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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
RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE
INSTALLATION
INSTRUCTIONS
LHT/LDT302
HEAT PUMP AND DUAL-FUEL PACKAGED UNITS
508635-01
5/2024
4
5
6
6
6
8
8
8
9
9
10
10
11
11
13
(25 Ton)
R-454B
16
22
22
25
26
26
27
27
29
30
32
34
40
44
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Summary of Contents for Lennox LHT302
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Page 1: Table Of Contents
INSTALLATION ©2024 INSTRUCTIONS WARNING LHT/LDT302 Improper installation, adjustment, alteration, ser vice (25 Ton) or maintenance can cause property damage, personal HEAT PUMP AND DUAL-FUEL PACKAGED UNITS injury or loss of life. Installation and ser vice must be 508635-01 performed by a licensed professional HVAC installer or 5/2024 equivalent, service agency, or the gas supplier R-454B... - Page 2 CAUTION WARNING As with any mechanical equipment, contact with sharp •This appliance must be installed in accordance with sheet metal edges can result in personal in jury. Take local and national wiring regulations. care while handling this equipment and wear gloves and •If the appliance is not fitted with an option for full protective clothing.
- Page 3 A2L Refrigerant Considerations When breaking into the refrigerant circuit to make repairs – or for any other purpose – conventional procedures shall Ensure that the work area is adequately ventilated before be used. However, for flammable refrigerants it is important breaking into the system or conducting any hot work.
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Page 4: Dimensions
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 control- lers and thermostats are set to the OFF position before performing maintenance. -
Page 5: Parts Arrangement
LHT302 PARTS ARRANGEMENT INDOOR FILTERS COIL (SIX - 24 X 24 X 2”) BLOWERS OUTDOOR ECONOMIZER FANS DAMPERS (OPTIONAL) BLOWER MOTOR BLOWER INVERTER INDOOR COIL RDS SENSOR (BEHIND COIL) CONDENSATE DRAIN UNIT OUTDOOR CONTROLLER COILS COMPRESSORS COMPRESSOR DISCONNECT RDS SENSOR... -
Page 6: Shipping And Packing List
TABLE 1 Shipping and Packing List UNIT CLEARANCES Package 1 of 1 contains: ¹Unit 1 - Assembled unit Clearance in.(mm) in.(mm) in.(mm) in.(mm) Clearance Service Unob- Check unit for shipping damage. Receiving party Clearance (1524) (914) (914) (1676) structed should contact last carrier immediately if shipping Clearance to Unob- damage is found. - Page 7 Minimum R454B Space and CFM Requirements Minimum Airflow¹ Refrigerant Charge R-454B Unit (CFM) (m³h) Unit (lbs) (kg) LHT/LDT302 1302 LHT/LDT302 Stage 1 29.00 13.15 LHT/LDT302 Stage 2 28.00 12.70 ¹ NOTE - The minimum airflow is the lowest CFM allowed during venting operation (leak mitigation).
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Page 8: Unit Support
This appliance is not intended for use by persons be installed before setting the unit. (including children) with reduced physical, sensory, or 5 - Units require support along all four sides of unit mental capabilities, or lack of experience and knowledge, base. -
Page 9: Condensate Drain Connection
CONDENSATE DRAIN CONNECTION RIGGING *Weight Unit Lbs. CAULK AROUND NOTE - Allow clearance to CONDENSATE 2774 1258 LH 302 open doors when installing COUPLING condensate piping. 2874 1304 LD 302 UNIT *Maximum weight with all available factory-installed accessories. Minimum Pitch 1”... -
Page 10: Pressure Test Gas Piping
After all connections have been made, check all piping OUTSIDE OF UNIT GAS PIPING connections for gas leaks. Also check existing unit gas TO GAS connections up to the gas valve; loosening may occur VALVE during installation. Use a leak detection solution or other preferred means. -
Page 11: Electrical Connections - Power Supply
TABLE 2 FIELD WIRE ROUTING HIGH ALTITUDE DERATE Unit Altitude Ft.* Gas Manifold Pressure 2000-4500 2000-4500 See Unit Nameplate Derate 2% / 1000 Ft. 169 KBtuh 4500 & Above Above Sea Level OPTIONAL Derate 2% / 1000 Ft. SIDE ENTRY 260-380 KBtuh 4500 &... - Page 12 A-Thermostat Location FIELD WIRING WITH ELECTRONIC AND Room thermostat mounts vertically on a standard 2” X 4” ELECTRO-MECHANICAL THERMOSTATS handy box or on any non-conductive flat surface. (Thermostat Mode) 24 V POWER Locate thermostat approximately 5 feet (1524mm) above J297 P297 the floor in an area with good air circulation at average temperature.
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Page 13: Mobile Service App
D-App Menus Mobile Service App See FIGURE 10 for the menu overview. Follow the app Setup and configure each rooftop unit using the mobile prompts in the Install, Network Integration, and Test and service app (Android or iOS devices supported). Balance menus. - Page 14 INSTALL MENU RTU NAME INSTALL* DATE AND MODEL NUMBER CONFIGURATION ID 1 NEW UNIT SETUP TIME SERIAL NUMBER CONFIGURATION ID 2 SELECT CATALOG NUMBER INSTALL OPTION Partial menu shown. Complete all three menu paths and select “Finish” at the summary screen. *Under “Settings”...
