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1-Compressors B1 and B2
All units use two scroll compressors. Compressor capacity
of each compressor is added to reach the total capacity
WARNING
Electrical shock hazard. Compressor must be
grounded. Do not operate without protective
coverover terminals. Disconnect power before
removing protective cover. Discharge capacitors
before servicing unit. Failure to follow these
precautions could cause electrical shock resulting
in injury or death.
Each compressor is energized by a corresponding
compressor contactor.
NOTE-Refer to the wiring diagram section for specic unit
operation.
IMPORTANT
Some scroll compressors have an internal vacuum
protector that will unload scrolls when suction
pressure goes below 20 psig. A hissing sound
will be heard when the compressor is running
unloaded. Protector will reset when low pressure
in system rises above 40 psig. DO NOT REPLACE
COMPRESSOR.
2-Thermal Protectors S5, S8
Some compressors have thermal protectors located on
+
+++
3-Freezestats S49 and S50
Each unit is equipped with a low temperature switch
on the corresponding evaporator coils.
contactors. Each freezestat is a SPST N.C. auto-reset
+ +
+ +
operation to temporarily disable the respective compressor
until the coil temperature rises.
charge before allowing unit back in operation. Make sure
to eliminate conditions which might promote evaporator
ice buildup.
4-High Pressure Switches S4 and S7
The high pressure switch is a manual reset SPST N.C.
switch which opens on a pressure rise.
compressor discharge line and are wired in series with the
respective compressor contactor coils.
opens and the respective compressor is de-energized
temperature switch and a head pressure controller. This
kit allows mechanical cooling operation by maintaining
or slowing the outdoor fans.
ambient operation. Liquid line pressure transducers are
installed to convert the pressure to an analog signal which
pressure controller provides a variable output which slows
condenser fan operation at lower ambient temperatures
6-Crankcase Heaters HR1, HR2
around compressor B2. Crankcase heater wattage varies
by compressor manufacturer.
7- Filter Drier
refrigerant circuit at the exit of each condenser coil. The
drier removes contaminants and moisture from the system.
8- Condenser Fans B4, B5
condenser fans used have single-phase motors. The fan
assembly may be removed for servicing and cleaning.
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