Lennox SL280UHNV, SL280UH060NV36A, SL280UH080NV48B Series Manual

Page 1

UNIT INFORMATION

Corp 1601-L8

Service Literature

ICOMFORT®-ENABLED SL280UHNV SERIES UNITS

SL280UHNVseries units are 80% efﬁ ciency gas furnac- es used for upﬂ ow or horizontal applications only, man- ufactured with Lennox Duralok heat exchangers formed of aluminized steel. SL280UHNV units are available in heating capacities of 40,000 to 100,000 Btuh and cooling applications up to 5 tons. Refer to Engineering Handbook for proper sizing.

Units are approved for installations up 4500 ft and factory equipped for use with natural gas only. SL280UHNV model units are equipped with the iComfort® enabled SureLight® two-stage variable speed integrated control. SL280UHNV unit meets the California Nitrogen Oxides (NOx) Standards and California Seasonal Efﬁ ciency re- quirements. All units use a redundant gas valve to assure safety shut-off as required by C.S.A.

All speciﬁ cations in this manual are subject to change. Procedures outlined in this manual are presented as a recommendation 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 constitute code.

SL280UHNV

Contents

I-Unit Components..........................................................4

Blower Data ..................................................................16

II-Placement and Installation ........................................ 31

III-Start-Up .................................................................... 31

IV-Heating System Service Checks ..............................32

V-Typical Operating Characteristics .............................34

VI-Maintenance ............................................................35

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

VIII- Field Wiring With Conventional Thermostat ..........42

IX- Program Unit Capacity Size Modes ........................46

X- Troubleshooting ....................................................... 47

Page 1

WARNING

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

CAUTION

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

Page 2

SPECIFICATIONS

Gas Heating Performance

High Fire

Temperature rise range - °F 30 - 60 30 - 60

Gas Manifold Pressure (in. w.g.)

Low Fire

Temperature rise range - °F 20 - 50 20 - 50

Gas Manifold Pressure (in. w.g.)

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

Connections

Flue connection − in. round 4 4

in.

Indoor

Wheel nominal diameter x width - in. 10 X 8 11-1/2 X 9

Blower

Tons of add-on cooling 2 - 3 2.5 - 4

Air Volume Range - cfm 606 - 1345 679 - 2002

Electrical Data Voltage 120 volts - 60 hertz - 1 phase

Blower motor full load amps 7.7 12.8

Maximum overcurrent protection 15 20

Shipping Data lbs. - 1 package 112 138

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

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

furnaces.

Model No. SL280UH060NV36A SL280UH080NV48B

AFUE 80% 80%

Input - Btuh 60,000 80,000

Output - Btuh 48,000 64,000

3.4 3.4

Natural Gas Only

Input - Btuh 39,000 52,000

Output - Btuh 31,000 41,000

1.5 1.5

Natural Gas Only

Cooling 1.0 1.0

Gas pipe size IPS 1/2 1/2

Motor output - hp 1/2 1.0

SPECIFICATIONS

Gas Heating Performance

High Fire

Temperature rise range - °F 30 - 60 30 - 60

Gas Manifold Pressure (in. w.g.)

Low Fire

Temperature rise range - °F 20 - 50 25 - 50

Gas Manifold Pressure (in. w.g.)

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

Connections

Flue connection − in. round 4 4

in.

Indoor

Wheel nominal diameter x width - in. 11-1/2 X 10 11-1/2 X 10

Blower

Tons of add-on cooling 3 - 5 3 - 5

Air Volume Range - cfm 826 - 2305 812 - 2125

Electrical Data Voltage 120 volts - 60 hertz - 1 phase

Blower motor full load amps 12.8 12.8

Maximum overcurrent protection 20 20

Shipping Data lbs. - 1 package 157 161

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

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

furnaces.

Model No. SL280UH080NV60C SL280UH100NV60C

AFUE 80% 80%

Input - Btuh 80,000 100,000

Output - Btuh 64,000 80,000

3.4 3.4

Natural Gas Only

Input - Btuh 52,000 65,000

Output - Btuh 41,000 52,000

1.5 1.5

Natural Gas Only

Cooling 1.0 1.0

Gas pipe size IPS 1/2 1/2

Motor output - hp 1.0 1.0

Page 2

Page 3

Combustion Air Inducer

Gas Valve

Air Intake Pipe

Heat Exchanger

ccess Panel

Inner Access

Panel

(includes two-stage integrated control,

transformer and circuit breaker)

FIGURE 1

Control Box

Blower Assembly

Page 3

Page 4

I-Unit Components

SL280UHNV unit components are shown in Figure 1. The gas valve, combustion air inducer and burners can be accessed by removing the access panel. Electrical components are in the control box (Figure 2) found in the blower section.

SL280UHNV units are factory equipped with a bottom return air panel in place. The panel is designed to be ﬁ eld removed as required for bottom air return. Markings are provided for side return air and may be cut out in the ﬁ eld.

ELECTROSTATIC DISCHARGE (ESD)

Precautions and Procedures

CAUTION

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

A- Control Box

1. Control Transformer (T1)

A transformer located in the control box provides power tothe low voltage section of the unit. Transformers on allmodels are rated 40VA with a 120V primary and a 24V

secondary.

2. Door Interlock Switch (S51)

A door interlock switch rated 14A at 125VAC is wired in series with line voltage. When the inner blower access panel

is removed the unit will shut down.

CONTROL BOX

Transformer

Circuit Breaker

Interlock Switch

SureLight

FIGURE 2

3. Circuit Breaker (CB8)

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

Integrated Control

CIRCUIT BREAKER CB8

PRESS TO RESET

FIGURE 3

WARNING

Shock hazard. Disconnect power before servicing. Integrated control is not ﬁ eld repairable. If control is inoperable, simply replace entire control. Can cause injury or death. Unsafe operation will resul if repair is attempted.

4. Integrated Control (A92)

Units are equipped with the icomfort enabled SureLight ® two-stage, variable speed integrated control. This control is used with the icomfort Wi-Fi® thermostat as part 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 (Figure 4 and Figure 5) with control pin designations in Table 1, Table 2 and Table 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 ﬂ ame signal. The control features a seven-segment LED display, indicating furnace status (including indoor blower) and error codes. The LED ﬂ ashes in single dig- its. 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 humidiﬁ er and a 120 volt accesso- ry terminal. Both rated at (1) one amp each.

Electronic Ignition

At the beginning of the heat cycle the integrated control monitors the ﬁ rst stage and second stage combustion air inducer prove switch. The control will not begin the heating cycle if the ﬁ rst 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 ﬁ rst stage heat. However, if the second stage prove switch closes during the ﬁ rst stage heat pre-purge, the control will allow second stage heat.

Once the ﬁ rst stage prove switch is determined to be open, the combustion air inducer is energized on low (ﬁ rst stage) heat speed. When the differential in the prove switch is great enough, the prove switch closes and a 15-second pre-purge begins.

Page 4

Page 5

NOTE - During abnormal conditions such as low supply voltage or low outdoor temperatures and the low ﬁ re pres- sure switch does not close, the combustion air inducer will switch to high ﬁ re. After a 15 second pre-purge the high ﬁ re pressure switch will close and the unit will begin operation on high ﬁ re. After 10 to 20 seconds of high ﬁ re operation the unit will switch to low ﬁ re.

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 ﬂ ame 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 seconds. After a total of ﬁ ve trials for ignition (including the initial 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 positioned 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, the burners will always ﬁ re on ﬁ rst-stage heat. The combustion air in- ducer will operate on low speed and indoor blower will operate on low heat speed. The unit will switch to second stage heat after a “recognition period”. DIP switch 2, labeled SECOND STAGE DELAY, is factory set in the OFF position for a 7 minute recognition period. The switch can be moved to the ON position for a 12 minute recognition period, after which time the unit will switch to secondstage heat.

