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Service Literature
The LDT156, 180 and 240 units are configure to order units
(CTO) with a wide selection of factory installed options.
The LDT156 is available in 169,000 to 360,000 Btuh. The
LDT180/240 is available in 169,000 to 480,000 Btuh..
Gas heat sections are designed with stainless steel tube
heat exchangers with stainless steel as an option.
Cooling capacities range from 13 to 20 tons. The LDT 156,
180 & 240 utilize two compressors and six condenser fans.
Multi-Stage Air Volume MSAV
The VFD-driven blower will operate at lower speeds when
demand is low and increase to higher speeds when
demand is high.
All LDT units are designed to accept any of several different
energy management thermostat control systems with
minimum field wiring. Factory- or field-provided control
options connect to the unit through Smartwiret
connectors. When "plugged in" the controls become an
integral part of the unit wiring.
The CORE Control System is designed to accelerate
equipment install and service. Standard with all Enlight
rooftop units, control system integrates key technologies
that lower installation costs, drive system efficiency, and
protect your investments.
The CORE Unit Controller is a microprocessor-based
controller that provides flexible control of all unit functions.
Information contained in this manual is intended for use by
qualified service technicians only. All specifications are
subject to change. Procedures outlined in this manual are
presented as a recommendation only and do not
supersede or replace local or state codes.
If the unit must be lifted for service, rig unit by attaching four
cables to the holes located in the unit base rail (two holes at
each corner). Refer to the installation instructions for the
proper rigging technique.
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person
al injury or loss of life. Installation and service must
be performed by a qualified installer or service
agency.
100083
LDT156 through 240
®
blower option is
available.
LDT SERIES
WARNING
To prevent serious injury or death:
1-Lock-out/tag out before performing maintenance.
2- If system power is required (e.g., smoke detector
maintenance, disable power to blower, remove fan
belt where applicable, and ensure all controllers and
thermostats are Set to the "OFF" position before per
forming maintenance.
3- Always keep hands, hair, clothing, jewelery, tools,
etc.,c away from moving parts.
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Related Manuals for Lennox LDT Series
Summary of Contents for Lennox LDT Series
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Page 1: Table Of Contents
LDT SERIES 13 to 20 ton 100083 Service Literature LDT156 through 240 The LDT156, 180 and 240 units are configure to order units (CTO) with a wide selection of factory installed options. The LDT156 is available in 169,000 to 360,000 Btuh. The LDT180/240 is available in 169,000 to 480,000 Btuh.. -
Page 2: Options / Accessories
OPT IONS / A C C ESSORIES Unit Model No Catalog Item Description Number COOLING SYSTEM 22H54 Condensate Drain Trap Copper 76W27 Conventional Fin/Tube Condenser Coil Factory Drain Pan Overflow Switch 21Z07 Refrigerant Type R-410A HEATING SYSTEM Bottom Gas Piping Kit 85M31 Combustion Air Intake Extensions (order two) 89L97... - Page 3 OPT IONS / A C C ESSORIES Unit Model No Catalog Item Description Number CONTROLS Blower Proving Switch 21Z10 Commercial Controls CPC Einstein Integration Factory LonTalk Module 54W27 ® Novar Factory ® Dirty Filter Switch 53W68 Fresh Air Tempering 21Z08 Smoke Detector - Supply or Return (Power board and one sensor) 22H56 22H57...
- Page 4 OPT IONS / A C C ESSORIES Unit Model No Catalog Item Description Number ECONOMIZER High Performance Economizer (Approved for California Title 24 Building Standards AMCA Class 1A Certified) High Performance Economizer 23G24 Downflow or Horizontal Applications - Includes Outdoor Air Hood. Order Downflow or Horizontal Barometric Relief Dampers separately.
- Page 5 OPT IONS / A C C ESSORIES Unit Model No Catalog Item Description Number ROOF CURBS Hybrid Roof Curbs, Downflow 8 in. height 11F58 14 in. height 11F59 18 in. height 11F60 24 in. height 11F61 Adjustable Pitch Curb 14 in. height 43W26 Standard Roof Curbs, Horizontal - Requires Horizontal Return Air Panel Kit 26 in.
