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© 2024 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.
Contents
Unit Dimensions - inches (mm) ......................................2
ML196DFEK Gas Furnace .............................................3
Shipping and Packing List ..............................................3
Safety .............................................................................3
Use of Furnace as a Construction Heaterl .....................4
General ...........................................................................5
Combustion, Dilution, Ventilation Air...............................5
Setting Equipment ..........................................................8
Filters ............................................................................ 11
Duct System .................................................................12
Pipe Fittings Specifications...........................................12
Joint Cementing Procedure ..........................................14
Venting Practices ..........................................................15
Gas Piping ....................................................................33
the
refrigerant
detection
INSTALLATION
INSTRUCTIONS
ML196DFEK
MERIT
SERIES GAS FURNACE
®
DOWNFLOW AIR DISCHARGE
508571-01
11/2024
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.
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.
Electrical .......................................................................35
Ignition Control .............................................................38
Twinning .......................................................................43
Low GWP .....................................................................44
Unit Start Up .................................................................47
Gas Pressure Measurement.........................................48
Proper Combustion.......................................................49
High Altitude .................................................................49
Other Unit Adjustments.................................................50
Service..........................................................................51
Repair Parts List ...........................................................53
Start Up Check List.......................................................55
Blower Data ..................................................................57
Page 1
WARNING
CAUTION
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Table of Contents
Related Manuals for Lennox MERIT ML196DFEK
Summary of Contents for Lennox MERIT ML196DFEK
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Page 1: Table Of Contents
As with any mechanical equipment, contact with sharp sheet metal edges can result in personal injury. Take This furnace is equipped with an ignition control care while handling this equipment and wear gloves and factory enabled for use with Lennox A2L refrigerant protective clothing. systems. Disabling... -
Page 2: Unit Dimensions - Inches (Mm)
Unit Dimensions - inches (mm) 9/16 (14) Flue Condensate Trap Assembly COMBUSTION AIR INTAKE Furnished for external field installation (178) RETURN AIR OPENING on either side of unit. EXHAUST AIR (See installation instructions OUTLET for additional information.) 2-1/16 (52) 9/16 2-1/4 (14) (57) -
Page 3: Ml196Dfek Gas Furnace
ML196DFEK Gas Furnace Shipping and Packing List Package 1 of 1 contains The ML196DFEK Category IV gas furnace is shipped ready for installation in the downflow position. 1 - Assembled ML196DFEK unit The furnace is equipped for installation in natural gas applica- 1 - Bag assembly containing the following: tions. -
Page 4: Use Of Furnace As A Construction Heaterl
In the absence of local codes, units must be installed In Canada, all electrical wiring and grounding for the unit according to the current National Fuel Gas Code (AN- must be installed according to the current regulations of SI-Z223.1/NFPA 54). The National Fuel Gas Code is avail- the Canadian Electrical Code Part I (CSA Standard C22.1) able from the following address: and/or local codes. -
Page 5: General
FAILURE TO FOLLOW THE ABOVE INSTALLATION IN- Chlorine base swimming pool chemicals STRUCTIONS VOIDS THE MANUFACTURER’S EQUIP- Water softening chemicals MENT LIMITED WARRANTY. LENNOX DISCLAIMS ALL LIABILITY IN CONNECTION WITH INSTALLER’S De-icing salts or chemicals FAILURE TO FOLLOW THE ABOVE INSTALLATION IN- Carbon tetrachloride STRUCTIONS. -
Page 6: Unconfined Space
When the furnace is installed so that supply ducts car- CAUTION ry air irculated 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 If air from outside is brought in for combustion and ventila- (Inlet Air from Ventilated Crawlspace and Outlet Air to Outside) 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: Installation - Setting Equipment
Shipping Bolt Removal EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE Units with 1/2 and 3/4 hp blower motor are equipped (All Air Through Ventilated Attic) with three flexible legs and one rigid leg. The rigid leg is equipped with a shipping bolt and a flat white plastic wash- er (rather than the rubber mounting grommet used with ROOF TERMINATED a flexible mounting leg). -
Page 9: Setting Equipment
WARNING WARNING Blower access panel must be securely in place when Improper installation of the furnace can result in personal blower and burners are operating. Gas fumes, which injury or death. Combustion and flue products must could contain carbon monoxide, can be drawn into living never be allowed to enter the return air system or air space resulting in personal injury or death. - Page 10 The unit may be installed three ways in downflow applica- TABLE 1 tions: on non-combustible flooring, on combustible floor- NON-COMBUSTIBLE FLOOR OPENING SIZE ing using an additive base, or on a reverse-flow cooling coil cabinet. Do not drag the unit across the floor in the Front to Rear Side to Side Cabinet...
