Page 24
-
frigerant circuit at the exit of each condenser coil. The dri-
er removes contaminants and moisture from the system.
See SPECIFICATIONS tables at the front of this manual
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
each refrigeration circuit. Temperature thermistors pro-
vide continuous temperature input to the unit controller
for proper cooling operation as well as system protection.
Controller logic will de-energize compressors for each re-
frigeration circuit when evaporator coil temperature falls
C-Blower Compartment
The blower compartment is located between the evapo-
rator coil and the compressor / control section on the op-
posite side of the condenser coil. The blower assembly is
accessed by disconnecting the blower motor wiring (and
all other plugs) and removing the screws on either side of
1-Blower Wheels
All units have two 15 in. x 15 in. (381 mm x 381 mm) blow-
er 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.
(table of contents) in the front of this manual. Units may
be equipped with motors manufactured by various manu-
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 volt-
age 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 blow-
er. 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
thermostat demand. The following steps apply to applica-
tions using a typical electro-mechanical thermostat.
1 - Blower operation is manually set at the thermostat
subbase fan switch. With fan switch in ON position,
blowers will operate continuously.
2 - With fan switch in AUTO position, the blowers will
cycle with demand. Blowers and entire unit will be
OFF position.
IMPORTANT
Three Phase Scroll Compressor Voltage Phasing
Three phase scroll compressors must be phased
sequentially 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.
rotation is not correct:
3-Disconnect all remote electrical power supplies.
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 separately. Contact technical support if the
blower is rotating incorrectly.
To Next Page
Loading...