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Page 6: Specifications
SP ECIF ICATIONS General Data Nominal Tonnage 13 Ton 15 Ton 20 Ton Model Number LDT156H4M LDT180H4M LDT240H4M Efficiency Type High High High Blower Type MSAV MSAV MSAV ® ® ® Multi-Stage Air Volume Multi-Stage Air Volume Multi-Stage Air Volume Cooling Gross Cooling Capacity - Btuh 154,000... -
Page 7: Gas Heat Specifications / High Altitude
Two-stage heat models can be operated with four stages of gas heating when controlled in either zone sensor, Discharge Air Control, or fresh air tempering mode on the Lennox CORE unit controller (available when using the CS8500 thermostat or when connected to Building Automation Systems using BACnet, LonTalk, or S-Bus ®... - Page 8 Page 8...
- Page 9 BLOWER DATA BLOWER D ATA FACTORY INSTALLED BELT DRIVE KIT SPECIFICATIONS Nominal Maximum Drive Kit Number RPM Range 3.45 535 - 725 3.45 710 - 965 5.75 685 - 856 5.75 850 - 1045 5.75 945 - 1185 8.63 850 - 1045 8.63 945 - 1185 8.63...
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Page 10: Blower Data
BLOWER D ATA POWER EXHAUST FAN PERFORMANCE Return Air System Static Pressure Air Volume Exhausted in. w.g. 0.00 8630 0.05 8210 0.10 7725 0.15 7110 0.20 6470 0.25 5790 0.30 5060 0.35 4300 0.40 3510 0.45 2690 0.50 1840 CEILING DIFFUSER AIR RESISTANCE - in. w.g. Step-Down Diffuser Flush Diffuser RTD11-185S... -
Page 11: Electrical Data
ELECTR ICAL D ATA 1 3 TO N Model No. LDT156H4 Voltage - 60Hz 208/230V - 3 Ph 460V - 3 Ph 575V - 3 Ph Compressor 1 Rated Load Amps 17.6 (Non-Inverter) Locked Rotor Amps 66.1 55.3 Compressor 2 Rated Load Amps 22.4 10.6... - Page 12 ELECTRIC AL DATA 2 0 TO N 20 TON HIGH EFFICIENCY LDT240H4 Voltage - 60Hz 208/230V - 3 Ph 460V - 3 Ph 575V - 3 Ph Compressor 1 Rated Load Amps 32.6 14.8 11.1 (Non-Inverter) Locked Rotor Amps 93.7 Compressor 2 Rated Load Amps 31.1...
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Page 13: Unit Parts Arrangement
PARTS ARRANGEMENT INDOOR FILTERS COIL (SIX - 24 X 24 X 2”) OUTDOOR BLOWERS FANS ECONOMIZER DAMPERS (OPTIONAL) BLOWER MOTOR BLOWER INVERTER 8.8.8.8 CONDENSATE DRAIN OUTDOOR COILS UNIT CONTROLLER DISCONNECT COMPRESSORS (FACTORY-INSTALLED COMBUSTION BURNERS OPTION) AIR INDUCER GAS VALVE FIGURE 1 I-UNIT COMPONENTS 1-Disconnect Switch S48 Units with higher SCCR rating may be equipped with an... - Page 14 Components Arrangement FIGURE 3 Components Arrangement FIGURE 4 Page 14...
- Page 15 4-Terminal Block TB13 control will restart the ignition sequence and continue until flame is established or system locks out. For a more TB13 terminal block distributes line voltage power to the detailed description see the Gas Heat Components line voltage items in the unit. section.
- Page 16 Temperature Sensors The return air (RT16) and discharge air (RT6) duct probes and the outdoor air (RT17) are all two wire thermistors. The resistance vs. temperature table is shown below: Table 1 Resistance vs. Temperature Temperature °F Temp. °F (°C) Resistance +/-2% Resistance +/-2% Temp.
