Lennox LCT036 Installation Instructions Manual
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Lennox LCT036 Installation Instructions Manual

Lennox LCT036 Installation Instructions Manual

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©2024
WARNING
Improper installation, adjustment, alteration, ser vice
or maintenance can cause property damage, personal
injury or loss of life. Installation and ser vice must be
performed by a licensed professional HVAC installer or
equivalent, service agency, or the gas supplier

Table of Contents

Dimensions . . . . . . . . . . . . . . . . . . . . . . 3
Parts Arrangement . . . . . . . . . . . . . . . . . . 4
Shipping and Packing List . . . . . . . . . . . . . . 5
General . . . . . . . . . . . . . . . . . . . . . . . . 5
Requirements . . . . . . . . . . . . . . . . . . . . . 5
Unit Support. . . . . . . . . . . . . . . . . . . . . . 7
Duct Connection . . . . . . . . . . . . . . . . . . . 8
Rigging Unit for Lifting . . . . . . . . . . . . . . . . 8
Horizontal Air Discharge . . . . . . . . . . . . . . . 8
Condensate Drains . . . . . . . . . . . . . . . . . . 9
Connect Gas Piping (Gas Units) . . . . . . . . . . .10
High Altitude Derate. . . . . . . . . . . . . . . . . .12
Mobile Service App . . . . . . . . . . . . . . . . . .15
Blower Operation and Adjustments . . . . . . . . . .18
Refrigerant Leak Detection System . . . . . . . . . .26
Cooling Start-Up . . . . . . . . . . . . . . . . . . .26
Diagnostic Sensors . . . . . . . . . . . . . . . . . .36
RDS Sensors . . . . . . . . . . . . . . . . . . . . .39
Cooling Operation. . . . . . . . . . . . . . . . . . .41
Gas Heat Start-Up (Gas Units) . . . . . . . . . . . .42
RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE
Use this QR code to download the mobile service app. Follow the prompts
to pair the app with the Unit Controller. Refer to the "Mobile Service App"
section in this manual. The QR code is also available in the unit control area.
The app can be downloaded from the appropriate iOS or Android store.
INSTALLATION
INSTRUCTIONS
LGT/LCT036
LGT/LCT048
LGT/LCT060
LGT/LCT072
GAS AND COOLING PACKAGED UNITS
508400-01
6/2024
Supersedes 9/2023
To prevent serious injury or death:
1- Lock-out/tag-out before performing maintenance.
2- If system power is required (e.g., smoke detector
mainte nance), disable power to blower, remove fan
belt where applicable, and ensure all controllers
and thermostats are set to the "OFF" position before
performing maintenance.
3- Always keep hands, hair, clothing, jewelry, tools, etc.,
away from moving parts.
Preventative Maintenance / Repair . . . . . . . . . .46
Factory Unit Controller Settings. . . . . . . . . . . .59
Decommissioning . . . . . . . . . . . . . . . . . . .62
Attention!
Look for the following icon.
(3 TON)
(4 TON)
(5 TON)
(6 TON)

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Summary of Contents for Lennox LCT036

  • Page 1: Table Of Contents

    INSTALLATION ©2024 WARNING INSTRUCTIONS Improper installation, adjustment, alteration, ser vice LGT/LCT036 or maintenance can cause property damage, personal (3 TON) injury or loss of life. Installation and ser vice must be LGT/LCT048 performed by a licensed professional HVAC installer or...
  • Page 2 A2L refrigerants. CAUTION Leak Detection System installed. Unit must be powered except for service. CAUTION Servicing shall be performed only as recommended by the manufacturer. LGT/LCT036, 048, 060, 072 Page 2...

  • Page 3: End View

    LGT/LCT036, 048, 060, 072 DIMENSIONS in. - Gas heat section shown 16−1/4 (143) (279) (413) (457) 5 (127) 7 (178) BOTTOM RETURN OPENING BOTTOM (508) SUPPLY (737) OPENING 47 (1194) BASE CENTER 25−3/4 (654) GRAVITY 9−1/2 6−5/8 (241) (168) 26−1/2...

  • Page 4: Parts Arrangement

    CONDENSATE DRAIN COMBUSTION AIR INDUCER BURNERS GAS VALVE COMPRESSOR UNIT RDS SENSOR CONTROLLER COMPRESSOR (BEHIND CABINET) LCT036, 048, 060, 072 PARTS ARRANGEMENT REHEAT COIL BLOWER EVAPORATOR (OPTIONAL) (DIRECT DRIVE) CONDENSER COIL FILTERS (4) 20 X 20 X 2” COIL GUARDS...

