitude

Unit

Input

Natural Gas

Orifice Kit

7501 -

10,000 ft.

070 73W37 11K51 11K46 77W09

090 73W37 11K51 11K46 77W09

110 73W37 11K51 11K46 77W09

Natural Gas to

LP/ Propane Kit

0 - 7500 ft.

7501 -

10,000 ft.

LP/Propane

Natural Gas

Kit

0 - 7500 ft.

Page 33

Page 34

V-TYPICAL OPERATING CHARACTERISTICS

A-Blower Operation and Adjustment

When the thermostat is set to “FAN ON,” the indoor blower will run continuously at approximately 38% of the second-stage cooling speed when there is no cool ing or heating demand.

When the SL280DFV is running on high fire or low fire (low fire is 91% of high fire), the indoor blower will run on the heating speed designated by the positions of DIP switches 11 and 12.

When the SL280DFV is running on second-stage cool or first-stage cool (second-stage cool is 70% of firststage cool), the indoor blower will run on the cooling speed designated by the positions of DIP switches 5 and 6.

B-Temperature Rise

Temperature rise for SL280DFV units depend on unit in put, blower speed, blower horsepower and static pressure as marked on the unit rating plate. The blower speed must be set for unit operation within the range of “TEMP. RISE °F” listed on the unit rating plate for high fire and low fire.

To Measure Temperature Rise:

1 - Place plenum thermometers in the supply and return

air plenums. Locate supply air thermometer in the first horizontal run of the plenum where it will not pick up ra diant heat from the heat exchanger.

2 - Set thermostat to highest setting. Confirm unit is on

high fire by checking rate.

3 - After plenum thermometers have reached their high

est and steadiest readings, subtract the two readings. The difference should be in the range listed on the unit rating plate. If the temperature is too low, decrease blower speed.

4 - Repeat on low fire. Do not adjust low fire manifold pres

sure.

C-External Static Pressure

1 - Tap locations shown in figure 19.

2 - Punch a 1/4” diameter hole

in supply and return air ple nums. Insert manometer hose flush with inside edge of hole or insulation. Seal around the hose with perma gum. Connect the zero end of the manometer to the dis charge (supply) side of the system. On ducted sys tems, connect the other end of manometer to the return duct as above. Open all return air registers and check for clean filter.

3 - With only the blower motor running and the evaporator

coil dry, observe the manometer reading. Adjust blow er motor speed to deliver the air desired according to the job requirements. For heating speed external static pressure drop must not be more than 0.8” W.C. For cooling speed external static pressure drop must not be more than 1.0” W.C.

4 - Seal the hole when the check is complete.

STATIC PRESSURE TEST

filter

coil

FIGURE 19

VI-MAINTENANCE

Annual Furnace Maintenance

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

A “Disconnected Vent” warning sticker should be attached to a visible area of the plenum near the vent pipe. If the sticker is not legible or missing, order kit 66W04 for re placement stickers.

WARNING

Disconnect power before servicing unit.

CAUTION

Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dan gerous operation. Verify proper operation after ser vicing.

WARNING

The inner blower access panel and vent pipe 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.

1- Check wiring for loose connections, voltage at indoor

unit and amperage of indoor motor

2- Check the condition of the belt and shaft bearings if ap

plicable.

3- Inspect all gas pipe and connections for leaks

4- Check the cleanliness of filters and change if necessary

(monthly).

IMPORTANT

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

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

5- Check the condition and cleanliness of burners and

heat exchanger and clean if necessary.

Page 34

Page 35

6- Check the cleanliness of blower assembly and clean

the housing, blower wheel and blower motor if neces sary

. The blower motors are prelubricated for extended

bearing life. No further lubrication is needed.

7- Inspect the combustion air inducer and clean if neces

sary.

8- Evaluate the heat exchanger integrity by inspecting the

heat exchanger per the AHRI heat exchanger inspec tion procedure. This procedure can be viewed at www.ahrinet.org

9- Ensure sufficient combustion air is available to the fur

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

air

10 Inspect the furnace venting system to make sure it is in

place, structurally sound, and without holes, corrosion, or blockage. Vent system must be free and clear of ob structions and must slope upward away from the fur

. Vent system should be installed per the National

nace Fuel Gas Code

11 Inspect the furnace return air duct connection to ensure

the duct is sealed to the furnace. Check for air leaks on supply and return ducts and seal where necessary

12 Check the condition of the furnace cabinet insulation

and repair if necessary.

