Trane RTUB 207-224, RTCA 108-216 manual Shutdown procedures, Subcooling, Seasonal Unit Start-up

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 8-10°C, depending on the units. If subcooling for either circuit does not fall within these values, check the overheating for the circuit and adjust if necessary. If overheating is normal but subcooling is not, contact a qualified service technician.

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 chilled-water circuits.

4.Open all the valves in the evaporator chilled-water circuits.

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 chilled-water circuit. When all air is removed from the system (including each pass), install the vent plugs in the evaporator water boxes.

￿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 de-energizes.

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 freeze-up.

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 chilled-water pump. Lock the switches in the "Open" position.

￿CAUTION

Lock the chilled-water pump disconnects open to prevent pump damage.

3.Close all chilled-water supply valves. Drain the water from the evaporator.

4.Open the unit main electrical disconnect and unit-mounted disconnect (if installed) and lock in the "Open" position. If the optional control-power transformer is not installed, open and lock the 115 V disconnect.

￿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 liquid-line service valves, oil line, compressor discharge service valves, and suction service valves are open (backseated).

￿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 fused-disconnect switches that provide power to the chilled-water pump.

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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