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Page 11: Filters
FURNACE FURNACE SUPPLY AIR PLENUM PROPERLY COMBUSTIBLE SIZED FLOOR FLOORING BASE COOLING COIL OPENING PROPERLY SIZED FLOOR OPENING PLENUM FIGURE 15 2 - After opening is cut, set the combustible flooring FIGURE 16 base into opening. 3 - Check fiberglass strips on the combustible flooring PLENUM SECURE FROM base to make sure they are properly glued and... -
Page 12: Duct System
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 information is provided in Service and Application Note ACC002 (August 2000). -
Page 13: Specification
CAUTION IMPORTANT Solvent cements for plastic pipe are flammable liquids ML196DFEK exhaust and intake connections are made and should be kept away from all sources of ignition. of PVC. Use PVC primer and solvent cement when Do not use excessive amounts of solvent cement when using PVC vent pipe. -
Page 14: Joint Cementing Procedure
TABLE 5 OUTDOOR TERMINATION USAGE* STANDARD CONCENTRIC Flush Mount Wall Kit 1-1/2 inch 2 inch 3 inch Vent Pipe Input Size 2 inch 3 inch Field Dia. in. 71M80 (US) 69M29 (US) 60L46 (US) Fabricated 51W11 (US) 22G44 (US) 44W92 44W92 444W93 44J40 (US) -
Page 15: Venting Practices
1 - In areas where piping penetrates joists or interior Venting Practices walls, hole must be large enough to allow clearance NOTE - For any Low GWP refrigerant systems with ex- on all sides of pipe through center of hole using a posed line set joints installed in the same space, each hanger. -
Page 16: Vent Piping Guidelines
NOTE - Exhaust pipe MUST be glued to furnace exhaust fittings. NOTE - Lennox offers a glueless vent adapter kit 17H92 as an NOTE - Exhaust piping should be checked carefully to make sure there option for exhaust exiting at the furnace top cap coupling. - Page 17 TABLE 7 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 calcu- lation.
- Page 18 TABLE 7 CONTINUED 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 calcu- lation.
- Page 19 TABLE 8 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 - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.
- Page 20 TYPICAL EXHAUST PIPE CONNECTIONS 045/070 Only 2” 1−1/2” 2” 2” 2” TRANSITION 2” 2” Exhaust Exhaust 3” DO NOT transition from larger to smaller pipe in horizontal runs TRANSITION of exhaust pipe. INTAKE EXHAUST DO NOT transition from smaller *2” to larger pipe size in horizontal TOP VIEW runs of exhaust pipe.
- Page 21 Intake Piping TYPICAL AIR INTAKE PIPE CONNECTIONS The ML196DFEK furnace may be installed in either direct NON−DIRECT VENT APPLICATIONS vent or non-direct vent applications. In non-direct vent applications, when intake air will be drawn into the furnace INTAKE SCREEN from the surrounding space, the indoor air quality must be (Provided) considered.
- Page 22 In Direct Vent applications, combustion air is taken from EQUIPMENT IN CONFINED SPACE outdoors and the flue gases are discharged to the out- (Inlet Air from Ventilated Attic and Outlet Air to Outside) doors. The ML196DFEK is then classified as a direct vent, Category IV gas furnace.
- Page 23 TABLE 9 Maximum Allowable Exhaust Vent Pipe Length (in ft.) Without Insulation In Unconditioned Space For Winter Design Temperatures Single - Stage High Efficiency Furnace Winter Design Unit Input Size Vent Pipe Diameter Temperatures °F (°C) 1-1/2 in 32 to 21 2 in (0 to -6) 2-1/2 in...
- Page 24 ‡ 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 locally adopted installation codes.
- Page 25 ‡ 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 25...
- Page 26 Details of Intake and Exhaust Piping Terminations for 3”(76mm) MAX. Direct Vent Installations Inches(mm) NOTE - In Direct Vent installations, combustion air is taken UNCONDITIONED from outdoors and flue gases are discharged to outdoors. ATTIC SPACE 8” (203mm) MIN NOTE - Flue gas may be slightly acidic and may adverse- ly affect some building materials.
- Page 27 7 - If intake and exhaust piping must be run up a side wall to position above snow accumulation or other obstructions, iping must be supported. At least EXHAUST 12” one bracket must be used within 6” from the top of (305mm) VENT the elbow and then every 24”...
- Page 28 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 29 PORTION OF CHIMNEY Crawl Space and Extended Horizontal Venting 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 41.
