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©2024
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
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
INSTALLATION
INSTRUCTIONS
LGT/LCT302H
LGT/LCT360H
GAS AND COOLING PACKAGED UNITS
508634-01
6/2024
4
4
5
5
5
7
8
8
8
9
10
10
10
12
15
18
(25 TON)
(30 TON)
R-454B
23
23
36
38
39
40
41
41
43
46
49
54
55
63
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Summary of Contents for Lennox LGT302H
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Page 1: Table Of Contents
INSTALLATION ©2024 INSTRUCTIONS RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE LGT/LCT302H (25 TON) LGT/LCT360H WARNING (30 TON) Improper installation, adjustment, alteration, ser- GAS AND COOLING PACKAGED UNITS vice, or maintenance can cause property damage, 508634-01 personal injury, or loss of life. Installation and ser- 6/2024 vice must be performed by a licensed professional HVAC installer or equivalent, service agency, or the... - 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 disconnection from power, a means of disconnection...
- 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 that best practices be followed since flammability is a A degree of ventilation shall continue during the period...
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Page 4: End View
LGT/LCT302, 360 Parts Arrangement REHEAT COIL EVAPORATOR CONDENSER FILTERS COIL FANS (6) (TWELVE 20 X 20 X 2”) ECONOMIZER DAMPERS (OPTIONAL) BLOWER MOTOR FILTER DRIERS UNIT CONTROLLER CONDENSER COILS CONDENSATE DRAIN COMPRESSORS (4) BURNERS GAS VALVES COMBUSTION AIR INDUCERS (2) LGT/LCT302, 360 Dimensions - LGT Heat Section Shown... -
Page 5: Shipping And Packing List
• Air filters must be replaced and pre-filters must be Shipping and Packing List removed upon construction completion Package 1 of 1 contains: • The input rate and temperature rise must be set per the unit rating plate 1 - Assembled unit •... - Page 6 Minimum R454B Space and CFM Requirements Minimum Airflow Refrigerant Charge R-454B Unit (CFM) (m³h) Unit (lbs) (kg) LCT/LGT302 LGT/LCT302 Stage 1 6 75 3 06 LCT/LGT360 LGT/LCT302 Stage 2 6 50 2 95 LGT/LCT302 Stage 3 6 69 3 03 ¹...
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Page 7: Unit Support
TABLE 1 UNIT CLEARANCES ¹Unit Clearance A in. (mm) B in. (mm) C in. (mm) D* in. (mm) Top Clearance Service Clearance 60 (1524) 36 (914) 36 (914) 66 (1676) Unobstructed Service Clearance - Units With High Static Exhaust Fans 60 (1524) 36 (914) 80 (2032) -
Page 8: Duct Connection
Recommended minimum frame height is 14 inch (356 mm) RIGGING 4 - Dust must be attached to the roof mounting frame *Weight and not to the unit Supply and return plenums must Unit Lbs. be installed before setting the unit LGT/LCT 302, 360 3585 1626... -
Page 9: Condensate Drain Connection
OUTSIDE OF UNIT GAS PIPING CONDENSATE DRAIN CONNECTION CAULK AROUND VALVE Note - Allow clearance to open CONDENSATE COUPLING sate piping. UNIT GROUND Minimum Pitch JOINT UNION 1” (25 mm) per MANUAL MAIN OPEN VENT SHUT-OFF VALVE 10' (3 m) of line MOUNTING FRAME SUPPLY... -
Page 10: Pressure Test Gas Piping (Gas Units)
Pressure Test Gas Piping (Gas Units) High Altitude Derate When pressure testing gas lines, the gas valve must Locate the high altitude conversion sticker in the unit liter- be disconnected and isolated. Gas valves can be ature bag. Fill out the conversion sticker and affix next to damaged if subjected to more than 0.5 psig (3.5 kPa). - Page 11 7 - Secure side seals to the hood sides as shown in HOOD SIDE VIEW FIGURE 10 8 - Install longer front filter bracket on hood top as shown in FIGURE 7 and FIGURE 9 Insert four filters. 9 - Slide fifth filter into back filter bracket and hold in place at the top of the opening with the shorter front bracket Align holes on hood with bracket holes and secure filter bracket with sheet metal screws.
