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Lennox SL297UHNV Series Unit Information

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Service Literature
COMMUNICATING ENABLED SL297UHNV SERIES UNITS
SL297UHNV series units are 90% efficiency gas furnaces
used
for
upflow
or
SL297UHNV units are available in heating capacities of
40,000 to 80,000 Btuh and cooling applications up to 4
tons. Refer to Product Specifications Manual for proper siz­
ing.
Units are factory equipped for use with natural gas.
SL297UHNV model units are equipped with a communicat­
®
ing enabled SureLight
two-stage variable speed integrated
control. All units use a redundant gas valve to assure safety
shut-off as required by C.S.A.
All specifications in this manual are subject to change. Pro­
cedures outlined in this manual are presented as a recom­
mendation only and do not supersede or replace local or
state codes. In the absence of local or state codes, the
guidelines and procedures outlined in this manual (except
where noted) are recommendations only and do not consti­
tute code.
TABLE OF CONTENTS
Specifications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I Unit Components
. . . . . . . . . . . . . . . . . . . . . . .
II Installation
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
III Start Up
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV Heating System Service Checks
V Typical Operating Characteristics
VI Maintenance
. . . . . . . . . . . . . . . . . . . . . . . . . .
VII Wiring and Sequence of Operation
VIII Field Wiring and Jumper Settings
IX Program Unit Capacity Size Mode
X Troubleshooting
. . . . . . . . . . . . . . . . . . . . . . . .
horizontal
applications
Page 2
Page 11
Page 33
Page 51
. . . . . . . . .
Page 52
. . . . . . . . .
Page 58
Page 58
. . . . . .
Page 61
. . . . . . .
Page 66
. . . . . . .
Page 70
Page 71
Corp. 1802-L1
Revised 02/2021
only.
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person­
al injury or loss of life. Installation and service must
be performed by a licensed professional HVAC in­
staller (or equivalent), service agency or the gas sup­
plier.
As with any mechanical equipment, contact with
sharp sheet metal edges can result in personal in­
jury. Take care while handling this equipment and
wear gloves and protective clothing.
Page 1
SL297UHNV
WARNING
CAUTION
© 2021 Lennox Industries Inc.

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Summary of Contents for Lennox SL297UHNV Series

  • Page 1 SL297UHNV Corp. 1802-L1 Revised 02/2021 Service Literature COMMUNICATING ENABLED SL297UHNV SERIES UNITS SL297UHNV series units are 90% efficiency gas furnaces used upflow horizontal applications only. SL297UHNV units are available in heating capacities of 40,000 to 80,000 Btuh and cooling applications up to 4 tons.
  • Page 2 SPECIFICATIONS Model No. SL297UH040NV36B SL297UH060NV36B Heating AFUE 97.5% 97.5% Performance High Input - Btuh 40,000 60,000 Fire Output - Btuh 39,000 58,000 Temperature rise range - °F 30-60 50-80/25-55 Gas Manifold Pressure (in. w.g.) Nat. Gas / LPG/Propane Input - Btuh 26,000 39,000 Fire...
  • Page 3 OPTIONAL ACCESSORIES - ORDER SEPARATELY NOTE - FURNACES CANNOT BE TWINNED! “B” Width “C” Width Models Models CABINET ACCESSORIES Horizontal Suspension Kit - Horizontal only 51W10 51W10 Return Air Base - Upflow only 50W98 50W99 High Performance Economizer (Commercial Only) 10U53 10U53 CONDENSATE DRAIN KITS...
  • Page 4 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 5 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 6 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 7 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 8 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 250 for 080NV48C and 450 cfm for 080NV60C.
  • Page 9 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 10 Exhaust Vent Pipe Burner Assembly Intake Air Assembly Heat Exchanger Rollout Switch Gas Valve Inlet Vent Pipe Exhaust Coupling Gas Pipe Inlet Combustion (right side only) Air Inducer Cabinet Indoor Blower Inner Panel Panel Two-Stage Control FIGURE 1 Page 10...
