Lennox EL297UHE Series Manual

Lennox EL297UHE Series Manual

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S e r v i c e L i t e r a t u r e
EL297UHE series units are high efficiency condensing
gas furnaces used for upflow or horizontal applications
only, manufactured with Lennox Duralok heat exchangers
formed of aluminized steel. EL297UHE units are available
in heating capacities of 44,000 to 132,000 Btuh and cool-
ing applications up to 5 tons. Refer to Product Specifica-
tions Manual for proper sizing.
Units are factory equipped for use with natural gas. Kits
are available for conversion to LPG operation. EL297UHE
model units are equipped with the SureLight® two-stage
integrated control. EL297UHE unit meets the California
Nitrogen Oxides (NOx) Standards and California Season-
al Efficiency requirements. 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.
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.

TABLE OF CONTENTS

Specifications ....................................................... Page 2
I Unit Components ................................................ Page 7
II Installation ....................................................... Page 22
III Start Up .......................................................... Page 45
IV Heating System Service Checks .................... Page 46
V Typical Operating Characteristics ................... Page 50
VI Maintenance................................................... Page 51
VII Wiring and Sequence of Operation ............... Page 54
X Troubleshooting............................................... Page 62
UNIT INFORMATION
UNIT INFORMATION
100093
EL297UHE SERIES UNITS
Page 1
WARNING
Improper
installation,
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.
EL297UHE
C C C C
I I I I
HI
HI
adjustment,
alteration,
©2016 Lennox Industries, Inc.

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Do you have a question about the EL297UHE Series and is the answer not in the manual?

Questions and answers

benita zahn
January 28, 2025

what is the efficiency rating I'm applying for a rebate for a EL297UHE furnace

1 comments:
Mr. Anderson
May 14, 2025

The Lennox EL297UHE furnace is described as a high-efficiency condensing gas furnace. However, the exact efficiency rating (e.g., AFUE percentage) is not specified in the provided information.

This answer is automatically generated

Summary of Contents for Lennox EL297UHE Series

  • Page 1: Table Of Contents

    S e r v i c e L i t e r a t u r e EL297UHE SERIES UNITS EL297UHE series units are high efficiency condensing gas furnaces used for upflow or horizontal applications only, manufactured with Lennox Duralok heat exchangers formed of aluminized steel.
  • Page 2: Specifications

    SP ECIF ICATIONS Model No. EL297UH045XE36B EL297UH070XE36B EL297UH090XE48C Heating AFUE Performance High Input - Btuh 44,000 66,000 88,000 Fire Output - Btuh 43,000 65,000 86,000 Temperature rise range - °F 30-60 35-65 40-70 Gas Manifold Pressure (in. w.g.) 3.5 / 10.0 3.5 / 10.0 3.5 / 10.0 Nat.
  • Page 3 OPT IONAL AC C ESSORIES - ORD ER SEPARAT ELY “B” Width “C” Width “D” Width Models Models Models CABINET ACCESSORIES Horizontal Suspension Kit - Horizontal only 51W10 51W10 51W10 Return Air Base - Upflow only 50W98 50W99 51W00 High Performance Economizer (Commercial Only) 10U53 10U53 10U53...
  • Page 4 BLO WER DATA EL297UH045XE36B PERFORMANCE (Less Filter) Air Volume / Watts at Various Blower Speeds External Static High Medium-High Medium Medium-Low Pressure (Black) (Brown) (Blue) (Yellow) (Red) in. w.g. Watts Watts Watts Watts Watts 0.00 1416 1286 1174 0.10 1395 1246 1139 0.20...
  • Page 5 BLO WER DATA EL297UH110XE60C PERFORMANCE (Less Filter) Air Volume / Watts at Different Blower Speeds Single Side Return Air - Air volumes in bold (over 1800 Bottom Return Air, Side Return Air with Return Air from cfm) require Optional Return Air Base and field fabricated External Both Sides or Return Air from Bottom and One Side.
  • Page 6 PARTS IDENTIFICATION Field Make Up Box Burner Box Assembly Heat Exchanger Gas Valve Combustion Pressure Air Inducer Switch Assembly Bag Assemblies (shipping location) Door Interlock Primary Limit Switch Constant Torque Indoor Blower Motor Outer Access Panel Inner Access Panel Two-Stage Integrated Control FIGURE 1 Page 6...
  • Page 7: I Unit Components