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Page 12: Electrical Connections
the reliability of all electrical components in the unit Un- Electrical Connections balanced power is a result of the power delivery system POWER SUPPLY supplied by the local utility company A-Wiring Factory-installed inverters are sized to drive blower mo- tors with an equivalent current rating using balanced Route field wiring in conduit between bottom power entry three-phase power When unbalanced three-phase pow- disconnect See FIGURE 11 This does not supersede lo-... - Page 13 Control Panel (NCP) can also be used to provide IMPORTANT - Terminal connections at the wall plate or subbase must be made securely. Loose control wire setpoints A thermostat or return air sensor can be connections may result in intermittent operation. used as a back-up mode Make zone sensor wiring 2 - Zone Sensor Mode - The Unit Controller will connections as shown in FIGURE 13...
- Page 14 Wire runs over 150 feet (45720 mm): 24 VOLT FIELD WIRING Use a local, isolated 24VAC transformer such as Lennox FOR UNITS WITH SUPPLY AIR VFD cat #18M13 (20VA minimum) to supply power to RH sen- sor as shown in FIGURE 16 Use two shielded cables...
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Page 15: Mobile Service App
D-App Menus Mobile Service App See FIGURE 18 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 Verify the app is setup properly for the A-Mobile Device Requirements unit application (including the date and time) Refer to... -
Page 16: Install Menu
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”... -
Page 17: 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 18: 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 19: Blower Assembly
TABLE 5 MINIMUM AND MAXIMUM PULLEY ADJUSTMENT Belt Min. Turns Open Max. Turns Open A Section No minimum B Section *No minimum number of turns open when B belt is used on pulleys 6” O D or larger LOCATION OF STATIC PRESSURE READINGS INSTALLATIONS WITH DUCTWORK INSTALLATIONS WITH CEILING DIFFUSERS ROOFTOP UNIT... -
Page 20: Pulley Alignment
D-Blower Belt Adjustment 2 - Apply perpendicular force to center of span (X) with enough pressure to deflect belt 1/64” for every inch Maximum life and wear can be obtained from belts only if of span length or 1 5mm per 100mm of span length proper pulley alignment and belt tension are maintained Tension new belts after a 24-48 hour period of operation Example: Deflection distance of a 40”... - Page 21 Page 21 508634-01 10/2024...
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Page 22: 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... -
Page 23: Refrigerant Leak Detection System
TABLE 6 MANUFACTURER’S NUMBERS (60 HZ) DRIVE COMPONENTS Drive ADJUSTABLE SHEAVE FIXED SHEAVE BELTS SPLIT BUSHING Supplier No. OEM Part No. Supplier No. OEM Part No. Supplier No. OEM Part No. Supplier No. OEM Part No. 1VP71x1-3/8 100239-06 BK140H 100788-13 BX78 100245-44 H - 1-3/16... - Page 24 3 - Units contain four refrigerant circuits or systems 4 - Each refrigerant circuit is separately charged with Evaporator and condenser coil refrigerant circuits R-454B refrigerant See unit rating plate for correct 1 and 2 make up stage 1 cooling Evaporator and amount of charge condenser refrigerant circuits 3 and 4 make up 5 - Refer to Cooling Operation and Adjustment section...
- Page 25 C-Refrigerant Charge and Check Refrigerant Charge R-454B WARNING - Do not exceed nameplate charge under Unit (lbs) (kg) any condition. LGT/LCT302 Stage 1 6 75 3 06 This unit is factory charged and should require no further LGT/LCT302 Stage 2 6 50 2 95 adjustment If the system requires additional refrigerant,...
- Page 26 • The recovered refrigerant shall be returned to the refrigerant supplier in the correct recovery cylinder, and the relevant waste transfer note arranged Do not mix refrigerants in recovery units and especially • If compressors or compressor oils are to be removed, ensure that they have been evacuated to an acceptable level to make certain that flamma- ble refrigerant does not remain within the lubricant...
- Page 27 TABLE 7 LGT/LCT302H Normal Operating Pressures Outdoor Coil Entering Air Temperature 65°F 75°F 85°F 95°F 105°F 115°F Suct Disc Suct Disc Suct Disc Suct Disc Suct Disc Suct Disc (psig) (Psig) (psig) (Psig) (psig) (Psig) (psig) (Psig) (psig) (Psig) (psig) (Psig) Circuit 1 Circuit 2...
- Page 28 Circuit 2 - 302 Reheat & No Reheat Outdoor Temperature (°F) Suction Pressure (psig) Circuit 3 - 302 Reheat & No Reheat Outdoor Temperature (°F) Suction Pressure (psig) LGT/LCT302H, 360H Page 28...