While in the two-stage thermostat mode (two DIP switch setting) the burners will ﬁ re on ﬁ rst-stage heat. The com- bustion 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 ﬁ rst and second stage heat, the unit will ﬁ re an ﬁ rst stage heat and switch to sec- ond stage heat after 30 seconds of operation. See Sequence of Operation ﬂ ow 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 Combustuion 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

Not Used

Page 5

Page 6

HUM

LINE 1

7 SEGMENT LED

FLAME SENSE

DIAGNOSTIC

PUSH BUTTON

DIP SWITCHES

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 = 24VAXC COMMON

RS-BUS INDOOR (TB84)

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

Page 6

Page 7

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

7 MIN

DELAY

12 MIN

DELAY

FLAME SENSE

123456

S4S3

911

OUTDOOR

SENSOR

DISCHARGE

AIR SENSOR

I+ I

DIAGNOSTIC

PUSH BUTTON

UPSTAGE

HUM

CLG BLOWER SPEED ADJUSTMENT

DEFAULT

ACC

−

I+ I−CRI+ I−

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

INDOOR EQUIPMENT

W1W2GY2

ON−BOARD LINK

OPTION SELECTION

A/C UNIT

W951

HEAT PUMP

DO NOT CUT

HEAT PUMP UNIT

W951

HEAT PUMP

CUT LINK

HEAT PUMP LINK

(JUMPERS R to O)

W951

+ 10%

− 10%

DIAGNOSTIC

LED

SureLight

Y1 C C DH L O DSR

HSI/CAI

NO HARMONY ZONING

NO SIGNATURESTAT W/ DS CONNECTION

IGN

CAI1

CAI2

P79

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

NEUTRALS

CONTINUOUS FAN MODE BLOWER SPEED

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

Page 7

Page 8

TABLE 4

Integrated Control Diagnostic Modes

Dispaly 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 ﬂ ame signal mode

Solid “P” (variable speed only) Program unit capacity/size (Unit Code)

Two horizontal bars = Soft disable

* 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 5)

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

Diagnostic Push Button (Figure 5)

The diagnostic push button is located adjacent to the seven-segment diagnostic LED. This button is used to enable the Error Code Recall “E” mode and the Flame Signal “F” mode. Press the button and hold it to cycle through a menu of options. Every ﬁ ve 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 ﬂ ashing to conﬁ rm command to delete codes. Press the button until a solid “≡” is displayed to exit the Error Code Recall mode.

Flame Signal Mode

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

• Flame signal mode is exited after any of the following: Power is reset

• Pressing and holding push button until 3 horizontal lines “≡” are displayed

• 10 minutes after entering the ﬂ ame sense mode.

Program Unit Capacity/Size Mode

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

Soft Disable

Soft disabling is when thermostat ﬁ nds a device on the BUS that it does not recognize and the thermostat sends a the device a message to be in soft disabling mode until properly conﬁ gured. Two horizontal bars will display.

Steps to follow if the damper control module is displaying the soft disable code.

1 - Conﬁ rm proper wiring between all devices

(thermostat, damper control module, indoor and outdoor).

2 - Cycle power to the control that is displaying the soft

disable code.

3 - Put the room thermostat through set up.

4 - Go to setup / system devices / thermostat / edit

/ then push reset.

5 - Go to setup / system devices / thermostat / edit /

then push resetAll.

Page 8

Page 9

TABLE 5

Integrated Diagnostic Codes/Status of Equipment

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).

A Cubic feet per minute (cfm) setting for

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

C Cooling stage (1 second ON, 0.5 second

OFF) / 1 or 2 displayed / Pause / cfm setting displayed / Pause / Repeat codes).

d Dehumidiﬁ cation mode (1 second ON) /

1 second OFF) / cfm setting displayed / Pause / Repeat Codes).

h Heat pump stage (1 second ON, 0.5

second OFF) / % of input rate displayed / Pause / cfm setting / Pause / Repeat codes.

H Gas Heat Stage (1 second ON, 0.5 second

OFF) / 1 or 2 displayed / Pause / cfm setting displayed / Pause / Repeat codes. Blinking during ignition.

dF Defrost mode.

U Discharge Air Temperature

E105 Device communication problem - No other

devices on RS BUS (Communication system).

E110 Low line voltage. Line Voltage Low (Voltage lower than nameplate rating). Check power line

E111 Low line voltage. Reverse line power voltage wiring. System resumes normal operation 5

E112 Ground not detected System shuts down. Provide proper earth ground. System resumes normal

E113 High line voltage. Line Voltage High (Voltage higher than nameplate rating). Provide power

E114 Line voltage frequency out-of-range. No 60 Hertz Power. Check voltage and line power frequency. Correct

E115 Low 24V - Control will restart if the error

recovers.

E116 High 24V. 24 Volt Power High (Range is 18 to 30 volts). Check and correct voltage.

E117 Poor ground detected (Warning only) Provide proper grounding for unit. Check for proper earth ground to the

E120 Unresponsive device. Communication

only.

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 voltage source of noise close to the system. Fault clears after communication is restored.

voltage and correct. Alarm clears 5 seconds after fault recovered.

seconds after fault recovered.

operation 5 seconds after fault recovered.

voltage within proper range. System resumes normal operation 5 seconds after fault recovered.

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

24-Volt Power Low (Range is 18 to 30 volts). Check and correct voltage. Check for additional power-robbing equipment connected to system. May require installation of larger VA transformer to be installed in furnace / air handler. Clears after fault recovered.

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

system. Warning only will clear 30 seconds after fault recovered.

Usually caused by delay in outdoor unit responding to indoor unit poling. Recycle power. Check all wiring connections. Cleared after unresponsive device responds to any inquiry.

Page 9

Page 10

TABLE 5 Continued

Code

E124 Active communicating thermostat signal

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

Equipment lost communication with the thermostat. Check

missing for more than 3 minutes.

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

E125 Control failed self-check, internal error,

failed hardware. Will restart if error recovers. Integrated control not communicating.

Hardware problem on the control. Cycle power on control. Replace if problem prevents service and is persistent. Criti-

cal alert. Cleared 300 seconds after fault recovered. Covers hardware errors (ﬂ ame sense cir- cuit faults, pin shorts, etc.).

E126 Control internal communication problem. Hardware problem on the control. Cycle power on con-

trol. Replace if problem prevents service and is persistent.

Cleared 300 seconds after fault recovered.

E131 Corrupted control parameters (Verify con-

ﬁ guration of system). Communicating only.

Reconﬁ gure the system. Replace control if heating or cool-

ing is not available. Only applicable in the communicating

mode, not in startup. Exit from Commissioning and Execute

‘Set Factory Default mode Control will still operate on default

parameter settings

E180 Outdoor air temperature sensor failure.

Only shown if shorted or out-ofrange.

Compare outdoor sensor resistance to temperature/ resis-

tance charts in unit installation instructions. Replace sensor

pack if necessary. At beginning of (any) conﬁ guration, furnace

or air handler control will sense outdoor air and discharge

air temperature sensor(s). If detected (reading in range),

appropriate feature will be set as ‘installed’ and that could

be seen in ‘About’ screen. In normal operation after control

recognizes sensors, alarm will be sent if valid temperature

reading is lost. To get rid of setting and alarm, redo conﬁ gu-

ration and make sure that temperature sensor is marked as

‘not installed’ in Indoor Unit ‘About’ screen. When Indoor unit

control is replaced, thermostat will ‘tell’ new control if tem-

perature sensor is in system or not. Clears 30 seconds after

fault recovered.

E200 Hard lockout - Rollout circuit open or pre-

viously open.

E201 Indoor blower communication failure - Un-

able to communicate with blower motor.

Correct cause of rollout trip, or replace ﬂ ame rollout switch.

Test furnace operation. Cleared after fault recovered.

Indoor blower communication failure (including power out-

age). 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.

E202 Indoor blower motor mis-match - Indoor

motor horsepower does not match unit capacity.

Incorrect appliance capacity code selected. Check for proper

conﬁ guring under: Unit Size Codes for Furnace/Air Handler

on conﬁ guration guide or in installation instructions. Cleared

after the correct match is detected following a reset. (Re-

move thermostat from system while applying power and re-

programming.)

E203 Appliance capacity / size is NOT pro-

grammed. Invalid unit codes refer to conﬁ guration ﬂ ow chart.

No appliance capacity code selected. Check for proper con-

ﬁ guring under: Unit Size Codes for Furnace on conﬁ guration

guide or in installation instructions. Critical Alert. Cleared af-

ter valid unit code is read following a reset. (Remove thermo-

stat from system while applying power and reprogramming.)

E204 Gas valve mis-wired. Check gas valve operation and wiring. Clears when repaired.

E205 Gas valve control relay contact shorted. Check wiring on control and gas valve. If wiring is correct,

replace control.

Page 10

Page 11

TABLE 5 Continued

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

E206 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.

E207 Hot surface ignitor sensed open. Measure resistance of hot surface ignitor. Replace if

open or not within speciﬁ ed range found in IOM. Re- sumes normal operation after fault is cleared.

E223 Low pressure switch failed open. Check pressure (inches w.c.) of low pressure switch

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

E224 Low pressure switch failed closed. Check operation of low pressure switch to see if it is

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

E225 High pressure switch failed open. Check pressure (inches w.c.) of high pressure switch

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

E226 High pressure switch failed closed Check operation of high pressure switch closing on heat

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

E227 Low pressure switch open during trial for ignition

or run mode.

E228 Combustion air inducer calibration failure Unable to perform pressure switch calibration. Check

E229 Ignition on high ﬁ re IFC switched to high ﬁ re ignition because low ﬁ re pres-

E240 Low ﬂ ame current - Run mode. Check micro-amperes of ﬂ ame sensor using control

E241 Flame sensed out of sequence - Flame still pres-

ent.

E250 Limit switch circuit open. Check for proper ﬁ ring rate on furnace. Ensure there is

E252 Discharge air temperature too high (gas heat only). Check temperature rise, air ﬂ ow and input rate. Cleared

E270 Soft lockout - Exceeded maximum number of re-

tries. No ﬂ ame current sensed.