13 Perform a complete combustion analysis during the fur

nace inspection to ensure proper combustion and oper ation. Consult Service Literature for proper combustion values.

14 Verify operation of CO detectors and replace batteries

as required.

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

1 - Check the operation of the ignition system, inspect

and clean flame sensor. Check microamps before and after. Check controls and safety devices (gas valve, flame sensor, temperature limits). Consult Service Manual for proper operating range. Thermal Limits should be checked by restricting airflow and not dis connecting the indoor blower. For additional details, please see Service and Application Note H049.

2 - Verify that system total static pressure and airflow set

tings are within specific operating parameters.

3 - Clock gas meter to ensure that the unit is operating at

the specified firing rate. Check the supply pressure and the manifold pressure. On two-stage gas furnaces check the manifold pressure on high fire and low fire. If manifold pressure adjustment is necessary, consult the Service Literature for unit specific information on adjusting gas pressure. Not all gas valves are ad justable. Verify correct temperature rise.

Page 35

Page 36

A-Heat Exchanger and Burners

Cleaning the Heat Exchanger and Burners

NOTE - Use papers or protective covering in front of the fur nace during cleaning.

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

nace.

2 - Remove flue pipe, top cap, flue chase and internal flue

pipe assembly 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.

SL280DFV BURNER, C.A.I ASSEMBLY &

HEAT EXCHANGER REMOVAL

gasket

5 - Remove the collector box located behind the combus

tion air inducer. Be careful with the collector box gas ket. 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. Re move the four screws securing the burner manifold as sembly to the vestibule panel and remove the assem bly from the unit.

7 - Remove screws securing burner box and remove

burner box.

8 - Remove screws from both sides, top and bottom of

vestibule panel.

9 - 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 21.

internal flue pipe

combustion air inducer

rollout switch

(alternate location)

sensor

gasket

Sight glass

orifice plate

rollout switch

manifold and gas valve

burner box cover plate

gasket

heat exchanger

collector box

pressure switch

retention rings

cross over

FIGURE 20

Page 36

Page 37

10- Back wash using steam. Begin from the burner open

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

11- To clean burners, run a vacuum cleaner with a soft

brush attachment over the face of burners. Visually in spect inside the burners and crossovers for any block age caused by foreign matter. Remove any blockage. Figure 20 shows burner detail.

12- 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.

13- Reinstall heat exchanger in vestibule. (Replace the

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

14- Reinstall collector box, combustion air assembly, inter

nal flue pipe and flue chase. Seal with high tempera ture RTV. 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.

15- Reinstall burner box, manifold assembly and burner

box cover.

16- Reconnect all wires.

17- Reconnect top cap and vent pipe to combustion air in

ducer outlet.

18- Reconnect gas supply piping.

19- Turn on power and gas supply to unit.

20- Set thermostat and check for proper operation.

21- Check all piping connections, factory and field, for gas

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

22- If a leak is detected, shut gas and electricity off and re

pair leak.

23- Repeat steps 21 and 23 until no leaks are detected.

24- Replace access panel.

Remove five screws if necessary

(either side of cabinet)

CAUTION

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

FIGURE 21

Page 37

Page 38

VII- Wiring and Sequence of Operation

SL280DFV Schematic Wiring Diagram

Integrated Control Self Check

When there is a call for heat, the icomfort enabled inte

grated control runs a self check. The control checks for S10

primary limit, S21 secondary limit (s) and S47 rollout switch

normally closed contacts. The control also checks for S102

high heat and S128 low heat prove switch normally open

contacts. Once self check is complete and all safety

switches are operational, heat call can continue.

NOTE - The ignition control thermostat selection DIP switch is factory-set in the “TWO-STAGE” position.

WARNING

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

WARNING

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

Page 38

Page 39

CAUTION

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

Applications Using a Two-Stage Thermostat

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 inte grated 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 ener gized at low speed.

2. Once the control receives a signal that the low pres sure switch has closed, the combustion air inducer be gins 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 in ducer 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 igni tion 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 con tinue this operation as long as the thermostat has a first-stage heating demand.

