Lennox SL280UHNV Series Manual
Lennox SL280UHNV Series Manual

Lennox SL280UHNV Series Manual

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S e r v i c e L i t e r a t u r e
ICOMFORT
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 facto-
ry 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 lo-
cal or state codes. In the absence of local or state codes,
the guidelines and procedures outlined in this manual (ex-
cept where noted) are recommendations only and do not
constitute code.
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
IX- Program Unit Capacity Size Modes ........................46
X- Troubleshooting .......................................................47
UNIT INFORMATION
UNIT INFORMATION
Corp 1601-L8
®
-ENABLED SL280UHNV SERIES UNITS
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.
SL280UHNV
©2017 Lennox Industries, Inc.

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Summary of Contents for Lennox SL280UHNV Series

  • Page 1: Table Of Contents

    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.
  • Page 2 SPECIFICATIONS Model No. SL280UH060NV36A SL280UH080NV48B Heating AFUE Performance High Input - Btuh 60,000 80,000 Fire Output - Btuh 48,000 64,000 Temperature rise range - °F 30 - 60 30 - 60 Gas Manifold Pressure (in. w.g.) Natural Gas Only Input - Btuh 39,000 52,000 Fire...
  • Page 3 Heat Exchanger Combustion Air Inducer Gas Valve Air Intake Pipe Inner Access Control Box Access Panel Panel (includes two-stage integrated control, transformer and circuit breaker) Blower Assembly FIGURE 1 Page 3...
  • Page 4: I-Unit Components

    I-Unit Components CIRCUIT BREAKER CB8 SL280UHNV unit components are shown in Figure 1. The gas valve, combustion air inducer and burners can be ac- cessed by removing the access panel. Electrical compo- nents are in the control box (Figure 2) found in the blower PRESS TO RESET section.
  • Page 5 NOTE - During abnormal conditions such as low supply TABLE 1 voltage or low outdoor temperatures and the low fi re pres- ® SureLight Control 5 Pin Terminal Designation sure switch does not close, the combustion air inducer will PIN# Function switch to high fi...
  • Page 6 HS/ CAI LINE 1 NEUTRAL 7 SEGMENT LED FLAME SENSE INDOOR BLOWER DIAGNOSTIC CONNECTOR PUSH BUTTON DIP SWITCHES 12 PIN LOW OUTDOOR AIR VOLTAGE SENSOR CONNECTOR TERMINALS DISCHARGE AIR W915 Y1 TO Y2 SENSOR 2 STAGE COMPR TERMINALS W951 R TO O HEAT PUMP TB83 COMMUNICATING...
  • Page 7 INTEGRATED CONTROL CONFIGURATION GUIDE CLG BLOWER SPEED ADJUSTMENT 2ND STAGE HEAT ON DELAY DEFAULT 7 MIN CONTINUOUS FAN MODE BLOWER SPEED UPSTAGE THERMOSTAT SELECTION DELAY + 10% MEDIUM−LOW SPEED TWO STAGE (38%) THERMOSTAT 12 MIN UPSTAGE − 10% MEDIUM−HIGH DELAY SPEED 1−STAGE (70%)
  • 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...
  • 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). Cubic feet per minute (cfm) setting for indoor blower (1 second ON, 0.5 second OFF) / cfm setting for current mode displayed.
  • Page 10 TABLE 5 Continued Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E124 Active communicating thermostat signal Equipment lost communication with the thermostat. Check missing for more than 3 minutes. four wiring connections, ohm wires and cycle power at the thermostat.
  • 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 un- able to operate 2nd stage, replace control. E207 Hot surface ignitor sensed open.
  • 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- Check pressure (inches w.c.) of low pressure switch clos- tries. Last retry failed due to the pressure switch ing on heat call.
  • 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- Warning Only. Restricted airfl ow - Indoor blower is running at a re- ous fan mode is lower than cfm setting. 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”...
  • 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.
  • Page 15 Ramping Option C TABLE 8 • Motor runs at 100% until demand is satisfi ed. Cooling Blower Speed Adjustment • Once demand is met, motor runs at 100% for 45 sec- Adjustment Switch 7 Switch 8 onds then ramps down to stop. +10% (approx) Factory Default 100% CFM...
  • Page 16: Blower Data