- Page 29 Circuit 4 - 302 Reheat & No Reheat Outdoor Temperature (°F) Suction Pressure (psig) TABLE 8 LGT/LCT360H No Reheat Normal Operating Pressures Outdoor Coil Entering Air Temperature 65°F 75°F 85°F 95°F 105°F 115°F Suct Disc Suct Disc Suct Disc Suct Disc Suct Disc...
- Page 30 Circuit 1 - Enlight 30T Outdoor Temperature (°F) Suction Pressure (psig) Circuit 2 - 360 - No Reheat Outdoor Temperature (°F) Suction Pressure (psig) LGT/LCT302H, 360H Page 30...
- Page 31 Circuit 3 - 360 - No Reheat Outdoor Temperature (°F) Suction Pressure (psig) Circuit 4 - 360 - No Reheat Outdoor Temperature (°F) Suction Pressure (psig) Page 31 508634-01 10/2024...
- Page 32 TABLE 9 LGT/LCT360H Reheat Normal Operating Pressures Outdoor Coil Entering Air Temperature 65°F 75°F 85°F 95°F 105°F 115°F Suct Disc Suct Disc Suct Disc Suct Disc Suct Disc Suct Disc (psig) (Psig) (psig) (Psig) (psig) (Psig) (psig) (Psig) (psig) (Psig) (psig) (Psig) Circuit 1...
- Page 33 Circuit 2 - 360 - Reheat (OD Temp °F) Suction Press. (psig) Circuit 3 - 360 - Reheat OD Temp (°F) Suction Press. (psig) Page 33 508634-01 10/2024...
- Page 34 Circuit 4 - 360 - Reheat OD Temp (°F) Suction Press. (psig) LGT/LCT302H, 360H Page 34...
- Page 35 D-Compressor Controls CONDENSER FAN CYCLING See unit wiring diagram to determine which controls are used on each unit 1 - High Pressure Switch (S4, S7, S28, S96) - The COND. EVAP COIL COND. FAN 1 compressor circuit is protected by a high pressure FAN 4 K150 switch which opens at 610 psig + 15 psig (4206 kPa...
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Page 36: Diagnostic Sensors
Diagnostic Sensors TABLE 10 THERMISTOR LOCATION Units are equipped with two factory-installed thermistors (RT46 and RT48) located on different points on the Unit Sensor Figure refrigerant circuit Indoor Coil RT46, 47, 50, 51 FIGURE 31 The thermistors provide the Unit Controller with constant Outdoor Coil RT48, 49, 52, 53 FIGURE 32... - Page 37 LGT/LCT302, 360 CONDENSER COIL RT48, 49, 52, 53 (Rear View) 23V50 23V50 BLUE GREEN RT49 RT53 SEE DETAIL I SEE DETAIL F 23V50 23V50 YELLOW RT48 RT52 SEE DETAIL H SEE DETAIL G DETAILS NOT TO SCALE FIGURE 32 Page 37 508634-01 10/2024...
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Page 38: Rds Sensors
RDS Sensors TABLE 11 RDS Sensor Figures Units are equipped with factory-installed RDS Sensors located on different points on the unit. The RDS sensors Model Qty. Type Figure provide the Unit Controller with continuous readings for LGT/LCT302-360 2 sensors INDOOR SENSOR FIGURE 33 leaked refrigerant concentration levels and sensor health COMPRESSOR... -
Page 39: Gas Heat Start-Up (Gas Units)
LGT/LCT 302-360 COMPRESSOR RDS SENSOR FIGURE 34 WARNING Gas Heat Start-Up (Gas Units) FOR YOUR SAFETY, READ BEFORE LIGHTING Electric shock hazard. Can cause injury BEFORE LIGHTING smell all around the appliance area or death. Do not use this unit if any part for gas. -
Page 40: Heating Operation And Adjustments
10 - Set thermostat to desired setting WARNING 11 - The ignition sequence will start Electric shock hazard. Can cause injury 12 - If the appliance does not light the first time (gas or death. Before attempting to perform line not fully purged), it will attempt up to two more any service or maintenance, turn the ignitions before locking out electrical power to unit OFF at disconnect... -
Page 41: Electric Heat Start-Up (Lch Units)
Electric Heat Start-Up (LCH Units) LIMIT LOCATION Factory or Field-Installed Option DRIP Electric heat will stage on and cycle with thermostat de- SHIELD mand Number of stages of electric heat will vary depend- ing on electric heat assembly See electric heat wiring dia- gram on unit for sequence of operation Variable Air Volume Start-Up Units may contain an optional supply air blower equipped... - Page 42 D-Set Damper Minimum Position PRESSURE TRANSDUCER WIRING To maintain required minimum ventilation air volumes when the unit is in the occupied mode, two minimum damper positions must be set The Unit Controller will open the damper to “Min OCP Blwr High” when blower CFM is at or ABOVE the “midpoint”...