NOTE - If the indoor thermostat is set on CONTINU

OUS FAN ON mode, the furnace will light on high fire (second-stage) for 60 seconds to improve heat ex changer warm up. After 60 second warm-up period, furnace will switch to low fire (first-stage).

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.

Applications Using A Single-Stage Thermostat B - Heating Sequence -- Integrated Control Thermostat Selection DIP Switch 1 ON in “Single-Stage” Position

NOTE - In these applications, two-stage heat will be initi ated by the integrated control if heating demand has not been satisfied after the field adjustable period (7 or 12 min utes).

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

sending a signal to the integrated control. The inte grated 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 ener gized at low speed.

2. Once the control receives a signal that the low pres

sure switch has closed, the combustion air inducer be gins 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 in ducer 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 igni tion 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 con trol 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.

- 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.

Page 39

Page 40

icomfort Wi-Fi® Thermostat with SL280DFV

and Non-Communicating Outdoor Unit

icomfort Wi-Fi® Thermostat with SL280DFV

and icomfort-ENABLED Outdoor Unit

icomfort Wi-Fi® Thermostat icomfort-Enabled SL280DFV Indoor Furnace Non-Communicating Outdoor Air Conditioner

icomfortENABLED

SL280DFV

OPTIONAL DISCHARGE AIR SENSOR

icomfort Wi-Fi® THERMOSTAT

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

TWO-STAGE OPERATION

FURNACE

OPTIONAL OUTDOOR

AIR SENSOR

NON-COMMUNICATING

OUTDOOR AIR

CONDITIONING UNIT -

1 OR 2 STAGE

icomfort Wi-Fi® Thermostat icomfort-Enabled SL280DFV Indoor Furnace icomfort-Enabled Outdoor Air Conditioner or Heat Pump

icomfortENABLED

SL280DFV

FURNACE

OPTIONAL

DISCHARGE

AIR SENSOR

OPTIONAL OUTDOOR

AIR SENSOR

icomfort Wi-Fi® THERMOSTAT

icomfort- ENABLED

OUTDOOR AIR CONDITIONING

OR HEAT PUMP UNIT

Outdoor Unit

Communicating systems using the icomfort Wi-Fi® thermostat require four thermostat wires between the thermostat and the furnace/air handler control and four wires be tween the outdoor unit and the furnace/air handler control. When a thermostat cable with more than four wires is used, the extra wires must be properly connected to avoid electrical noise. The wires must not be left disconnected.

Use wire nuts to bundle the four unused wires at each end of the cable. A single wire should then be connected to the indoor unit end of the wire bundle and attached to the “C” terminals as shown below.

icomfort Integrated Control

icomfort Touch

Page 40

Page 41

Optional Accessories for use with any icomfort Touch® System

NOTE: icomfort Wi-Fi® THERMOSTAT SENSES HUMIDITY & CONTROLS HUM CONTACTS TO CYCLE HUMIDIFIER BASED ON DEMAND. NO OTHER CONTROL OR HUMIDIS TAT REQUIRED.

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

120V CONNECTIONS

“HUM” CONTACT IS CLOSED ANYTIME HUMIDITY DEMAND IS PRESENT

Discharge Air

Sensor (Required

for even heat)

icomfort Wi-Fi THERMOSTAT

RSBus

Maximum total length of all con nections on the RSBus is limited to 1500ft.

Wire gauge of RSBus wire is 18.

icomfort ENABLED SL280DFV FURNACE

ENABLED OUTDOOR

AIR CONDITIONING OR

HEAT PUMP UNIT

icomfort 

NOTE: 24V UV LIGHT APPLICATIONS

In an icomfort by Lennox system, neither furnace nor air handler former will have adequate VA to power 24V UV light applications. An additional transformer for UV light applications is required.

trans

icomfort Wi-Fi

THERMOSTAT

DEHUMIDIFIER CONTROL

Rf WGhGsCf

HVAC EQUIP

24V HUMIDIFIER CONNECTIONS

CS 7000 THERMOSTAT

CONVENTIONAL NON-COMMUNI CATING SYSTEM

COMMUNICATING SYSTEM

*24V IN jumper not used in noncommunicating configuration

*24V IN JUMPER

icomfort ENABLED SL280DFV FURNACE

icomfort ENABLED

SL280DFV FURNACE

HEPA BYPASS FILTER X2680 HEPA INTERLOCK KIT

icomfort ENABLED

SL280DFV FURNACE

LVCS VENTILATION CONTROL SYSTEM

SL280DFV FURNACE

icomfort ENABLED

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

PASS INDOOR BLOWER MOTOR COMMON WIRE THROUGH CURRENT LOOP.