  • Page 5: Shipping And Packing List

    Turn off gas and electrical power to unit before performing any maintenance or servicing operations on the unit. Follow lighting instructions attached to unit when putting unit back into operation and after service or maintenance. LGT/LCT036, 048, 060, 072 Page 5...
  • Page 6 “Halt” rows and then multiply the value needed from the tables above by the altitude factor number. Example: For the minimum airflow in CFM for an LCT/LGT036 at 1000 ft. above see level, multiply 84 by 1.05 to get 88.2 CFM as the new Q LGT/LCT036, 048, 060, 072 Page 6...

  • Page 7: Unit Support

    RTU, duct work / base. Supports must be constructed of steel or duct drops / diffuser assemblies must be supported suitably treated wood materials. independently to the building structure. LGT/LCT036, 048, 060, 072 Page 7...

  • Page 8: Duct Connection

    CENTER OF GRAVITY HORIZONTAL RETURN AIR DUCTWORK WITH ECONOMIZER UNIT UNIT CAUTION - Do not walk on unit. HORIZONTAL RETURN AIR DUCT FIGURE 2 INSTALL BAROMETRIC RELIEF DAMPERS AND HOOD IN RETURN AIR DUCT FIGURE 4 LGT/LCT036, 048, 060, 072 Page 8...

  • Page 9: Condensate Drains

    DRAIN PAN of unit. See FIGURE 9. CAULK AROUND REMOVE DRAIN PAN CONDENSATE COUPLING OPEN VENT MOUNTING FRAME Minimum Pitch 1” (25 mm) per 10' (3 m) of line FIGURE 6 DRAIN PAN FIGURE 9 LGT/LCT036, 048, 060, 072 Page 9...

  • Page 10: Connect Gas Piping (Gas Units)

    9 - Use a field-provided 3/4” plug to seal side drain connection. 10 - Replace the condensate drain mullion. LGT/LCT036, 048, 060, 072 Page 10...

  • Page 11: Pressure Test Gas Piping (Gas Units)

    PRESSURE TEST GAS LINE ELBOW 7” NIPPLE MANUAL MAIN SHUT-OFF VALVE TO GAS SUPPLY 2-1/2” NIPPLE MANUAL MAIN SHUT-OFF VALVE DRIP LEG Grommets for both gas pipe openings are field provided. GAS VALVE FIGURE 12 FIGURE 13 LGT/LCT036, 048, 060, 072 Page 11...

  • Page 12: High Altitude Derate

    Use18 AWG wire for all applications using remotely installed electro-mechanical electronic thermostats. 2 - Install thermostat assembly in accordance with instructions provided with thermostat. LGT/LCT036, 048, 060, 072 Page 12...
  • Page 13 Use a local, isolated 24VAC transformer such as Lennox instructions provided with sensor. A DDC input may cat #18M13 (20VA minimum) to supply power to RH be used to initiate dehumidification instead of a sensor as shown in FIGURE 18. Use two shielded cables sensor.
  • Page 14 A55 UNIT FIELD WIRING REHEAT UNITS (Using A Humidity CONTROLLER Sensor With Less Than 150 Ft. Wire Runs) P298 J298A J298A P298 DRAIN AI-1 CONNECTED AI−1 DO-1 DO−1 DO-2 DI-1 FIGURE 18 FIGURE 16 LGT/LCT036, 048, 060, 072 Page 14...

  • Page 15: Mobile Service App

    * Automatic rmware updates BACnet MS/TP * Allows daisy-chain connection * Manual Firmware Updates * System Logs and Reports tandard on CORE Unit Controller * Con guration save/copy * New objects supported FIGURE 20 LGT/LCT036, 048, 060, 072 Page 15...
  • Page 16 LONTalk Duct Sensor R + C Module Room Humidistat J378 S-BUS SmartWire™ Spare Smoke Thermostat and RH Sensor System J304 Analog 24VAC Inputs Sensors Digital Inputs S-BUS Inputs GLO+Service Factory Test Relay FIGURE 24 LGT/LCT036, 048, 060, 072 Page 16...
  • Page 17 Press (In Pre-Install TSTAT Override StAt state) White Button: Long FIGURE 25 Press (NOT in Pre-In- TSTAT Test tESt stall state) Short Press : 2 to 5 seconds. Long Press : 5 to 8 seconds. LGT/LCT036, 048, 060, 072 Page 17...