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Page 30: Condensate Trap Location
1 - Determine which side condensate piping will exit and line. Heat cable kit is available from Lennox in various the unit, location of trap, field-provided fittings and lengths;... - Page 31 Furnace with Evaporator Coil Condensate Trap With Optional Overflow Switch Using a Separate Drain From Evaporator Coil HorizontalFurnace4” Min. to 5” Max.above condensatedrain connection) Field Provided Vent 1” min. 2” max. above condensate drain. Condensate FurnaceCondensate Drain Connection DrainConnection Optional Evaporator Drain Line (vent required) Drain...
- Page 32 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 33: Gas Piping
IMPORTANT Gas Piping Gas supply piping should not allow more than 0.5”W.C. Compounds used on threaded joints of gas piping must drop in pressure between gas meter and unit. Supply gas be resistant to the actions of liquified petroleum gases. pipe must not be smaller than unit gas connection. - Page 34 Left Side Piping AUTOMATIC MANUAL (Standard) GAS VALVE MAIN SHUT-OFF MANUAL (with manual VALVE AUTOMATIC MAIN SHUT-OFF shut-off valve) (1/8 in. NPT GAS VALVE VALVE plugged tap (with manual (1/8 in. NPT shown) shut-off valve) plugged tap shown) GROUND JOINT UNION GROUND JOINT...
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Page 35: Electrical
Removal of the Furnace from Common Vent Electrical In the event that an existing furnace is removed from a ELECTROSTATIC DISCHARGE (ESD) venting system commonly run with separate gas applianc- Precautions and Procedures es, the venting system is likely to be too large to properly CAUTION vent the remaining attached appliances. - Page 36 The power supply wiring must meet Class I restrictions. Install the room thermostat according to the instructions Protected by either a fuse or circuit breaker, select circuit provided with the thermostat. See FIGURE 53 for thermo- protection and wire size according to unit nameplate. stat designations.
- Page 37 FIGURE 53 Page 37...
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Page 38: Ignition Control
Indoor Blower Operation DIP Switch Settings IGNITION CONTROL The heat fan-on time of 30 seconds is not adjustable The Integrated Control DIP Switch Settings heat fan-off delay (amount of time that the blower oper- ML196DFEK units are equipped with a single-stage inte- ates after the heat demand has been satisfied) may be grated control. -
Page 39: Wiring Connections
On Board Links Must NOT Be Cut To Select Thermostat Wiring Connections AC ON System Options Heat / Cool FURNACE OUTDOOR T'STAT TERM. STRIP UNIT DO NOT CUT ANY ON-BOARD LINKS FIGURE 54 Wiring Connections On Board Links Must Be Cut To Select Thermostat Heat Pump Options FURNACE... - Page 40 Single Stage, Constant Torque, Non-Communicating 107792-01 FIGURE 56 TABLE 12 TABLE 13 1/4” QUICK CONNECT TERMINALS THERMOSTAT INPUT TERMINALS HEAT 120V HUM POWER FOR HUMIDIFIER (120 VAC COMMON GROUND LINE INCOMING POWER LINE (120 VAC) 24V AC XFMR TRANSFORMER PRIMARY (120 VAC) CIRC INDOOR BLOWER MOTOR (120 VAC) COOL...
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Page 41: Ignition Control Diagnostic Codes
IGNITION CONTROL DIAGNOSTIC CODES DIAGNOSTIC CODES / STATUS OF FURNACE CODE IDLE MODE (DECIMAL BLINKS AT 1 HERTZ -- 0.5 SECONDS ON, 0.5 SECONDS OFF INDOOR BLOWER OPERATION: CONTINUOUS FAN MODE (CONSTANT TORQUE ONLY) INDOOR BLOWER OPERATION: FOLLOWED BY CFM SETTING FOR INDOOR BLOWER (1 SECOND ON, 0.5 SECOND OFF) / CFM SETTING FOR MODE DISPLAYED (VARIABLE SPEED ONLY) COOLING STAGE (1 SECOND ON, 0.5 SECOND OFF) 1 OR 2 DISPLAYED / PAUSE / REPEAT CODES. -
Page 42: Performance Warning
IGNITION CONTROL DIAGNOSTIC CODES (CONTINUED) SOFT LOCKOUT FAULTS (60 MINUTES) SOFT LOCKOUT-FLAME FAILURE ON IGNITION, IGNITION RETRY>MAX, LAST FAILED RETRY DUE E270 TO FLAME FAILURE SOFT LOCKOUT-PRESSURE SWITCH OPEN, IGNITION RETRY>MAX, LAST FAILED RETRY DUE TO E271 LPSW OPEN SOFT LOCKOUT-PRESSURE SWITCH OPEN, IN RUN MODE HEATING RECYCLES>MAX, LAST FAILED E272 RETRY DUE TO LPSW OPEN SOFT LOCKOUT-FLAME FAILURE IN RUN MODE,HEATING RECYCLES>MAX, LAST FAILED RETRY... -
Page 43: Twinning
The 24 VAC secondary of the two systems must be in Twinning Two ML196DFEK Furnaces phase. All thermostat connections are made to one control The control board in this furnace is equipped with a provi- only. See diagram below. sion to ”twin” (interconnect) two(2) adjacent furnaces with The twinned furnace without thermostat connections is a common plenum such that they operate as one (1) large to have the call for heat supplied by an external 24VAC... -
Page 44: Low Gwp
Low GWP Application DIP Switch Settings WARNING Configuration Switch 1 Switch 2 For use with Lennox approved evaporator coil and LGWP One (1) sensor, connected to SEN- sensors only. Use original manufacturer recommended SOR 1 plug (enable) (disable) LGWP sensors if using non Lennox approved evaporator Two (2) sensors, connected to SEN- coil. - Page 45 Leak Detected TABLE 18 When the furnace control board detects a refrigerant leak: LGWP Test Button Function 1. The furnace control board shuts off the (R) input Mode of Operation Press the Test Button to: (24VAC power) to the thermostat, which de- Trigger a leak detection energizes the outdoor unit compressor and heat sources, such as gas and/or electric strip heat.