SEE HEPA INTERLOCK KIT FOR INSTALLATION DE TAILS

SEE LVCS VENTILATION INSTRUCTIONS FOR DAMPER & SENSOR WIRING

FIGURE 1

Page 41

HVAC EQUIPMENT

STANDARD 1 OR 2

STAGE AC OR HP UNIT

2 STAGE FURNACE

CUT R-DS W914

NON-COMMUNICATING SYSTEM WIRING

COMMUNICATING SYSTEM WIRING

Page 42

VIII- 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:

Yes

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

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

Solid P starts blinking on 7-Segment LED

Furnace control in IDLE mode

No heating, cooling or indoor fan

operation)

UNIT SIZE

CODE

−

Turn room thermostat to OFF

FURNACE MODEL

SL280DF070V36A

SL280DF090V48B

SL280DF090V60C

SL280DF110V60C

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).

−

. If

−

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 three horizontal bars display, board does not recognize unit size code function must be repeated)

. Programming

FINISHED

Page 42

Page 43

IX- SL280 Field Wiring Applications With Conventional Thermostat

DIP Switch Settings and On-Board Links (See figure 4)

Thermostat

1 Heat / 1 Cool

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

DIP Switch 1

Thermostat

Heating

Stages

On Board Links Must Be Cut To Select

System Options

DO NOT CUT ANY ON-BOARD LINKS

T'STAT

Wiring Connections

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.

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

W915

2 STAGE

COMPR

CUT ON-BOARD LINK

W914

DEHUM

HARMONY

T'STAT

FURNACE

TERM. STRIP

FURNACE

TERM. STRIP

OUTDOOR

UNIT

OUTDOOR

UNIT

* Not required on all units.

Page 43

Page 44

SL280 Field Wiring Applications With Conventional Thermostat Continued

DIP Switch Settings and On-Board Links (See figure 4)

Thermostat

DIP Switch 1

Thermostat

Heating

On Board Links Must Be Cut To Select

System Options

Stages

2 Heat / 2 Cool OFF

CUT ON-BOARD LINK

W915

2 STAGE

COMPR

Wiring Connections

T'STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

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

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

OFF

CUT ON-BOARD LINK

W915

2 STAGE

COMPR

CUT ON-BOARD LINK

W914

DEHUM

HARMONY

CUT ON-BOARD LINK

W914

DEHUM

HARMONY

T'STAT

FURNACE

TERM. STRIP

FURNACE

TERM. STRIP

OUTDOOR

UNIT

OUTDOOR

UNIT

2 Heat / 1 Cool OFF

* Not required on all units.

DO NOT CUT ANY ON-BOARD LINKS

Page 44

T'STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

Page 45

SL280 Field Wiring Applications With Conventional Thermostat Continued

DIP Switch Settings and On-Board Links (figure 4)

DIP Switch 1

Thermostat

Heating

On Board Links Must Be Cut To Select

System Options

Stages

Dual Fuel Single Stage

OFF

Heat Pump

CUT ON-BOARD LINK

ComfortSense 7000 L7742U thermostat w/

W951 HEAT

PUMP

dual fuel capa bilities Capable of 2 stage gas heat control

Wiring Connections

L7742U T'STAT

FURNACE

TERM. STRIP

HEAT PUMP

67M41*

Dual Fuel Two Stage Heat Pump

ComfortSense

OFF

CUT ON-BOARD LINK

W915

2 STAGE

COMPR

L7742U T'STAT

FURNACE

TERM. STRIP

HEAT PUMP

67M41*

7000 L7742U thermostat w/ dual fuel capa bilities Capable of 2 stage gas heat

CUT ON-BOARD LINK

W951 HEAT

PUMP

control

outdoor sensor

* 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.

outdoor

sensor

out blue

Page 45

Page 46

SL280 Field Wiring Applications With Conventional Thermostat Continued

DIP Switch Settings and On-Board Links (figure 4)

