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© 2025 Lennox Industries Inc.
Dallas, Texas USA
WARNING
This furnace is equipped with an ignition control
factory enabled for use with Lennox A2L refrigerant
systems.
Disabling
functionality on A2L system is prohibited by safety
codes. Refer to furnace installation instructions for
non-A2L and non-Lennox refrigerant system setup.
CAUTION
As with any mechanical equipment, personal injury can
result from contact with sharp sheet metal edges. Be
careful when you handle this equipment.
Table of Contents
Unit Dimensions - inches (mm) .....................................2
Shipping and Packing List ..............................................3
Safety Information ..........................................................3
Use of Furnace as Construction Heater .........................4
General ...........................................................................5
Shipping Bolt Removal ...................................................8
Installation - Setting Equipment ......................................8
Filters ............................................................................13
Duct System .................................................................13
Pipe & Fittings Specifications .......................................14
Joint Cementing Procedure ..........................................15
Venting Practices ..........................................................16
Gas Piping ....................................................................36
Electrical .......................................................................39
the
refrigerant
detection
INSTALLATION
INSTRUCTIONS
EL297UHVK
ELITE
SERIES GAS FURNACE
®
UP/FLOW HORIZONTAL AIR DISCHARGE
508581-01
01/2025
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
This is a safety alert symbol and should never be
ignored. When you see this symbol on labels or in man-
uals, be alert to the potential for personal injury or death.
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.
A thermostat is not included and must be ordered
separately.
A communicating
communicating applications.
In
non-communicating
ComfortSense® 7500 thermostat may be used, as well
as other non-communicating thermostats.
In all cases, setup is critical to ensure proper system
operation.
which begin on Page 41.
Ignition Control .............................................................50
Blower Data ..................................................................55
Low GWP Application ...................................................61
Unit Start Up .................................................................64
Gas Pressure Adjustment .............................................65
Proper Combustion.......................................................66
High Altitude .................................................................66
Combustion Air for Non-Direct Vent Applications .........67
Repair Parts..................................................................67
Other Unit Adjustments.................................................68
Heating Sequence of Operation ...................................68
Service..........................................................................70
Program Unit Capacity/Size Mode ...............................72
Start-Up and Performace Checklist ..............................76
Page 1
WARNING
NOTICE
thermostat
must
be
applications,
the
used
in
Lennox
non-
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Summary of Contents for Lennox ELITE EL297UHVK
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Page 1: Table Of Contents
NOTICE WARNING A thermostat is not included and must be ordered This furnace is equipped with an ignition control separately. factory enabled for use with Lennox A2L refrigerant A communicating thermostat must used systems. -
Page 2: Unit Dimensions - Inches (Mm)
Unit Dimensions - inches (mm) NOTE - 60C and 60D size units that require air volumes over 1800 cfm must have one of the following: 1. Single side return air and Optional Return Air Base with transition that must accommodate required 20 x 25 x 1 inch (508 x 635 x 25 mm) air filter to EXHAUST AIR 3-1/4... -
Page 3: Shipping And Packing List
EL297UHVK Gas Furnace Shipping and Packing List Package 1 of 1 contains The EL297UHVK Category IV gas furnace is shipped ready for installation in the upflow or horizontal position. 1 - Assembled EL297UHVK unit The furnace is shipped with the bottom panel in place. The 1 - Bag assembly containing the following: bottom panel must be removed if the unit is to be installed 1 - Snap bushing... -
Page 4: Use Of Furnace As Construction Heater
In order to ensure proper unit operation in non-direct vent applications, combustion and ventilation air supply must Heating Unit Installed Parallell to Air Handler Unit Dampers be provided according to the current National Fuel Gas (open during heating operation only) Code or CSA-B149 standard. -
Page 5: General
FAILURE TO FOLLOW THE ABOVE INSTALLATION IN- Water softening chemicals STRUCTIONS VOIDS THE MANUFACTURER’S EQUIP- De-icing salts or chemicals MENT LIMITED WARRANTY. LENNOX DISCLAIMS ALL LIABILITY IN CONNECTION WITH INSTALLER’S Carbon tetrachloride FAILURE TO FOLLOW THE ABOVE INSTALLATION IN- Halogen type refrigerants STRUCTIONS. -
Page 6: Unconfined Space
When the furnace is installed so that supply ducts carry CAUTION air circulated by the furnace to areas outside the space containing the furnace, the return air must be handled by Do not install the furnace in a corrosive or contaminated ducts which are sealed to the furnace casing and which atmosphere. - Page 7 Air from Outside EQUIPMENT IN CONFINED SPACE (Inlet Air from Ventilated Crawlspace and Outlet Air to Outside) If air from outside is brought in for combustion and ventila- tion, the confined space shall be provided with two perma- nent openings. One opening shall be within 12” (305mm) Roof Terminated of the top of the enclosure and one within 12”...