  • Page 11 I-UNIT COMPONENTS 3. Circuit Breaker (CB8) A 24V circuit breaker is also located in the control box. The switch provides overcurrent protection to the trans­ SL297UHNV unit components are shown in figure 1. The former (T1). The breaker is rated 3A at 32V. If the current gas valve, combustion air inducer and burners can be ac­...
  • Page 12 the combustion air inducer is energized on low (first stage) TABLE 1 heat speed. When the differential in the prove switch is ® SureLight Control 5 Pin Terminal Designation great enough, the prove switch closes and a 15-second PIN # Function pre-purge begins.
  • Page 13 INTEGRATED CONTROL HS/ CAI LINE 1 NEUTRAL 7 SEGMENT LED FLAME SENSE INDOOR BLOWER DIAGNOSTIC CONNECTOR PUSH BUTTON DIP SWITCHES 12 PIN LOW OUTDOOR AIR VOLTAGE SENSOR CONNECTOR TERMINALS DISCHARGE AIR W915 Y1 TO Y2 SENSOR 2 STAGE COMPR TERMINALS W951 R TO O TB83 HEAT PUMP...
  • Page 14 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 15 TABLE 4 Integrated Control Diagnostic Modes Display Action (when button released) No change (idle)* Remain in idle mode Solid “E” Enter diagnostic recall mode Solid “F” Enter flame signal mode Solid “D” Discharge Air Installed Solid “P” (variable speed only) Program unit capacity/size (Unit Code) Soft disable Two horizontal bars __...
  • Page 16 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 17 TABLE 5 Continued Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E 124 Active communicating thermostat signal missing for more than 3 min­ Equipment lost communication with the thermostat. utes. Check four wiring connections, ohm wires and cycle power at the thermostat.
  • Page 18 TABLE 5 Continued Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E 206 Gas valve second-stage relay failure Furnace will operate on 1 stage for remainder of the heating demand. Will clear after fault recovered. If unable to operate 2nd stage, replace control. E 207 Hot surface ignitor sensed open Measure resistance of hot surface ignitor.
  • Page 19 TABLE 5 Continued Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E 271 Soft lockout - Exceeded maximum number of retries. Last retry failed due Check pressure (inches w.c.) of low pressure switch to the pressure switch opening. closing on heat call.
  • Page 20 TABLE 5 Continued Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E 312 Restricted air flow in cooling or continuous fan mode is lower than cfm Warning Only. Restricted airflow - Indoor blower is setting. running at a reduced CFM (Cutback Mode - 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 21 TABLE 5 Continued Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E 406 LSOM - Compressor open start circuit. Required amount of current is not passing through Start current transformer. Clears the error after cur­ rent is sensed in START sensor, or after power re­ set.
  • Page 22 -10% to better suit the application. Table 8 below provides Ramping Option C S Motor runs at 100% until demand is satisfied. blower speed adjustments that will result from different switch settings. Refer to blower data tables for correspond­ S Once demand is met, motor runs at 100% for 45 sec­ ing cfm values.
  • Page 23 With Heat Pump - Cut W914 (R to DS) & W951 (R to O) on SureLight control ® Use Dave Lennox ComfortSense 7500 thermostat Y2081 4 heat / 2 cool for this application *Dehumidification blower speed is 70% of COOL speed for all units .
  • Page 24 With Heat Pump - Cut W914 (R to DS) & W951 (R to O) on SureLight control ® Use Dave Lennox ComfortSense 7500 thermostat Y2081 4 heat / 2 cool for this application. *Normal operation first stage cooling blower speed is 70% COOL speed.
  • Page 25 DC filter capacitors inside the controller. If the discon­ nect switch is bounced when the disconnect is closed, the dis­ Earlier ECM motors used on other Lennox furnace models are not interchangeable with motors used on connect contacts may become welded. Try not to bounce the the SL297UH furnace line.
  • Page 26 Motor Start‐Up Troubleshooting Motor Operation When B3 begins start‐up, the motor gently vibrates back and To verify motor operation see steps below and figures 8 forth for a moment. This is normal. During this time the elec­ tronic controller is determining the exact position of the rotor. and 9.