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Page 43: Multi-Staged Air Volume Start-Up
TABLE 15 HEATING, VENTILATION, & SMOKE MINIMUM AND MAXIMUM CFM Heating CFM Vent CFM Smoke CFM Model Speed Heat Code Default Min. Max. Default Min. Max. Default Min. Max. Medium S, M 5925 LGT302H5M 10500 12000 10500 3750 12000 10500 3750 12000 High... -
Page 44: Press Save
C-Set Blower Speeds TABLE 17 1 - Use the following menu to enter the blower design CFM DESIGN SPECIFICATIONS - specified CFM into the Unit Controller. Make sure 300 & 360 UNITS WITH STAGED BLOWER blower CFM is within limitations shown in TABLE No. - Page 45 TABLE 18 MINIMUM AND MAXIMUM CFM - 302 & 360 UNITS WITH STAGED BLOWERS Unit Gas Heat Size Airflow CFM Gas Heat Minimum CFM LGT302 Std , Med 5950 LGT302 High 7125 LGT360 Std , Med 5950 LGT360 High 7125 Electric Heat Minimum CFM Unit Heat Size (kW)
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Page 46: Hot Gas Reheat Start-Up And Operation
Reheat will terminate when the indoor relative humidity Hot Gas Reheat Start-Up and Operation falls 3% (57% default) or the digital output de-energizes General The reheat deadband can be adjusted at Settings - Con- trol menu Hot gas reheat units provide a dehumidifying mode of op- eration These units contain a reheat coil adjacent to and A91 Humidity Sensor downstream of the evaporator coil Reheat coil solenoid... - Page 47 COOLING MODE REFRIGERANT ROUTING 300, 360H4M EVAPORATOR COIL MIXED INDOOR/OUTDOOR “NEUTRAL” DEHUMIDIFIED REHEAT COIL CONDENSER COIL REHEAT COIL OUTDOOR REFRIGERANT CIRCUIT 1 REFRIGERANT CIRCUIT 2 REFRIGERANT CIRCUIT 3 REFRIGERANT CIRCUIT 4 REHEAT VALVE CHECK VALVE THERMAL EXPANSION VALVES FIGURE 40 Check-Out For other reheat control options, refer to the Unit Control- ler manual...
- Page 48 TABLE 20 REHEAT OPERATION Two-Stage Thermostat - Default Operation T’stat and Humidity Demands 300, 360 (4-Compressors) Reheat Only Compressor 1 & 2 Reheat Compressor 1 & 2 Reheat Reheat & Y1 Compressor 3 Cooling¹ Reheat & Y1 & Y2 Compressor 1, 2, 3, & 4 Cooling³ Three-Stage Thermostat (Transfer relay required) Operation T’stat and Humidity Demands...
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Page 49: Optional Economizer Settings
SETUP → TEST & BALANCE → DAMPER → MIN Optional Economizer Settings DAMPER POSITION BLOWER ON LOW = % A-Control Settings C-Economizer Operation The economizer, when configured, controls: NOTE - Use indicating lights on Unit Controller to deter- • Damper position, which determines how much out- mine thermostat demand. - Page 50 TABLE 22 MENU INTERFACE (LEVEL 1 - SETTINGS) - T (TEMPERATURE ECONOMIZER) Use the ADJUST and SET VALUES arrows Level 2 Level 3 Level 4 Level 5 to scroll up or down for selection of options. ECONOMIZER TEMP ECON TYPE = TEMPERATURE OFFSET OR TEMPERATURE SETPOINT ECONOMIZER OAT SETPOINT = XX X F FREE COOLING...
- Page 51 TABLE 24 DEMAND CONTROL VENTILATION PARAMETERS Control Parameter Control Value Units Description Parameter Short Screen Name Min. Default Max. Description Demand Control Maximum allowed demand control DCV MAX DAMPER OPEN Ventilation Maximum ventilation damper open position Damper Open • Damper “start open” CO2 set point for Demand Control Demand Control Ventilation DCV DAMP START OPEN...
