Lennox CBK45UHET-024 Unit 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.
IMPORTANT
The Clean Air Act of 1990 bans the intentional venting of
refrigerant (CFCs, HCFCs and HFCs) as of July 1, 1992.
Approved methods of recovery, recycling or reclaiming
must be followed. Fines and/or incarceration may be
levied for noncompliance.
NOTICE
A thermostat is not included and must be ordered
separately.
• A Lennox communicating thermostat must be used in
communicating applications.
• In non-communicating applications, the Lennox
ComfortSense® thermostat may be used, as well as
other non-communicating thermostats.
In all cases, setup is critical to ensure proper system
operation.
Field wiring for both communicating and non-
communicating applications is illustrated in diagrams,
which begin on page 29.
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.
UNIT INFORMATION
100110
May 30, 2025
CBK45UHET (R454B) SERIES UNITS
Page 1
Table of Contents
Unit Dimensions – Upflow .............................................6
Unit Dimensions – Horizontal .........................................7
Specifications and Electrical Data ..................................8
Model Number Identification ...........................................9
Blower Data ..................................................................10
Unit Components ..........................................................12
ECB45 Electric Heat ....................................................13
Heat Section Installation ...............................................18
Configuration Modification ...........................................20
Brazing Connections ...................................................22
Installing the Condensate Drain ..................................25
Electrical Connections .................................................27
Inspecting and Replacing Filters .................................28
Wiring Diagrams ...........................................................28
Professional Maintenance ...........................................30
Check-out Procedures .................................................30
Sequence of Operation ................................................31
Constant Torque Speed Blower Motor (ECM) (B3) ....31
Decommissioning ........................................................33
General Information
This indoor unit with all-aluminum coil is designed for
installation with optional field-installed electric heat and
a matched outdoor unit that is charged with R454B re-
frigerant. These units, designed for indoor installation in
multiple positions, are completely assembled for upflow
and horizontal right-hand discharge before being shipped
from the factory.
All CBK45UHET air handlers are equipped with a facto-
ry-installed, internally mounted check / expansion valve,
which is suitable for use in R454B applications.
This air handler is compatible with the ComfortSense®
non-communicating thermostat and any conventional
non-communicating 24VAC thermostat.
NOTE - For downflow or horizontal left-hand air discharge,
certain field modifications are required.
IMPORTANT: Special procedures are required for clean-
ing the all-aluminum coil in this unit. See page 30 in this
instruction for information.
CBK45UHET