Lennox LGT240H - User Manual

2022
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
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.
Table of Contents
Dimensions Page 2.................................
Parts Arrangements Page 5.........................
Shipping and Packing List Page 6....................
General Page 6....................................
Unit Support Page 7................................
Duct Connection Page 8............................
Rigging Unit For Lifting Page 8.......................
Condensate Drains Page 8..........................
Gas Piping Page 9.................................
Pressure Test Gas Piping Page 9.....................
High Altitude Derate Page 10.........................
Download Mobile Service App Page 10.................
Electrical Connections - Power Supply Page 11.........
INSTALLATION
INSTRUCTIONS
LGT/LCT156H
LGT/LCT180H
LGT/LCT210H
LGT/LCT240H
LGT/LCT300S
(13 Ton)
(15 Ton)
(17.5 Ton)
(20 Ton)
(25 Ton)
ROOFTOP PACKAGED UNITS
508288-01
9/2022
Electrical Connections - Control Wiring Page 12.........
Blower Operation and Adjustments Page 13............
Cooling Start-Up Page 20............................
Temperature Thermistor Sensors Page 51..............
Gas Heat Start-Up Page 58...........................
Heating Operation and Adjustments Page 59............
Electric Heat Start-Up Page 59........................
Multi-Staged Air Volume Start-Up Page 60..............
Multi-Staged Air Volume & VAV Operation Page 62......
Hot Gas Reheat Start-Up Page 73.....................
Service Page 77....................................
Unit Controller Parameter Settings Page 82.............
RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE
Use this QR code to download the mobile service app. Follow the prompts
to pair the app with the unit control system and configure the unit. Refer to the
“Download Mobile App” section in this manual and the Setup Guide provided
with this unit. The QR code is also available in the unit control area.
The app can be downloaded from the appropriate iOS or Android store.
Look for the following icon.
Attention!

Lennox LGT240H Specifications

General

SEER	Up to 16
Operating Voltage	208/230V
Phase	1
Refrigerant	R-410A
Cooling Capacity	24000 BTU/h

Summary

Unit Support

Rigging Unit For Lifting

Connect Gas Piping

Pressure Test Gas Piping

Electrical Connections - Power Supply

A-Wiring

Covers routing field wiring in conduit from the bottom power entry.

Electrical Connections - Control Wiring

C-Wire Connections

Unit operation modes based on thermostat or zone sensor settings.

Blower Operation and Adjustments

A-Blower Operation

Three Phase Scroll Compressor Voltage Phasing

LOCATION OF STATIC PRESSURE READINGS

D-Blower Belt Adjustment

Cooling Start-Up

A-Preliminary Checks

Lists crucial checks before initiating unit start-up for safety and functionality.

B-Start-Up

Details the process for initiating cooling demands and compressor operation.

C-R410 A Refrigerant

Information on R410A refrigerant, its properties, and compatibility.

D-Refrigerant Charge and Check - All-Aluminum Coil

E-Charge Confirmation and Fine Tuning - Liquid Temperature Check

Explains how to confirm and fine-tune refrigerant charge using liquid temperature.

F-Compressor Controls

Prognostic Sensors

Gas Heat Start-Up (Gas Units)

FOR YOUR SAFETY READ BEFORE LIGHTING

Emphasizes safety checks and procedures before attempting to light the unit.

A-Placing Unit In Operation

Provides a sequence of steps for safely placing the gas unit into operation.

Gas Valve Operation for Honeywell VR8205 Q; VR8305 Q and White Rodgers 36 H54

Heating Operation and Adjustments (Gas Units)

A-Heating Sequence of Operation

Multi-Staged Air Volume Start-Up

A-Design Specifications

Guides on filling in design specified blower CFM for the unit.

B-Set Maximum CFM

Procedure to adjust blower pulley to achieve desired CFM based on static pressure.

C-Set Blower Speeds

Details using the mobile app to enter and set blower design CFM and speeds.

D-Set Damper Minimum Position

Set Minimum Position 2

E-Inverter Bypass Option

Hot Gas Reheat Start-Up

General

Check-Out

Step-by-step guide to test the hot gas reheat operation using the service app.

Service

C-Burners (Gas Units)

D-Combustion Air Inducer (Gas Units)

F-Evaporator Coil

H-Condenser Coil

Factory Unit Controller Settings

START-UP REPORT

Inspections and Checks

Covers initial checks for damage, voltage, and accessories.

Cooling Checks

Lists checks for compressor rotation, amps, volts, pressures, and fan amps.

Blower Checks

Heating Checks - Electric

Heating Checks - Gas

Checks for gas heat operation, including fuel type, pressure, and manifold pressure.