112 RTAA-SVX01A-EN
Unit 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 Clear Language Display. The compressors will
continue to operate and, after unloading for 20 seconds, will stop when
the compressor contactors de-energize. The condenser fans will be de-
energized at this time.
2. The unit disconnect switch and unit-mounted disconnect (if installed)
should remain closed to keep the compressor sump heaters energized.
3. Maintain power to keep the evaporator heat tape energized.
4. Stop the chilled water circulation by turning off the chilled water pump.
To restart the unit after a temporary shutdown, restart the chilled water pump
and press the AUTO key. The unit will start normally, provided the following
conditions exist:
1. The UCM must receive a call for cooling and the differential to-start must
be above the setpoint.
2. All system operating interlocks and safety circuits must be satisfied.
Extended Shutdown Procedure
The following procedure is to be followed if the system is to be taken out of
service for an extended period of time, eg., 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 switch in the “OPEN” position.
CAUTION
Pump Damage!
Lock the chilled water pump disconnect open to prevent pump
damage.
3. Close all chilled water supply valves. Drain the chilled water from the
evaporator. If the unit will be exposed to freezing ambient conditions,
flush the evaporator with an antifreeze solution or energize the evapora-
tor heat tape.
CAUTION
Evaporator Freezing Damage!
To prevent damage to the evaporator by freezing, flush the
evaporator with an antifreeze solution or energize the evaporator
heat tape.
4. Open the unit main electrical disconnect and unit-mounted disconnect (if
installed) and lock on the “OPEN” position.
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