STULZ CyberRow Chilled Water Series Installation, Operation & Maintenance Manual
(Dec., 2013)
1-7
will not produce AC inverter whine.
During start up, the fans begin operating in stages
with fi ve second time delays. The middle fan starts
fi rst, then the upper fan, then the lower fan. The
system controller monitors fan operation. If a fan
failure is detected, the controller alerts the operator
with an alarm message and increases the speed of the
remaining fan(s) to compensate for the loss of air fl ow.
The system controller may be used to confi gure
the fans for (1) zone temperature control with
independently variable fan speeds or (2) static pressure
control with all three fans operating at the same
variable speed (See Section 4.4.4).
1.5.6 Temperature/Humidity Sensors
Control and alarm recognition takes place by means of the
controller analyzing signal inputs from the sensors to man-
age the operation of the A/C unit consistent with the set
points entered in the system controller. The system control-
ler monitors three NTC type temperature sensors and a
4-20 mA temperature/humidity (T/H) sensor.
The NTC sensors are factory installed in pre-determined
supply air fan zones inside the cabinet. Each NTC sensor
is used by the system controller to manage the speed
of the fan for that zone to meet the supply air setpoint
temperature. The return air is monitored by a temperature/
humidity (T/H) sensor which is typically mounted inside the
cabinet. As an option, the return air T/H sensor may be
removed from the cabinet and mounted in the hot aisle.
The actual sensor values may be viewed from the controller
user interface display using the Information menu loop.
1.6 Optional
Equipment
1.6.1 Remote Mounted Supply
Temperature/Humidity
Sensor
As an option, a supply T/H sensor may be provided
for fi eld installation (see Section 2.6.2). This is to be
mounted in the supply (cold aisle) space for monitoring
or control purposes. Refer to the electrical drawing
supplied with your unit for wiring details specifi c to
your system.
1.6.2 Humidifi er
CyberRow CRS-180 systems may be equipped with an
optional electrode steam humidifi er. The humidifi er is
factory installed inside the air conditioner and includes
fi ll and drain valves and associated piping to the top
(or bottom) of the cabinet for connecting a source of
water and a drain line.
Operation of the humidifi er’s fi ll and drain cycles is
based on water conductivity and is maintained by the
on-board humidifi er controller. An operating manual
for the humidifi er is provided under separate cover.
Refer to that manual for detailed information on the
operation of the humidifi er.
1.6.3 Water Detector
As an option, STULZ offers spot type or strip/cable
type water detectors see Section 2.6.1). Upon sensing
a water leak, the water detector control circuit will
signal the system controller of the alarm condition. The
system will continue operating.
1.6.4 Smoke Detector
Optionally mounted in the return air stream, a photo-
electric smoke detector is used to sense the presence of
smoke and signal the controller when a smoke alarm
condition exists and shuts down the air conditioner.
1.6.5 Firestat
Optionally mounted in the return air stream, a fi re
detector senses high return air temperature and signals
the controller when a fi re alarm condition exists and
shuts down the air conditioner.
1.6.6 Dual Power Auto Transfer Switching
An automatic transfer, main power switching system is
available for critical operations. With this option, two
main power service disconnect switches are provided
on the electric box to connect two independent power
sources. If the primary power source (Power Supply
A) is interrupted or, if an under-voltage, phase loss or
imbalance occurs, the automatic transfer switching
circuitry immediately transfers operation of the precision
A/C system to a secondary power source (Power Supply
B). If power is transferred, the system controller provides
an alarm message and the alarm display indicates which
power source failed. When the primary power source is
functionally restored, the operation of the A/C system
is automatically transferred back to the primary power
source.