Lennox ML180UHEK Unit Information
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Lennox ML180UHEK Unit Information

Lennox ML180UHEK Unit Information

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S e r v i c e L i t e r a t u r e
ML180UHEK series units are mid-efficiency gas furnac-
es used for upflow or horizontal applications only, man-
ufactured with Lennox Duralok heat exchangers formed
of aluminized steel. ML180UHEK units are available in
heating capacities of 44,000 to 132,000 Btuh and cooling
applications 2 to 5 tons. Refer to Engineering Handbook
for proper sizing.
Units are factory equipped for use with natural gas. Kits
are available for conversion to LP/Propane operation.
ML180UHEK model units are equipped with a hot surface
ignition system. The ML180UHEK unit meets the Califor-
nia Nitrogen Oxides (NOx) Standards and California Sea-
sonal 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 su-
persede 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 recom-
mended only and do not constitute code.
WARNING
This furnace is equipped with an ignition control
factory enabled for use with A2L refrigerant systems.
Disabling the refrigerant detection functionality on
A2L system is prohibited by safety codes. Refer
to furnace installation instructions for refrigerant
system setup.

TABLE OF CONTENTS

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . Page 3
Blower Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4
Parts Identification . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
Twinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
I Unit Components . . . . . . . . . . . . . . . . . . . . . . . . Page 9
II Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 25
III Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 25
V Typical Operating Characteristics . . . . . . . . . Page 29
VI Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 30
VII Low GWP Application. . . . . . . . . . . . . . . . . . . Page 33
IX Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . .Page 37
UNIT INFORMATION
UNIT INFORMATION
ML180UHEK With R-454B SERIES UNITS
100161
Electric Shock Hazard. Can cause injury
or death. Unit must be properly grounded
in accordance with national and local
codes.
Line voltage is present at all components
when unit is not in operation on units
with single-pole contactors. Disconnect
all remote electric power supplies before
opening access panel. Unit may have
multiple power supplies.
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.
Page 1
ML180UHEK
WARNING
CAUTION

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Summary of Contents for Lennox ML180UHEK

  • Page 1: Table Of Contents

    Units are factory equipped for use with natural gas. Kits are available for conversion to LP/Propane operation. ML180UHEK model units are equipped with a hot surface ignition system. The ML180UHEK unit meets the Califor- nia Nitrogen Oxides (NOx) Standards and California Sea- sonal Efficiency requirements.

  • Page 2: Specifications

    SP ECIF ICATIONS Model ML180UH ML180UH ML180UH ML180UH Heating 045E36AK 070E36AK 070E36BK 090E48BK Performance Model - Low Nox ML180UH ML180UH ML180UH ML180UH 045XE36AK 070XE36AK 070XE36BK 090XE48BK AFUE Input - Btuh 44,000 66,000 66,000 88,000 Output - Btuh 36,000 53,000 53,000 72,000 Temperature rise range - °F 15 - 45...

  • Page 3: Optional Accessories

    OPT IONAL AC C ESSORIES - ORD ER SEPARAT ELY “A” Width “B” Width “C” Width “D” Width Models Models Models Models CABINET ACCESSORIES Horizontal Suspension Kit - Horizontal only 51W10 51W10 51W10 51W10 Return Air Base - Upflow only 65W75 50W98 50W99...

  • Page 4: Blower Data

    BLOWER DATA ML180UH045E36AK 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 0.10 1383 1179 0.20 1346 1132 0.30 1308 1083 0.40...
  • Page 5 BLOWER D ATA ML180UH090E48BK 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 0.10 1740 1528 1404 1348 1205 0.20 1697 1479...
  • Page 6 BLOWER DATA ML180UH110E60CK PERFORMANCE (Less Filter) Air Volume / Watts at Different Blower Speeds Bottom Return Air, Side Return Air with Return Air from Single Side Return Air − Air volumes in bold (over 1800 Both Sides or Return Air from Bottom and One Side. cfm) require Optional Return Air Base and field fabricated External transition to accommodate 20 x 25 x 1 in.

  • Page 7: Parts Arrangement

    PARTS ARRANGEMENT Make-Up Box Heat Exchanger Combustion Air Inducer Combustion Air Inducer Pressure Switch Burner Box (includes sensor, ignitor and rollout switches) Gas Valve Primary Limit Control Box (under (includes integrated control, combustion interlock switch and transformer) air inducer) Upper Access Panel Blower Assembly Blower Access Panel Power Choke...