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

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

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

diagnostics or ﬁ eld-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.

Shut off gas. Check for gas valve leak. Replace, if necessary. Alert clears when fault is recovered.

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

when heat call is ﬁ nished.

Check for proper gas ﬂ ow. Ensure that ignitor is lighting burner. Check ﬂ ame sensor current. Clears when heat call ﬁ nishes successfully.

Page 11

Page 12

TABLE 5 Continued

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

E271 Soft lockout - Exceeded maximum number of re-

tries. Last retry failed due to the pressure switch opening.

E272 Soft lockout - Exceeded maximum number of re-

cycles. Last recycle due to the pressure switch opening.

E273 Soft lockout - Exceeded maximum number of re-

cycles. Last recycle due to ﬂ ame failure.

E274 Soft lockout - Exceeded maximum number of re-

cycles. Last recycle failed due to the limit circuit opening or limit remained open longer than 3 minutes

E275 Soft lockout - Flame sensed out of sequence.

Flame signal is gone.

E276 Watchguard calibration failure. Unable to perform pressure switch calibration. Check vent

E290 Ignitor circuit fault - Failed ignitor or triggering cir-

cuitry.

E291 Heat air ﬂ ow restricted below the minimum. Check for dirty ﬁ lter and air ﬂ ow restriction. Check blower

E292 Indoor blower motor unable to start due to ob-

structed wheel, seized bearings.

E294 Combustion air inducer over current. Check combustion blower bearings, wiring and amps. Re-

E295 Indoor blower motor temperature is too high. Indoor blower motor over temperature (motor tripped on

E310 Discharge error temperature sensor failure. Only

shown if shorted or out of range.

E311 Heat rate reduced to match indoor blower air ﬂ ow. Warning Only. Furnace blower in cutback mode due to

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

Check micro-amperes of ﬂ ame sensor using control diag- nostics or ﬁ eld-installed mode. Clean or replace sensor. Measure voltage of neutral to ground to ensure good unit ground. Clears when heat call ﬁ nishes successfully.

Shut down system. 1-hour soft lockout. Check ﬁ ring rate and air ﬂ ow. Check for blockage. Clears when heat call ﬁ nishes successfully.

Shut off gas. Check for gas valve leak. 1-hour soft lockout. Clears when ﬂ ame has been proven stable.

system and pressure switch wiring connections. 1-hour soft lockout. Clears when calibration has ﬁ nished successfully.

Measure resistance of hot surface ignitor. Replace if open or not within speciﬁ cations. 1-hour soft lockout. Clears when ﬂ ame has been proven stable.

performance. 1-hour soft lockout. Cleared when heat call ﬁ nishes successfully.

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

place if does not operate or does not meet performance standards. Clears after inducer current is sensed to be inrange after the ignition following the soft lockout or reset.

internal protector). Check motor bearings and amps. Replace if necessary. Cleared after blower demand is satisﬁ ed.

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

restricted airﬂ ow. Reduce ﬁ ring rate every 60 seconds to match available CFM. Check ﬁ lter and duct system. To clear, replace ﬁ lter if needed or repair/ add duct. 2-stage controls will reduce ﬁ ring rate to 1st stage. Clears when heat call ﬁ nishes successfully.

Page 12

Page 13

TABLE 5 Continued

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

E312 Restricted air ﬂ ow in cooling or continu-

ous fan mode is lower than cfm setting.

E313 Indoor or outdoor unit capacity mismatch.

Communication only.

E331 Global network connection - Communica-

tion link problem.

E334 Relay “Y1” stuck on interated control. Replace integrated control.

E347 No 24 Volt output on Y1 of ”integrated

control” with non communicating outdoor unit.

E348 No 24 Volt output on Y2 of ”integrated

control” with non?communicating outdoor unit.

E349 No 24 Volts between R & O on ”integrated

control” with non communicating outdoor unit (Dual fuel module required for heat pump application

E370 Interlock switch sensed open for 2 min-

utes.

E400 LSOM - Compressor internal overload

tripped.

E401 LSOM Compressor long run cycle or low

system pressure.

E402 LSOM - Outdoor unit system pressure

trip.

E403 LSOM - Compressor short-cycling. .(Run-

ning less than 4 minutes). Outdoor unit pressure trip

E404 LSOM - Compressor rotor locked. Com-

pressor short-cycling. (Running less than 4 minutes).

E405 LSOM - Compressor open circuit. Compressor circuit open (due to power disconnection, open fuse,

Warning Only. Restricted airﬂ ow - Indoor blower is running at a re- duced 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 ﬁ lter and duct system. To clear, re- place ﬁ lter if needed or repair/add duct. Cleared after the current service demand is satisﬁ ed.

Incorrect indoor/outdoor capacity code selected. Check for proper conﬁ guring in installation instructions. Alarm is just a warning. The system will operate, but might not meet efﬁ ciency and capacity pa- rameters. Alarm will clear when commissioning is exited. Cleared after commissioning is complete.

For Future Use.

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 input back to IFC chip). Critical Alert. Cleared after reset and Y1 input sensed.

Conﬁ guration link R to O needs to be restored. Replace link or hard- wire. Applicable in non communicating mode. Critical Alert.

Control sees the loss of 24VAC for 2 minutes.Terminate all services and wait for interlock switch to close. The alarm will clear when 24VAC is continuously sensed on DS terminal for a minimum of 10 seconds or on a power reset.

Thermostat demand Y1 is present; but, compressor is not running. Check power to outdoor unit. Clears the error after current is sensed in both RUN and START sensors for at least 2 seconds, or after service is removed, or after power reset.

Compressor ran more than 18 hours to satisfy a single thermostat demand. Critical Alert. Clears the error after 30 consecutive normal run cycles or power reset. Also monitors low pressure switch trips.

Discharge or suction pressure out-of-limits, or 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 consecutive normal run cycles or power reset.

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

etc.) Clears the error after 1 normalcompressor run cycle.

Page 13

Page 14

TABLE 5 Continued

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

E406 LSOM - Compressor open start circuit. Required amount of current is not passing through Start cur-

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

E407 LSOM - Compressor open run circuit. Required amount of current is not passing through Run current

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

E408 LSOM - Compressor contactor is welded. Compressor runs continuously. Clears the error after 1 normal

compressor run cycle or after power reset.

E409 LSOM - Compressor low voltage. Secondary voltage is below 18VAC. After 10 minutes, oper-

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

DIP Switch Settings

NOTE - All icomfort settings are set at the icomfort Wi-Fi

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

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

used with either a single-stage or two-stage thermostat. The thermostat selection is made using a DIP switch which must be properly positioned for the particular application. The DIP switch is factory-positioned for use with a 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 controlled by a

two-stage heating thermostat (factory setting);

b. Select “ON” for two-stage heating operation controlled by

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

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

mine the second stage on delay when a single-stage thermostat is being used. The switch is factory-set in the OFF position, which provides a 7-minute delay before 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 satisﬁ ed) 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 atisfy individual applicationsAdjust the blower off delay to achieve a supply air temperature between 90° and 110°F at the exact moment that the blower is de-energized. Longer off delay settings provide lower supply air temperatures; shorter settings provide higher supply air temperatures. Table 6 provides the blower off timings that will result from different switch settings.

TABLE 6

Blower Off Delay Switch Settings

Blower Off Delay

Seconds

60 On Off

90 (factory) Off Off

120 Off On

180 On On

Switch 3 Switch 4

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

unit is shipped from the factory with the dip switches positioned for high speed (4) indoor blower motor operation during the cooling mode. Table 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 ﬁ rst-stage cfm. Refer to 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 Adjust-

ment

-- The unit is shipped from the factory with the dip switches positioned for NORMAL (no) adjustment. The dip switches may be positioned to adjust the blower speed by +10% or

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

Page 14

Page 15

TABLE 8

Cooling Blower Speed Adjustment

Adjustment Switch 7 Switch 8

+10% (approx) On Off

Factory Default Off Off

-10% (approx) Off Off

Ramping Option C

• Motor runs at 100% until demand is satisﬁ ed.

• 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

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

hance dehumidiﬁ cation performance. The switches are factory set at option A which has the greatest effect on dehumidiﬁ cation 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.

TABLE 9

Cooling Mode Blower Speed Ramping

Ramping Switch 9 Switch 10

A (Factory) Off Off

BOffOn

COnOff

DOnOn

Ramping Option A (Factory Selection)

• Motor runs at 50% for 30 seconds.

• Motor then runs at 82% for approximately 7-1/2 minutes.

• If demand has not been satisﬁ ed after 7-1/2 minutes, motor runs at 100% until demand is satisﬁ ed.

• Once demand is met, motor runs at 50% for 30 seconds 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 D

• Motor runs at 100% until demand is satisﬁ ed.

• 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 provides factory default heat speed. Refer to Table 10 for switches 11, 12 and 13 that provided the corresponding increases or decrease to both high and low heat demand.