  • Page 27 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 J49 4 Pin P48 5 Pin P49 4 Pin J49 4 Pin Control Connector J48 5 Pin Line Voltage Connector J48 Connector...
  • Page 28 Troubleshooting Motor Windings TEST B Ensure that motor windings are not damaged by perform­ Use an ohmmeter to measure the motor phase-to-phase ing the following tests: resistance by checking these combinations of the the 3-pin NOTE - If your ohm meter is not an auto-ranging type, set it motor plug.
  • Page 29 The switch may have a different one orifice located between the gas valve and the air intake set point for each unit model number. See Lennox Repair assembly (figure13). To check or replace the orifice remove...
  • Page 30 SL297UHNV HEATING COMPONENTS Heat Exchanger Gaskets Burner Box Air Gas Plenum Burner Rollout Switch (location) Sensor Primary Limit Air Orifice Ignitor Gas Valve Gas Orifice FIGURE 13 Page 30...
  • Page 31 SL297UHNV Ignitor Check Test 1 Check ignitor circuit for correct resistance. Remove 5-pin plug from control. Check ohms reading across terminals 1 and 5. Reading should be between 39 and 70 ohms. If value is correct, this is the only test needed. If the reading on the meter is not correct, (0 or infinity) then a second test is needed.
  • Page 32 8. Combustion Air Inducer Prove Switch (S18) FIGURE 15 SL297UHNV series units are equipped with a dual combus­ COMBUSTION AIR PRESSURE SWITCH tion air proving switch (first and second stage) located on the combustion air inducer housing. See figures 15 and 16.
  • Page 33 II-PLACEMENT AND INSTALLATION IMPORTANT All pipe, fittings, primer and solvent cement must conform with American National Standard Institute and the Ameri­ SL297UHNV exhaust and intake connections are can Society for Testing and Materials (ANSI/ASTM) stan­ made of PVC. Use PVC primer and solvent cement dards.
  • Page 34 TABLE 19 OUTDOOR TERMINATION USAGE* STANDARD CONCENTRIC Flush­ Wall Kit Wall Ring Kit Mount 1-1/2 inch 2 inch 3 inch 2 inch 3 inch 2 inch Vent Pipe Input Size Field 51W11 Dia. in. 71M80 69M29 Fabricated 44J40 (US) 22G44 (US) 60L46 (US) (US) (US)
  • Page 35 Conduct the following test while each appliance is operat­ Venting Practices ing and the other appliances (which are not operating) re­ main connected to the common venting system. If the venting system has been installed improperly, you must correct the system as indicated in the general venting re­ quirements section.
  • Page 36 Vent Piping Guidelines 1 - Remove the caution sticker from vent adapter. ® NOTE - Lennox has approved the use of DuraVent 2 - Fully insert vent adapter with both bands loosely at­ Centrotherm manufactured vent pipe and terminations as tached on the furnace exhaust coupling.
  • Page 37 Standard or concentric? used. Contact Lennox' Application Department for assis­ See table 19. tance in sizing vent pipe in these applications. NOTE - The exhaust collar on all models is sized to ac­...
  • Page 38 TABLE 21 Maximum Allowable Intake or Exhaust Vent Length in Feet NOTE - Size intake and exhaust pipe length separately. Values in table are for Intake OR Exhaust, not combined total. Both Intake and Exhaust must be same pipe size. NOTE - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.
  • Page 39 TABLE 22 Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated Attic or Crawl Space For Intake Air in Feet NOTE - Size intake and exhaust pipe length separately. Values in table are for Intake OR Exhaust, not combined total. Both Intake and Exhaust must be same pipe size.
  • Page 40 TYPICAL EXHAUST AND INTAKE PIPE CONNECTIONS IN UPFLOW APPLICATIONS EXHAUST EXHAUST INTAKE 2” 2” 2” 2” 3” Appliance TRANSITION Appliance 2” Adaptor DO NOT transition Adaptor *2” from smaller to larger 2” 3” pipe in horizontal runs *2” of exhaust pipe. INTAKE TRANSITION * When transitioning up in pipe size, use the shortest length of 2”...