  • Page 18: Blower Operation And Adjustments

    ROOFTOP UNIT RETURN AIR READING LOCATION RETURN AIR READING LOCATION SUPPLY SUPPLY TURN TURN FIRST BRANCH OFF OF MAIN RUN MAIN DUCT RUN SUPPLY AIR SUPPLY AIR READING READING DIFFUSER LOCATION LOCATION FIGURE 26 LGT/LCT036, 048, 060, 072 Page 18...
  • Page 19 FREE COOLING STAGE-UP DELAY speed. Default 300 seconds. Installer - Record any parameter changes under “Field Setting” column. Settings need to be recorded by installer for use when Unit Controller is replaced or reprogrammed. LGT/LCT036, 048, 060, 072 Page 19...
  • Page 20 LGT/LCT036, 048, 060, 072 Page 20...
  • Page 21 LGT/LCT036, 048, 060, 072 Page 21...
  • Page 22 LGT/LCT036, 048, 060, 072 Page 22...
  • Page 23 LGT/LCT036, 048, 060, 072 Page 23...
  • Page 24 LGT/LCT036, 048, 060, 072 Page 24...
  • Page 25 FD11-95S 2600 24 - 29 19 - 24 2800 25 - 30 20 - 28 3000 27 - 33 21 - 29 1 Effective throw based on terminal velocities of 75 ft. per minute. LGT/LCT036, 048, 060, 072 Page 25...

  • Page 26: Refrigerant Leak Detection System

    Ensure that the unit is earth grounded prior to If weighing facilities are not available, or to check the charging the system with refrigerant. charge, use the following procedure: • Label the system when charging is complete (if not already). LGT/LCT036, 048, 060, 072 Page 26...
  • Page 27 If measured liquid temperature is higher than the target liquid temperature, add refrigerant to the sys- tem. • If measured liquid temperature is lower than the target liquid temperature, recover some refrigerant from the system.. LGT/LCT036, 048, 060, 072 Page 27...
  • Page 28 Suct Disc (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) 036 CHARGING CURVE - NO REHEAT - ALL-ALUMINUM COIL - 581061-02 (°F) Temp Temp Suction Press. (psig) Suction Press. (psig) LGT/LCT036, 048, 060, 072 Page 28...
  • Page 29 Suct Disc (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) 048 CHARGING CURVE - NO REHEAT - ALL-ALUMINUM COIL - 581062-02 (°F) Temp Temp Suction Press. (psig) Suction Press. (psig) LGT/LCT036, 048, 060, 072 Page 29...
  • Page 30 Suct Disc (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) 060 CHARGING CURVE - NO REHEAT - ALL-ALUMINUM COIL - 581063-02 (°F) Temp Temp Suction Press. (psig) Suction Press. (psig) LGT/LCT036, 048, 060, 072 Page 30...
  • Page 31 Suct Disc (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) 072 CHARGING CURVE - NO REHEAT - ALL-ALUMINUM COIL - 581064-02 (°F) Temp Temp Suction Press. (psig) Suction Press. (psig) LGT/LCT036, 048, 060, 072 Page 31...
  • Page 32 Disc Suct Disc (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) 036 CHARGING CURVE - REHEAT - ALL-ALUMINUM COIL - 581108-02 (°F) Temp Temp Suction Press. (psig) Suction Press. (psig) LGT/LCT036, 048, 060, 072 Page 32...
  • Page 33 Disc Suct Disc (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) 048 CHARGING CURVE - REHEAT - ALL-ALUMINUM COIL - 581109-02 (°F) Temp Temp Suction Press. (psig) Suction Press. (psig) LGT/LCT036, 048, 060, 072 Page 33...
  • Page 34 Disc Suct Disc (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) 060 CHARGING CURVE - REHEAT - ALL-ALUMINUM COIL - 581110-02 (°F) Temp Temp Suction Press. (psig) Suction Press. (psig) LGT/LCT036, 048, 060, 072 Page 34...
  • Page 35 Disc Suct Disc (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) (psig) 072 CHARGING CURVE - REHEAT - ALL-ALUMINUM COIL - 581111-02 (°F) Temp Temp Suction Press. (psig) Suction Press. (psig) LGT/LCT036, 048, 060, 072 Page 35...

