Lennox LHT Series Service Manual

S e r v i c e L i t e r a t u r e
The LHT156, 180and 240 are configure to order units
(CTO) with a wide selection of factory installed options.
Optional electric heat is factory- or field-installed. Electric
heat operates in single or multiple stages depending on
the kW input size. 15kW to 60 kW heat sections are avail-
able for the LHT156 and 180 units and 15 kW to 90 kW
heat sections are available for the LHT240.
Cooling capacities range from 13 to 20 tons. The LHT 156,
180 & 240 utilize two compressors and six condenser fans.
Multi-Stage Air Volume MSAV
The VFD-driven blower will operate at lower speeds when
demand is low and increase to higher speeds when de-
mand is high.
All LHT 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 through Smartwire connectors.
When "plugged in" the controls become an integral part of
the unit wiring.
The CORE Control System is designed to accelerate
equipment install and service. Standard with all Enlight
rooftop units, control system integrates key technologies
that lower installation costs, drive system efficiency, and
protect your investments.
The CORE Unit Controller is a microprocessor-based
controller that provides flexible control of all unit functions.
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.
WARNING
Improper installation,
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
UNIT INFORMATION UNIT INFORMATION
LHT156 through 240
blower option is available.
®
adjustment, alteration,
100084
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.
Options / Accessories . . . . . . . . . . . . . . . . . . . . . Page 2
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 6
Blower Data .. . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
Electrical / Electric Heat Data.. . . . . . . . . . . . . . . Page 10
Unit Parts Arrangement . . . . . . . . . . . . . . . . . . . Page 14
I-Unit Components . . . . . . . . . . . . . . . . . . . . . . . Page 14
II-Placement and Installation . . . . . . . . . . . . . . . Page 29
III-Charging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 29
IV Start Up - Operation . . . . . . . . . . . . . . . . . . . . Page 31
V-System Service Checks . . . . . . . . . . . . . . . . . Page 31
VI-Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . Page 31
VII-Accessories. . . . . . . . . . . . . . . . . . . . . . . . . . Page 32
VIII-Staged Blower
IX-Wiring and Operation Sequence . . . . . . . . . . Page 39
Page 1
LHT SERIES
13 to 20 ton
WARNING

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