    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 17 First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position. Continuous Fan Only speed is selectable at 28%, 38%, 70% and 100% of the selected second stage cooling speed - minimum 380 cfm. Lennox iHarmony Zoning System Applications - Minimum blower speed is 380 cfm.
  • Page 18 First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position. Continuous Fan Only speed is selectable at 28%, 38%, 70% and 100% of the selected second stage cooling speed - minimum 380 cfm. Lennox iHarmony ®...
  • 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.
  • Page 20 First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position. Continuous Fan Only speed is selectable at 28%, 38%, 70% and 100% of the selected second stage cooling speed - minimum 450 cfm. Lennox iHarmony Zoning System Applications - Minimum blower speed is 450 cfm.
  • Page 21 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 *Dehumidifi cation blower speed is 70% of COOL speed for all units .
  • Page 22 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.
  • Page 23 Try IMPORTANT not to bounce the disconnect switch when applying power to the unit. Earlier ECM motors used on other Lennox furnace models are not interchangeable with motors used on the SL280UH furnace line. Page 23...
  • Page 24 Motor Start-Up Troubleshooting Motor Operation When B3 begins start-up, the motor gently vibrates back To verify motor operation see steps below and Figure 8 and forth for a moment. This is normal. During this time and Figure 9. the electronic controller is determining the exact position 1 - Remove J48 (5 pin power plug) from P48 on the of the rotor.
  • Page 25 BLOWER B3 HARNESS CONNECTORS BLOWER B3 HARNESS CONNECTORS P48 5 Pin P48 5 Pin P49 4 Pin SHAFT SHAFT P49 4 Pin MOTOR with INTEGRATED MOTOR with INTEGRATED CONTROLLER CONTROLLER J48 5 Pin P48 5 Pin J49 4 Pin P49 4 Pin J49 4 Pin Control Connector J48 Connector J48 5 Pin Line Voltage Connector...
  • Page 26 Troubleshooting Motor Windings TEST A Measure the resistance between each of the three motor Ensure that motor windings are not damaged by perform- leads (3-pin plug) and the unpainted part of the end shield. ing the following tests: If the winding resistance to ground is <100k ohms, re- NOTE - If your ohm meter is not an auto-ranging type, set place the motor and control module.
  • Page 27 The switch may have a different set point for each unit terminals energizes the valve. Inlet and outlet pressure model number. See Lennox Repair Parts Handbook if limit taps are located on the valve. A regulator adjustment switch must be replaced.
  • Page 28 HEATING COMPONENTS Air Gas Plenum Burner Gasket Gas Valve Sensor Ignitor Orifice Housing Gas Orifice Air Orifice Intake Air Screen Thermal Intake Air Switch Elbow (location) FIGURE 13 Page 28...
  • Page 29 SL280UHNV Ignitor Check Out (exploded view for clarity) Test 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) Integrated control detail Test 2 Seperate the 2-pin jack plug near the manifold and check resistance of the ignitor.
  • Page 30: Ii-Placement And Installation

    8. Combustion Air Inducer Prove Switch (S18) installed for loose connections. Tighten as required. SL280UHNV series units are equipped with a single com- 2 - Check voltage at disconnect switch. Voltage must bustion air proving switch (fi rst and second stage) located be within range listed on the nameplate.
  • Page 31: Iv-Heating System Service Checks

    10 - Is pressure switch closed? Obstructed fl ue will cause unit to shut off at pressure switch. Check fl ue GAS VALVE and outlet for blockages. MANIFOLD PRESSURE ADJUSTMENT 11 - Are fl ame rollout switches tripped? If fl ame rollout (TURN CCW TO INCREASE PRESSURE) switches are tripped, call the service technician for NEGATIVE AIR...
  • Page 32 Gas Leak Detector is strongly recommended. It Furnace should operate at least 5 minutes before check- is available through Lennox under part number 31B2001. ing gas fl ow. Determine time in seconds for two revolu- See Corp. 8411-L10, for further details.
  • Page 33: V-Typical Operating Characteristics

    V-Typical Operating Characteristics C-External Static Pressure 1 - Tap locations shown in Figure 19. A-Blower Operation and Adjustment 2 - Punch a 1/4” diameter hole in supply and return 1 - Blower operation is dependent on thermostat control air plenums. Insert manometer hose fl ush with system.
  • Page 34: Vi-Maintenance

    At the beginning of each heating season, and to comply the heat exchanger per the AHRI heat exchanger with the Lennox Limited Warranty, your system should be inspection procedure. This procedure can be checked by a licensed professional technician (or equiva- viewed at www.ahrinet.org...
  • Page 35 10 - To clean the combustion air inducer visually inspect A-Heat Exchanger and Burners Figure 20 and using a wire brush clean where necessary. Use Cleaning the Heat Exchanger and Burners compressed air to clean off debris and any rust. 11 - Reinstall heat exchanger in vestibule.
  • Page 36 Heat Exchanger and Burner Assembly Removal * Re-install screws per the numbered sequence shown Air Fuel Plenum Heat Exchanger Gasket *Air Fuel Plenum Gas Valve Burner Gasket Gasket (replace) Debri Screen Air Intake Assembly FIGURE 20 Remove 5 screws if necessary (cabinet for reference only) FIGURE 21 Page 36...
  • Page 37: Vii- Wiring And Sequence Of Operation