TABLE 10

Heating Mode Blower Speeds

Heat Speed Switch 11 Switch 12 Switch 13

Increase 24% On On On

Increase 18% On On Off

Increase 12% On Off On

Increae 6% On Off Off

Factory

Off Off Off

Default

Decrease 6% Off Off On

Decrease

Off On Off

12%

Decrease

Off On On

18%

Switches 14 and 15 -- Continuous Blower Speed --

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

Ramping Option B

• Motor runs at 82% for approximately 7-1/2 minutes. If

demand has not been satisﬁ ed after 7-1/2 minutes,mo- tor runs at 100% until demand is satisﬁ ed.

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

OFF

7 1/2 MIN

82%CFM

COMPRESSOR DEMAND

100% CFM

OFF

Page 15

TABLE 11

Continuous Blower Speed

Coninuous Blower Speed Switch 14 Switch 15

28% of High Cool Speed Off On

38% of High Cool Speed

(Factory)

70% of High Cool Speed On Off

100% of High Cool Speed On On

Off Off

Page 16

BLOWER DATA

SL280UH060NV36A BLOWER PERFORMANCE (less ﬁ lter) BOTTOM RETURN AIR 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1030 1140

+18% 965 1075

+12% 925 1020

+6% 870 965

Factory Default 825 915

–6% 775 865

–12% 735 810

–18% 685 760

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 595 715 815 920 845 1015 1175 1340

Factory Default 565 680 735 840 790 945 1070 1215

– 510 610 695 780 715 845 980 1120

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-High

High

SL280UH060NV36A BLOWER PERFORMANCE (less ﬁ lter) SINGLE SIDE RETURN AIR 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

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

Settings

+24% 985 1100

+18% 950 1050

+12% 875 1000

+6% 850 935

Factory Default 800 890

–6% 750 840

–12% 700 790

–18% 680 740

COOLING

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

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

High Low Medium-Low Medium-High

High

+ 575 700 800 890 835 990 1145 1300

Factory Default 535 630 745 825 760 890 1020 1185

– 475 580 645 750 690 820 950 1055

Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for speciﬁ 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 iHarmony® Zoning System Applications - Minimum blower speed is 250 cfm.

Page 16

Page 17

BLOWER DATA

SL280UH080NV48B BLOWER PERFORMANCE (less ﬁ lter) BOTTOM RETURN AIR 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1350 1500

+18% 1270 1420

+12% 1200 1340

+6% 1130 1270

Factory Default 1060 1190

–6% 970 1130

–12% 880 1025

–18% 845 950

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 640 870 1030 1200 1020 1310 1535 1750

Factory Default 590 770 925 1100 935 1200 1400 1600

– 545 635 750 960 815 1080 1260 1430

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-High

High

SL280UH080NV48B BLOWER PERFORMANCE (less ﬁ lter) SINGLE SIDE RETURN AIR 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

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

Settings

+24% 1245 1385

+18% 1180 1320

+12% 1130 1245

+6% 1045 1185

Factory Default 1095 1120

–6% 1020 1050

–12% 825 975

–18% 840 865

COOLING

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

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

High Low Medium-Low Medium-High

High

+ 600 810 995 1165 995 1265 1490 1680

Factory Default 560 705 855 1050 905 1140 1350 1525

– 540 585 750 910 735 1010 1200 1365

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

Factory default setting.

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

Zoning System Applications - Minimum blower speed is 380 cfm.

Page 17

Page 18

BLOWER DATA

SL280UH080NV48B BLOWER PERFORMANCE (less ﬁ lter) SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1300 1445

+18% 1230 1355

+12% 1145 1300

+6% 1215 1225

Factory Default 1015 1150

–6% 1050 1070

–12% 860 1000

–18% 750 935

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 625 835 1000 1190 1000 1280 1500 1715

Factory Default 590 760 910 1070 910 1180 1360 1560

– 540 655 800 940 760 1040 1230 1380

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-High

High

SL280UH080NV60C BLOWER PERFORMANCE (less ﬁ lter) BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

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

Settings

+24% 1375 1530

+18% 1330 1450

+12% 1260 1390

+6% 1185 1315

Factory Default 1130 1235

–6% 1050 1165

–12% 980 1090

–18% 940 1020

COOLING

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

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

High Low Medium-Low Medium-High

+ 1080 1235 1410 1655 1540 1745 2000 2300

Factory Default 975 1125 1290 1500 1390 1595 1815 2130

– 880 1010 1165 1360 1265 1440 1630 1930

High

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

Factory default setting.

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

Zoning System Applications - Minimum blower speed is 380 cfm for 08048B and 450cfm for 08060C

Page 18

Page 19

BLOWER DATA

SL280UH080NV60C BLOWER PERFORMANCE (less ﬁ lter)

Single Side Return Air - Air volumes in bold require Optional Return Air base and ﬁ eld fabricated transition to accommodate 20 x

25 x 1 in. air ﬁ lter in order to maintain proper air velocity. 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% 1350 1485

+18% 1280 1420

+12% 1220 1345

+6% 1155 1270

Factory Default 1100 1200

–6% 1020 1135

–12% 965 1070

–18% 870 980

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1050 1180 1350 1570 1500 1700 1915 2240

Factory Default 960 1080 1225 1420 1370 1540 1760 2035

– 845 950 1110 1290 1235 1390 1570 1840

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

COOLING

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

High Low Medium-Low Medium-High

High

Page 19

Page 20

BLOWER DATA

SL280UH100NV60C BLOWER PERFORMANCE (less ﬁ lter) BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

Settings

+24% 1745 1930

+18% 1670 1825

+12% 1580 1740

+6% 1500 1655

Factory Default 1425 1565

–6% 1310 1470

–12% 1260 1390

–18% 1190 1300

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

+ 1200 1250 1380 1585 1710 1790 1950 2270

Factory Default 1075 1150 1275 1460 1570 1610 1785 2065

– 1010 1050 1150 1320 1410 1480 1625 1880

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-High

High

SL280UH100NV60C BLOWER PERFORMANCE (less ﬁ lter)

Single Side Return Air - Air volumes in bold require Optional Return Air base and ﬁ eld fabricated transition to accommodate 20 x

25 x 1 in. air ﬁ lter in order to maintain proper air velocity. 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range

HEATING

Heating Speed

DIP Switch

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

Settings

+24% 1600 1785

+18% 1530 1685

+12% 1440 1600

+6% 1370 1515

Factory Default 1290 1415

–6% 1260 1390

–12% 1175 1290

–18% 1065 1190

COOLING

Cooling Speed

DIP Switch

Settings

Low Medium-Low Medium-High

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

High Low Medium-Low Medium-High

High

+ 1140 1180 1300 1480 1615 1695 1865 2160

Factory Default 1040 1060 1190 1365 1460 1530 1690 1960

– 930 970 1070 1240 1325 1380 1520 1760

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

Factory default setting.

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

Zoning System Applications - Minimum blower speed is 450 cfm.

Page 20

Page 21

On-Board Links

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

damage. Refer to Table 12 for operation sequence in applications including SL280UHNV, a thermostat which features humidity control and a single-speed outdoor unit. Table 13 gives the operation sequence in applications with a two-speed outdoor unit.

WARNING

Carefully review all conﬁ guration information provided. Failure to properly set DIP switches, jumpers and onboard links can result in improper operation!

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

On-board link W914, is a clippable connection between terminals R and DS on the integrated control. W914 must be cut when the furnace is installed with either the Harmony III zone control or a thermostat which features humidity control. If the link is left intact the PMW signal from the Harmony III control will be blocked and also lead to control

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

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

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

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

TABLE 12

OPERATING SEQUENCE

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

OPERATING SEQUENCE SYSTEM DEMAND SYSTEM RESPONSE

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

Dehumidiﬁ cation

call

PRECISION MODE (operates independent of a Y1 demand)

Normal Operation 1 On On On Acceptable

Dehumidiﬁ cation

Call

Dehumidiﬁ cation

Call Only

Dave Lennox ComfortSense® 7500 thermostat to use for this application - Y2081 4 heat / 2 cool *Dehumidiﬁ cation 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.