- Page 17 LINE VOLTAGE IN TELEMECANIQUE OVERLOAD RELAY TRIP INDICATION CLEAR COVER WINDOW DETAIL SHOWING RESET BUTTON (SHOWN ADJUSTED TO MANUAL POSITION CLOSED) AMP SETTING Lift clear cover and turn adjustment screw STOP POINTER counterclockwise. Reset screw will pop out BUTTON when pointer is in M (manual position). Close (RED) cover to lock reset screw into position.
- Page 18 Compressor Detail B1, B2 FIGURE 7 REFRIGERANT CIRCUITS INDOOR COIL CIRCUIT 1 & 2 ARE INTERLACED CIRCUIT 1 OUTDOOR COIL CIRUIT 2 OUTDOOR COIL FIGURE 8 Page 18...
- Page 19 B-Cooling Components 2-Crankcase Heaters HR1 and HR2 All LDT units use insertion type heaters. Heater HR1 is Enlight units use independent cooling circuits consisting of installed around compressor B1 and heater HR2 one compressor, one condenser coil, and one evaporator compressor B2.
- Page 20 6-Filter Drier (all units) is energized during cooling demand and during defrost. Reversing valve L1 & L2 are controlled by the A55 Control Units have a filter drier located in the liquid line of each board in response to a cooling demand or by defrost. refrigerant circuit at the exit of each condenser coil.
- Page 21 THERMISTOR LOCATION OUTDOOR COIL (RT48, RT49) YELLOW BLUE RT49 RT48 FIGURE 10 Page 21...
- Page 22 C-Blower Compartment IMPORTANT The blower compartment is located between the evaporator coil and the compressor / control section on the Three Phase Scroll Compressor Voltage Phas opposite side of the condenser coil. The blower assembly is Three phase scroll compressors must be phased se accessed by disconnecting the blower motor wiring (and all quentially to ensure correct compressor and blower* other plugs) and removing the screws on either side of the...
- Page 23 1- The following measurements must be made with a dry 4- The blower RPM can be adjusted at the motor pulley. indoor coil. Run blower (G demand) without a cooling Loosen Allen screw and turn adjustable pulley demand. Measure the indoor blower shaft RPM. Air clockwise to increase CFM.
- Page 24 D-Blower Belt Adjustment E-Check Belt Tension Maximum life and wear can be obtained from belts only if Overtensioning belts shortens belt and bearing life. Check proper pulley alignment and belt tension are maintained. Tension new belts after a 24-48 hour period of operation. belt tension as follows: This will allow belt to stretch and seat into pulley grooves.
- Page 25 D-GAS HEAT COMPONENTS the unit will lockout for 60 minutes. After lockout, the ignition control automatically resets and provides three more See SPECIFICATIONS tables or unit nameplate for Btuh attempts at ignition. Manual reset after lockout requires capacities. Units are equipped with two identical gas heat breaking and remaking power to the ignition control.
- Page 26 GAS HEAT COMPONENTS FIGURE 16 Page 26...
- Page 27 NORMAL IGNITION SEQUENCE - TIMINGS NOMINAL ON / CLOSED É É É OFF / OPEN SECONDS 0 END OF DEMAND É É É É É É É É É É É É É THERMOSTAT DEMAND COMBUSTION AIR BLOWER É É É É É É É É É É É É É É...
- Page 28 2-Heat Exchanger (Figure 20) through each tube by the combustion air blower, exhaust gases are drawn out the top and fresh air/gas mixture is Units use aluminized steel cluster inshot burners with drawn in at the bottom. Heat is transferred to the air stream matching tubular aluminized (stainless steel is an option) from all surfaces of the heat exchanger tubes.
- Page 29 3-Burner Assembly (Figure 21) 4-Primary High Temperature Limits S10 & The burners are controlled by the spark electrode, flame sensing electrode, gas valve and combustion air blower. S10 is the primary high temperature limit for gas heat The spark electrode, flame sensing electrode and gas section one and S99 is the primary high temperature limit valve are directly controlled by ignition control.
