Trane RTCA 108-216, RTUB 207-224 manual Start-up Procedures, Overheating

Operation

motor rotation requires confirmation of the electrical phase sequence of the power supply.The motor is internally connected for clockwise rotation with the incoming power supply phased A-B-C.

When rotation is clockwise, the phase sequence is usually called "ABC;" when counterclockwise, "CBA."This direction may be reversed outside the alternator by interchanging any two of the line wires. It is this possible interchange of wiring that makes a phase sequence indicator necessary if the operator is to quickly determine the phase rotation of the motor.

1.Press the Stop key on the UCM- CLD.

2.Open the electrical disconnect or circuit protection switch that provides line power to the line- power terminal block(s) in the starter panel (or to the unit- mounted disconnect).

3.Connect the phase-sequence indicator leads to the line power terminal block as follows:

Phase Sequence LeadTerminal

Black (Phase A) L1

Red (Phase B) L2

Yellow (Phase C) L3

4.Turn power on by closing the unit supply-power fused-disconnect switch.

5.Read the phase sequence on the indicator.The "ABC" LED on the face of the phase indicator will glow if the phase is "ABC."

￿WARNING

To prevent injury or death due to electrocution, take extreme care when performing service procedures with electrical power energized.

6.If the "CBA" indicator glows instead, open the unit main-power disconnect and interchange two line leads on the line-power terminal block(s) (or the unit- mounted disconnect). Close the main-power disconnect and recheck the phasing.

Do not interchange any load leads that are from the unit contactors or the motor terminals. Doing so may damage the equipment.

7.Reopen the unit disconnect and disconnect the phase-sequence indicator.

Water-System Flow Rates Establish a balanced chilled-water flow through the evaporator.The flow rates should be between the minimum and maximum values given on the pressure-drop curves.

Water-System Pressure Drop Measure the water-pressure drop through the evaporator at the field- installed pressure taps on the system water piping. Use the same gauge for each measurement. Do not include valves, strainers, or fittings in the pressure-drop readings.

Start-up Procedures

Daily Unit Start-up Procedure When the verification operations prior to start-up have been performed (see previous sections), the unit is ready to start.

•Press the Stop key on the UCM-CLD.

•If necessary, adjust the setpoint values in the UCM-CLD reports (refer to the UCM-CLD user guide).

•Close the fused disconnect switch for the chilled water pumps and the cooling water pumps.

•Energize the pumps to start the water circulation.

•Check the service valves on the discharge line, suction line, oil line and liquid line for each circuit. These valves must be open before starting the compressors.

￿WARNING

To prevent compressor damage, do not operate the unit until all refrigerant and oil-line valves are opened.

•Verify that the chilled water pump runs for one minute after the chiller is commanded to stop for normal chilled water systems).

•Press the Auto key. If the chiller

control calls for cooling and all the safety interlocks are closed, the unit will start.The compressor(s) will load and unload in response to the temperature of the leaving chilled- water temperature.

After the system has been operating for approximately 30 minutes and has become stabilized, complete the start-up procedure as follows:

•Check the evaporator refrigerant pressure and the condenser refrigerant pressure in the Refrigerant report of the UCM-CLD.

•Measure the system overheat.

•Measure the system subcooling.

A shortage of refrigerant is indicated if the operating pressures and the subcooling are low. If the operating pressures, superheat, and subcooling readings indicate a refrigerant shortage, gas-charge refrigerant into each circuit as required. With the unit running, add refrigerant vapor by connecting the charging line to the suction service valve and charging through the backseat port until operating conditions become normal.

￿WARNING

If both suction and discharge pressures are low and subcooling is normal, a problem other than refrigerant shortage exists. Do not add refrigerant, as this may result in overcharging the circuit.

Only use the refrigerant specified on the unit nameplate.

•If operating conditions indicate a refrigerant overcharge, remove refrigerant at the liquid line service valve. Allow refrigerant to escape slowly to minimize oil loss. Do not discharge refrigerant into the atmosphere.

￿WARNING

Do not allow refrigerant to directly contact skin, or injury from frostbite may result.

Overheating

Normal overheating for each circuit is approximately 3-4°C at full

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