Step

2 On On On Demand 0 VAC High 70%*

1 On On On Demand 0 VAC High 70%*

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

Thermostat Demand Relative Humidity

Y1 O G W1 Status D

VAC

Compre

ssor

High 100%

Blower

CFM

(cool)

Comments

Compressor and indoor blower follow thermostat demand

ComfortSense® 7500

thermostat energizes Y1 and de-energizes

D on a call for de-

humidiﬁ cation

Dehumidiﬁ cation

mode begins when

humidity is greater

than set point

ComfortSense® 7500 thermostat will try to maintain room humidity setpoint by

allowing the room space to maintain

a cooler room

thermostat setpoint**

Page 21

Page 22

TABLE 13

OPERATING SEQUENCE

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

OPERATING

SEQUENCE

System

Condition

Step

NO CALL FOR DEHUMIDIFICATION

Normal Operation

1 On On On Acceptable

2 On On On On Acceptable

ROOM THERMOSTAT CALLS FOR FIRST STAGE COOLING

BASIC MODE (only active on a Y1 thermostat demand)

Normal Operation 1 On On On Acceptable

Dehumidiﬁ cation

call

2 On On On On Demand

PRECISION MODE (operates independent of a Y1 demand)

Normal Operation 1 On On On Acceptable

Dehumidiﬁ cation

Call

Dehumidiﬁ cation

Call Only

2 On On On On Demand

1 On On On On Demand

ROOM THERMOSTAT CALLS FOR FIRST AND SECOND STAGE COOLING

BASIC MODE (only active on a Y1 thermostat demand)

Normal Operation 1 On On On On Acceptable

Dehumidiﬁ cation

Call

2 On On On On Demand

PRECISION MODE (operates independent of a Y1 thermostat demand)

Normal Operation 1 On On On Acceptable

Dehumidiﬁ cation

Call

Dehumidiﬁ cation

Call ONLY

2 On On On On Demand

1 On On On On Demand

Jumpers at indoor unit with a two stage outdoor unit

Cut factory jumper from Y1 to Y2 or cut W915 (Y1 to Y2)

With Condensing unit - Cut W914 (R to DS) on SureLight® control

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

Dave Lennox ComfortSense® 7500 thermostat to use for this application - Y2081 4 heat / 2 cool *Normal operation ﬁ rst stage cooling blower speed is 70% COOL speed. **Dehumidiﬁ cation 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.

SYSTEM DEMAND SYSTEM RESPONSE

Thermostat Demand Relative Humidity

Y1 Y2 O G W1 W2 Status D

VAC

Compre

ssor

Low 70%*

High 100%

Low 70%*

High 70%**

Low 70%*

High 70%**

High 100%

High 70%**

Low 70%*

High 70%**

Blower

CFM

(cool)

Comments

Compressor and indoor blower follow thermostat demand

ComfortSense® 7500 thermostat energizes Y1 and de-energizes D on a call for de-humidiﬁ cation

Dehumidiﬁ cation mode begins when humidity is greater than set point

ComfortSense® 7500 thermostat will try to maintain room humidity setpoint by allowing the room space to maintain a cooler room thermostat setpoint**

ComfortSense® 7500 thermostat energizes Y2 and de-energizes D on a call for de-humidiﬁ cation

Dehumidiﬁ cation mode begins when humidity is greater than set point

ComfortSense® 7500 thermostat will try to maintain room humidity setpoint by allowing the room space to maintain a cooler room thermostat setpoint***

Page 22

Page 23

B- Indoor Blower Motor

Power Choke

(4 and 5 Ton Only)

To Remove Blower From Unit: Remove access panels,

Control box, Bolts and Wiring Jackplugs.

Blower Motor

(B3)

Then Slide Out Front of Unit.

FIGURE 6

WARNING

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

During blower operation, the ECM motor emits energy that may interfere with pacemaker operation. Interference is reduced by both the sheet metal cabinet and distance. 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. SL280UHNV 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-magnettype 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 electrically connected to the controller. This arrangement allows motor windings to turn on and off in sequence by the controller.

IMPORTANT

Earlier ECM motors used on other Lennox furnace models are not interchangeable with motors used on the SL280UH furnace line.

A solid-state controller is permanently attached to the motor. The controller is primarily an A.C. to D.C. converter. Converted D.C. power is used to drive the motor. The controller contains a microprocessor which monitors varying conditions inside the motor (such as motor workload).

BLOWER MOTOR COMPONENTS

STATOR

(WINDINGS)

BEARING

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 sequence, the rotor shaft turns the blower.

All SL280UHNV 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 attached to the motor shell. The messages sent back and forth between the two controls serve to communicate rotational 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 controller monitors the static work load on the motor and motor ampdraw 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 relatively stable over a broad range of static pressure. Since the blower constantly adjusts rpm to maintain a speciﬁ ed cfm, motor rpm is not rated. Hence, the terms “cool speed”, “heat speed ” or “speed tap” in this manual, on the unit wiring diagram and on blower B3, refer to blower cfm regardless of motor 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 ﬁ lter capacitors inside the controller. If the disconnect switch is bounced when the disconnect is closed, the disconnect contacts may become welded. Try not to bounce the disconnect switch when applying power to the unit.

Page 23

Page 24

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 electronic 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 “softstart”). 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 restart. The shutdown feature provides protection in case of a frozen bearing or blocked blower wheel. The motor may attempt to start eight times. If the motor does not start after the eighth try, the controller locks out. Reset controller by momentarily turning off power to unit.

The DC ﬁ lter capacitors inside the controller are connect- ed 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 attempting to service motor.

DANGER

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

Troubleshooting Motor Operation

To verify motor operation see steps below and Figure 8 and Figure 9.

1 - Remove J48 (5 pin power plug) from P48 on the

motor.

2 - With the power on at the furnace and door switch

depressed, 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 - 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 SL280UHNV 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 24

Page 25

BLOWER B3 HARNESS CONNECTORS

P48 5 Pin

SHAFT

BLOWER B3 HARNESS CONNECTORS

P48 5 Pin

P49 4 Pin

SHAFT

MOTOR with INTEGRATED

CONTROLLER

J48 5 Pin

J49 4 Pin

J49 4 Pin Control Connector

J48 5 Pin Line Voltage Connector

P49 4 Pin

MOTOR with INTEGRATED

CONTROLLER

P48 5 Pin

P49 4 Pin

120v

J48 Connector

240v

FIGURE 8

J48 Connector

installed on motor

P49 4 Pin

24v Transformer

J49 Connector

FIGURE 9

Page 25

Page 26

Troubleshooting Motor Windings

Ensure that motor windings are not damaged by performing 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

Scale Measurement Range

In Words ohms

2M two megohm - two

million ohms

200k two hundred kilohm

- two hundred

thousand ohms

20k twenty kilohm --

twenty thousand

ohms

2k two kilohm -- two

thousand ohms

200 two hundred ohm 0 - 200

0 - 2,000,000

0 - 200,000

0-20,000

0 - 2,000

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 ﬁ ne. Pro- ceed to Test B.

Test A

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, replace the motor and control module.

FIGURE 10

Test B

FIGURE 12

Page 26

Page 27

C- Heating Components

1. Ignitor

The SureLight® ignitor is made of durable silicon nitride. Ignitor longevity is enhanced by controlling voltage to the ignitor. 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 SL280UHNV furnace contains electronic components that are polarity sensitive. Make sure that the furnace is wired correctly and is properly grounded.

2. Flame Sensor

A ﬂ ame sensor is located on the top of the air gas ple- num. See Figure 13. The sensor can be removed for service without removing the the burner. During operation, ﬂ ame is sensed by current passed through the ﬂ ame and sensing electrode. The SureLight control allows the gas valve to remain open as long as ﬂ ame signal is sensed. To check ﬂ ame sense signal use the push-button found on the integrated control and go to Field Test Mode. The menu will display the ﬂ ame signal. See Table 15 for ﬂ ame 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) 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 terminals energizes the valve. Inlet and outlet pressure taps are located on the valve. A regulator adjustment screw is located on the valve.

4. Thermal Switch

The auto-reset switch is located on the front of the intake air elbow. The switch will safely shut the unit down if excessive temperatures are detected. See Figure 13. When the switch senses excessive temperature, the circuit breaks and the ignition control immediately stops ignition and closes the gas valve.

5. Burner and Oriﬁ ce

Burners are factory set and require no adjustment. Always operate the unit with air gas plenum in place. The burner has one oriﬁ ce located between the gas valve and the air intake assembly (Figure 13). To check or replace the oriﬁ ce remove the intake air screen, coupling and intake air elbow.Using a 5/8” socket, go through the elbow and unscrew the gas oriﬁ ce. The burner uses an oriﬁ ce (see Table 16) that is precisely matched to the burner input. The burner can be removed for service. If burner has been removed, it is critical to replace all gaskets.

TABLE 16

Gas Oriﬁ ces

Unit Input Oriﬁ ce Size (0 - 4500 ft)

060 0.0595

080 0.0689

100 0.0810

6. Primary Limit Control (S10)

The primary limit (S10) is located in the heating vestibule panel. 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 automatically 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.

Page 27

Page 28

Gas Valve

Orifice Housing

Gas Orifice

Air Orifice

HEATING COMPONENTS

Air Gas Plenum

Sensor

Ignitor

Burner

Gasket

Intake Air Screen

Intake Air

Elbow

FIGURE 13

Thermal

Switch

(location)

Page 28

Page 29

Tes t 1

Remove 5-pin plug from control

Check ohms reading across terminals 1and 5

Ohm value should be between 39 - 70.

Meter

(set to ohms)

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.

Tes t 2

SL280UHNV Ignitor Check Out

(exploded view for clarity)

Integrated control detail

Meter

(set to ohms)

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 volts +

check for correct supply voltage to furnace.

