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Step 5 – Verify Freezestat Setting
Make sure the Freezestat is set appropriately for the
operating conditions of the chiller. The Freezestat is
in a password-protected menu of the chiller
controller. Refer to the controller operation section
for instruction on how to access this menu. It should
be set at 10°F
{-12°C}
below the minimum chilled
water temperature setting that the chiller will
operate. Be sure the coolant solution has sufficient
freeze protection (glycol) to handle at least 5°F
{-15°C}
below the Freezestat setting. All chillers ship
with the Freezestat set at 45°F
{7.2°C}
. This is to
protect against a possible freeze-up if no glycol is
present in the coolant. Once the proper glycol
solution is present, adjust the Freezestat to the
appropriate setting.
CAUTION: The manufacturer’s warranty does not
cover the evaporator from freezing. It is vital
that the Freezestat is set properly.
Step 6 – Turn On Control Power
Turn on the control power by touching the operator
interface. The panel displays should illuminate.
Due to extreme temperatures during shipment the
High Refrigerant Pressure switch may have tripped. If
this is the case, disconnect the main power and reset
the High Refrigerant Pressure by depressing the
manual reset button located on the switch.
Reconnect the main power and turn the control
power on by pressing the Power button. Clear the
alarm condition by pressing the Alarm Reset button.
Step 7 – Establish Coolant Flow
Establish flow through the evaporator(s). Set process
water flow through the evaporator(s). If a flow meter
is not available, run the chiller fully loaded and
balance the flow until a 10°F
{-12°C}
rise is
established. A water temperature rise of 5°F
{-15°C}
or less will result in a significant increase in flow
beyond the recommended rate and may damage the
evaporators and create excessive pressure drops that
influence the overall efficiency of the system.
Note: The compressors will not start as long as the flow switch
is open. There must be a positive flow through the
evaporator(s) before the compressor(s) can operate.
Step 8 – Intial Unit Operation
Enter the desired leaving fluid temperature on the
control panel. Unless otherwise specified, the chiller
is factory set to deliver coolant at 50°F
{10°C}
. Adjust
to the desired operating temperature. The chiller
should now be controlling to the selected
temperature. Please note that if there is insufficient
load the compressor may cycle on and off causing
swings in temperature.
WARNING: During normal operation, enable all
circuits. Failure to heed this warning may lead to
evaporator freeze-up. When shutting down a
circuit for servicing, shut off water to that
circuit’s evaporator.
WARNING: Under no circumstance should the
High Refrigerant Pressure or the Low Compressor
Pressure switch be deactivated. Failure to heed
this warning can cause serious compressor
damage, severe personal injury or death.
Starting a compressor is only possible if its cycle
time has expired, its liquid line solenoid valve is open
and meeting all of its safeties. The time to
completion displays on the screen. Once the
compressor starts, it will operate fully unloaded for
two minutes. If the demand requires additional
loading after the two minutes has expired, the
compressor will load accordingly. This sequence is to
improve the compressor’s liquid refrigerant handling
capability during start-up.
Low-Ambient Start-Up (Remote Condensers)
When a chiller system with an outdoor remote air-
cooled condenser stops, the temperature of the
refrigerant in the condenser will cool to the ambient
temperatures. The cooler the refrigerant gets, the
lower the refrigerant pressure will be. The chiller has
a low refrigerant pressure safety to protect the chiller
from damage due to the refrigerant pressure being
too low for proper operation. When starting a chiller
that has been off for an extended period the
refrigerant pressure in the system will often times be
lower than the set point of the low refrigerant
pressure alarm.
To allow for cold weather start-up of a remote
condenser system there is a low-low refrigerant
pressure safety that is set below the normal low
refrigeration pressure alarm. This low-low pressure
