9
SK Models IOM
Enertech Global
SECTION 6: CONTROLS
Features and Operations:
A microprocessor-based printed circuit board
controls the operating modes of the Fluid Cooler
and displays status and fault conditions. The
operating mode is configured via DIP switches.
The Fan and Pump state are determined by the
operating mode, fluid type, air temperature, and
fluid temperature. The
DIP switches and LEDs indicate the Fluid Cooler
configuration (operating mode and fluid type), as
well as fault conditions to aid in diagnostics.
Sensor Entering Air Temperature (EAT):
EAT sensor (10KΩ thermistor) is connected to EAT
on the Fluid Cooler Control board and measures
ambient air temperature near the heat exchanger.
Sensor Entering Water Temperature (EWT):
EWT sensor (10KΩ thermistor) is connected to EWT
on the Fluid Cooler Control board and measures
entering water/fluid temperature.
Flow Switch (FS):
Optional flow Switch is a dry contact input and
is connected to FS1 & FS2 on the Fluid Cooler
Control board. It indicates when the fluid is
circulating.
Control Input (CC In):
This is a 24 VAC input coming from CC
(Compressor Contactor) on the Lockout board in
the heat pump. It is connected to CC IN on the
Fluid Cooler Control board and indicates if the
compressor is running.
Control Input (O):
This is a 24 VAC input coming from the O terminal
on the Lockout board in the heat pump. It is
connected to O on the Fluid Cooler Control board
and it indicates when the heat pump is running in
cooling mode.
Fault Inputs:
This is a dry contact input coming from the Fan
Alarm output of the fan. It is connected to the FAN1
and FAN2 terminals on the circuit board. When the
fan is off, this input is open. When the fan is running
in normal operation, the fan alarm output is closed.
If the fan alarm output is open for 30 continuous
seconds while the
fan is running, a fan alarm is
tripped.
Fan Output:
This fan control output is 24 VAC which energizes
the fan relay. Power to the fan is applied via
Common and Normally Open relay contacts.
Pump Output:
If equipped, this pump control output is 24 VAC
which energizes the pump relay. Power to the pump
is applied via Common and Normally Open relay
contacts.
Power Connections:
The printed circuit board requires 24 VAC Input
coming from the transformer, which is either
installed in the fluid cooler (if the fluid cooler
is equipped with an internal flow switch) or is
connected from the heat pump (if the fluid cooler is
equipped with an internal pump).
Modes of Operation:
There are four different modes of operation for each
type of fluid (water and antifreeze).
Operating modes depend on the following:
• Loop pump is internal (equipped) or external
(flow center).
• Flow Switch is or is not equipped.
• CC and O control inputs from heat pump are
wired.
• Fluid type is water or antifreeze.
Please refer to the DIP SWITCH SELECTION table
and CONTROL BOARD LED IDENTIFICATION table
for details.
Note:
The flow requirements must be verified by
the installer for each specific application.
Water or Antifreeze Protection (SW3)
In all options, SW3 must be turned ON for a
loop with antifreeze and OFF for water. This DIP
setting will adjust the set points for the proper logic
and to help protect from freezing as described
below.
Option 1: Internal Pump, with CC & O:
SW1=OFF, SW2=OFF
In this mode, outputs from the heat pump enable
the fluid cooler to heat or cool the loop depending
on outdoor conditions.
In loop cooling mode (O call is present), when the