50
Centrifugal Chillers
D-EIMWC00804-14EN
draining and tubes must be blown out. Water permitted to remain in the piping and vessels can
rupture these parts if subjected to freezing temperature.
Forced circulation of antifreeze through the water circuits is one method of avoiding freeze
up.
1.
Take measures to prevent the shutoff valve in the water supply line from being accidentally
turned on.
2.
If a cooling tower is used, and if the water pump will be exposed to freezing temperatures, be
sure to remove the pump drain plug and leave it out so any water that can accumulate will
drain away.
3.
Open the compressor disconnect switch, and remove the fuses. If the transformer is used
for control voltage, the disconnect must remain on to provide power to the oil heater.
Set the manual UNIT ON/OFF switch in the Unit Control Panel to the OFF position.
4.
Check for corrosion and clean and paint rusted surfaces.
5.
Clean and flush water tower for all units operating on a water tower. Make sure tower
blowdown or bleed-off is operating. Set up and use a good maintenance program to prevent
“liming up” of both tower and condenser. It should be recognized that atmospheric air
contains many contaminants that increase the need for proper water treatment. The use of
untreated water can result in corrosion, erosion, sliming, scaling or algae formation. It is
recommended that the service of a reliable water treatment company be used. Daikin assumes
no responsibility for the results of untreated or improperly treated water.
6.
Remove condenser heads at least once a year to inspect the condenser tubes and clean if
required.
Annual Startup
A dangerous condition can exist if power is applied to a faulty compressor motor starter that has
been burned out. This condition can exist without the knowledge of the person starting the
equipment.
This is a good time to check all the motor winding resistance to ground. Semi-annual checking
and recording of this resistance will provide a record of any deterioration of the winding
insulation. All new units have well over 100 megohms resistance between any motor terminal
and ground.
Whenever great discrepancies in readings occur, or uniform readings of less than 50 megohms
are obtained, the motor cover must be removed for inspection of the winding prior to starting
the unit. Uniform readings of less than 5 megohms indicate motor failure is imminent and the
motor should be replaced or repaired. Repair before failure occurs can save a great deal of time
and labor spent in the cleanup of a system after a motor burnout.
1.
The control circuit must be energized at all times, except during service. If the control
circuit has been off and oil is cool, energize oil heaters and allow 24 hours for heater to
remove refrigerant from the oil before starting.
2.
Check and tighten all electrical connections.
3.
Replace the drain plug in the cooling tower pump if it was removed at shutdown time the
previous season.
4.
Install fuses in main disconnect switch (if removed).
5.
Reconnect water lines and turn on supply water. Flush condenser and check for leaks.
6.
Refer to Manual OM CentrifMicro II before energizing the compressor circuit.
