EasyManua.ls Logo

Lennox LGT120H4P User Manual

Lennox LGT120H4P
61 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
Page #1 background imageLoading...
Page #1 background image
Page 1
UNIT INFORMATIONUNIT INFORMATION
Service Literature
WARNING
Improper installation, adjustment, alteration,
service or maintenance can cause property damage,
personal injury or loss of life. Installation and service
must be performed by a licensed professional HVAC
installer or equivalent, service agency, or the gas
supplier
CAUTION
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.
Table of Contents
Options / Accessories . . . . . . . . . . . . . . . . . . . . . Page 2

Blower Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . Page 11
Parts Arrangement . . . . . . . . . . . . . . . . . . . . . . . Page 13
I-Unit Components . . . . . . . . . . . . . . . . . . . . . . . Page 14
II-Placement and Installation . . . . . . . . . . . . . . . Page 29
III-Charging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 29
IV-Start Up - Operation . . . . . . . . . . . . . . . . . . . . Page 34
V-System Service Checks . . . . . . . . . . . . . . . . Page 36
VI-Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 39
VII-Accessories . . . . . . . . . . . . . . . . . . . . . . . Page 39
VIII-Direct Drive Supply Air Blower . . . . . . . . . . Page 49


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 performing maintenance.
3- Always keep hands, hair, clothing, jewelry, tools,
etc., away from moving parts.
       
(CTO) with a wide selection of factory-installed options.

         
sections are designed with aluminized steel tube heat ex-
changers with stainless steel as an option.

are equipped with two compressors.
All models are equipped with direct drive blowers. The
blower will operate at lower speeds when demand is low
and increase to higher speeds when demand is high. The
following examples show the model numbers of tenton
units with all available blower options:

LGT12w are equipped with all aluminum condenser
coils with one two stage scroll compressor and one


        
nameplate. Operating pressures and pressure switch set-
-

󰀨-
ent energy management thermostat control systems with
-
tions connect to the unit with jack plugs. When ”plugged
in” the controls become an integral part of the unit wiring.
Information contained in this manual is intended for use

subject to change. Procedures outlined in this manual are
presented as a recommendation only and do not super-
sede or replace local or state codes.

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.
LGT SERIES
7.5 to 12.5 ton

LGT092H through 150H
Question and Answer IconNeed help?

Do you have a question about the Lennox LGT120H4P and is the answer not in the manual?

Lennox LGT120H4P Specifications

General IconGeneral
BrandLennox
ModelLGT120H4P
CategoryAir Handlers
LanguageEnglish

Summary

UNIT INFORMATION

WARNING

Critical safety warnings regarding potential hazards during operation or maintenance.

SPECIFICATIONS

Cooling Performance

Key performance metrics related to the cooling capabilities of the unit.

Refrigerant Charge

Information on the type and quantity of refrigerant used in the unit.

Electrical characteristics

Electrical requirements and characteristics for unit operation.

BLOWER DATA

ELECTRICAL DATA

7.5 ΤΟΝ

Electrical data specific to the 7.5 Ton models.

8.5 ΤΟΝ

Electrical data specific to the 8.5 Ton models.

10 ΤΟΝ

Electrical data specific to the 10 Ton models.

12.5 ΤΟΝ

Electrical data specific to the 12.5 Ton models.

I-UNIT COMPONENTS

WARNING (Electrical Shock)

Critical safety warning about electrical hazards.

CAUTION (ESD)

Precautions for handling electronic components to prevent static discharge damage.

A-Control Box Components

Identification and function of components within the control box.

PLUMBING, COMPRESSOR AND REFRIGERANT CIRCUITS DETAIL

FIGURE 6

Detailed diagram of refrigerant circuits, compressors, and coils.

B-Cooling Components

Overview of the components involved in the cooling process.

1-Compressors B1, B2

Information on the unit's scroll compressors and their configuration.

WARNING (Electrical Shock Hazard)

Critical safety warning regarding compressor electrical hazards.

2-Crankcase Heaters HR1, HR2

Details on crankcase heaters for compressor protection.

3-High Pressure Switches S4, S7

Description of high pressure switches for compressor protection.