- Page 30 Figure 24 shows gas valve components. Table 7 pressure fall and switch actuation allows the ignition shows factory gas valve regulation for LDT series units. sequence to continue (proves, by closing, that the Optional factory installed gas valves for single stage heat combustion air inducer is operating before allowing the gas only, are available for the LDT156, 180 and 240.
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Page 31: Ii-Placement And Installation
III-CHARGING IGNITOR A-Refrigerant Charge and Check - Fin/Tube Coil WARNING-Do not exceed nameplate charge under any condition. This unit is factory charged and should require no further adjustment. If the system requires additional refrigerant, ELECTRODE GROUND reclaim the charge, evacuate the system and add required nameplate charge. -
Page 32: Start Up - Operation
TABLE 9 Refer to unit diagram located on inside of unit control 180 Compressor 1 Frequency 56Hz - 581168-01 box cover. Outdoor Circuit 1 Circuit 2 3- Check to ensure that refrigerant lines are in good Coil En tering condition and do not rub against the cabinet or other Dis. - Page 33 FOR YOUR SAFETY READ BEFORE LIGHTING supplier's instructions. If you do not smell gas, go to the next step. WHITE RODGERS 36H54 GAS VALVE WARNING Two-Stage Danger of explosion. Can cause injury or product or property damage. If over heating occurs or if gas supply fails to shut off, shut off the manual gas valve to the appliance before shutting off electri...
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Page 34: V-System Service Checks
V- SYSTEMS SERVICE CHECKS within the range of the following values. Low pressure may result in erratic operation or “underfire.” High pressure can A-Heating System Service Checks result in permanent damage to the gas valve or “overfire.”. All LDT units are ETL/CSA design certified without See table 12 for supply pressures. - Page 35 TABLE 12 TYPICAL GAS BURNER ASSEMBLY Supply Pressure Manifold Pressure “W.C. BURNER “W.C. SUPPORT CAP Natural LP/Propane Natural Propane BURNERS High High 4.7 - 10.8 -13.5 10.5+ 10.5 1.6+ 0.2 3.7+0.3 5.5+ 0.3 Combustion gases Flue products must be analyzed and compared to the unit specifications.
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Page 36: Vi-Maintenance
TABLE 13 A-Filters LDT units use six 24 X 24 X 2” fiberglass throw-away type Nominal Signal Manufacturer Drop Out filters. Filters may be accessed through the economizer / Microamps filter access door. Filters should be checked monthly (or UTEC 0.5 - 1.0 more frequently in severe use) and cleaned or replaced NOTE-If the meter scale reads 0, the leads are... -
Page 37: Vii-Accessories
The units Optional supply/return transitions C1DIFF33C-1 and MUST be mounted level within 1/16” per linear foot or 5mm C1DIFF34C-1 are available for use with LDT series units per meter in any direction. utilizing optional C1CURB roof curbs. Transition must be installed in the roof curb before mounting the unit to the frame. - Page 38 E-E1ECON15C-2 Standard and C1DAMP10 MANUAL OUTDOOR AIR DAMPER E1ECON17C-1 High Performance Economizer (Field or Factory Installed) The optional economizer can be used with downflow and horizontal air discharge applications. The economizer uses outdoor air for free cooling when temperature and/or humidity is suitable.
- Page 39 2- A thermostat mounting box is installed on the vestibule used any time an economizer or power exhaust fans are of the heating compartment. Included in the box are the applied to LDT series units. An exhaust hood is furnished following thermostat switches: with the gravity exhaust damper.
- Page 40 I-Control Systems O-Optional UVC Lights The A55 Unit Controller provides all control function for the The Healthy Climate germicidal light emits ultraviolet rooftop unit. Default operation requires a standard room (UVC) energy that has been proven effective in reducing thermostat or direct digital controller (DDC).
- Page 41 Replacing the Sensor R-Bipolar Ionizer 1- Open the CORE Service App and navigate to Menu > (Setup) Network Integration > Wireless Sensor The Needlepoint Bipolar Ionizer (NBPI) kit is specifically Network Setup > Wireless Sensor Network. designed for LG/LC/LH/LD/KG/KC/KH 024-300 units. The 2- Click Add node on the Network Nodes screen.
