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Unit Operation
Modes of Operation
Pre-Cooler Mode
EcoFlex™ Controls
Modes of Operation
Optimization
Fan Control
Every fan will run at the same speed at all times. The fans are connected to each other
via ModBus RS485 and controlled using one of these three methods. Water Saver Logic
and Energy Saver Logic will need to be pre-ordered as extra devices and configuration are
added at the factory:
4. Customer provided Analog signal (0-10V, 10-0V and 4-20mA): Customers provide an
Analog Input signal to the controller from their rack controller or Energy Management
System. An equivalent signal is re- broadcasted to the fans via ModBus.
5. Pressure sensor (Head Pressure Control), Optional: A pressure sensor supplies an
Analog Input (4-20mA) to the controller to indicate head pressure. The controller
modulates the fan speed using a PID loop comparing the head pressure to the setpoint
to control the fan speed. The loop is tuned in such a way that the fans operate
smoothly to preserve the fan’s motor life and energy. The fans’ speed signal is sent to
the fans via ModBus. If the pressure sensor fails, the controller sends an alarm to the
interface screen and via ModBus to the customer; as well as sending a signal to the
fans to run at 80% via ModBus.
6. Customer provided communications: The unit is connected to the customer’s BAS
system via ModBus or BACnet. The speed signal is a ModBus or BACnet virtual point
that the controller sends to all fans to control speed. A full list of all points can be
found on page 16.
Pre-Cooler Mode Activation
During Dry Mode, the drain valve remains open while the make-up valve remains closed.
When the unit gets the signal to enter Pre-Cooler Mode, the following sequence occurs:
• The drain valve closes.
• The make-up valve opens to fill the sump, and remains on.
• When the sump is full and the float switch makes the pump turns on.
• The pump drains the sump as it fills the spray system and wets the Pre-Cooler Pads.
• If the incoming water pressure is low, the pump may turn off as the sump drains faster
with the pump in operation than the make-up valve can replenish the water. The pump
is rated to run dry for short periods of time without harm.
• The system will reach equilibrium when the spray system is filled, the Pre-Cooler Pads
are saturated, and the sump is filled. The unit will then follow the ‘Pump and Float
Control’ described on page 27.
1. Customer provided Analog signal (0-10V, 10-0V and 4-20mA): Customers provide an
Analog Input signal to the controller from their rack controller or Energy Management
System. An equivalent signal is re- broadcasted to the fans via ModBus.
2. Head Pressure Control Package, Optional: A pressure sensor supplies an Analog Input
(4-20mA) to the controller to indicate head pressure. The controller modulates the fan
speed using a PID loop comparing the head pressure to the setpoint to control the fan
speed. The loop is tuned in such a way that the fans operate smoothly to preserve the
fan’s motor life and energy. The fans’ speed signal is sent to the fans via ModBus. If
the pressure sensor fails, the controller sends an alarm to the interface screen and via
ModBus to the customer as well as sending a signal to the fans to run at 80%.
3. Customer provided communications: The unit is connected to the customer’s BAS
system via ModBus or BACnet. The speed signal is a ModBus or BACnet virtual point
that the controller sends to all fans to control speed. A full list of all points can be
found on page 18.
4. Leaving Fluid Temperature Control (TSDF2 Only): A temperature sensor supplies
an Analog Input (NTC) to the controller to indicate leaving fluid temperature. The
controller modulates the fan speed using a PID loop comparing the fluid temperature
to the setpoint to control the fan speed. The loop is tuned in such a way that the fans
operate smoothly to preserve the fan’s motor life and energy. The fans’ speed signal is
sent to the fans via ModBus. If the temperature sensor fails, the controller sends an
alarm to the interface screen and via ModBus to the customer; as well as sending a
signal to the fans to run at 80%.
NOTE: For winter operation, the
hose faucet can be used as
vent. Refer to Page 12 for more
information. Also, consult with a
licensed plumber.
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