DIP Switch 1

Thermostat

Heating

On Board Links Must Be Cut To Select

System Options

Stages

Dual Fuel Single Stage

OFF

Heat Pump

CUT ON-BOARD LINK

ComfortSense 7000 L7742U thermostat w/

W951 HEAT

PUMP

dual fuel capa bilities Capable of 2 stage gas heat control w/dehu

CUT ON-BOARD LINK

W914

DEHUM

HARMONY

midification control

Wiring Connections

L7742U T'STAT

FURNACE

TERM. STRIP

HEAT PUMP

67M41*

Dual Fuel Two Stage Heat Pump

ComfortSense 7000 L7742U thermostat w/ dual fuel capa bilities Capable of 2 stage gas heat control w/dehu midification

OFF

CUT ON-BOARD LINK

W915

2 STAGE

COMPR

CUT ON-BOARD LINK

W951 HEAT

PUMP

CUT ON-BOARD LINK

W914

DEHUM

HARMONY

L7742U T'STAT

FURNACE

TERM. STRIP HEAT PUMP

67M41*

outdoor sensor

* 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.

outdoor

sensor

out blue

Page 46

Page 47

X- Troubleshooting

Troubleshooting: Heating Sequence of Operation

CALL FOR FIRST-STAGE HEAT

CALL FOR

1ST STAGE HEAT

(LOW FIRE)

LIMIT SWITCH

ROLLOUT

PRESSURE

INDUCER ON

LOW SPEED

PRESSURE SWITCH

CLOSED WITHIN 120

SECONDS?

PRE−PURGE

(15 SECONDS)

H.S.I. ON

(20 SECONDS)

1ST STAGE GAS

VALVE ENERGIZED

IGNITION TRIAL

BEGINS (H.S.I. ON)

HIGH

CLOSED?

YES

CIRCUITS CLOSED?

YES

LOW

SWITCH

OPEN?

YES

LOW

YES

HEAT FAN ON DELAY

INDOOR BLOWER OFF AFTER

HEAT FAN OFF DELAY

(LOW HEAT SPEED)

ERROR

CODE

FLASHES

DE−ENERGIZE

GAS VALVE

ERROR CODE

FLASHES (AFTER

5 SECONDS)

LOW PRESSURE SWITCH OPENS

TIMER STARTED

INDOOR BLOWER

ON(LOW HEAT

SPEED)

HIGH

PRESSURE

SWITCH

OPEN

BEFORE

INDUCER WAS

TURNED ON?

YES

CLOSED WITHIN 3

INDUCER ON

(HIGH SPEED)

INDOOR BLOWER ON (LOW HEAT

SPEED)

INDUCER TO HIGH SPEED−

YES

ERROR CODE

INTERPURGE

(15 SECONDS)

LIMIT

SWITCH

MINUTES?

ERROR

CODE

FLASHES

AFTER HEAT FAN

OFF DELAY (LOW

ROLLOUT

CIRCUIT CLOSES

(MANUAL

RE−SET)

HARD LOCKOUT − ERROR CODE FLASHES

LOW & HIGH PRESSURE SWITCH CLOSED WITHIN 30

SECONDS?

INDOOR

BLOWER OFF

HEAT SPEED)

INDUCER OFF

AFTER POST

PURGE

INDOOR BLOWER OFF AFTER HEAT OFF DELAY

YES

INDUCER OFF−

WAIT 5 MINUTES ERROR CODE

FLASHES

WATCHGUARD − ERROR CODE FLASHES

YES

CALL

FOR HEAT

ENDS?

YES

INDOOR

BLOWER

ON?

YES

INDOOR

BLOWER

OFF AFTER

HEAT FAN

OFF DELAY

FLAME

SENSED WITHIN

4 SECONDS?

YES

H.S.I. OFF

INDOOR

BLOWER ON 45 SEC.

(LOW HEAT SPEED)

CALL FOR HEAT SATISFIED

GAS VALVE

DE−ENERGIZED

H.S.I. OFF

WATCHGUARD LOCKOUT AUTOMATICALLY RESETS AFTER ONE HOUR

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.

5TH

UNSUCCESSFUL

TRIAL?