5-Low Pressure Switches S87, S88

Description of low pressure switches for compressor protection.

C-Blower Compartment

IMPORTANT (Compressor Two)

Important note regarding compressor two phasing check.

A-Blower Operation

Instructions for operating the blower assembly.

WARNING (Unit Installation)

Safety precautions related to unit installation and wiring.

B-Blower Access

Procedure for accessing and servicing the blower assembly.

D-GAS HEAT COMPONENTS

1-Control Box Components A3, A55, T3, K13

Identification of control box components for gas heat.

WARNING (Shock Hazard)

Safety warning regarding high voltage in spark-related components.

Burner Ignition Control A3

Description of the burner ignition control module.

2-Heat Exchanger (Figure 14)

Description and diagram of the heat exchanger assembly.

4-Burner Box Assembly (Figure 16)

Description and diagram of the burner box assembly.

5-Primary High Temperature Limits S10

Description of the primary high temperature limit switch.

6-Flame Roll-out Limit S47

Description of the flame roll-out limit switch.

7-Combustion Air Prove Switch S18

Description of the combustion air prove switch.

8-Combustion Air Inducer B6

Details on the combustion air inducer motor.

10-Gas Valves GV1

Description of the two-stage redundant gas valve.

11-Spark Electrodes

Information on spark electrode assembly and gap setting.

12-Flame Sensors

Description of flame sensor operation and mounting.

III-CHARGING

A-Refrigerant Charge and Check

Procedure for checking and adjusting refrigerant charge.

WARNING (Do not exceed nameplate charge)

Safety warning against exceeding the unit's nameplate refrigerant charge.

IMPORTANT (Charge unit in standard cooling mode)

Important note on charging the unit in standard cooling mode.

IV-START-UP - OPERATION

A-Preliminary and Seasonal Checks

Checks to perform before unit start-up and during seasonal changeovers.

B-Cooling Start-up See figure 23

Procedure for starting the unit in cooling mode.

C-Heating Start-up

Procedure for starting the unit in heating mode.

WARNING (Danger of explosion)

Safety warning regarding potential explosion hazards.

IMPORTANT (Units equipped with a Hot Gas Reheat system)

Important note for units with Hot Gas Reheat system.

Placing Furnace In Operation

Step-by-step guide for placing the furnace into operation.

V-SYSTEMS SERVICE CHECKS

A-Heating System Service Checks

Procedures for servicing the heating system.

1-Gas Piping

Guidelines for gas piping installation and pressure.

2-Testing Gas Piping

Procedure for testing the gas piping system for leaks.

3-Testing Gas Supply Pressure

Procedure for testing the gas supply pressure.

4-Check and Adjust Manifold Pressure

Procedure for checking and adjusting manifold pressure.

CAUTION (For safety, connect a shut-off valve)

Safety caution for connecting a shut-off valve to the manometer.

Manifold Adjustment Procedure

Step-by-step guide for adjusting manifold pressure.

5-Proper Gas Flow

Procedure for checking proper gas flow to the burners.

VI-MAINTENANCE

WARNING (Electric shock hazard)

Safety warning regarding electrical shock during maintenance.

R- UVC Light

WARNING (Personal Burn Hazard)

Safety warning regarding personal burn hazard from hot lamps.

DANGER (UVC Radiation hazard)

Hazard warning regarding UVC radiation exposure.

VIII-Direct Drive Supply Air Inverter

IX-Staged Supply Air Operation

X-Wiring Diagrams and Sequence of Operation

GAS HEAT SEQUENCE OF OPERATION LGT092H-150H

Step-by-step sequence of operation for gas heat.

ECONOMIZER

WARNING (DISCONNECT ALL POWER)

Safety warning to disconnect all power before servicing the economizer.

Cooling Diagram with Higher SCCR

WARNING (ELECTRIC SHOCK HAZARD)

Safety warning regarding electric shock hazards.

LGT092H-150H SEQUENCE OF OPERATION

DIRECT DRIVE BLOWER SEQUENCE OF OPERATION / TROUBLESHOOTING

Related product manuals