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Page 8: Shipping Bolt Removal
The bolt and washer must be removed before the furnace EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE is placed into operation. After the bolt and washer have (All Air Through Ventilated Attic) been removed, the rigid leg will not touch the blower hous- ing. -
Page 9: Horizontal Application
SETTING EQUIPMENT UPFLOW APPLICATION Place level on blower Place level on the front blower deck screws to check deck to check side to side forward tilt UNIT FRONT AIR FLOW 1/2” max. SIDE VIEW HORIZONTAL APPLICATION UNIT FRONT AIR FLOW 1/2”... - Page 10 Return Air Guidelines WARNING Return air can be brought in through the bottom or either Improper installation of the furnace can result in side of the furnace installed in an upflow application. If the furnace is installed on a platform with bottom return, make personal injury or death.
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Page 11: Removing The Bottom Panel
Optional Return Air Base CONDENSATE (Upflow Applications Only) TRAP FURNACE FRONT 23 (584) 3−1/4 IF BASE Overall (83) IS USED (Maximum) Minimum WITHOUT 11 (279) IAQ CABINET, Maximum 22−7/16 INDOOR AIR A SINGLE Unit side return air 14 (356) QUALITY (570) RETURN AIR Opening... - Page 12 6 - Continue with exhaust, condensate and intake on a platform, as shown in Figure 19. A horizontal sus- piping installation according to instructions. pension kit (51W10) may be ordered from Lennox or use equivalent. NOTE - Heavy-gauge sheet metal straps may be used to suspend the unit from roof rafters or ceiling joists.
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Page 13: Filters
Lennox Product pulled back down the vent pipe and into the room. This Specifications bulletin. Additional information is provided... -
Page 14: Pipe & Fittings Specifications
CAUTION Pipe & Fittings Specifications All pipe, fittings, primer and solvent cement must conform Solvent cements for plastic pipe are flammable liquids with American National Standard Institute and the Ameri- and should be kept away from all sources of ignition. can Society for Testing and Materials (ANSI/ASTM) stan- Do not use excessive amounts of solvent cement when dards. -
Page 15: Joint Cementing Procedure
TABLE 3 OUTDOOR TERMINATION USAGE* STANDARD CONCENTRIC Wall Kit 1-1.2 inch 2 inch 3 inch Flush Mount Vent Pipe Dia. 2 inch 3 inch Input Size Field 71M80 (US) 69M29 (US) 60L46 (US) 51W11 (US) Fabricated 22G44 (US) 44J40 (US) 444W92 (CA) 444W92 (CA) 444W93 (CA) -
Page 16: Venting Practices
NOTE - Assembly should be completed within 20 Conduct the following test while each appliance is oper- ating and the other appliances (which are not operating) seconds after last application of cement. Hammer blows should not be used when inserting pipe. remain connected to the common venting system. -
Page 17: Vent Piping Guidlines
Figure 22 Vent Piping Guidlines NOTE - Lennox has approved the use of DuraVent® and TABLE 4 Centrotherm manufactured vent pipe and terminations MINIMUM VENT PIPE LENGTHS as an option to PVC. - Page 18 IMPORTANT Piping Size Process Do not use screens or perforated metal in exhaust or intake terminations. Doing so will cause freeze-ups and What is the may block the terminations. furnace capacity? Which style termination being used? Standard or concentric? Which needs most elbows? Intake or exhaust?
- Page 19 TABLE 5 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 No Of 1-1/2”...
- Page 20 TABLE 5 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 No Of 1-1/2”...