  • Page 36: Diagnostic Sensors

    Unit Unit Sensor Yellow Figure Controller to protect the compressor. Thermistors LGT/LCT036, 048, 060, 072 RT46 FIGURE 27 take the place of the freezestat and low ambient LGT/LCT036, 048, 060, 072 RT48 FIGURE 28 pressure switch. 4 - Compressor Crankcase Heater (HR1)
  • Page 37 LGT/LCT 036, 048, 060, 072 EVAPORATOR COIL RT46 22J06 YELLOW RT46 CLAMP THERMISTOR TO BARE COPPER. DETAILS NOT TO SCALE FIGURE 27 LGT/LCT036, 048, 060, 072 Page 37...
  • Page 38 LGT/LCT036, 048, 060, 072 CONDENSER COIL RT48 23V50 YELLOW RT48 DETAILS NOT TO SCALE FIGURE 28 LGT/LCT036, 048, 060, 072 Page 38...

  • Page 39: Rds Sensors

    Each sensor must be specifically placed for proper unit operation and to initiate valid alarms. To identify sensor locations see TABLE 15. INDOOR COIL RDS SENSOR LOCATION RDS SENSOR SCREW FIGURE 29 LGT/LCT036, 048, 060, 072 Page 39...
  • Page 40 COMPRESSOR RDS SENSOR LOCATION SCREW RDS SENSOR FIGURE 30 LGT/LCT036, 048, 060, 072 Page 40...

  • Page 41: Cooling Operation

    RTU MENU > COMPONENT TEST > COOLING > Y1 Demand - COOLING STAGE 2 Compressors Off Low Speed Compressor Operation Blower Low RTU MENU > COMPONENT TEST > COOLING > Dampers Modulate COOLING STAGE 1 LGT/LCT036, 048, 060, 072 Page 41...

  • Page 42: Gas Heat Start-Up (Gas Units)

    NOTE - When unit is initially started, steps 1 through 9 death. Do not attempt to light manually. Unit may need to be repeated to purge air from gas line. has a direct spark ignition system. 11 - The ignition sequence will start. LGT/LCT036, 048, 060, 072 Page 42...

  • Page 43: Heating Operation And Adjustments

    Steady Off Power applied. Control OK. 3 Flashes Ignition lockout from too many trials. 4 Flashes Ignition lockout from too many flame losses within single call for heat. 5 Flashes Control hardware fault detected. LGT/LCT036, 048, 060, 072 Page 43...

  • Page 44: Hot Gas Reheat Start-Up And Operation

    Control Panel (NCP). reheat valve is de-energized. Reheat will terminate when the indoor relative humidity falls 3% (57% default) or the digital output de-energizes. The reheat deadband can be adjusted at Settings - Control menu. LGT/LCT036, 048, 060, 072 Page 44...
  • Page 45 REHEAT COIL SUPPLY COMPRESSOR CONDENSER COIL CHECK VALVE REHEAT VALVE FIGURE 32 COOLING MODE REFRIGERANT ROUTING RETURN OUTDOOR EVAPORATOR EXPANSION COIL VALVE REHEAT COIL SUPPLY COMPRESSOR CONDENSER COIL CHECK VALVE REHEAT VALVE FIGURE 33 LGT/LCT036, 048, 060, 072 Page 45...

  • Page 46: Preventative Maintenance / Repair

    – refrigerating pipe or components are installed in a position where they are unlikely to be exposed to any substance which may corrode refrigerant containing components, unless the components are constructed of LGT/LCT036, 048, 060, 072 Page 46...
  • Page 47 5 - Locate the ignitor under the right burner. Check ignitor spark gap with appropriately sized twist drills or feeler gauges. See FIGURE 36. 6 - Replace burners and screws securing burner. See FIGURE 37. LGT/LCT036, 048, 060, 072 Page 47...
  • Page 48 108,000 BTUH - 5 BURNERS SENSOR SENSOR IGNITOR 65,000 BTUH - 3 BURNERS BURNERS GAS MANIFOLD SENSOR IGNITOR IGNITOR GAS VALVE FIGURE 37 FIGURE 35 IGNITOR SPARK GAP SHOULD BE 1/8” (3mm) FIGURE 36 LGT/LCT036, 048, 060, 072 Page 48...