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Page 15: Test Button
TEST BUTTON tESt * Short press will put the unit into test mode * Long press will put the unit into setup mode StAt for two-stage thermostate - RESET BUTTON CLdL * Short press will clear unit delays (lockouts) * Long press will reset the M4 Unit Controller - * Short press is about 2 to 5 seconds in duration. -
Page 16: Blower Operation And Adjustments
WARNING Blower Operation and Adjustments Supply Air Staged Units - The blower rotation will always 1- Make sure that unit is installed in accordance with the be correct on units equipped with an inverter. Checking installation instructions and applicable codes. blower rotation is not a valid method of determining 2- Inspect all electrical wiring, both field and factory- voltage phasing for incoming power. - Page 17 4 - The blower RPM can be adjusted at the motor pul- TABLE 5 ley. Loosen Allen screw and turn adjustable pulley MINIMUM AND MAXIMUM PULLEY ADJUSTMENT clockwise to increase CFM. Turn counterclockwise Belt Min. Turns Open Max. Turns Open to decrease CFM.
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Page 18: Pulley Alignment
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. belt tension as follows: Tension new belts after a 24-48 hour period of operation. 1 - Measure span length X. - Page 19 Page 19 508635-01 5/2024...
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Page 20: Blower Data
BLOWER DATA FACTORY INSTALLED BELT DRIVE KIT SPECIFICATIONS Motor Efficiency Nominal hp Maximum hp Drive Kit Number RPM Range Standard 5.75 660 - 810 Standard 5.75 770 - 965 Standard 5.75 570 - 720 Standard 5.75 480 - 630 Standard 5.75 410 - 535 Standard... - Page 21 Page 21 508635-01 5/2024...
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Page 22: Refrigerant Leak Detection System
B-Start-Up Refrigerant Leak Detection System Supply Air Staged Blower - Refer to the Multi-Staged Air A-System Test Volume Start-Up section. 1 - Initiate Refrigerant Leak Detection System Test by 1 - Initiate first and second stage cooling demands us- using the following mobile service app menu path: ing this mobile service app menu path: RTU MENU >... - Page 23 REFRIGERANT CIRCUITS INDOOR COIL CIRCUIT 1 & 2 ARE INTERLACED CIRCUIT 1 OUTDOOR COIL CIRUIT 2 OUTDOOR COIL FIGURE 21 C-R454B Refrigerant • Extreme care shall be taken not to overfill the unit. Units charged with R454B refrigerant operate at lower Prior to recharging the system, it shall be pressure- pressures than R410A.
- Page 24 • The recovered refrigerant shall be returned to the TABLE 7 refrigerant supplier in the correct recovery cylinder, Normal Operating Pressures - 581327-01 and the relevant waste transfer note arranged. Do CIRCUIT 1 CIRCUIT 2 Outdoor not mix refrigerants in recovery units and especially Coil Enter- Discharge Suction...
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Page 25: Heating Start-Up (Ldt)
4 - Outdoor Fan Operation WARNING Outdoor fans 1, 2, and 3 are energized when compressor 1 is energized. As cooling demand Danger of explosion. Can cause injury or increases, all six outdoor fans are energized. See product or property damage. If overheating FIGURE 22. -
Page 26: Heating Operation And Adjustments
which automatically lights the burner. Do not try to fore locking out the gas valve. light the burner by hand. 6 - For troubleshooting purposes, an ignition attempt af- 4 - Open or remove the heat section access panel. ter lock out may be re-established manually. Move thermostat to “OFF”... -
Page 27: Defrost Control
Adjust the blower RPM to deliver the target CFM based on Defrost Control the measured static pressure using the blower table. The defrost control ensures that the heat pump outdoor coil Measure the static pressure again and apply the static does not ice excessively during the heating mode. - Page 28 TABLE 10 HEATING, VENTILATION & SMOKE MINIMUM AND MAXIMUM CFM Unit Heating CFM (ECTO 0.04) Vent CFM Smoke CFM Ton- Heat Heat Model Default Default Default nage Option Code Medium S, M 5925 LDT302H High 7125 10500 12000 10500 3750 12000 10500 3750...
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Page 29: Multi-Staged Air Volume Operation
C-Three-Stage Thermostat Multi-Staged Air Volume Operation 1 - Economizer With Outdoor Air Suitable This is a summary of cooling operation. Refer to the Y1 Demand - sequence of operation provided in the Engineering Handbook or Service Manual for more detail. Compressors Off A-Two-Stage Thermostat Blower Cooling Medium... -
Page 30: Temperature Thermistor Sensors
feedback in certain modes of unit operation. In addition, the Unit Temperature Thermistor Sensors Controller uses these temperatures to initiate alarms such as loss Units are equipped with four factory-installed thermistors (RT46 - of outdoor or indoor coil airflow and loss of charge. RT49) located on different points on the refrigerant circuit. - Page 31 LHT/LDT302 OUTDOOR COIL RT48, RT49 22J08 22J08 BLUE YELLOW RT49 RT48 FIGURE 26 Page 31 508635-01 5/2024...