- Page 21 TABLE 6 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 22 TYPICAL EXHAUST AND INTAKE PIPE CONNECTIONS IN UPFLOW DIRECT OR NON-DIRECT VENT APPLICATIONS 2” 2” EXHAUST EXHAUST INTAKE INTAKE 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 23 Intake Piping TYPICAL AIR INTAKE PIPE CONNECTIONS The EL297UHVK furnace may be installed in either direct HORIZONTAL NON−DIRECT VENT APPLICATIONS (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 and Ventilation Air section must be followed.
- Page 24 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 an gases are discharged to the outdoors.
- Page 25 TABLE 7 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 32 to 21 2 in (0 to -6) 2-1/2 in...
- Page 26 ‡ Permitted only if veranda, porch, deck or balcony is fully open requirement and does not serve as a substitute for on a minimum of two sides beneath the floor. Lennox recommends avoiding this location if possible. locally adopted installation codes.
- Page 27 ‡ 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 32 Page 27...
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Page 28: Direct Vent Installations
Details of Intake and Exhaust Piping Terminations for any direction. When exhaust and intake piping must be run up an outside wall, the exhaust piping Direct Vent Installations must be terminated with pipe sized per table 8.The intake piping may be equipped with a 90° elbow NOTE - In Direct Vent installations, combustion air is taken turndown. - Page 29 TABLE 8 EXHAUST PIPE TERMINATION SIZE REDUCTION FIELD-PROVIDED Accelerator not required REDUCER MAY BE EL297UHVK Termination for 3” concentric REQUIRED TO ADAPT DIFFERENT VENT PIPE MODEL Pipe Size OUTSIDE SIZE TO TERMINATION INTAKE WALL *045 and 070 1-1/2” (38MM) EXHAUST EXHAUST *090 2”...
- Page 30 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 31 (USA) Crawl Space and Extended Horizontal Venting KIT 15Z70 Lennox provides kit 51W18 (USA) and kit 15Z70 (Cana- (CANADA) da) to install 2” or 3” PVC exhaust piping through the floor joists and into the the crawl space. See Figure 44.
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Page 32: Condensate Piping
Condensate Piping CONDENSATE TRAP AND PLUG LOCATIONS This unit is designed for either right- or left-side exit of (Unit shown in upflow position) condensate piping in upflow applications. In horizontal Trap applications, the condensate trap must extend below the (same on unit. - Page 33 (Unit shown in upflow position with remote trap) and line. Heating cable kit is available from Lennox in var- ious lengths; 6 ft. (1.8m) - kit no. 26K68; 24 ft. (7.3m) - kit FieldProvidedVent no.
- Page 34 IMPORTANT Furnace with Evaporator Coil Using a Common Drain When combining the furnace and evaporator coil drains together, the A/C condensate drain outlet must Evaporator drain be vented to relieve pressure in order for the furnace line required pressure switch to operate properly. (Trap at coil is optional) Condensate Trap With Optional Overflow Switch (1”...
- Page 35 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.
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Page 36: Gas Piping
6 - In some localities, codes may require installation of Gas Piping a manual main shut-off valve and union (furnished Gas supply piping should not allow more than 0.5”W.C. by installer) external to the unit. Union must be of drop in pressure between gas meter and unit. Supply gas the ground joint type. - Page 37 Upflow Application Upflow Application Left Side Piping Right Side Piping (Standard) (Alternate) 1/2” NPT 1/2” NPT MANUAL MAIN SHUT-OFF VALVE MANUAL MAIN SHUT-OFF VALVE GROUND GROUND JOINT JOINT UNION UNION DRIP LEG FIELD PROVIDED AND INSTALLED DRIP LEG NOTE - BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET Figure 55 Horizontal Applications Possible Gas Piping Configurations...
