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I−APPLICATION
CBX40UHV air handlers are designed for HFC−410A
applications only. All major air handler components
must
be
matched
recommendations for the unit to be covered under
warranty. Refer to the Engineering Handbook for approved
system matchups. A misapplied system will cause erratic
operation and can result in early unit failure. The units come
with factory installed check and expansion valve for all
applications. It has been installed internally and is accessible if
required.
ELECTROSTATIC DISCHARGE (ESD)
PRECAUTIONS AND PROCEDURES
CAUTION
Electrostatic discharge can affect electronic compo-
nents. Take precautions during unit installation and
service to protect the unit's electronic controls. Pre-
cautions will help to avoid control exposure to electro-
static discharge by putting the unit, the control and the
technician at the same electrostatic potential.
Neutralize electrostatic charge by touching hand and
all tools on an unpainted unit surface before perform-
ing any service procedure.
II−UNIT COMPONENTS
A−CONTROL BOX
The CBX40UHV control box is shown in figure 2. Line
voltage and electric heat connections are made in the
control box. Optional electric heat fits through an opening
located in the center of the control box. When electric heat
is not used, knockout plates cover the opening. The electric
heat control arrangement is detailed in the electric heat section
of this manual.
Low voltage connections are made on the air handler
control (AHC) also located in the control box. All AHC will
have factory installed clippable links connecting DS to R, R
to O and Y1 to Y2. These links will have to be removed in
certain unit application. See table 1.
Table 1. Links
Application
Harmony IIIt, Comfort-
®
Sense
7000 Thermostat
Heat Pump
Two−Stage Cooling
B−TRANSFORMER (T1)
All CBX40UHV series units use a single line voltage to
24VAC transformer mounted in the control box. The
transformer supplies power to the control circuits in the
indoor and outdoor unit. Transformers are rated at 70VA.
208/240VAC single-phase transformers use two primary
voltage taps.
CBX40UHV
according
to
Lennox
Remove Links
DS to R
R to O
Y1 to Y2
208 / 240 VOLT TRANSFORMER
PRIMARY
ORANGE
240 VOLTS
RED
208 VOLTS
BLACK
C−PLASTIC DRAIN PANS
Both up−flow/down−flow and horizontal drain pans are
provided and installed on the CBX40UHV units. The drain
pans are made from fiberglass-filled plastic. The drain hole
is used for right-hand air discharge only, and must be
plugged when the unit is configured for left-hand air
discharge. Each pan has a set of connections, one for a
primary drain and one for an auxiliary drain.
D−COIL
All CBX40UHV series units have dual slab coils arranged in
an "A" configuration. Each coil has two or three rows of
copper tubes fitted with ripple-edge aluminum fins. A check
and expansion valve complete with inlet screen feeds
multiple parallel circuits through the coils. The coil is
designed to easily slide out of the unit cabinet.
E−AIR HANDLER CONTROL (AHC)
The Air Handler Control manages electric heat, indoor
blower and accessory controls. The Air Handler Control
also
provides
adjustments plus diagnostic capabilities.
F−DISCHARGE SENSOR (DAT)
The Air Handler Control has two screw terminals marked
Discharge Air Sensor. The sensor is REQUIRED for
®
EvenHeater
operation and is field mounted and ordered
separately, use Lennox Catalog # 88K38.
In the EvenHeater mode, the discharge air sensor cycles
the electric heating elements as needed to maintain the Air
Handler control EvenHeater jumper selected discharge
setpoint.
The discharge air sensor should be mounted downstream
of the electric heat elements as illustrated in Figure 4, Detail
A. It must be placed in a location with unobstructed airflow,
where other accessories (such as humidifiers, UV lights,
etc.) will not interfere with its accuracy.
Wiring distance between the Air Handler Control and the
discharge air sensor should not exceed 10' (3m) when
wired with 18−gauge thermostat wire.
G−OUTDOOR AIR SENSOR
These terminals are for FUTURE USE. (DO NOT USE).
Page 9
SECONDARY
BLUE
YELLOW
Figure 3 Transformer
system
configuration
and
air−flow
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