Operation
operating load. Overheating may vary slightly on the circuit if the system load is lower, when the slide valve is moving.
Overheating must stabilize at approximately 4°C when the above components have stabilized.
Subcooling
Normal subcooling for each circuit ranges from
Seasonal Unit Start-up
1.Close all valves and reinstall the drain plugs in the evaporator.
2.Service the auxiliary equipment according to the startup and maintenance instructions provided by the respective equipment manufacturers.
3.Close the vents in the evaporator
4.Open all the valves in the evaporator
5.Open all refrigerant valves to verify they are in the open condition.
6.If the evaporator was previously drained, vent and fill the evaporator and
CAUTION
Ensure that the compressor and oil- separator heaters have been operating for a minimum of 24 hours before starting. Failure to do so may result in equipment damage.
7.Check the adjustment and operation of each safety and operating control.
8.Close all disconnect switches.
9.Refer to the sequence for daily unit startup for the remainder of the seasonal startup.
Shutdown procedures
Temporary Shutdown and Restart To shut the unit down for a short time, use the following procedure:
1.Press the Stop key on the UCM- CLD.The compressors will continue to operate and, after unloading for 20 seconds, will stop when the compressor contactor
2)Stop the water circulation by disconnecting the power supply to the chilled water and cooling water pumps.
CAUTION
Under freezing conditions, the chilled water pump must remain in operation during the full shutdown period of the chiller if the chilled water loop does not contain glycol, to prevent any risk of evaporator
Extended period shutdown The procedure below must be performed if the system has to be stopped for a prolonged period, for example seasonal shutdown.
1.Test the unit for refrigerant leakage and repair as necessary.
2.Open the electrical disconnect switches for the
CAUTION
Lock the
3.Close all
4.Open the unit main electrical disconnect and
CAUTION
Lock the disconnects in the "Open" position to prevent accidental startup
and damage to the system when it has been set up for extended shutdown.
5.At least every three months (quarterly), check the refrigerant pressure in the unit to verify that the refrigerant charge is intact.
CAUTION
During an extended shutdown period, especially over the winter season, the evaporator must be drained of water, if the chilled water loop does not contain glycol, to prevent any risk of evaporator freeze- up.
System Restart After Extended Shutdown
1.Verify that the
CAUTION
To prevent damage to the compressor, ensure that all refrigerant valves are open before starting the unit.
2.Check the oil separator oil level (see Maintenance section).
3.Fill the evaporator water circuit. Vent the system while it is being filled. Open the vent on the top of the evaporator and condenser while filling, and close it when filling is completed.
CAUTION
Do not use untreated or improperly treated water. Equipment damage may occur.
4.Close the
5.Start the evaporator water pump and, while water is circulating, inspect all piping for leakage. Make any necessary repairs before starting the unit.
6.While the water is circulating, adjust the water flows and check the water pressure drops through the evaporator. Refer to "Water-
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