- Page 38 TABLE 9 Gas Pipe Capacity - ft3/hr (m3/hr) Nominal Internal Length of Pipe - feet (m) Iron Pipe Diameter Size Inches inches (3.048) (6.096) (9,144) (12,192) (15.240) (18.288) (21.336) (24.384) (27.432) (30,480) (mm) (mm) .622 (12.7) (17.799) (4.87) (3.34) (2.69) (2.29) (2.03) (1.84)
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Page 39: Electrical
The power supply wiring must meet Class I restrictions. Electrical Protected by either a fuse or circuit breaker, select circuit protection and wire size according to unit nameplate. WARNING CAUTION Electrostatic discharge can affect electronic components. Take care Failure to use properly sized wiring and circuit breaker during unit installation and service to may result in property damage. -
Page 40: Field Wiring For Both Communicating And Non
When there is a cooling demand, For optimal performance in non-communicating applica- the fan will run on the first stage and second stage cool- tions, Lennox recommends use of a ComfortSense 7000 ® ing speed set using the thermostat in the installer setup high quality electronic digital thermostat or any other with mode. - Page 41 Communicating and Non Communicating Wiring Communicating Enabled Furnace with Communicating Enabled Furnace with a a Non-Communicating Outdoor Unit Communicating Enabled Outdoor Unit COMMUNICATING FURNACE COMMUNICATING FURNACE OPTIONAL DISCHARGE AIR SENSOR OPTIONAL DISCHARGE AIR SENSOR OPTIONAL OUTDOOR OPTIONAL COMMUNICATING AIR SENSOR OUTDOOR THERMOSTAT AIR SENSOR...
- Page 42 Communicating Wiring Optional Accessories for use with any Communicating System NOTE: ICOMMUNICATING THERMOSTAT SENSES HUMIDITY & CONTROLS HUM CONTACTS TO CYCLE HUMIDIFIER BASED 120V CONNECTIONS “HUM” CONTACT IS QUIRED. CLOSED ANYTIME HUMIDITY DEMAND IS PRESENT TIONS. BUILT INTO ALL COMMUNICATING ENABLED OUT DOOR UNITS).
- Page 43 LENNOX COMMUNICATING OUTDOOR UNIT INDOOR UNIT (1 OR 2 STAGE) FLOAT SWITCH LENNOX COMMUNICATING OUTDOOR UNIT LENNOX COMMUNICATING FURNACE EL297VK, SL280VK, SL280VNK, SL297VK, SLP99VK cutting DS to R will not cause communication interuption or error code CUT* R-DS W914 Figure 60...
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Page 44: Wiring Connections
TABLE 11 DIP Switch Settings and Field Wiring 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. - Page 45 TABLE 11 Continued DIP Switch Settings and Field Wiring 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 46 TABLE 11 Continued DIP Switch Settings and Field Wiring 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 FURNACE HEAT PUMP Dual Fuel T'STAT TERM.
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Page 47: System Options
TABLE 11 Continued DIP Switch Settings and Field Wiring DIP Switch Settings and On-Board Links DIP Switch 1 Thermostat On Board Links Must Be Cut To Select Wiring Connections Thermostat Heating System Options Stages FURNACE HEAT PUMP Dual Fuel T'STAT TERM. -
Page 48: Wiring Diagram
Wiring Diagram 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 STRIPE BRW RO(OUT) W / YEL GRN/YEL... - Page 49 Wiring Diagram -135 only 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 BRW W / YEL RO(OUT) STRIPE...
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Page 50: Ignition Control
Ignition Control TWO STAGE, VARIABLE SPEED, COMMUNICATING 107899-01 Figure 63 TABLE 14 TABLE 12 THERMOSTAT INPUT TERMINALS 1/4”QUICK CONNECT TERMINALS LOW STAGE HEAT 120 VAC OUTPUT TO HUMIDIFIER HIGH STAGE HEAT XMFR 120 VAC OUTPUT TO TRANSFORMER 120 VAC INPUT TO CONTROL LOW STAGE COOL CIRC 120 VAC OUTPUT TO CIRCULATING... -
Page 51: Ignition Control Diagnostic Codes
Ignition Control Diagnostic Codes DIAGNOSTIC CODES / STATUS OF FURNACE CODE IDLE MODE (DECIMALBLINKS AT 1 HERTZ -- 0.5 SECONDS ON, 0.5 SECONDS OFF INDOOR BLOWER OPERATION: CONTINUOUS FAN MODE (COSTANT TORQUE ONLY) INDOOR BLOWER OPERATION: FOLLOWED BY CFM SETTING FOR INDOOR BLOWER (1 SECOND ON, 0.5 SECOND OFF) / CFM SETTING FOR MODE DISPLAYED (VARIALBE SPEED ONLY) COOLING STAGE (1 SECOND ON, 0.5 SECOND OFF) 1 OR 2 DISPLAYED / PAUSE / REPEAT CODES. - Page 52 Ignition Control Diagnostic Codes (Continued) SOFT LOCKOUT FAULTS (60 MINUTES) UNABLE TO COMMUNICATE WITH CIRCULAR MOTOR E201 GAS VALVE RELAY (1ST OR 2ND STAGE) CONTACT SHORTED E205 HOT SURFACE IGNITOR (HSI) SENSED OPEN E207 SOFT LOCKOUT-FLAME FAILURE ON IGNITION, IGNITION RETRY>MAX, LAST FAILED RETRY DUE TO FLAME E270 FAILURE SOFT LOCKOUT-PRESSURE SWITCH OPEN, IGNITION RETRY>MAX, LAST FAILED RETRY DUE TO LPSW OPEN...