    VII- Wiring and Sequence of Operation WARNING When there is a call for heat, the iComfort® enabled in- Electric Shock Hazard. Can cause injury or tegrated control runs a self check. The control checks for death. Unit must be properly grounded in S10 primary limit and S47 rollout switch normally closed accordance with national and local codes.
  • Page 38 8 - When the thermostat demand for low-fi re heat is CAUTION satisfi ed, the gas valve is de-energized and the fi eld-selected indoor blower off delay begins. The Failure to use properly sized wiring and circuit breaker combustion air inducer begins a 5-second post- may result in property damage.
  • Page 39 ® ® ® iComfort Thermostat with a iComforti Thermostat with an iComfort Non-Communicating Outdoor Unit ENABLED Outdoor Unit ® iComforti Thermostat ® icomfort Thermostat ® iComfort -Enabled Indoor Furnace ® iComfort Enabled Indoor Furnace ® Non-Communicating Outdoor Air Conditioner iComfort Enabled Outdoor Air Conditioner or Heat Pump ®...
  • Page 40 “HUM” CONTACT IS OPTIONAL OUTDOOR AIR SENSOR FOR USE WITH HUMIDIFIER (IF CLOSED ANYTIME HUMIDITY DEMAND NOT ALREADY IN THE SYSTEM FOR OTHER FUNCTIONS. BUILT INTO IS PRESENT ALL icomfort® by Lennox® OUTDOOR UNITS). ® iComfort ENABLED 24V HUMIDIFIER CONNECTIONS FURNACE...
  • Page 41: Viii- Field Wiring With Conventional Thermostat

    VIII- Field Wiring With Conventional Thermostat DIP Switch Settings and On-Board Links DIP Switch 1 On Board Links Must Be Cut To Select Thermostat Thermostat Wiring Connections System Options Heating Stages 1 Heat / 1 Cool FURNACE OUTDOOR T'STAT TERM. STRIP UNIT NOTE - Use DIP switch 2 to set...
  • Page 42 Field Wiring With Conventional Thermostat (Continued) DIP Switch Settings and On-Board Links DIP Switch 1 On Board Links Must Be Cut To Select Thermostat Thermostat Wiring Connections System Options Heating Stages 2 Heat / 2 Cool FURNACE OUTDOOR T'STAT TERM. STRIP UNIT CUT ON-BOARD LINK W915...
  • Page 43 Field Wiring With Conventional Thermostat (Continued) DIP Switch Settings and On-Board Links DIP Switch 1 Wiring Connections Thermostat On Board Links Must Be Cut To Select Thermostat Heating System Options Stages Dual Fuel FURNACE HEAT PUMP T'STAT TERM. STRIP Single Stage Heat Pump CUT ON-BOARD LINK ComfortSense...
  • Page 44 Field Wiring With Conventional Thermostat (Continued) DIP Switch Settings and On-Board Links DIP Switch 1 On Board Links Must Be Cut To Select Wiring Connections Thermostat Thermostat Heating System Options Stages Dual Fuel FURNACE HEAT PUMP T'STAT TERM. STRIP Single Stage Heat Pump CUT ON-BOARD LINK ComfortSense...
  • Page 45: Ix- Program Unit Capacity Size Modes

    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: Furnace control in IDLE mode No heating, cooling or indoor fan operation)
  • Page 46: X- Troubleshooting

    X- Troubleshooting Heating Sequence of Operation CALL FOR FIRST-STAGE HEAT CALL FOR 1ST STAGE HEAT (LOW FIRE) INDOOR BLOWER OFF AFTER HEAT FAN OFF DELAY (LOW HEAT SPEED) INDOOR LIMIT BLOWER OFF HIGH ERROR INDOOR SWITCH WATCHGUARD − AFTER HEAT FAN LIMIT SWITCH CODE CLOSED WITHIN 3...
  • Page 47 Heating Sequence of Operation (Continued) CALL FOR SECOND-STAGE HEAT CALL FOR 2ND STAGE HEAT (HIGH FIRE) SINGLE STAGE 2 STAGE THERMOSTAT THERMOSTAT 2ND STAGE RECOGNITION DELAY ON DELAY (30 SECONDS) EXPIRED? EXPIRED? ONLY FOR 1ST REQUEST FOR 2ND STAGE HEAT INDUCER SWITCHED TO HIGH SPEED HIGH...
  • Page 48 Heating Sequence of Operation (Continued) CALL FOR HEAT SATISFIED FIRST-STAGE HEAT SECOND-STAGE HEAT RUN MODE: 1ST OR 2ND STAGE CALL FOR HEAT. ALL INPUTS MONITORED (LIMIT, PRESSURE, CALL FOR HEAT/COOL, FLAME LEVEL) 2ND STAGE HEAT 2ND STAGE CALL FOR HEAT SATISFIED? DE−ENERGIZE 2ND STAGE GAS VALVE...
  • Page 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) MAINTAIN INDOOR BLOWER (LOW COOLING MODE)
  • Page 50 Continuous Fan Sequence of Operation CALL FOR FAN CALL FOR FAN INDOOR BLOWER ON CONTINUOUS FAN SPEED CALL FOR FAN MAINTAIN INDOOR BLOWER AT REMOVED? CONTINUOUS FAN REQUEST MAINTAIN INDOOR FOR COOLING GO TO CALL FOR COOLING BLOWER AT RECEIVED? CONTINUOUS FAN REQUEST FOR HEAT...

This manual is also suitable for:

Sl280uh060nv36aSl280uh080nv48bSl280uh080nv60cSl280uh100nv60cSl280uhnv

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