Transformer; Plastic Drain Pans; Discharge Sensor; Variable Speed Blower Motor - Lennox CBX32MV-018/024 Manual

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 16.
Table 16. Links
Application
Harmony IIIt
Heat Pump
Two-Stage Cooling
A-TRANSFORMER (T1)
All CBX32MV 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.
208 / 240 VOLT TRANSFORMER
PRIMARY
ORANGE
240 VOLTS
RED
208 VOLTS
BLACK
Figure 27 Transformer
B-PLASTIC DRAIN PANS
Both up-flow/down-flow and horizontal drain pans are
provided and installed on the CBX32MV 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.
C-COIL
All CBX32MV 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.
Remove Links
DS to R
R to O
Y1 to Y2
SECONDARY
BLUE
YELLOW
D-AIR HANDLER CONTROL (AHC)
The Air Handler Control manages electric heat, indoor
blower and accessory controls. The Air Handler Control
also provides system
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 26,
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).
J-VARIABLE SPEED BLOWER MOTOR (ECM) (B3)
To Remove Blower From Unit: Remove wiring jack plug and
three screws and slide blower out.
Figure 28. Blower Motor (B3)
During blower operation, the ECM motor emits ener­
gy that may interfere with pacemaker operation. In­
terference is reduced by both the sheet metal cabinet
and distance.
The ECM (electronically commutated motor) communicates
with the air handler control via a 2-way serial connection. The
motor receives all necessary functional parameters from the
air handler control and does not rely on a factory program like
traditional variable speed motors. The wiring harness
connects the motor to the air handler control. See wiring
diagram regarding wiring harness. A solid‐state controller
is permanently attached to the motor. The controller is
Page 61
configuration and
Blower Motor (B3)
WARNING
air-flow
CBX32MV