10%. If voltage is above these values,

Tes t 3

Meter

(set to AC volts)

Integrated control detail

FIGURE 14

Page 29

Page 30

7. Combustion Air Inducer (B6)

All SL280UHNV units use a two-stage combustion air inducer to move air through the burners and heat exchanger during heating operation. The blower uses a 120VAC motor. The motor operates during all heating operation and is controlled by integrated control control A92. The inducer also operates for 15 seconds before burner ignition (prepurge) and for 5 seconds after the gas valve closes (postpurge). The inducer operates on low speed during ﬁ rststage heat, then switches to high speed for second stage heat.

8. Combustion Air Inducer Prove Switch (S18)

SL280UHNV series units are equipped with a single combustion air proving switch (ﬁ rst and second stage) located near the gas valve. See Figure 15. The switch is a single-pole single-throw proving switch electrically connected to the integrated control. The purpose of the switch is to prevent burner operation if the combustion air inducer is not operating or if the ﬂ ue becomes obstructed.

On heat demand (ﬁ rst or second stage) the switch senses that the combustion air inducer is operating. It closes a circuit to the integrated control when pressure inside the combustion air inducer decreases to a certain set point. The set point is 0.20” for low heat and high heat and the same for all SL280UHNV models. The pressure sensed by the switch is negative relative to atmospheric pressure. If the ﬂ ue becomes obstructed during operation, the switch senses a loss of pressure difference and opens the circuit to the furnace control and gas valve.

COMBUSTION AIR PRESSURE SWITCH

NOTE - The switch is factory set and is not ﬁ eld 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 bypassed, the control will not initiate ignition at start up.

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 ﬁ eld 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. SL280UHNV 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 - 2 - Set the thermostat to the lowest setting. 3 - Turn off all electrical power to the unit. 4 - This furnace is equipped with an ignition device

which automatically lights the burners. Do not try to

light the burners by hand. 5 - Remove the access panel. 6 - Turn switch on gas valve to OFF. Do not force. See

ﬁ gure 16. 7 - Wait ﬁ ve minutes to clear out any gas. If you then

smell gas, STOP! Immediately call your gas supplier

from a neighbor’s phone. Follow the gas supplier’s

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

Positive +

to air intake pipe

FIGURE 15

Negative -

to air intake

elbow

Page 30

Page 31

MANIFOLD PRESSURE ADJUSTMENT (TURN CCW TO INCREASE PRESSURE)

NEGATIVE AIR

PRESSURE PORT

GAS VALVE

POSITIVE AIR

PRESSURE PORT

10 - Is pressure switch closed? Obstructed ﬂ ue will

cause unit to shut off at pressure switch. Check ﬂ ue

and outlet for blockages. 11 - Are ﬂ ame rollout switches tripped? If ﬂ ame rollout

switches are tripped, call the service technician for

inspection.

C-Safety or Emergency Shutdown

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

D-Extended Period Shutdown

INLET

SUPPLY

PRESSURE

TAP

GAS VALVE SHOWN IN THE ON POSITION

OUTLET

MANIFOLD

PRESSURE TAP

FIGURE 16

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

Figure 16. 9 - Replace the 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

performed. 3 - Remove access panel. 4 - Move switch on valve to OFF. Do not force. 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 ﬁ lter dirty or plugged? Dirty or plugged ﬁ lters

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.

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

IV-Heating System Service Checks A-CSA Certiﬁ cation

All units are CSA design certiﬁ ed without modiﬁ cations. Refer to the SL280UHNV Installation Instruction.

B-Gas Piping

CAUTION

If a ﬂ exible 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.

WARNING

Do not over torque (800 in-lbs) or under torque (350 inlbs) 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 liqueﬁ ed petroleum gases.

C-Testing Gas Piping

IMPORTANT

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.

Page 31

Page 32

When pressure testing gas lines, the gas valve must be

disconnected and isolated. Gas valves can be damaged if subjected to more than 0.5 psig (14” W.C.). See Figure 17. If the pressure is greater than 0.5psig (14”W.C.), use the manual shut-off valve before pressure testing to isolate furnace from gas supply.

MANUAL MAIN

SHUT-OFF VALVE

WILL NOT HOLD

NORMAL TEST

PRESSURE

1/8 NPT PLUG

CAP

ISOLATE

GAS VALVE

FURNAC

FIGURE 17

When checking piping connections for gas leaks, use preferred means. Kitchen detergents can cause harmful corrosion 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, ﬂ ame or any other source of ignition to check for gas leaks.

D-Testing Gas Supply Pressure

A port on the inlet side of the gas valve provides access to the supply pressure tap. See ﬁ gure 16. Loosen the screw and connect a manometer to measure supply pressure. The minimum supply line is 4.5” w.c. And the maximum supply line is 13.0” w.c. Tighten screw after measurements have been taken.

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.

E-Rate Check Manifold Pressure Measurement

TABLE 17

Unit High Fire Low Fire

060

3.2 - 3.6 in wc 1.3 - 1.7 in wc080

100

F- Proper Combustion

Furnace should operate minimum 15 minutes with correct gas ﬂ ow rate before checking combustion. Take combus- tion sample beyond the ﬂ ue outlet. Table 18 shows ac- ceptable combustion for ALL SL280UHNV models. The maximum carbon monoxide reading should not exceed 100 ppm.

TABLE 18

Firing Rate CO2% For Natural

High Fire

6.0 - 7.5

Low Fire

G- Proper Gas Flow (Approximate)

Furnace should operate at least 5 minutes before check-

ing gas ﬂ ow. 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 19 below.

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

TABLE 19

GAS METER CLOCKING CHART

Seconds for One Revolution

SL280N Unit

Natural

1 cu ft Dial 2 cu ft Dial

060 60 120

080 45 90

100 36 72

Natural-1000 btu/cu ft

To correctly measure manifold pressure, follow the steps below:

1 - Remove the threaded plug from the outlet side of

the gas valve and install a ﬁ eld-provided barbed ﬁ tting. Connect measuring device “+” connection to barbed ﬁ tting to measure manifold pressure.

2 - Start unit on low heat and allow 15 minutes for unit

to reach steady state. 3 - After allowing unit to stabilize for 15 minutes, record

manifold pressure and compare to value given in

Table 17 4 - Repeat on high heat. 5 - Shut unit off and remove manometer as soon as

an accurate reading has been obtained. Take care

to remove barbed ﬁ tting and replace threaded plug. 6 - Start unit and perform leak check. Seal leaks if

found.

Page 32

Page 33

V-Typical Operating Characteristics

C-External Static Pressure

A-Blower Operation and Adjustment

1 - Blower operation is dependent on thermostat control

system.

2 - Generally, blower operation is set at thermostat

subbase fan switch. With fan switch in ON position,

blower operates continuously. With fan switch in

AUTO position, blower cycles with demand or runs

continuously while heating or cooling circuit cycles. 3 - Depending on the type of indoor thermostat, blower

and entire unit will be off when the system switch is

in OFF position.

B-Temperature Rise Figure 18

Temperature rise for SL280UHNV units depends on unit input, 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.

TEMPERATURE RISE

Supply Duct Temperature ________

Return Duct Temperature _ _____

Temperature Rise = ________

1 - Tap locations shown in Figure 19. 2 - Punch a 1/4” diameter hole in supply and return

air plenums. Insert manometer hose ﬂ ush with inside edge of hole or insulation. Seal around the hose with permagum. Connect the zero end of the manometer to the discharge (supply) side of the system. On ducted systems, connect the other end of manometer to the return duct as above.

3 - With only the blower motor running and the

evaporator coil dry, observe the manometer reading. Adjust blower motor speed to deliver the air desired according to the job requirements. For heating speed external static pressure drop must not be more than 0.5” W.C. For cooling speed external static pressure drop must not be more than

0.8” W.C.

4 - Seal the hole when the check is complete.

EXTERNAL STATIC PRESSURE

Supply Duct Static ________

Return Duct Static + _____

Total Duct Static = ________ (dry coil)

Supply Air

Return Air

FIGURE 18

Supply Air

Return Air

FIGURE 19

Page 33

Page 34

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 equivalent) as follows:

WARNING

Disconnect power before servicing unit..

CAUTION

Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing.

1 - Check wiring for loose connections, voltage at

indoor unit and amperage of indoor motor.

2 - Check the condition of the belt and shaft bearings

if applicable. 3 - Inspect all gas pipe and connections for leaks. 4 - Check the cleanliness of ﬁ lters and change if

necessary (monthly).

IMPORTANT

If a highefﬁ ciency ﬁ lter is being installed as part of this system to ensure better indoor air quality, the ﬁ lter must be properly sized. Highefﬁ ciency ﬁ lters have a higher static pressure drop than standardefﬁ ciency glass/foam ﬁ lters. If the pressure drop is too great, system capacity and performance may be reduced. The pressure drop may also cause the limit to trip more frequently during the winter and the indoor coil to freeze in the summer, resulting in an increase in the number of service calls.

