STULZ CyberRow DX Series Installation, Operation & Maintenance Manual
1-7
1.5.1 Electrical Compartment
The electrical components are protected inside an
electric box located behind the rear access panel.
The electric box cover is safety interlocked with the
service disconnect switch (See Figure 1) preventing
the cover from being opened when the switch in the
On position. The switch must be turned Off to gain
access to the electrical compartment.
The service disconnect switch may be used to turn
the unit off for emergency shutdown or when routine
maintenance is performed. The handle of the switch
may be locked in the “Off” position to prevent unin-
tended operation.
1.5.2 Circuit Breakers/Motor Start Protectors
CyberRow
units incorporate state of the art compo-
nent protection with the use of motor start protec-
tors and circuit breakers. If an overload occurs the
switches must be manually re-set after the overload
condition is cleared.
1.5.3 Compressor
A scroll compressor is utilized in DX based
CyberRow systems. With fewer moving parts,
scroll compressors have demonstrated superior
durability. The scroll compressor is designed around
two identical spirals or scrolls that, when inserted
together, form crescent shaped pockets. During a
compression cycle, one scroll remains stationary
while the other scroll orbits around the fi rst. As this
motion occurs, gas is drawn into the scrolls and
moved in increasingly smaller pockets toward the
center. At this point, the gas, now compressed to a
high pressure, is discharged from a port in the center
if the fi xed scroll. During each orbit, several pockets
of gas are compressed simultaneously, creating
smooth, nearly continuous compression.
1.5.3.1 Electronic Thermal Expansion Valve
An auxiliary control module mounted to the door
of the electric box, manages the operation of the
electronic expansion valve (EEV). The control
module manages the EEV based on input signals
from the suction pressure and temperature sensors.
It regulates the amount of refrigerant entering
the evaporator to maintain the correct superheat
temperature.
1.5.3.2 Electronic Hot Gas Bypass
Used for freeze protection and capacity control, an
electronically controlled hot gas bypass valve is
managed by the same auxiliary control module that
manages the EEV valve. The hot gas bypass system
allows the compressor to run continuously instead
of cycling the compressor on and off for capacity
control. The hot gas bypass system manages
system capacity based on the suction temperature.
The hot gas regulator valve meters hot gas into the
evaporator coil during low load periods or when
evaporator air fl ow is reduced.
1.5.4 Coil(s)
Cooling coils are aluminum fi nned/copper tube
construction. The coils are leak tested and cleaned
before installation by the factory. Condensate drain
pans are provided to collect water condensed by the
coils. The drain pans are emptied by a condensate
pump that directs the water to a pipe stub located
either at the top or the bottom of the A/C unit
depending on the piping confi guration (see Section
2.7.1.1 and 2.8.1.1).
A fl oat switch is placed in the lower condensate pan
to detect if the water level rises. If the condensate
pan fails to drain, the fl oat switch signals the
controller to annunciate an alarm and turn off the
compressor and the fans.
1.5.5 Condensate Pump
A condensate pump is factory installed in the lower
drain pan. The pump automatically eliminates con-
densate water from the drain pan. The pump has an
internal fl oat switch which turns the pump on and off
based on the water level.
1.5.6 EC Fans
The unit is equipped with three high effi ciency, Elec-
tronically Commutated (EC) fans. EC fans utilize a
brushless motor equipped with permanent magnets
and permanently lubricated ball bearings. The fan
impellers are backward curved and attached to the
rotor casing. The fan is balanced and aerodynami-
cally optimized to minimize vibration.
The fans do not utilize drive belts. Fan speed is
variable via a 0 to 10 VDC signal from the system
controller. The fan motor is equipped with integral
electronics and does not require the addition of
secondary electronics such as thermal protection, in-
verters or fi lters. The fan will not produce AC inverter
whine.
Содержание CyberRow DX CRS-042-G
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