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Page 53: Integrated Control
TABLE 16 Integrated Control Switch Settings Conventional Thermostat (non-communicating) Blower Off Delay Switch Settings EL297UHVK units are equipped with a two-stage, vari- Blower Off Delay Switch 3 Switch 4 able speed integrated control. This control manages igni- Seconds tion timing, heating mode fan off delays and indoor blower speeds based on selections made using the control dip 90 (factory) switches and jumpers. - Page 54 NOTE - The off portion of the selected ramp profile also Ramping Option D applies during heat pump operation in dual fuel applica- • Motor runs at 100% until demand is satisfied. tions. • Once demand is met, motor ramps down to stop. TABLE 19 Cooling Mode Blower Speed Ramping Ramping...
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Page 55: 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% and 38% of the selected second stage cooling speed - minimum 250 cfm. Lennox iHarmony Zoning System Applications - Minimum blower speed is 250 cfm. - Page 56 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% and 38% of the selected second stage cooling speed - minimum 380 cfm. Lennox iHarmony Zoning System Applications - Minimum blower speed is 380 cfm.
- Page 57 Continuous Fan Only speed is selectable at 28% and 38% of the selected second stage cooling speed - minimum 380 cfm. Lennox iHarmony Zoning System Applications - Minimum blower speed is 450 cfm. for EL297UH090XV60C and 380 cfm for EL297UH110XV48C ®...
- Page 58 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% and 38% of the selected second stage cooling speed - minimum 450 cfm. Lennox iHarmony Zoning System Applications - Minimum blower speed is 450 cfm.
- Page 59 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® 7000 thermostat to use for this application - Y2081 4 heat / 2 cool *Dehumidification blower speed is 70% of COOL speed for all units .
- Page 60 With Heat Pump - Cut W914 (R to DS) & W951 (R to O) on SureLight® control Dave Lennox ComfortSense® 7000 thermostat to use for this application - Y2081 4 heat / 2 cool *Normal operation first stage cooling blower speed is 70% COOL speed.
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Page 61: Low Gwp Application
Low GWP Application WARNING For use with Lennox approved evaporator coil and LGWP sensors only. Use original manufacturer recommended LGWP sensors if using non Lennox approved evaporator coil. CONNECTING THE FURNACE CONTROL BOARD SENSOR. See FIGURE 53 and follow steps below: 1 - Route sensor wire #1 through provided grommet. - Page 62 FURNACE CONTROL BOARD LOW GWP MODES OF 2. The furnace control board activates the blower (high OPERATION speed). The blower purges refrigerant from the cabinet, plenum, and ductwork. The modes of operation for the furnace control board are Initializing, Normal, Leak Detected, and Fault. 3.