  • Page 41 Intake Piping At vent termination, care must be taken to maintain protective coatings over building materials (prolonged The SL297UHNV furnace is installed in direct vent appli­ exposure to exhaust condensate can destroy protective cations. coatings). It is recommended that the exhaust outlet not be Follow the next two steps when installing the unit in Direct located within 6 feet (1.8m) of an outdoor AC unit because Vent applications, where combustion air is taken from...
  • Page 42 TABLE 23 Maximum Allowable Exhaust Vent Pipe Length (in ft.)Without Insulation In Unconditioned Space For Winter Design Temperatures Two - Stage High Efficiency Furnace Unit Input Size Winter Design Vent Pipe Temperatures °F (°C) Diameter 2 in. 32 to 21 (0 to -6) 2-1/2 in.
  • Page 43 ‡ Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor. Lennox recommends avoiding this location if possible. FIGURE 25 Page 43...
  • Page 44 Details of Intake and Exhaust Piping Terminations for TABLE 24 EXHAUST PIPE TERMINATION SIZE REDUCTION Direct Vent Installations SL297UHNV Termination NOTE - In Direct Vent installations, combustion air is tak­ MODEL Pipe Size en from outdoors and flue gases are discharged to out­ 1-1/2”...
  • Page 45 sized per table 24. The intake piping may be 8. A multiple furnace installation may use a group of up to equipped with a 90° elbow turndown. Using turndown four terminations assembled together horizontally, as will add 5 feet (1.5m) to the equivalent length of the shown in figure 33.
  • Page 46 2” EXTENSION FOR 2” PVC PIPE1” EXTENSION FOR 3” 12” PVC PIPE EXHAUST (305MM) FURNACE VENT 5-1/2” 5” EXHAUST (140mm) (127MM) INTAKE PIPE 18” MAX. FURNACE Front View (457MM) INTAKE PIPE EXHAUST VENT 12” (305MM) Min. GLUE EXHAUST above grade or END FLUSH INTO average snow TERMINATION...
  • Page 47 2 - For furnaces with a 1/2” drain connection use a 3/8 5 - Figures 39 and 41 show the furnace and evaporator allen wrench and remove plug (figure 35) from the cold coil using a separate drain. If necessary the conden­ end header box at the appropriate location on the side sate line from the furnace and evaporator coil can of the unit.
  • Page 48 Heating cable kit is UNIT With Evaporator Coil available from Lennox in various lengths; 6 ft. (1.8m) - Using A Separate Drain kit no. 26K68; 24 ft. (7.3m) - kit no. 26K69; and 50 ft.
  • Page 49 Unit with Evaporatoir Coil Using a Separate Drain (Unit shown in horizontal left-hand discharge position) Field Provided Vent Evaporator (4” min. to 5” max. above Coil condensate connection) 4”min 5”max 5’ max. PVC Pipe Only Trap at coil is option Condensate Drain Connection Drain Pan...
  • Page 50 TRAP / DRAIN ASSEMBLY USING 1/2” PVC OR 3/4” PVC COLD END HEADER BOX WITH 3/4 DRAIN CONNECTION Optional Condensate Drain Connection Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) 90° Street Elbow 3/4 inch PVC (not furnished) Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) Condensate Drain...
  • Page 51 III-START‐UP 4 - This furnace is equipped with an ignition device which automatically lights the burners. Do not try to light the A-Preliminary and Seasonal Checks burners by hand. 1 - Inspect electrical wiring, both field and factory installed 5 - Remove the upper access panel. for loose connections.
  • Page 52 Use of a specialty Refer to the SL297UHNV Installation Instruction. Gas Leak Detector is strongly recommended. It is available B-Gas Piping through Lennox under part number 31B2001. See Corp. 8411-L10, for further details. CAUTION Do not use matches, candles, flame or any other source of ignition to check for gas leaks.
  • Page 53 Manifold and Signal Pressure Measurement Air Orifice Replacement Do not replace the air orifice until the problem has been de­ To correctly measure manifold and signal pressure, follow termined. If the unit has difficulty igniting the orifice is over­ the steps below: sized and brings in too much air.