    I-UNIT COMPONENTS The breaker can be manually reset by pressing the button on the face. See FIGURE 3. EL297UHE unit components are shown in FIGURE 1. The gas valve, combustion air inducer and burners can be CIRCUIT BREAKER CB8 accessed by removing the access panel. Electrical com- ponents are in the control box (FIGURE 2) found in the blower PRESS TO RESET...
  • Page 8 After the 15-second pre-purge period, the SureLight ® TABLE 1 nitor warms up for 20 seconds after which the gas valve SureLight Control 5 Pin Terminal Designation ® opens for a 4-second trial for ignition. The ignitor remains Pin # Function energized during the trial until flame is sensed.
  • Page 9 Integrated Control 103699 INTEGRATED CONTROL 24VAC Indoor Ignitor and Combustion Blower Terminals Air Inducer Neutrals Flame Sense S4 DIP Switches Diagnostic Push Button On Board Links THERMOSTAT CONNECTIONS (TB1) 3/16” QUICK CONNECT TERMINALS DS = DEHUMIDIFICATION SIGNAL FLAME SENSE SIGNAL W2 = HEAT DEMAND FROM 2ND STAGE T/STAT HI COOL 24VAC W1 = HEAT DEMAND FROM 1ST STAGE T/STAT...
  • Page 10 Integrated Control 107048 Line Voltage Ignitor and Combustion Accessories Humidifier Air Inducer Neutrals ECM DRIVE - 24VAC Line Voltage Flame Sense On Board Links Thermostat Connections 3/16” QUICK CONNECT TERMINALS THERMOSTAT CONNECTIONS HI COOL (24VAC) DS= Dehumidification signal LO COOL (24VAC) W2= Heat demand from 2 stage Tstat HI HEAT (24VAC)
  • Page 11 INTEGRATED CONTROL CONFIGURATION GUIDE 2ND STAGE HEAT ON DELAY 7 MIN UPSTAGE THERMOSTAT SELECTION DELAY COOLING BLOWER-OFF DELAY TWO STAGE THERMOSTAT 12 MIN UPSTAGE *45 SECOND DELAY COOL BLOWER 1−STAGE OFF DELAY THERMOSTAT (TIMED STAGING) −SEE SW #2 HSI/CAI 2 SECOND COOL BLOWER HEATING BLOWER−OFF DELAY OFF DELAY...
  • Page 12 TABLE 3 Integrated Control Diagnostic Modes Display Action (when button released) No Change Remain in idle mode Solid “E” Enter diagnostic recall mode Solid “F” Enter flame signal mode TABLE 4 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).
  • Page 13 TABLE 4 Continued Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E125 Control failed self-check, internal error, Hardware problem on the control. Cycle power on control. Replace failed hardware. Will restart if error recovers. if problem prevents service and is persistent. Critical alert. Cleared Integrated control not communicating.
  • Page 14 TABLE 4 Continued Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E270 Soft lockout - Exceeded maximum number of Check for proper gas flow. Ensure that ignitor is lighting burner. retries. No flame current sensed. Check flame sensor current. Clears when heat call finishes successfully.
  • Page 15 Integrated Control DIP Switches TABLE 5 EL297UHE units are equipped with a two-stage integrat- Blower Off Heating Mode Delay Switch Settings ed control. This control manages ignition timing, heating Blower Off Delay mode fan off delays and indoor blower speeds based on Switch 3 Switch 4 Seconds...
  • Page 16 B- Indoor Blower Motor BLOWER WHEEL REPLACEMENT IMPORTANT Center Blower Wheel in Blower Housing Each blower is statically and dynamically balanced as an assembly before installation in the unit. EL297UHE units are equipped with a constant torque ECM motor. It has a DC motor coupled to an electronic control module both contained in the same motor housing.
  • Page 17 Multi−Meter (set to VAC) Multi−Met e (set to VA Test 3 (if necessary) "9A” NOTE- Ignition control illustration is typical Check for 120 volts across terminals “L1” and “Neutrals” on the "7A” integrated control. If voltage is present, problem is with the har ness.
  • Page 18 Replacing the Motor Module Motor Test NOTE - Not all motors have field replaceable control mod- ules. Only motors that utilize a 4 pin power connector and 5 pin signal connector as shown below may have replace- able controls. Motors that use a 3 pin power connector and 6 pin signal connector do not have field replaceable control modules.
  • Page 19 The switch may have a different set point for each unit and go to Field Test Mode. The menu will display the flame model number. See Lennox Repair Parts Handbook if lim- signal. See TABLE 9 for flame signal. it switch must be replaced. When removing switch make TABLE 9 note of orientation.
  • Page 20 HEATING COMPONENTS Burner Assembly Intake Air Top Cap Sensor Rollout Switch Rollout Switch Ignitor Manifold And Gas Orifices Burner Box Cover Two-Stage Gas Valve FIGURE 15 Page 20...
  • Page 21 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 22: Installation