Before using any ﬁ lter with this system, check the speciﬁ cations provided by the ﬁ lter manufacturer against the data given in the appropriate Lennox Product Speciﬁ cations bulletin. Additional information is provided in Service and Application Note ACC002

(August 2000).

WARNING

The blower access panel must be securely in place when the blower and burners are operating. Gas fumes, which could contain carbon monoxide, can be drawn into living space resulting in personal injury or death.

5 - Check the condition and cleanliness of burners and

heat exchanger and clean if necessary. 6 - Check the cleanliness of blower assembly and

clean the housing, blower wheel and blower motor

if necessary. The blower motors are prelubricated

for extended bearing life. No further lubrication is

needed.

7 - Inspect the combustion air inducer and clean if

necessary.

8 - Evaluate the heat exchanger integrity by inspecting

the heat exchanger per the AHRI heat exchanger inspection procedure. This procedure can be viewed at www.ahrinet.org

9 - Ensure sufﬁ cient combustion air is available to the

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

10 - Inspect the furnace venting system to make sure

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

11 - Inspect the furnace return air duct connection to

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

12 - Check the condition of the furnace cabinet insulation

and repair if necessary.

13 - Perform a complete combustion analysis during the

furnace inspection to ensure proper combustion and operation. Consult Service Literature for proper combustion values.

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 shutoff operation.

1 - Check the operation of the ignition system, inspect

and clean ﬂ ame sensor. Check microamps before and after. Check controls and safety devices (gas valve, ﬂ ame sensor, temperature limits). Consult Service Manual for proper operating range. Thermal Limits should be checked by restricting airﬂ ow and not disconnecting the indoor blower. For additional details, please see Service and Application Note H049.

2 - Verify that system total static pressure and airﬂ ow

settings are within speciﬁ c operating parameters.

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

at the speciﬁ ed ﬁ ring rate. Check the supply pressure and the manifold pressure. On two-stage gas furnaces check the manifold pressure on high ﬁ re and low ﬁ re. If manifold pressure adjustment is necessary, consult the Service Literature for unit speciﬁ c information on adjusting gas pressure. Not all gas valves are adjustable. Verify correct temperature rise.

Page 34

Page 35

A-Heat Exchanger and Burners Figure 20 Cleaning the Heat Exchanger and Burners

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

1 - Turn off both electrical and gas power supplies to

furnace.

2 - Remove ﬂ ue pipe and top cap (some applications

top cap can remain) from the unit. 3 - Label the wires from gas valve, thermal switch,

primary limit switch and make-up box then

disconnect them. 4 - Remove the screws that secure the combustion air

inducer to the collector box. 5 - Disconnect gas supply piping. Remove the screw

securing the air fuel plenum and remove along with

the air inake assembly as one component. 6 - Remove screws from both sides, top and bottom of

vestibule panel. 7 - Remove heat exchanger. It may be necessary

to spread cabinet side to allow more room. If so,

remove ﬁ ve screws from the left side or right side of

cabinet. See Figure 21. 8 - Back wash using steam. Begin from the burner

opening on each tube. Steam must not exceed

275°F. 9 - To clean burner and intake debris screen, run a

vacuum cleaner over the face of burners. Visually

inspect inside the burner. Remove any blockage.

Figure 20 shows burner detail. Replace gasket

between burner plate and air fuel plenum then re-

install burner plate.

10 - 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.

11 - Reinstall heat exchanger in vestibule. (Replace the

ﬁ ve screws in the cabinet from step 7 if removed).

12 - Reinstall the air fuel plenum and air intake

assembly. Make note of the numbered sequence when re-installing the air fuel plenum. Follow the sequence as shown in Figure 20. Torque screws to a maximum of 100 + 5 in - lbs. and a minimum 60 in - lbs.

13 - Re-install the combustion air inducer assembly.

Make note to re-install all screws. Failure to replace all screws may cause leaks. Reconnect all wires.

14 - Reconnect top cap and vent pipe to combustion air

inducer outlet. 15 - Reconnect gas supply piping. 16 - Turn on power and gas supply to unit. 17 - Set thermostat and check for proper operation. 18 - Check all piping connections, factory and ﬁ eld, for

gas leaks. Use a leak detecting solution or other

preferred means.

CAUTION

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

19 - If a leak is detected, shut gas and electricity off and

repair leak. 20 - Repeat steps 18 and 19 until no leaks are detected. 21 - Replace access panel

Page 35

Page 36

Air Fuel Plenum

Heat Exchanger and Burner Assembly Removal

* Re-install screws per the numbered sequence shown

Heat Exchanger

Gasket

Burner

Gasket

Debri Screen

Remove 5 screws if necessary

(cabinet for reference only)

Gas Valve

Air Intake Assembly

*Air Fuel Plenum

FIGURE 20

Gasket (replace)

FIGURE 21

Page 36

Page 37

VII- Wiring and Sequence of Operation

When there is a call for heat, the iComfort® enabled integrated control runs a self check. The control checks for S10 primary limit 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.

Page 37

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 ﬁ re, causing property damage, severe injury or death. Use copper wire only with this product.

Page 38

CAUTION

Failure to use properly sized wiring and circuit breaker may result in property damage. Size wiring and circuit breaker(s) per Product Speciﬁ cations 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 ﬁ rst-stage contacts

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

2 - Once the control receives a signal that the pressure

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

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

ignitor warm-up period begins. The combustion air inducer continues to operate at low speed.

4 - After the 20-second warm-up period has ended,

the gas valve is energized on low ﬁ re and ignition occurs. At the same time, the control module sends a signal to begin an indoor blower 30-second ONdelay. When the delay ends, the indoor blower motor is energized on the low ﬁ re heating speed, the HUM contacts close energizing the humidiﬁ er and 120V ACC terminal is energized. The furnace will continue this operation as long as the thermostat has a ﬁ rst-stage heating demand.

NOTE - If the indoor thermostat is set on CONTINUOUS FAN ON mode, the furnace will light on high ﬁ re (second-stage) for 60 seconds to improve heat exchanger warm up. After 60 second warm-up period, furnace will switch to low ﬁ re (ﬁ rst- stage).

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

second- 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

control energizes the combustion air inducer at high speed. The gas valve is energized on high ﬁ re and the indoor blower motor is energized for operation at the high ﬁ re heating speed.

7 - When the demand for high ﬁ re heat is satisﬁ ed, the

combustion air inducer is switched to the low-ﬁ re heating speed and the gas valve reduces to low ﬁ re. The low-ﬁ re gas valve continues operation. The indoor blower motor is switched to the low-ﬁ re heating speed.

8 - When the thermostat demand for low-ﬁ re heat is

satisﬁ ed, the gas valve is de-energized and the

ﬁ eld-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

complete, 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 initiated by the integrated control if heating demand has not been satisﬁ ed after the ﬁ eld adjustable period (7 or 12 minutes).

1 - On a call for heat, thermostat ﬁ rst-stage contacts

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

2 - Once the control receives a signal that the pressure

switch has closed, the combustion air inducer

begins a 15-second pre-purge in low speed. 3 - After the pre-purge is complete, a 20-second initial

ignitor warm-up period begins. The combustion air

inducer continues to operate at low speed. 4 - After the 20-second warm-up period has ended,

the gas valve is energized on low ﬁ re (ﬁ rst stage)

and ignition occurs. At the same time, the control

module sends a signal to begin an indoor blower

30-second ON-delay. When the delay ends, the

indoor blower motor is energized on the low ﬁ re

heating speed and the HUM contacts are energized.

The integrated control also initiates a second-stage

on delay (factory-set at 7 minutes; adjustable to 12

minutes). 5 - If the heating demand continues beyond the

secondstage on delay, the integrated control

energizes the combustion air inducer at high speed.

The gas valve is energized on high ﬁ re and the

indoor blower motor is energized for operation at

the high ﬁ re heating speed. 6 - When the thermostat heating demand is satisﬁ ed,

the combustion air inducer begins a 5-second low

speed post-purge. The ﬁ eld-selected indoor blower

off delay begins. The indoor blower operates at the

low-ﬁ re heating speed. 7 - When the combustion air post-purge period is

complete, 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 38

Page 39

iComfort® Thermostat with a

Non-Communicating Outdoor Unit

iComforti® Thermostat with an iComfort

ENABLED Outdoor Unit

iComforti® Thermostat iComfort

-Enabled Indoor Furnace

Non-Communicating Outdoor Air Conditioner

iComfort

ENABLED

OPTIONAL

DISCHARGE

AIR SENSOR

iComfort

TWO-STAGE OPERATION

ENABLED

THERMOSTAT

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

FURNACE

NON-COMMUNICATING

OUTDOOR AIR

CONDITIONING UNIT -

1 OR 2 STAGE

OPTIONAL

OUTDOOR

AIR SENSOR

icomfort® Thermostat iComfort iComfort

DISCHARGE

AIR SENSOR

OPTIONAL OUTDOOR

AIR SENSOR

® ®

OPTIONAL

iComfort

THERMOSTAT

Enabled Indoor Furnace Enabled Outdoor Air Conditioner or Heat Pump

iComfort ENABLED FURNACE

iComfort

OUTDOOR AIR CONDITIONING

OR HEAT PUMP UNIT

- ENABLED

Outdoor Unit

Communicating systems using the iComfort®thermostat require four thermostat wires between the thermostat and the furnace/air handler control and four wires between 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.