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Page 32: Rds Sensors
RDS Sensors TABLE 12 RDS Sensor Figures Units are equipped with factory-installed RDS Sensors Model Qty. Type Figure located on different points on the unit. The RDS sensors provide the Unit Controller with continuous readings for INDOOR SENSOR FIGURE 27 leaked refrigerant concentration levels and sensor health LHT/LDT302 2 sensors... - Page 33 LHT/LDT 302 COMPRESSOR RDS SENSOR SCREW RDS SENSOR USE WIRE TIES TO KEEP HARNESS WIRES AWAY FROM HOT OR SHARP SURFACES. FIGURE 28 Page 33 508635-01 5/2024...
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Page 34: Preventative Maintenance / Repair
– refrigerating pipe or components are installed in a Preventative Maintenance / Repair position where they are unlikely to be exposed to any IMPORTANT MAINTENANCE / REPAIR SAFETY substance which may corrode refrigerant containing INSTRUCTIONS components, unless the components are constructed of materials which are inherently resistant to being corroded Prior beginning... - Page 35 B-Lubrication WARNING All motors are lubricated at the factory. No further lubrication is required. Danger of explosion. Can cause injury or death. Do not overtighten main burner Blower shaft bearings are prelubricated. For extended bearing mounting screws. Snug tighten only. life, relubricate at least once every two years with a lithium base grease, such as Alvania 3 (Shell Oil), Chevron BRB2 (Standard BURNER BOX ASSEMBLY...
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Page 36: Burner Box
Under normal operating conditions, the combustion air inducer IGNITOR wheel should be checked and cleaned prior to the heating season. However, it should be examined periodically during the SPARK GAP heating season to establish an ideal cleaning schedule. With SHOULD BE power supply disconnected, the condition of the inducer wheel can be determined by looking through the vent opening. - Page 37 I-Replacement Fuses HEAT EXCHANGER ASSEMBLY See the following tables for the proper replacement fuse HEAT sizes. EXCHANGER ELECTRIC HEAT REPLACEMENT FUSES TUBE Rating Electric Heat Qty. COMBUSTION Volt AIR INDUCER EHA240-7.5-1Y,2Y EHA360-15-,1Y2Y EHA360-22.5-1Y,2Y 3 EA. 25 & 50 EHA360-45-1Y,2Y 50 & 60 EHA240-7.5-1G,2G EHB240-10-1G EHB240-20-1G...
- Page 38 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. LHT302 continued Electric Heat Size 45 KW 60 KW...
- Page 39 LHT302 continued Electric Heat Size 90 KW 120 KW Unit Voltage 208V - 3 Ph 240V - 3Ph 480V - 3 Ph 575V - 3 Ph 208V - 3 Ph 240V - 3 Ph 480V - 3 Ph 575V - 3 Ph...
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Page 40: Factory Unit Control Settings
Factory Unit Control Settings TABLE 14 - 581038-01 Units With BACnet Module Settings Use the mobile service app to adjust parameters; menu paths are shown in each table. Refer to the Unit Controller RTU Menu > Network Integration > Network Setup Wizard > BACnet MS/TP >... - Page 41 TABLE 16 4-COMPRESSOR STAGED BLOWER Factory Setting Parameter Field Setting Description 302H Note: Any changes to Smoke CFM setting must be adjusted before the other CFM settings. Use SETTINGS > RTU OPTIONS > EDIT PARAMETERS (CFM) 10000 BLOWER CFM DURING SMOKE DETECTION SETUP >...
- Page 42 M = Manual Bypass Unconfigured = U U = Unconfigured Power Exhaust Control [4] [5] Network Module Not Installed = N N = Not Installed Damper Position = A L = LonTalk (Lennox) A34 Pressure Sensor = C FIGURE 34 LHT/LDT302 Page 42...
- Page 43 Phase / Voltage Detection * [5] [6] IAQ Options N = Not Installed N = Not Installed 1 = Enabled Internal (Lennox) 1 = UV Lamp Installed 2 = External (A42) Phase Detection 2 = Bipolar Ionizer Installed on DI-2...
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Page 44: Decommissioning
f) Make sure that cylinder is situated on the scales before Decommissioning recovery takes place. Before carrying out this procedure, it is essential that g) Start the recovery machine and operate in accordance the technician is completely familiar with the equipment with instructions. -
Page 45: Start-Up Report
START-UP REPORT Job Name:___________________________________ Inspections and Checks Store No.___________Start-Up Date:______________ Damage? R454B If yes, reported to:____________________________ Address:_____________________________________ City:______________________________State:______ Verify factory and field-installed accessories. Start-Up Contractor:____________________________ Check electrical connections. Tighten if necessary. Technician:___________________________________ Supply voltage: L1-L2______L1-L3_____L2-L3_____ Model No.:___________________________________ If unit contains a 208-230/240 volt transformer: Serial No.:____________________________________ Check primary transformer tap Transformer secondary voltage: __________...
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