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Page 42: Viii-Staged Blower
VIII--Multi-Staged Blower RTU MENU > SETTINGS > RTU OPTIONS > DAMPER Tap "Next" to skip tabs and complete damper position NOTE - VFD Bypass is only offered in LDT156,180 models. calibration until "Damper Calibration Blower Speed High" A-Design Specifications tab appears. Use the “Blower CFM Design Specifications”... - Page 43 F-Unit Operation 5- Restore power to unit. Blower will operate in constant air volume (CAV) mode. Use the mobile app to check unit mechanical operation. See the Service - Test section of the Unit Controller Note - The indoor blower motor will start as soon as the main manual.
- Page 44 TABLE 15 HEATING, VENTILATION & SMOKE MINIMUM AND MAXIMUM CFM Unit Heating CFM Vent CFM Smoke CFM Default Default Model Speed Heat Code Default 2725 LDT156H 4325 6000 4500 6250 5200 1950 62500 5200 1950 6250 HP W/O EH 3900 LHT156H 15, 30, 45, 60, 90 KW E, J, K, L,...
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Page 45: Ix-Wiring And Operation Sequence
BURNER 2 P228(1) P228(1) P228(2) P228(2) DENOTES OPTIONAL COMPONENTS AND WIRING Model: LGT, LDT Series RTU − Gas Heat HEATI N G COOLI N G COOLI N G ACCS ACCS Input Heat Capacity 169k − 480k Btuh SECTI O N... - Page 46 BURNER 2 P228(1) P228(1) P228(2) P228(2) DENOTES OPTIONAL COMPONENTS AND WIRING Model: LGT, LDT Series RTU − Gas Heat HEATI N G COOLI N G COOLI N G ACCS ACCS Input Heat Capacity 169k − 480k Btuh SECTI O N...
- Page 47 Sequence of Operation Gas Heat LDT156/240 Heating Type Determination - On a heating demand if SECOND STAGE HEAT: the outdoor air temperature is above Balance Set Point, proceed to Heat Pump Heat. If outdoor With first stage heat operating, an additional temperature is below the Balance Point Set Point, heating demand initiates W2 in the thermostat.
- Page 48 THERMOSTAT A173 CTRL SMOKE DETECT J250 P250 P251 J251 J252 P252 P253 J253 FIRE ALARM CONTACT SUPPLIED BY OTHERS FROM IAQ WIRING DIAGRAM DI−1 P299 P387 J299 J387 MAIN CTRL J297 J298 P297 P298 J387 J298 J297 J299 IAQ+ IAQ+ BACNET GATEWAY TO PROVIDE THREE IAQ+ IAQ−...
- Page 49 Economizer MS7110K RANGE 2−10 VDC NF24−SR AF24−SR RANGE 2−10 VDC P104 P105 RT16 J104 J105 P384 J384 MAIN CTRL Model: LC, LG, LH, LD Series RTU HTG CLG ACCS ACCS Economizer & Motorized OAD WI R I N G D I A GRAM F LOW Voltage: All Voltages 538072−01...
- Page 50 Sequence of Operation LDT156/180/240 Line voltage from TB13 energizes transformer T1 and T18. Transformer T1 and T18 provides 24VACpower to the main controller A55. The transformers also provides 24VAC power to the unit cooling, heating and blower controls and thermostat. ECONOMIZER OPERATION The A55 Unit Controller receives a demand and energizes exhaust fan relay K65 and K231 with 24VAC at 50% (travel) outside air damper open (adjustable).
- Page 51 LHT,LDT156/180/240 Y Voltage No By-Pass 538224-01 Page 51...
- Page 52 LHT, LDT156/180/240 G, J Voltage No By-Pass 538223-01 Page 52...
- Page 53 LHT, LDT156/180 Y Voltage With By-Pass 538222-01 Page 53...
- Page 54 LHT, LDT156/180 G, J Voltage With By-Pass 538221-01 Page 54...