    0.75 0.45 (FIGURE 17) -110 0.95 0.55 EL297UHE series units are equipped with a dual combus- -135 0.80 0.40 tion air pressure switch (first and second stage) located on the CEHB. The switch is connected to the cold end header box by means of flexible silicone hoses.
  • Page 23 II-PLACEMENT AND INSTALLATION TABLE 14 Continued All pipe, fittings, primer and solvent cement must conform CANADA PIPE & FITTING & SOLVENT MARKING with American National Standard Institute and the Ameri- CEMENT can Society for Testing and Materials (ANSI/ASTM) stan- PVC & CPVC Pipe and Fittings dards.
  • Page 24 TABLE 15 OUTDOOR TERMINATION USAGE* STANDARD CONCENTRIC Wall Kit 1-1.2 inch 2 inch 3 inch Flush Mount Vent Pipe 2 inch 3 inch Input Size Field 71M80 (US) 69M29 (US) 60L46 (US) Dia. in. 51W11 (US) Fabricated 44W92 44W92 44W93 22G44 (US) 44J40 (US) 51W12...
  • Page 25 7 - Immediately after applying last coat of cement to Removal of the Furnace from Common Vent pipe, and while both inside socket surface and end In the event that an existing furnace is removed from a of pipe are wet with cement, forcefully insert end of venting system commonly run with separate gas applianc- pipe into socket until it bottoms out.
  • Page 26 7 - If a venting problem is found during any of the Vent Piping Guidelines preceding tests, the common venting system must NOTE - Lennox has approved the use of DuraVent® and be modified to correct the problem. Resize the Centrotherm manufactured vent pipe and terminations common venting system to the minimum vent pipe as an option to PVC.
  • Page 27 Horizontal Installation Offset Requirements Piping Size Process Exhaust Pipe 12” Min. 12” Max. What is the Horizontal furnace capacity? Gas Furnace Which style termination being used? Standard or concentric? NOTE - Which needs ward unit. A minimum of 1/4” (6mm) drop for each 12” (305mm) most elbows? of horizontal run is mandatory for drainage.
  • Page 28 TABLE 17 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 Standard Termination at Elevation 0 - 4500 ft Number 1-1/2”...
  • Page 29 TABLE 17 Continued 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. Concentric Termination at Elevation 0 - 4500 ft Number 1-1/2”...
  • Page 30 TABLE 18 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 31 TYPICAL EXHAUST AND INTAKE PIPE CONNECTIONS IN UPFLOW DIRECT OR NON-DIRECT VENT APPLICATIONS 2” EXHAUST EXHAUST INTAKE INTAKE 2” 2” 2” 2” 2” 3” 3” 045/070 Only 1−1/2” TRANSITION Exhaust 2” 6” Min Exhaust DO NOT transition from larger to smaller DO NOT transition pipe in horizontal runs from smaller to larger...
  • Page 32 Intake Piping TYPICAL AIR INTAKE PIPE CONNECTIONS HORIZONTAL NON−DIRECT VENT APPLICATIONS The EL297UHE furnace may be installed in either direct (Horizontal Right−Hand Air Discharge Application Shown) vent or non-direct vent applications. In non-direct vent applications, when intake air will be drawn into the furnace from the surrounding space, the indoor air quality must be considered and guidelines listed in Combustion, Dilution PVC pipe...
