Lennox LGH102H4B - User Manual

Corp. 1008-L2
LGH SERIES
Service Literature
7.5 to 12.5 ton
38.1 to 70.3 kW
Revised 5/2015
LGH092H through 152U
The LGH092H, 094U, 102H, 120H, 122U, 150S and
152U units are configure to order units (CTO) with a wide
selection of factory-installed options. Units are avail
able in 130,000, 180,000 Btuh or 240,000 Btuh (38.1,
52.7 or 70.3 kW) heating inputs. Gas heat sections are
designed with Lennox' aluminized steel tube heat ex
changers with stainless steel as an option.
Cooling capacities range from 7.5 to 12.5 tons (38.1 to
70.3 kW). All units are equipped with two compressors.
Ultra-high efficiency units are available with an optional di
rect drive blower or belt drive blower equipped with a sup
ply air inverter. Standard and high efficiency units are
available with a belt drive blower equipped with an option
al supply air inverter. 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 ten-
ton units with all available blower options:
LGH120H4B High Efficiency Belt Drive
LGH120H4M High Efficiency Belt Drive with Inverter
LGH122U4M Ultra High Efficiency Belt Drive with Inverter
LGH122U4E Ultra High Efficiency Direct Drive
Note - Ten-ton units are available in high and ultra high effi
ciencies only.
Standard and high efficiency units come standard with a
lightweight, all-aluminum condenser coil; optional, fin/
tube condenser coils are available. Ultra-high efficiency
units come standard with a tube/fin condenser coil.
Ultra high efficiency units come standard with two single-
speed compressors plumbed in tandem to form a single re
frigerant circuit.
Units are also designed for R410A refrigerant. See unit
nameplate. Operating pressures and pressure switch set
tings are significantly higher than R22 charged units. Ser
vice equipment must be rated for R410A.
Standard and high efficiency units offer mechanical cooling
down to 0°F when properly equipped. Ultra-high efficiency
units offer mechanical cooling down to 40°F.
All LGH units are designed to accept any of several differ
ent energy management thermostat control systems with
minimum field wiring. Factory or field provided control op
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 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 super
sede 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.
3
3
Table of Contents
Options / Accessories Page 2.....................
Specifications Page 8............................
Blower Tables Page 14............................
Electrical Data Page 19...........................
Parts Arrangement Page 25.......................
I-Unit Components Page 28.......................
II-Placement and Installation Page 47...............
III-Charging Page 47..............................
IV-Start Up - Operation Page 55....................
V-System Service Checks Page 57................
High Altitude Page 59.........................
VI-Maintenance Page 59..........................
VII-Accessories Page 60..........................
VIII-Belt Drive Supply Air Inverter Page 67...........
IX-Direct Drive Supply Air Blower Page 70...........
X-Staged Supply Air Operation Page 71.............
XI-Wiring and Operation Sequence Page 72.........
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property va, personal in
jury 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 in
jury. Take care while handling this equipment and
wear gloves and protective clothing.
© 2015

Summary

Gas Heat Specifications and Derate

Gas Heat Specs for 092 H-150 S

Gas heat input, output, and efficiency for LGH092H-150S.

ELECTRICAL DATA

Direct Drive Electrical Data (7.5 and 10 Ton)

Electrical data for direct drive 7.5 and 10 ton LGH models.

Direct Drive Electrical Data (12.5 Ton)

Electrical data for direct drive 12.5 ton LGH models.

UNIT COMPONENTS

Compressor, VFD, and Relay Components

COOLING COMPONENTS

Compressors, Heaters, and High Pressure Switches

BELT TENSION CHECK AND FIELD DRIVES

GAS HEAT COMPONENTS

Control Box Components and Burner Ignition Control

Heat Exchanger, Inserts, and Burner Assembly Details

Safety Limits, Air Prove Switch, and Gas Valves

REFRIGERANT CHARGE AND CHECK

All-Aluminum Coil Refrigerant Charge

Procedure for charging and checking refrigerant in all-aluminum coils.

Fin;Tube Coil Refrigerant Charge (TXV)

Procedure for charging and checking refrigerant in fin/tube coils with TXV.

Fin;Tube Coil Refrigerant Charge (RFC)

Procedure for charging and checking refrigerant in fin/tube coils with RFC.

Fin;Tube Coil & TXV Refrigerant Charge for 094;122;152 Units

Refrigerant charge check for 094, 122, 152 units using fin/tube coils and TXV.

START-UP AND OPERATION

Preliminary Checks and Cooling Start-Up

Heating Start-Up Procedures

Steps for starting the unit in heating mode, including safety.

SYSTEM SERVICE CHECKS

Heating System Checks

Procedures for checking gas piping, pressure, and manifold settings.

Gas Flow, Burner, Electrode, and Heat Exchanger Checks

Cooling System Checks

Checks for filters, lubrication, blower wheel, and coils.

ECONOMIZER OPERATION

Economizer System and Control Modes

FACTORY HOT GAS REHEAT OPERATION

SUPPLY AIR INVERTER AND BLOWER CONTROL

VFD Inputs and Operation;Adjustment

Required inputs for VFD staging and inverter operation/adjustment.

DIRECT DRIVE SUPPLY AIR INVERTER

Setting Blower Speed and Damper Position

STAGED SUPPLY AIR OPERATION

WIRING DIAGRAMS AND SEQUENCES

LGH092;150 S & H Operation Sequence

Step-by-step sequence for unit operation in cooling and heating.

GAS HEAT OPERATION AND TROUBLESHOOTING

Gas Heat Sequence of Operation

Detailed sequence for gas heat operation, including stages and lockout.

THERMOSTAT WIRING AND ACCESSORIES

SUPPLY AIR INVERTER SEQUENCE OF OPERATION

No Bypass Sequence

Sequence of operation for direct drive blowers without bypass.

Bypass Sequence and Fault Handling

Sequence of operation with bypass and fault handling procedures.

DIRECT DRIVE BLOWER OPERATION;TROUBLESHOOTING

Blower Fault Sequences and Troubleshooting

Troubleshooting steps for direct drive blower faults and failures.

DIRECT DRIVE BLOWER MOTOR TROUBLESHOOTING

Lennox LGH102H4B Specifications

General

Brand	Lennox
Model	LGH102H4B
Category	Air Handlers
Language	English