- Page 52 538072-01 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,SC,SG Series ACCS ACCS Economizer & Motorized OAD WIRING DIAGRAM FLOW Voltage: All Voltages 538072-01 Supersedes: N/A Form No: Rev: 2 REV EC NO.
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Page 53: Mechanical Cooling
TABLE 25 ECONOMIZER OPERATION - Standard Two-Stage Thermostat (Default Option) THERMOSTAT DEMAND DAMPER POSITION UNOCC. DAMPER POSITION OCCUPIED MECHANICAL COOLING OUTDOOR AIR IS NOT SUITABLE FOR FREE COOLING CLOSED CLOSED CLOSED MINIMUM CLOSED MINIMUM STAGE 1 CLOSED MINIMUM STAGES 1 AND 2 OUTDOOR AIR IS SUITABLE FOR FREE COOLING CLOSED CLOSED... -
Page 54: Optional Outdoor Air Cfm Control
Optional Outdoor Air CFM Control VELOCITY SENSOR LOCATION Outdoor Air CFM Control is a factory-installed option avail- able on units equipped with a supply air variable frequen- cy drive (VFD) and economizer SENSOR The Unit Controller modulates outdoor air dampers to maintain a constant amount of outdoor air regardless of blower speed This ensures minimum ventilation require- ments are met at lower supply air speeds... -
Page 55: Preventative Maintenance / Repair
– the ventilation machinery and outlets are operating Preventative Maintenance / Repair adequately and are not obstructed; IMPORTANT MAINTENANCE / REPAIR SAFETY – if an indirect refrigerating circuit is being used, the INSTRUCTIONS secondary circuit shall be checked for the presence of Prior beginning work... - Page 56 Clean burners as follows: REMOVE FILTERS 1 - Turn off both electrical power and gas supply to unit. 2 - Open burner compartment access panel 3 - Remove screws securing burner assembly to burner support and remove assembly See FIGURE 44 Clean as necessary SEMBLY PULL TO...
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Page 57: Top View
7 - Replace access panel WARNING 8 - Restore electrical power and gas supply Follow Danger of explosion. Can cause injury or lighting instructions attached to unit and use product or property damage. Do not use inspection port in access panel to check flame. matches, candles, flame or other sources D-Combustion Air Inducer (Gas Units) of ignition to check for leaks. - Page 58 5 - Return combustion air inducer motor and vent M-Replacement Fuses connector to original location and secure with See the following tables for the proper replacement fuse sizes retained screws It is recommended that the combustion air inducer gasket be replaced during ELECTRIC HEAT REPLACEMENT FUSES reassembly Rating...
- Page 59 TABLE 29 LGT MODELS FUSE TABLE Unit Voltage 208/230V - 3 Ph 460V - 3Ph 575V - 3Ph Power Exhaust Option W / P.E. W / O P.E. W / P.E. W / O P.E. W / P.E. W / O P.E. Diagram Class Model...
- Page 60 TABLE 30 LCT MODELS FUSE TABLE Electric Heat Size 0 KW 30 KW 208/230V - 460V - 3 575V - 3 Unit Voltage 575V - 3 Ph 208V - 3 Ph 240V - 3 Ph 460V - 3 Ph 3 Ph W / O W / O W / O...
- Page 61 TABLE 31 LCT MODELS FUSE TABLE (CONTINUED) Electric Heat Size 45 KW 60 KW 208V - 3 240V - 3 460V - 3 575V - 3 208V - 3 240V - 3 460V - 3 575V - 3 Unit Voltage Power Exhaust Option P.E.
- Page 62 TABLE 32 LCT MODELS FUSE TABLE (CONTINUED) Electric Heat Size 90 KW 120 KW 208V - 3 240V - 3 460V - 3 575V - 3 208V - 3 240V - 3 460V - 3 575V - 3 Unit Voltage Power Exhaust Option P.E.
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Page 63: Decommissioning
g) Start the recovery machine and operate in accordance Decommissioning with instructions Before carrying out this procedure, it is essential that h) Do not overfill cylinders (no more than 80% volume the technician is completely familiar with the equipment liquid charge) and all its detail It is recommended good practice that all i) Do not exceed the maximum working pressure of the refrigerants are recovered safely... -
Page 64: 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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