  • Page 33 General Guidelines for Vent Terminations CAUTION In Non-Direct Vent applications, combustion air is taken If this unit is being installed in an application with from indoors or ventilated attic or crawlspace and the flue combustion air coming in from a space serviced by gases are discharged to the outdoors.
  • Page 34 TABLE 19 Maximum Allowable Exhaust Vent Pipe Length (in ft. ) Without Insulation In Unconditioned Space For Winter Design Temperatures Two - Stage High Efficiency Furnace Winter Design Unit Input Size Vent Pipe Temperatures1 °F Diameter (°C) 1-1/2 in 32 to 21 2 in (0 to -6) 2-1/2 in...
  • Page 35 ‡ Permitted only if veranda, porch, deck or balcony is fully open NOTE - This figure is intended to illustrate clearance on a minimum of two sides beneath the floor. Lennox recommends requirement and does not serve as a substitute for avoiding this location if possible.
  • Page 36 ‡ Permitted only if veranda, porch, deck or balcony is fully open on a minimum of locally adopted installation codes. two sides beneath the floor. Lennox recommends avoiding this location if possible. FIGURE 30 Page 36...
  • Page 37 Details of Intake and Exhaust Piping Terminations for Exiting Exhaust and Intake Vent Direct Vent Installations (different pressure zone) NOTE - In Direct Vent installations, combustion air is taken from outdoors and flue gases are discharged to outdoors. NOTE - Flue gas may be slightly acidic and may adverse- ly affect some building materials.
  • Page 38 7 - If intake and exhaust piping must be run up a side wall to position above snow accumulation or other obstructions, piping must be supported. At least FIELD-PROVIDED Accelerator not required REDUCER MAY BE one bracket must be used within 6” from the top of for 3”...
  • Page 39 FIELD FABRICATED WALL TERMINATION NOTE − FIELD−PROVIDED REDUCER MAY BE 2” (51mm) 3” (76mm) REQUIRED TO ADAPT LARGER VENT PIPE SIZE Vent Pipe Vent Pipe TO TERMINATION A− Minimum clearance above grade or average 12” (305 mm) 12” (305 mm) snow accumulation B−...
  • Page 40 Crawl Space and Extended Horizontal Venting SNOW ACCUMULATION Lennox provides kit 51W18 (USA) and kit 15Z70 (Cana- da) to install 2” or 3” PVC exhaust piping through the floor joists and into the the crawl space. See figure below. 3” (76mm) OR...
  • Page 41 If this is not possible, a heat cable kit may be used on the condensate trap and line. Heating cable kit is available from Lennox in various lengths; 6 ft. (1.8m) - kit no. 26K68 and 24 ft. (7.3m) - kit no.
  • Page 42 CONDENSATE TRAP LOCATIONS Condensate Trap With Optional Overflow Switch (Unit shown in upflow position with remote trap) From Evaporator Coil HorizontalFurnace4” Min. to 5” Max.above FieldProvidedVent condensatedrain connection) Min. 1” Above Condensate Drain Connection 1” Min. 2” Max. FurnaceCondensate DrainConnection *5’...
  • Page 43 Furnace with Evaporator 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 Condensate Drain Connection (Trap at coil is optional) Drain Pan Piping from furnace and evaporator coil must slope down a minimum 1/4”...
  • Page 44 TRAP / DRAIN ASSEMBLY USING 1/2” PVC OR 3/4” PVC 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 Connection In Unit 1 (25 mm) Min.
  • Page 45: Start Up