  • Page 8: Twinning

    The 24 VAC secondary of the two systems must be in Twinning 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 9: I Unit Components

    I-UNIT COMPONENTS 3. Circuit Breaker (CB8) ML180UHEK unit components are shown in figure 1.The A 24V circuit breaker is also located in the control box. The gas valve, combustion air inducer and burners can be ac- switch provides overcurrent protection to the transform- cessed by removing the upper access panel.
  • Page 10 Indoor Blower Operation DIP Switch Settings TABLE 1 The heat fan-on time of 30 seconds is not adjustable The 1/4” QUICK CONNECT TERMINALS heat fan-off delay (amount of time that the blower oper- 120V HUM POWER FOR HUMIDIFIER (120 VAC ates after the heat demand has been satisfied) may be LINE INCOMING POWER LINE (120 VAC)
  • Page 11 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 3 Wiring Connections On Board Links Must Be Cut To Select Thermostat Heat Pump Options Dual Fuel...
  • Page 12 Single Stage, Constant, Torque, Non-Communicating 107792-XX FIGURE 6 Indoor Blower Speeds 1 - When the thermostat is set to “FAN ON,” the indoor blower will run continuously on the fan speed when there is no cooling or heating demand. See TABLE 5 for allowable circulation speeds. 2 - When the ML180UHE(K) is running in the heating mode, the indoor blower will run on the heating speed.
  • Page 13 TABLE 6 Integrated Diagnostic Codes/Status of Equipment Code Diagnostic Codes/Status of Equipment Indoor Blower Operation: Continuous Fan only mode Defrost mode Idle mode (Decimal blinks at 1 Hertz -- 0.5 second ON, 0.5 second OFF). Cooling stage (1 second ON, 0.5 second OFF) 1 or 2 displayed / Pause / Repeat codes. Dehumidification mode (1 second ON, 1 second OFF) / Pause / Repeat Codes).
  • Page 14 The sensor #1 is of a type not suitable for use in the application. incorrect Replace the sensor with a Lennox approved replacement part. This fault clears when a sensor suitable for the application is detected by the furnace control board, but blower will latch for a minimum of 5 minutes.
  • Page 15 TABLE 4 Continued Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E164 Low GWP Test Low GWP Test mode activates by manually engaging Low GWP test button. Normal operations resumes and code clears automatically after 1-minute E200 Hard lockout - Rollout circuit open or previously Correct cause of rollout trip, or replace flame rollout switch.
  • Page 16 2. Primary Limit Control Primary Limit Under Combustion Air Inducer The primary limit on ML180UHEK units is located in the Primary heating vestibule panel under the combustion air inducer. Limit See FIGURE 8. When excess heat is sensed in the heat exchanger, the limit will open.

  • Page 17: Digital Meter

    Flame (microamp) signal is an electrical current which 4 - Connect (-) lead to flame sensor wire. passes from the integrated control to the sensor during 5 - Connect (+) lead to Terminal “Flame Sense” on inte- unit operation. Current passes from the sensor through grated control.
  • Page 18 070E36BK 1.316” 5. Combustion Air Inducer (B6) 090E48BK, 090E60CK 1.531” All ML180UHEK units use a combustion air inducer to 110E60CK 1.690” move air through the burners and heat exchanger during 135E60DK 1.940”...
  • Page 19 IGNITOR CHECKS Test 1 Check ignitor circuit for correct resistance. Remove HSI /CAI 4-pin plug from control. Check ohms reading across terminals 2 and 4. The 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 20: Troubleshooting

    7. Combustion Air Inducer Pressure Switch (S18) TABLE 9 ML180UHEK series units are equipped with a combustion inches wc Unit air pressure switch located on the combustion air inducer Make Break + 0.05 orifice bracket. The switch is connected to the combustion 045E36AK -0.75...

  • Page 21: Multiple Venting

    Remove the four mounting screws, rotate the assembly (assembly consists of orifice plate, proving switch, gasket The ML180UHEK furnace can vent in multiple positions. and combustion air inducer), then reinstall the mounting See FIGURE 12. The make up box may be removed and screws.
  • Page 22 Each blower is statically and dynamically balanced as an assembly before installation in the unit. ML180UHEK 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 23 Multi−Meter (set to V AC) Multi-met (set to VAC) "9A” Test 3 (if necessary) NOTE- Ignition control illustration is typical "7A” Check for 120 volts across terminals “L1” and “Neutrals” on the Turn power on to unit. Check for 120 volts integrated control.

  • Page 24: Motor Test

    Replacing the Motor Module Motor Test 1 - Disconnect electrical power to unit. 2 - Remove unit access panel. 3 - Unplug the two harnesses from the motor control module. See FIGURE 16. NOTE - Not all motors have field replaceable control mod- ules.

  • Page 25: Installation

    IV-HEATING SYSTEM SERVICE CHECKS A- C.S.A. Certification INLET All units are C.S.A. design certified without modifications. PRESSURE Refer to the ML180UHEK Installation Instruction. PORT GAS VALVE SHOWN IN ON POSITION B- Gas Piping FIGURE 20 Gas supply piping should not allow more than 0.5”W.C.
  • Page 26 3 - While waiting for the unit to stabilize, observe the specialty Gas Leak Detector is strongly recommended. It flame. Flame should be stable and should not lift is available through Lennox under part number 31B2001. from burner. Natural gas should burn blue. See Corp. 8411-L10, for further details.
  • Page 27 TABLE 13 Manifold Pressure Settings at all Altitudes Line Pressure in. wg. Model 7501 - 10,000 0 - 2000 ft. 2001 -4500 ft . 4501 - 7500 ft. Input Size 13.0 LP/Propane 10.0 10.0 10.0 10.0 11.0 13.0 13.0 LP/Propane 10.0 10.0 10.0...
  • Page 28 H- Proper Ground and Voltage TABLE 15 A poorly grounded furnace can contribute to poor flame Measurement VAC Furnace Status sense signal. Use the following procedure to check for Expected Maximum ground and voltage to the integrated control. Power on Furnace Idle 1 - Measure the AC voltage between Line Neutral (spade terminals) and “C”...