  • Page 49: Heat Exchanger Assembly

    HEAT EXCHANGER ASSEMBLY Two-Stage Shown HEAT EXCHANGER TUBE COMBUSTION AIR INDUCER FLUE BOX COVER BURNER PRIMARY ROLLOUT GAS VALVE LIMIT VENT SWITCH CONNECTOR FIGURE 38 LGT/LCT036, 048, 060, 072 Page 49...
  • Page 50 SUPPLY AIR COVER AND THE BACK OF THE IONIZER BRACKET. BE SURE CURE THE FRONT TO ENGAGE THE IONER BRACKET OF THE IONIZER TO WHEN REPLACING THE SCREW. THE BLOWER DECK. IONIZER FIGURE 40 LGT/LCT036, 048, 060, 072 Page 50...
  • Page 51 NOTE - The bands around the lamp should be evenly spaced as shown in the diagram. 4 - Remove the screw in wire tie from the UVC assembly and disconnect the 4-pin connector from FIGURE 42 the lamp end. LGT/LCT036, 048, 060, 072 Page 51...
  • Page 52 LFL of the refrigerant and shall be calibrated to the refrigerant employed, and the appropriate percentage of gas (25 % maximum) is confirmed. Leak detection fluids LGT/LCT036, 048, 060, 072 Page 52...
  • Page 53 T1/E1EH0300N-1G to take place. Ensure that the outlet for the vacuum pump K1/E1EH0057AN1M is not close to any potential ignition sources and that K1/E1EH0115AN1M ventilation is available. K1EH0172AN1M E1EH0172N-1M K1/E1EH0230N-1M LGT/LCT036, 048, 060, 072 Page 53...
  • Page 54 W / O P.E. Diagram Class Blower HP Amps F10² F61² F61² CB10³ CB10³ ² Fuses F10 and F61 are only used on units with SCCR installed. ³ Units using Circuit Breakers will use CB10 option. LGT/LCT036, 048, 060, 072 Page 54...
  • Page 55 CB10³ CB10³ ¹ When SCCR is installed, F4 fuse is Class J. ² Fuses F10 and F61 are only used on units with SCCR installed. ³ Units using Circuit Breakers will use CB10 option. LGT/LCT036, 048, 060, 072 Page 55...
  • Page 56 CB10³ CB10³ ¹ When SCCR is installed, F4 fuse is Class J. ² Fuses F10 and F61 are only used on units with SCCR installed. ³ Units using Circuit Breakers will use CB10 option. LGT/LCT036, 048, 060, 072 Page 56...
  • Page 57 CB10³ CB10³ ¹ When SCCR is installed, F4 fuse is Class J. ² Fuses F10 and F61 are only used on units with SCCR installed. ³ Units using Circuit Breakers will use CB10 option. LGT/LCT036, 048, 060, 072 Page 57...
  • Page 58 F61² CB10³ ¹ When SCCR is installed, F4 fuse is Class J. ² Fuses F10 and F61 are only used on units with SCCR installed. ³ Units using Circuit Breakers will use CB10 option. LGT/LCT036, 048, 060, 072 Page 58...

  • Page 59: Factory Unit Controller Settings

    Controlled by RH sensor (A91) connected to input A55_P298_5 and set point set at parameter 106 (default 60%). 10 sec (All-Aluminum HI CL REHEAT TMOUT: Number of seconds Reheat Valve remains energized upon thermo- Coils Only) stat call for high stage cooling (default 0 sec onds). LGT/LCT036, 048, 060, 072 Page 59...
  • Page 60 M = Manual Bypass Power Exhaust Control [4] U = Unconfigured Not Installed = N Damper Position = A [5] Network Module A34 Pressure Sensor = C N = Not Installed L = LonTalk FIGURE 44 LGT/LCT036, 048, 060, 072 Page 60...
  • Page 61 Phase / Voltage Detection * [5] [6] IAQ Options Not Installed = N N = Not Installed Enabled Internal (Lennox) = 1 1 = UV Lamp Installed External (A42) Phase Detection = 2 2 = Bipolar Ionizer Installed on DI-2...

  • Page 62: Decommissioning

    Pump down refrigerant system, if possible. e) If a vacuum is not possible, make a manifold so that refrigerant can be removed from various parts of the system. LGT/LCT036, 048, 060, 072 Page 62...

  • Page 63: Start-Up Report

    Return Air Temp.:______ Supply Air Temp.:_____ Altitude:____________ Primary Limits Operate: Manifold Pressure Gas Valve Low Fire High Fire Accessory Checks Power Exhaust Amps 1 _____________ 2 ____________ None Control Type Economizer Operation Min. Pos. Motor travel full open/close LGT/LCT036, 048, 060, 072 Page 63...

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