    III-START-UP 3 - Turn off all electrical power to the unit. 4 - This furnace is equipped with an ignition device A-Preliminary and Seasonal Checks which automatically lights the burners. Do not try to light the burners by hand. 1 - Inspect electrical wiring, both field and factory installed for loose connections.
  • Page 46: Heating System Service Checks

    Use of a specialty Gas Leak Detector is strongly recommended. It All units are CSA design certified without modifications. is available through Lennox under part number 31B2001. Refer to the EL297UHE Installation Instruction. See Corp. 8411-L10, for further details.
  • Page 47 MANIFOLD PRESSURE CHECK SET UP Gas Valve Regulator Manifold Post Vent Hose (to burner box) 2” Long Clamp Square Tubing 5/16” Round Hose Reducer Fitting 10” Long Square Tubing Measuring Device FIGURE 53 F- Proper Gas Flow (Approximate) G- Proper Combustion Furnace should operate at least 5 minutes before check- Furnace should operate minimum 15 minutes with correct ing gas flow.
  • Page 48 TABLE 23 Manifold and Supply Line Pressure 0-10,000ft. Manifold Pressure in. wg. Supply Line Pressure in. w.g EL297 0 - 4500 ft 4501 - 5500 ft. 5501 - 6500 ft 6501 - 7500 ft 7501 - 10,000 ft 0 - 10,000 ft. Model High High...
  • Page 49 I- Proper Ground and Voltage 2 - In addition, measure the AC voltage from Line Hot to Line Neutral (spade terminals) on the integrated con- Furnace must be properly grounded for proper perfor- trol. See FIGURE 54. This voltage should be in the mance.
  • Page 50: Typical Operating Characteristics

    V-TYPICAL OPERATING CHARACTERISTICS C-External Static Pressure 1 - 1 - Tap locations shown in FIGURE 56. 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.
  • Page 51: Maintenance

    Condensate Hose Screens Before using any filter with this system, check the specifications provided by the filter manufacturer against the data given in the appropriate Lennox Product Specifications bulletin. Additional...
  • Page 52 Cleaning Heat Exchanger 21 - Remove screws along vestibule sides and bottom which secure vestibule panel and heat exchanger If cleaning the heat exchanger becomes necessary, follow assembly to cabinet. Remove two screws from the below procedures and refer to figure 1 when disas- blower rail which secure bottom heat exchanger sembling unit.
  • Page 53 45 - Reconnect gas supply piping. Turn on power and 6 - Disconnect combustion air intake pipe. It may be gas supply to unit. necessary to cut the existing pipe to remove burner box assembly. 46 - Follow lighting instructions on unit nameplate to light and operate furnace for 5 minutes to ensure 7 - Remove four screws which secure burner box the furnace is operating properly.
  • Page 54: Wiring And Sequence Of Operation

    VII- Wiring and Sequence of Operation Wiring Diagram EL297UHE COMBUSTION AIR COMBUSTION AIR BLOWER MOTOR BLOWER MOTOR DOOR IGNITOR INTERLOCK CIRC FLAME SENSE WHT/PINK FLAME SENSOR 120V BLUE BLUE MV COM PINK PURPLE S102 HIGH HEAT PRESSURE SWITCH PURPLE S128 LOW HEAT PRESSURE SWITCH BLUE...
  • Page 55 Wiring Diagram EL297UHE-135 COMBUSTION AIR COMBUSTION AIR BLOWER MOTOR BLOWER MOTOR DOOR IGNITOR INTERLOCK CIRC FLAME SENSE WHT/PINK FLAME SENSOR 120V BLUE BLUE MV COM PINK PURPLE S102 HIGH HEAT PRESSURE SWITCH PURPLE S128 LOW HEAT PRESSURE SWITCH BLUE BRN W / YEL STRIPE RO(OUT) GRN/YEL...
  • Page 56 Electronic Ignition When the delay ends, the indoor blower motor is energized on the low fire heating speed, the HUM The two-stage, variable speed integrated control used in contacts close energizing the humidifier and 120V EL297UHE units has an added feature of an internal ACC terminal is energized.
  • Page 57 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) See FIGURE 59 for ignition control sequence and ignition occurs. At the same time, the control B - Heating Sequence -- Integrated Control Thermostat module sends a signal to begin an indoor blower Selection DIP Switch 1 ON in “Single-Stage”...
  • Page 58: Field Wiring And Jumper Settings