  • Page 54 REMOVE SCREWS Screws Screw FIGURE 46 Air Orifice Replacement Gray Coupling Air Orifice and Part Number Air Intake Coupling FIGURE 47 Page 54...
  • Page 55 Operating Signal Pressure Measurement Honeywell Valve FIGURE 48 TABLE 28 Production Resonance (more air) Difficulty Igniting (less air) Unit Orifice Size (Part No) Orifice Size Cat No Orifice Size Cat No 0.800 (16) 0.812 (01) 21U23 0.787 (20) 21U01 0.995 (14) 1.010 (21) 21U02 0.980 (13)
  • Page 56 Troubleshooting Poor Ignition or Combustion Resonance Issues Check Air Orifice See Figure 47. Check the following 1-Does the unit have the correct air orifice size? See table 28. 2 -Is the orifice fully seated tight against the elbow ? 3 -Is the orifice damaged in any­ way? 4 - Is the air inlet screen clear of any obstruction ?
  • Page 57 H- Proper Ground and Voltage IMPORTANT A poorly grounded furnace can contribute to premature ig­ nitor failure. Use the following procedure to check for For safety, shut unit off and remove manometer as ground and voltage to the integrated control. soon as an accurate reading has been obtained.
  • Page 58 V-TYPICAL OPERATING CHARACTERISTICS EXTERNAL STATIC PRESSURE A-Blower Operation and Adjustment Supply Duct Static ________ 1 - Blower operation is dependent on thermostat control Return Duct Static + _____ system. Total Duct Static = ________(dry coil) 2 - Generally, blower operation is set at thermostat sub­ base fan switch.
  • Page 59 7 - Remove heat exchanger. It may be necessary to specifications provided by the filter manufacturer spread cabinet side to allow more room. against the data given in the appropriate Lennox 8 - Back wash using steam. Begin from the burner open­ Product Specifications bulletin. Additional informa­...
  • Page 60 SL297UHNV HEATING COMPONENTS Heat Exchanger Gaskets Burner Box Air Gas Plenum Burner Rollout Switch (location) Ignitor Primary Limit O ring Sensor Gas Valve Gas Orifice FIGURE 53 Page 60...
  • Page 61 VII- Wiring and Sequence of Operation SL297UHNV Schematic Wiring Diagram Page 61...
  • Page 62 the combustion air inducer will switch to high fire. After CAUTION a 15 second pre-purge the high fire pressure switch will close and the unit will begin operation on high fire. Failure to use properly sized wiring and circuit After 10 to 20 seconds of high fire operation the unit breaker may result in property damage.
  • Page 63 Applications Using A Single-Stage Thermostat 4 - After the 20-second warm-up period has ended, the gas valve is energized on low fire (first stage) and ignition oc­ See figure 55 for ignition control sequence curs. At the same time, the control module sends a sig­ B - Heating Sequence -- Integrated Control Thermostat nal to begin an indoor blower 30-second ON-delay.
  • Page 64 Communicating Thermostat with SL297UHNV Communicating Thermostat with SL297UHNV and Non-Communicating Outdoor Unit and Communicating Outdoor Unit COMMUNICATING ENABLED COMMUNICATING SL297UHNV ENABLED FURNACE SL297UHNV OPTIONAL FURNACE DISCHARGE AIR SENSOR OPTIONAL DISCHARGE AIR SENSOR OPTIONAL OUTDOOR OPTIONAL AIR SENSOR OUTDOOR COMMUNICATING AIR SENSOR THERMOSTAT COMMUNICATING THERMOSTAT...
  • Page 65 ® Optional Accessories for use with any icomfort Touch System ® NOTE: ico Wi-Fi THERMOSTAT SENSES HUMIDITY & CON­ TROLS HUM CONTACTS TO CYCLE HUMIDIFIER BASED ON 120V CONNECTIONS DEMAND. NO OTHER CONTROL OR HUMIDISTAT REQUIRED. “HUM” CONTACT IS OPTIONAL OUTDOOR AIR SENSOR FOR USE WITH HUMIDI­ CLOSED ANYTIME FIER (IF NOT ALREADY IN THE SYSTEM FOR OTHER FUNC­...