  • Page 29: Typical Operating Characteristics

    B-Temperature Rise (FIGURE 24) 0.8” W.C. Temperature rise for ML180UHEK units depends on unit 4 - Seal the hole when the check is complete. input, blower speed, blower horsepower and static pres- sure as marked on the unit rating plate.

  • Page 30: Maintenance

    At the beginning of each heating season, and to comply 6 - Check the cleanliness of blower assembly and with the Lennox Limited Warranty, your system should be clean the housing, blower wheel and blower motor checked by a licensed professional technician (or equiva- if necessary .
  • Page 31 3 - Clock gas meter to ensure that the unit is operating 3 - Label the wires from gas valve, rollout switches, at the specified firing rate. Check the supply primary limit switch and make-up box then disconnect pressure and the manifold pressure. On two-stage them.
  • Page 32 7 - NOX units only - Remove screw securing NOX NOx INSERTS insert. Remove NOX insert. See FIGURE 27. 8 - Remove screws from both sides, top and bottom of vestibule panel. 9 - Remove heat exchanger. It may be necessary to spread cabinet side to allow more room.

  • Page 33: Low Gwp Application

    VII- 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 31 and follow steps below: FIGURE 30 1 - Route sensor wire #1 through provided grommet.
  • Page 34 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.

  • Page 35: Start-Up Procedure

    LGWP TEST BUTTON FUNCTIONALITY External Alarm (For applications with external alarms wired directly to the The furnace control board is equipped with a Test/Reset furnace control board) push button. The Test button can be used to perform sev- The furnace control board triggers the external alarm sys- eral functions, depending on the mode of operation of the tem when it enters Leak Detected mode.

  • Page 36: Wiring And Sequence Of Operation

    VIII- Wiring and Sequence of Operation BLOWER SPEED CHART COMBUSTION AIR INDUCER FACTORY CONNECTED SPEED TAPS COMBUSTION AIR PROVING SWITCH UNIT COOL HEAT PARK 120V ACC (IF USED) 045(X)E36AK 070(X)E36BK 090(X)E48BK BLACK BLUE BROWN,YELLOW 090E60CK 110(X)E60CK 135E60DK BROWN BLUE BLACK,YELLOW GAS VALVE BLOWER SPEED SELECTION SPEED TAPS...

  • Page 37: Ix - Troubleshooting

    IX - Troubleshooting HEATING SEQUENCE OF OPERATION ABNORMAL HEATING MODE NORMAL HEATING MODE POWER ON GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER DELAY OFF. CONTROL SELF-CHECK OKAY? (RESET CONTROL BY TURNING MAIN POWER OFF.) SEVEN SEGEMENT LED FLASHES E111 IS POLARITY CORRECT? - POLARITY REVERSED.
  • Page 38 HEATING SEQUENCE CONTINUED 15 SECOND COMBUSTION AIR INDUCER PREPURGE INITIATED BY CLOSED PRESSURE SWITCH. SEVEN SEGEMENT LED E110 LOW LINE VOLTAGE. ONCE VOLTAGE IS ABOVE IGNITOR WARM UP -- 20 SECONDS. IS VOLTAGE ABOVE 70 VOLTS? 75 VOLTS, HEATING SEQUENCE RESTARTS. 4 SECOND TRIAL FOR IGNITION.
  • Page 39 COOLING SEQUENCE OF OPERATION POWER ON IGNITION CONTROL MAIN POWER ON. GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF WITH NORMAL DELAY. CONTROL SELF DIAGNOSTIC CHECK. SIGNAL CIRCUIT BOARD FAILURE AT LED. IS CONTROL OPERATING NORMALLY? INTERRUPT MAIN POWER TO RESET CONTROL. SEVEN SEGEMENT LED FLASHES E117 IMPROPER GROUND IS THERE A PROPER GROUND? CONTROL WILL CONTINUE TO CALL FOR COOLING...
  • Page 40 CONTINUOUS FAN SEQUENCE OF OPERATION MANUAL FAN SELECTION MADE AT THERMOSTAT. CONTROL (G) ENERGIZES SYSTEM FAN AT FAN SPEED. EAC TERMINAL IS ENERGIZED. THERMOSTAT CALLS FOR HEAT (W). SYSTEM FAN CONTINUES FAN SPEED WITHOUT THERMOSTAT CALLS FOR COOLING. INTERRUPTION. EAC TERMINAL REMAIN ON. HUM TERMINAL IS ENERGIZED WITH COMBUSTION SYSTEM FAN SWITCHED TO COOL SPEED.

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