Indoor Unit Controller

iComfort

Single wire

Single wire to terminal C

Unused wires

to terminal C

Unused wires

thermostat

Page 39

Page 40

Optional Accessories for use with any iComfort Touch

System

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

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

iComfort®ENABLED

Discharge Air

Sensor (Required

for even heat)

iComfort

THERMOSTAT

FURNACE

RSBus

Maximum total

nections on the RSBus is limited to 1500ft.

Wire gauge of RSBus wire is 18.

icomfort

DOOR AIR CONDITIONING

OR HEAT PUMP UNIT

ENABLED

icomfort

FURNACE

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

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.

HVAC EQUIPMENT

iComfort

THERMOSTAT

DEHUMIDIFIER CONTROL

Rf WGh

HVAC EQUIP

Cf Gs

120V CONNECTIONS

“HUM” CONTACT IS CLOSED ANYTIME HUMIDITY DEMAND IS PRESENT

24V HUMIDIFIER CONNECTIONS

THERMOSTAT

CONVENTIONAL

CATING SYSTEM

COMMUNICATING SYSTEM

*24V IN jumper not used in noncommunicating configuration

*24V IN JUMPER

iComfort® ENABLED FURNACE

HEPA BYPASS FILTER X2680 HEPA INTERLOCK KIT

PASS INDOOR BLOWER MOTOR COMMON WIRE

ENABLED

FURNACE

THROUGH CURRENT LOOP.

SEE HEPA INTERLOCK KIT

TAILS

icomfort

LVCS VENTILATION CONTROL SYSTEM

SEE LVCS VENTILATION INSTRUCTIONS FOR DAMPER & SENSOR WIRING

ENABLED

FURNACE

icomfort

Page 40

STANDARD 1 OR 2

STAGE AC OR HP UNIT

2 STAGE FURNACE

CUT R-DS W914

NON-COMMUNICATING SYSTEM WIRING

COMMUNICATING SYSTEM WIRING

Page 41

VIII- Field Wiring With Conventional Thermostat

DIP Switch Settings and On-Board Links

Thermostat

DIP Switch 1

Thermostat

On Board Links Must Be Cut To Select

Heating

Stages

1 Heat / 1 Cool

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

DO NOT CUT ANY ON-BOARD LINKS

ON-12 minutes.

System Options

Wiring Connections

T'STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

1 Heat / 2 Cool

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

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 41

Page 42

DIP Switch 1

Thermostat

Heating

Stages

2 Heat / 2 Cool OFF

Field Wiring With Conventional Thermostat (Continued)

DIP Switch Settings and On-Board Links

On Board Links Must Be Cut To Select

System Options

CUT ON-BOARD LINK

W915

2 STAGE

COMPR

T'STAT

Wiring Connections

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 42

T'STAT

FURNACE

TERM. STRIP

OUTDOOR

UNIT

Page 43

Thermostat

Dual Fuel Single Stage Heat Pump

ComfortSense thermostat w/

Field Wiring With Conventional Thermostat (Continued)

DIP Switch Settings and On-Board Links

DIP Switch 1

Thermostat

Heating

Stages

OFF

On Board Links Must Be Cut To Select

System Options

CUT ON-BOARD LINK

W951 HEAT

PUMP

Wiring Connections

T'STAT

FURNACE

TERM. STRIP

HEAT PUMP

67M41*

bilities Capable of 2 stage gas heat control

Dual Fuel Two Stage Heat Pump

ComfortSense thermostat w/

bilities Capable of 2 stage gas heat control

OFF

CUT ON-BOARD LINK

W915

2 STAGE

COMPR

CUT ON-BOARD LINK

W951 HEAT PUMP

T'STAT

FURNACE

TERM. STRIP

67M41*

outdoor

sensor

HEAT PUMP

out blue

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 furnace integrated control.

Page 43

Page 44

Thermostat

Dual Fuel Single Stage Heat Pump

ComfortSense thermostat w/

Field Wiring With Conventional Thermostat (Continued)

DIP Switch Settings and On-Board Links

DIP Switch 1

Thermostat

Heating

Stages

OFF

On Board Links Must Be Cut To Select

System Options

CUT ON-BOARD LINK

W951 HEAT

PUMP

Wiring Connections

T'STAT

FURNACE

TERM. STRIP

HEAT PUMP

67M41*

bilities Capable of 2 stage gas heat

midification control

Dual Fuel Two Stage Heat Pump

ComfortSense thermostat w/

bilities Capable of 2 stage gas heat

midification

OFF

CUT ON-BOARD LINK

W914

DEHUM

HARMONY

CUT ON-BOARD LINK

W915

2 STAGE

COMPR

CUT ON-BOARD LINK

W951 HEAT

PUMP

CUT ON-BOARD LINK

W914

DEHUM

HARMONY

T'STAT

FURNACE

TERM. STRIP

67M41*

outdoor

sensor

HEAT PUMP

out blue

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 furnace integrated control.

Page 44

Page 45

IX- Program Unit Capacity Size Modes

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.

Furnace control in IDLE mode

No heating, cooling or indoor fan

operation)

UNIT SIZE

CODE

−

Turn room thermostat to OFF

FURNACE MODEL

SL280UH060NV36A

SL280UH080NV48B

SL280UH080NV60C

SL280UH100NV60C

Solid P starts blinking on 7-Segment LED

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

FINISHED

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

Page 45

Page 46

X- Troubleshooting Heating Sequence of Operation

CALL FOR FIRST-STAGE HEAT

CALL FOR

1ST STAGE HEAT

(LOW FIRE)

HIGH

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)

CLOSED?

YES

CIRCUITS

CLOSED?

YES

LOW

SWITCH

OPEN?

YES

LOW

YES

HEAT FAN ON DELAY

TIMER STARTED

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

INDOOR BLOWER

ON(LOW HEAT

SPEED)

HIGH

PRESSURE

SWITCH

OPEN

BEFORE

INDUCER WAS

TURNED ON?

INDUCER ON

(HIGH SPEED)

INDOOR BLOWER

ON (LOW HEAT

SPEED)

INTERPURGE

(15 SECONDS)

YES

LIMIT

SWITCH

CLOSED WITHIN 3

MINUTES?

ERROR

CODE

FLASHES

INDUCER TO

HIGH SPEED−

ERROR CODE

FLASHES

AFTER HEAT FAN

OFF DELAY (LOW

ROLLOUT

CIRCUIT

CLOSES

INDOOR BLOWER OFF AFTER HEAT OFF DELAY

HARD LOCKOUT − ERROR CODE FLASHES

LOW & HIGH

PRESSURE SWITCH

CLOSED WITHIN 30

SECONDS?

INDOOR

BLOWER OFF

HEAT SPEED)

INDUCER OFF

AFTER POST

PURGE

YES

WATCHGUARD − ERROR CODE FLASHES

YES

INDUCER OFF−

WAIT 5 MINUTES ERROR CODE

FLASHES

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 30 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 46

YES

POSTPURGE (5 SECONDS)

INDUCER

OFF

WATCHGUARD − ERROR CODE FLASHES

Page 47

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

(30 SECONDS)

EXPIRED?

(HIGH FIRE)

YES

INDUCER SWITCHED

TO HIGH SPEED

HIGH

PRESSURE SWITCH

CLOSED WITHIN 10

SECONDS?

YES

2ND STAGE GAS VALVE

ENERGIZED

INDOOR BLOWER ENERGIZED

ON HIGH HEAT SPEED

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 S4.

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

Page 47

Page 48

Heating Sequence of Operation (Continued)

CALL FOR HEAT SATISFIED

FIRST-STAGE HEAT SECOND-STAGE HEAT

2 3

2ND STAGE HEAT

INDUCER SPEED SWITCHED

2ND STAGE

CALL FOR HEAT

SATISFIED?

YES

DE−ENERGIZE 2ND STAGE

GAS VALVE

TO LOW SPEED

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

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

INDOOR BLOWER SWITCHED

TO LOW HEAT SPEED

1ST STAGE HEAT

1ST STAGE

CALL FOR HEAT

SATISFIED?

GAS VALVE

DE−ENERGIZED

INDUCER OFF AFTER

5 SECOND POST PURGE

INDOOR BLOWER OFF

AFTER FIELD SELECTABLE

OFF DELAY

YES

Page 48

Page 49

Cooling Sequence of Operation

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 49

Page 50

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

INDOOR BLOWER OFF

GO TO CALL FOR COOLING

GO TO CALL FOR 1ST STAGE HEAT

Page 50

Lennox SL280UHNV, SL280UH060NV36A, SL280UH080NV48B Series Manual

Specifications and Main Features

Frequently Asked Questions

User Manual