  • Page 66 VIII- SL297UHNV Field Wiring Applications With Conventional Thermostat TABLE 30 DIP Switch Settings and On-Board Links (See figure 4) DIP Switch 1 On Board Links Must Be Cut To Select Thermostat Thermostat Wiring Connections System Options Heating Stages 1 Heat / 1 Cool FURNACE OUTDOOR T'STAT...
  • Page 67 TABLE 30 SL297 Field Wiring Applications With Conventional Thermostat (Continued) DIP Switch Settings and On-Board Links (See figure 4) DIP Switch 1 On Board Links Must Be Cut To Select Thermostat Thermostat Wiring Connections System Options Heating Stages 2 Heat / 2 Cool FURNACE OUTDOOR T'STAT...
  • Page 68 TABLE 30 SL297 Field Wiring Applications With Conventional Thermostat (Continued) DIP Switch Settings and On-Board Links (figure 4) DIP Switch 1 Wiring Connections Thermostat On Board Links Must Be Cut To Select Thermostat Heating System Options Stages Dual Fuel FURNACE HEAT PUMP L7724U TERM.
  • Page 69 TABLE 30 SL297 Field Wiring Applications With Conventional Thermostat (Continued) DIP Switch Settings and On-Board Links (figure 4) DIP Switch 1 Wiring Connections Thermostat On Board Links Must Be Cut To Select Thermostat Heating System Options Stages Dual Fuel FURNACE HEAT PUMP L7724U TERM.
  • Page 70 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 71 X- Troubleshooting 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 WATCHGUARD − SWITCH INDOOR AFTER HEAT FAN LIMIT SWITCH CODE ERROR CODE...
  • Page 72 Troubleshooting: Heating Sequence of Operation (Continued) CALL FOR SECOND-STAGE HEAT CALL FOR 2ND STAGE HEAT (HIGH FIRE) SINGLE STAGE 2 STAGE THERMOSTAT THERMOSTAT 2ND STAGE RECOGNITION DELAY ON DELAY (30 SECONDS) EXPIRED? ONLY FOR 1ST EXPIRED? REQUEST FOR 2ND STAGE HEAT INDUCER SWITCHED TO HIGH SPEED HIGH...
  • Page 73 Troubleshooting: Heating Sequence of Operation (Continued) CALL FOR HEAT SATISFIED FIRST-STAGE HEAT SECOND-STAGE HEAT RUN MODE: 1ST OR 2ND STAGE CALL FOR HEAT. ALL INPUTS MONITORED (LIMIT, PRESSURE, CALL FOR HEAT/COOL, FLAME LEVEL) 2ND STAGE HEAT 2ND STAGE CALL FOR HEAT SATISFIED? DE−ENERGIZE 2ND STAGE GAS VALVE...
  • Page 74 Troubleshooting: Cooling Sequence of Operation (Continued) CALL FOR COOLING 1ST STAGE COOLING REQUEST RECEIVED WAIT FOR COMPRESSOR TIMED OFF DELAY TO EXPIRE ENERGIZE 1ST STAGE COOLING CONTACTOR (COMPRESSOR & FAN) INDOOR BLOWER 2 SECOND ON DELAY ENERGIZE INDOOR BLOWER (LOW COOLING MODE) MAINTAIN INDOOR BLOWER (LOW COOLING MODE)
  • Page 75 Troubleshooting: Continuous Fan Sequence of Operation CALL FOR FAN CALL FOR FAN INDOOR BLOWER ON CONTINUOUS FAN SPEED CALL FOR FAN MAINTAIN INDOOR REMOVED? BLOWER AT CONTINUOUS FAN REQUEST MAINTAIN INDOOR FOR COOLING GO TO CALL FOR COOLING BLOWER AT RECEIVED? CONTINUOUS FAN REQUEST...

This manual is also suitable for:

Sl297uh040nv36bSl297uh060nv36bSl297uh080nv48cSl297uh080nv60c