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2018 Lennox Industries Inc.
Corp. 0906-L2
CBX40UHV
Service Literature
Revised August, 2018
INSTALLATION AND SERVICE
PROCEDURE
CBX40UHV (HFC-410A) SERIES UNITS (Communicating)
NOTICE
A thermostat is not included and must be ordered
separately.
D A Lennox communicating thermostat must be used in
communicating applications
(CBX40UHV-XXX-230-6-02 and later).
D In non-communicating applications, the Lennox
ComfortSense
®
7500 thermostat may be used, as well
as other non-communicating thermostats.
In all cases, setup is critical to ensure proper system
operation.
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause personal injury, loss of life, or
damage to property.
Installation and service must be performed by a licensed
professional installer (or equivalent) or a service agency.
CAUTION
Physical contact with metal edges and corners while
applying excessive force or rapid motion can result in
personal injury. Be aware of, and use caution when
working near these areas during installation or while
servicing this equipment.
TABLE OF CONTENTS
Model Number Identification 2.......................
Specifications / Electrical Data 2.....................
Blower Performance 3..............................
Parts Arrangement 3...............................
Application 9......................................
Unit Components 9.................................
Field Wiring 13....................................
Air Handler Control Button, Display and Jumpers 17....
Variable Speed ECM Blower Motor 20................
Optional ECB40 Electric Heat 25.....................
Optional Humidity Control 25........................
Unit Sequence of Operations 33.....................
Unit Status and Alarm Codes 35.....................
Application Configuration Modifications 38.............
Start-Up Operation 41..............................
Operating Characteristics 41........................
Maintenance 42....................................
Configuring Unit Flow Charts 43.....................
Unit Diagram 52...................................
Electric Heat Diagrams and Sequence of
Operations 53.....................................
CBX40UHV series units are designed to be matched with
Lennox two‐stage or single‐stage HFC-410A air conditioner
units and heat pumps. Several models are available in sizes
ranging from 2 through 5 tons. All units are equipped with
factory installed HFC-410A check and expansion valve for
cooling or heat pump applications.
This air handler is compatible with the ComfortSense® 7500
non-communicating thermostat and non-communicating
outdoor units. In addition, this unit has the enhanced
capability of communicating with a communicating
thermostat and compatible outdoor units using the Lennox
RSBus protocols.
Optional ECB40 electric heat is available in several kW
sizes, and can be field installed in the cabinets.
This document provides service information on the
following model builds:
1. Non-communicating version (CBX40UHV-XXX-
230-6-01)
2. Communicating version (CBX40UHV-XXX-
230-6-02) or later.
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