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Page 46: Start-Up Procedure
START UP PROCEDURE External Alarm (For applications with external alarms wired directly to the The furnace control board is equipped with a LGWP Test/ furnace control board) Reset button, see “Test Button Functionality”. After the The furnace control board triggers the external alarm sys- furnace control board has been mounted and wired, re- tem when it enters Leak Detected mode. -
Page 47: Unit Start Up
6 - Adjust the thermostat to deactivate the heating Unit Start-Up demand and wait for the combustion air inducer to FOR YOUR SAFETY READ BEFORE OPERATING stop. At this point, the trap should be primed with WARNING sufficient water to ensure proper condensate drain operation. -
Page 48: Gas Pressure Measurement
Failure To Operate Furnace should operate at least 5 minutes before check- ing gas flow. Determine time in seconds for two revolu- If the unit fails to operate, check the following: tions of gas through the meter. (Two revolutions assures 1 - Is the thermostat calling for heat? a more accurate time). -
Page 49: Proper Combustion
Proper Combustion High Altitude Information 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 50: Testing Non Direct Vent Appliances For Proper Air
8 - If improper venting is observed during any of the Testing of Non-Direct Vent Applications for Proper above tests, the venting system must be corrected Venting and Sufficient Combustion Air or sufficient combustion/make-up air must be provided. The venting system should be re-sized WARNING to approach the minimum size as determined by using the appropriate tables in appendix G in the... -
Page 51: Service
At the beginning of each heating season, and to comply 11- Inspect the furnace return air duct connection to with the Lennox Limited Warranty, your system should be ensure the duct is sealed to the furnace. Check for checked as follows:... - Page 52 Perform a general system test. Turn on the furnace 7 - Remove four screws which secure burner box to check operating functions such as the start-up and assembly to vest panel. Remove burner box from shut-off operation. the unit. 1 - Check the operation of the ignition system, inspect 8 - Use the soft brush attachment on a vacuum cleaner and clean flame sensor.
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Page 53: Repair Parts List
ADDENDUM FOR ALL THE PROVINCES OF CANADA See below for venting in all the provinces of Canada. Lennox approves the following termination for use in all the provinces of Canada. 12”... -
Page 54: Approved Carbon Monoxide Detectors
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 equipment Revise NFPA-54 section 10.8.3 to add the following shall not approve the installation unless, upon requirements: inspection, the inspector observes carbon monoxide For all side wall, horizontally vented, gas-fueled equip-... -
Page 55: Start Up Check List
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 56: 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... -
Page 57: Blower Data
Blower Data ML196DF045XE36BK PERFORMANCE (Less Filter) Air Volume / Watts at Various Blower Speeds External High Medium-High Medium Medium-Low Static (Black) (Brown) (Blue) (Yellow) (Red) Pressure in. w.g. Watts Watts Watts Watts Watts 0.00 1414 1259 1161 0.10 1385 1230 1125 0.20 1356... - Page 58 Blower Data ML196DF110XE60CK PERFORMANCE (Less Filter) Air Volume / Watts at Various Blower Speeds External High Medium-High Medium Medium-Low Static (Black) (Brown) (Blue) (Yellow) (Red) Pressure in. w.g. Watts Watts Watts Watts Watts 0.00 2217 1980 1828 1714 1531 0.10 2169 1929 1770...
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