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6-Filter Drier (all units)
Units have a filter drier located in the liquid line of each refrig
erant circuit at the exit of each condenser coil. The drier re
moves contaminants and moisture from the system.
7-Condenser Fans B4, B5, B21, B22 (all units)
B23, B24 (210, 240, 300)
See SPECIFICATIONS tables at the front of this manual
for specifications of condenser fans used in all units. All
condenser fans used have single-phase motors. The fan
assembly may be removed for servicing and cleaning.
8-High Temperature Sensor S5
S5 is a high temperature sensor installed in variable speed
compressor B1 only. The sensor is wired in series with high
pressure switch S4. When opened due to high temperature
the compressor is de-energized.
9-Temperature Thermistor RT42/57
Temperature thermistors are located on specific points for
each refrigeration circuit. Temperature thermistors provide
continuous temperature input to the unit controller for prop
er cooling operation as well as system protection. Con
troller logic will de-energize compressors for each refriger
ation circuit when evaporator coil temperature falls below
32°F (0°C) to prevent evaporator freeze-up
C-Blower Compartment
The blower compartment is located between the evapora
tor coil and the compressor / control section on the opposite
side of the condenser coil. The blower assembly is ac
cessed by disconnecting the blower motor wiring (and all
other plugs) and removing the screws on either side of the
sliding base. The base pulls out as shown in figure 9.
1-Blower Wheels
All units have two 15 in. x 15 in. (381 mm x 381 mm) blower
wheels. Both wheels are driven by one motor.
2-Indoor Blower Motor B3
All units use three‐phase single‐speed blower motors.
CFM adjustments are made by adjusting the motor pulley
(sheave). Motors are equipped with sealed ball bearings.
All motor specifications are listed in the SPECIFICA
TIONS (table of contents) in the front of this manual. Units
may be equipped with motors manufactured by various
manufacturers, therefore electrical FLA and LRA specifi
cations will vary. See unit rating plate for information spe
cific to your unit.
OPERATION / ADJUSTMENT
Supply Air Staged Units - The blower rotation will always
be correct on units equipped with an inverter. Checking
blower rotation is not a valid method of determining voltage
phasing for incoming power.
Supply Air Staged Units and Units Equipped With Op
tional Voltage or Phase Detection - The Unit Controller
checks the incoming power during start-up. If the voltage or
phase is incorrect, the Unit Controller will display an alarm
and the unit will not start.
A-Blower Operation
Refer to the Unit Controller Setup Guide to energize blower.
Use this mobile service app (the QR is located in the control
area) menu:
SERVICE > TEST > BLOWER
Instructions provided with the thermostat may also be used
to initiate blower only (G) demand. Unit will cycle on ther
mostat demand. The following steps apply to applications
using a typical electro-mechanical thermostat.
1. Blower operation is manually set at the thermostat sub
base fan switch. With fan switch in ON position, blow
ers will operate continuously.
2. With fan switch in AUTO position, the blowers will cycle
with demand. Blowers and entire unit will be off when
system switch is in OFF position.
IMPORTANT
Three Phase Scroll Compressor Voltage Phasing
Three phase scroll compressors must be phased se
quentially to ensure correct compressor and blower*
rotation and operation. Compressor and blower are wired
in phase at the factory. Power wires are color-coded as
follows: line 1-red, line 2-yellow, line 3-blue.
1-Observe suction and discharge pressures and blower*
rotation on unit start-up.
2-Suction pressure must drop, discharge pressure must rise
and blower* rotation must match rotation marking.
If pressure differential is not observed or blower* rotation
is not correct:
3-Disconnect all remote electrical power supplies.
4-Reverse any two field-installed wires connected to the
line side of S48 disconnect or TB13 terminal strip. Do not
reverse wires at blower contactor.
5-Make sure the connections are tight.
Discharge and suction pressures should operate at
their normal start‐up ranges.
*Supply air inverter blower motors should rotate in the
correct direction; verify scroll compressor rotation sep
arately. Contact technical support if the blower is rotat
ing incorrectly.
WARNING
1-Make sure that unit is installed in accordance with the
installation instructions and applicable codes.
2-Inspect all electrical wiring, both field‐ and factory‐
installed, for loose connections. Tighten as required.
3-Check to ensure that refrigerant lines do not rub against
the cabinet or against other refrigerant lines.
4-Check voltage at disconnect switch. Voltage must be
within range listed on nameplate. If not, consult power
company and have voltage condition corrected before
starting unit.
5-Make sure filters are new and in place before start‐up.
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