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Page 63: Start-Up Procedure
LGWP TEST BUTTON FUNCTIONALITY THERMOSTAT COMPATIBILITY The furnace control board is equipped with a Test/Reset Thermostats that preserve memory settings are compati- push button. The Test button can be used to perform sev- ble with the furnace control board. Examples include: eral functions, depending on the mode of operation of the •... -
Page 64: Unit Start Up
WARNING Unit Start Up FOR YOUR SAFETY READ BEFORE OPERATING If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal WARNING injury or death. Do not use this furnace if any part has been underwater. Gas Valve Operation (Figure 67) A flood-damaged furnace is extremely dangerous. -
Page 65: Gas Pressure Adjustment
NOTE - Pressure test adapter kit (10L34) is available from will cause the limit control to shut the unit off. Lennox to facilitate manifold pressure measurement. 6 - Is gas turned on at the meter? A manifold pressure post located on the gas valve pro- 7 - Is the manual main shut-off valve open? vides access to the manifold pressure. -
Page 66: Proper Combustion
Proper Cumbustion High Altitude Furnace should operate minimum 15 minutes with correct NOTE - In Canada, certification for installations at eleva- manifold pressure and gas flow rate before checking com- tions over 4500 feet (1372 m) is the jurisdiction of local bustion. -
Page 67: Combustion Air For Non-Direct Vent Applications
Repair Parts After the EL297UHVK gas furnace has been started, the The following repair parts are available through Lennox following test should be conducted to ensure proper vent- dealers. When ordering parts, include the complete fur-... -
Page 68: Other Unit Adjustments
Applications Using a Two-Stage Thermostat Other Unit Adjustments See Figure 68 for ignition control sequence NOTE - See troubleshooting flow charts if any safety A - Heating Sequence -- Integrated Control Thermostat switches are found to be open. Selection DIP Switch 1 OFF in “Two-Stage” Position Primary Limit. - Page 69 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 69 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”...
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Page 70: Service
14 - Verify operation of CO detectors and replace At the beginning of each heating season, and to comply batteries as required. with the Lennox Limited Warranty, your system should 15 - Inspect the Low GWP sensor / sensors and rubber be checked as follows:... - Page 71 Winterizing and Condensate Trap Care 7 - Use the soft brush attachment on a vacuum cleaner to gently clean the face of the burners. Visually 1 - Turn off power to the furnace. inspect the inside of the burners and crossovers for 2 - Have a shallow pan ready to empty condensate any blockage caused by foreign matter.
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Page 72: Program Unit Capacity/Size Mode
Program Unit Capacity/Size Mode Power-Up - Number displayed represents by integrated control unit size code (furnace model − − − and capacity). If three horizontal bars are displayed followed by continuous E203, furnace control does not recognize unit size code. Configure per the following: Furnace control in IDLE mode No heating, cooling or indoor fan operation) -
Page 73: Requirements For Commonwealth Of Massachusetts
Requirements for Commonwealth of Massachusetts Modifications to NFPA-54, Chapter 10 4 - INSPECTION. The state or local gas inspector of the side wall, horizontally vented, gas-fueled Revise NFPA-54 section 10.8.3 to add the following equipment shall not approve the installation unless, requirements: upon inspection, the inspector observes carbon For all side wall, horizontally vented, gas-fueled equip-... - Page 74 ADDENDUM FOR ALL PROVINCES OF CANADA See below for venting in all provinces of Canada. Lennox approves the following termination for use in all provinces of Canada. 12” 2” (51MM) 3” (76MM) Vent Pipe Vent Pipe A − Clearance above grade or 12”...
- Page 75 TABLE 31 Allowable Heating Speeds EL297UH -18% -12% Default +12% +18% +24% Model 045XV36BK 070XV36BK 090XV36CK Allowed Allowed 090XV48CK Factory Allowed Alloweed Allowed Allowed Allowed Setting 090XV60CK 110XV48CK Not Allowed Not Allowed 110XV60CK Allowed Allowed 135XV60DK Not Allowed Not Allowed TABLE 32 Allowable Circulation Speeds EL297UHK Model Number...
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Page 76: Unit Setup
Start-Up & Performance Check List UNIT SET UP (typical) Furnace: Model Number_______________ Serial Number_________________ SUPPLY Line Voltage GAS SUPPLY LP Propane Gas Natural Gas Piping Connections Tight Leak Tested Flter Supply Line Pressure “W.C.________ RETURN AIR Gas Supply Pressure DUCT SYSTEM SUPPLY AIR DUCT Sealed INTAKE / EXHAUST PIPE... -
Page 77: Unit Operation
UNIT OPERATION HEATING MODE COOLING MODE GAS MANIFOLD PRESSURE “W.C._____ INDOOR BLOWER AMPS______ COMBUSTION SAMPLE CO CO PPM_______ TEMPERATURE DROP ______ Return Duct Temperature _________ INDOOR BLOWER AMPS______ Supply Duct Temperature _______ Temperature Drop = _________ TEMPERATURE RISE TOTAL EXTERNAL STATIC (dry coil) Supply Duct Temperature ________ Supply External Static _______ Return Duct Temperature...
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