Page 47

YES

POSTPURGE (5 SECONDS)

INDUCER

OFF

WATCHGUARD − ERROR CODE FLASHES

Page 48

Troubleshooting: Heating Sequence of Operation (Continued)

CALL FOR SECOND-STAGE HEAT

2 STAGE THERMOSTAT

RECOGNITION DELAY

ONLY FOR 1ST

REQUEST FOR

2ND STAGE HEAT

CALL FOR 2ND STAGE HEAT

(HIGH FIRE)

(30 SECONDS)

EXPIRED?

YES

INDUCER SWITCHED

TO HIGH SPEED

HIGH

PRESSURE SWITCH

CLOSED WITHIN 10

SECONDS?

2ND STAGE GAS VALVE

ENERGIZED

INDOOR BLOWER ENERGIZED

ON HIGH HEAT SPEED

YES

SINGLE STAGE

THERMOSTAT

2ND STAGE

ON DELAY

EXPIRED?

YES

INDUCER SWITCHED

TO LOW SPEED

5 MINUTE DELAY

(ERROR CODE FLASHES)

CALL FOR HEAT SATISFIED

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

WHEN USED WITH A SINGLE STAGE THERMOSTAT, SET SW1 TO THE ON POSITION IN DIP SWITCH S1.

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.

Page 48

Page 49

Troubleshooting: Heating Sequence of Operation (Continued)

CALL FOR HEAT SATISFIED

FIRST-STAGE HEAT SECOND-STAGE HEAT

2 3

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?

YES

DE−ENERGIZE 2ND STAGE

GAS VALVE

INDUCER SPEED SWITCHED

TO LOW SPEED

INDOOR BLOWER SWITCHED

TO LOW HEAT SPEED

1ST STAGE HEAT

1ST STAGE

CALL FOR HEAT

SATISFIED?

YES

GAS VALVE

DE−ENERGIZED

INDUCER OFF AFTER

5 SECOND POST PURGE

INDOOR BLOWER OFF

AFTER FIELD SELECTABLE

OFF DELAY

Page 49

Page 50

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)

2ND STAGE

COOLING

REQUEST?

YES

ENERGIZE 2ND STAGE COOLING CONTACTOR

(COMPRESSOR & FAN)

2ND STAGE

COOLING REQUEST

STILL ACTIVE?

MAINTAIN INDOOR

BLOWER

(LOW COOLING MODE)

YES

ENERGIZE INDOOR BLOWER

(HIGH COOLING MODE)

MAINTAIN INDOOR BLOWER

YES

1ST STAGE

COOLING REQUEST

STILL ACTIVE?

(HIGH COOLING MODE)

DE−ENERGIZE 2ND

STAGE COOLING

CONTACTOR

(COMPRESSOR & FAN)

1ST STAGE

COOLING REQUEST

STILL ACTIVE?

DE−ENERGIZE 1ST

STAGE COOLING

CONTACTOR

(COMPRESSOR & FAN)

DE−ENERGIZE INDOOR

BLOWER

YES

ENERGIZE AND MAINTAIN

INDOOR BLOWER AT

(LOW COOLING MODE)

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

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

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

DIP SWITCHES ON THE CONROL.

Page 50

Page 51

Troubleshooting: Continuous Fan Sequence of Operation

CALL FOR FAN

INDOOR BLOWER ON

CONTINUOUS FAN

SPEED

CALL FOR FAN

REMOVED?

YES

REQUEST

FOR COOLING

RECEIVED?

REQUEST

FOR HEAT

RECEIVED?

DE-ENERGIZE INDOOR

BLOWER

YES

MAINTAIN INDOOR

BLOWER AT

CONTINUOUS FAN

MAINTAIN INDOOR

BLOWER AT

CONTINUOUS FAN

MAINTAIN INDOOR

BLOWER AT

CONTINUOUS FAN

GO TO CALL FOR COOLING

GO TO CALL FOR 1ST STAGE HEAT

1 - If continuous fan is active, unit will light and run at high fire

for 60 seconds to improve heat exchanger warm up.

Page 51

Lennox SL280UH090V36B, SL280DF070V36A, SL280UH070V36A, SL280UH090V48B, SL280UH090V60C Unit Information

Specifications and Main Features

Frequently Asked Questions

User Manual

PARTS IDENTIFICATION