    VIII- EL297UHE Field Wiring Applications TABLE 27 EL296 Field Wiring Applications 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...
  • Page 59 TABLE 28 EL296 Field Wiring Applications (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.
  • Page 60 TABLE 28 EL296 Field Wiring Applications (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...
  • Page 61 TABLE 28 EL296 Field Wiring Applications (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...
  • Page 62: Troubleshooting

    IX- Troubleshooting HEATING SEQUENCE OF OPERATION NORMAL AND ABNORMAL HEATING MODE POWER ON GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF. (RESET CONTROL BY CONTROL SELF-CHECK OKAY? TURNING MAIN POWER OFF.) POLARITY REVERSED. POLARITY OKAY? STATUS ERROR CODE 5 + 4. IS THERE A SIGNAL HOLDS UNTIL UNIT IS PROPERLY GROUNDED.
  • Page 63 HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT STATUS LED - HEARTBEAT. (Refer to box A on previous page) GAS VALVE OFF. COMBUSTION AIR INDUCER FIRST-STAGE (LOW FIRE) PRESSURE OFF. INDOOR BLOWER OFF. UNIT WILL RETRY SWITCH CLOSED WITHIN 2.5 MINUTES? AFTER 5-MINUTE WAIT PERIOD.
  • Page 64 HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT. STATUS LED -- HEARTBEAT. SEE BOX A. FLAME SIGNAL ABOVE ( 1.40 microamps) LOW FLAME SIGNAL (Does not affect control operation) STATUS ERROR CODE 1 + 2. SINGLE-STAGE THERMOSTAT MODE TWO STAGE THERMOSTAT MODE (DIP SWITCH SET AT “ON”) (DIP SWITCH SET AT “OFF”) START SECOND-STAGE RECOGNITION...
  • Page 65 HEATING SEQUENCE OF OPERATION CONTINUED SEE BOX A NORMAL OPERATION. SEE BOX B THERMOSTAT CALLS FOR HEAT. RETURN TO FIRST-STAGE HEAT MODE. FIRST-STAGE CONTINUES UNTIL SECOND- STAGE PRESSURE SWITCH CAN BE PROVEN SECOND-STAGE (HIGH FIRE) HEAT or HEAT DEMAND IS SATISFIED. A FIVE (5) PRESSURE SWITCH CLOSED? MINUTE WAIT PERIOD IS INITIATED BEFORE RETRY.
  • Page 66 COOLING SEQUENCE OF OPERATION POWER ON SIGNAL POLARITY REVERSED. CONTROL WILL CONTINUE TO CALL FOR COOLING IS POLARITY REVERSED? IN THIS CONDITION. STATUS ERROR CODE 5 + 4. SIGNAL IMPROPER GROUND AT LED. CONTROL WILL CONTINUE TO CALL FOR COOLING IS THERE IN THIS CONDITION.
  • Page 67 CONTINUOUS LOW SPEED FAN SEQUENCE OF OPERATION MANUAL FAN SELECTION MADE AT THERMOSTAT. AFTER 2 SECOND DELAY, INDOOR BLOWER IS ENERGIZED ON CONTINUOUS FAN SPEED. THERMOSTAT CALLS FOR FIRST STAGE COOL. THERMOSTAT CALLS FOR FIRST-STAGE HEAT. INDOOR BLOWER RAMPS TO FIRST STAGE AFTER 45-SECOND DELAY, INDOOR BLOWER COOLING SPEED AFTER A 2-SECOND DELAY.

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