RTWB-SVN01B-E4
32
Unit shutdown procedures
Temporary shutdown and restart
To shut the unit down for a short
time, use the following procedure:
• 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 contactor de-
energizes.
• Stop the water circulation by
turning off both the chilled-water
pump and the condenser-water
pump.
To restart the unit after a temporary
shutdown, restart the chilled-water
pump and the condenser-water
pump, and press the Auto key. The
unit will start normally if the
following conditions exist:
• The UCM must receive a call for
cooling and the differential-to-start
must be above the setpoint.
• 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 as a seasonal
shutdown:
Test the unit for refrigerant leakage
and repair as necessary.
Open the electrical disconnect
switches for the chilled-water pump
and the condenser-water pump. Lock
the switches in the “open“ position.
C
CA
AU
UT
TIIO
ON
N
Lock the chilled-water and
condenser-water pump disconnects
open, to prevent pump damage.
• Close all chilled-water supply
valves and the condenser-water
supply valves. Drain the water
from the evaporator and the
condenser.
• Open the unit main electrical
disconnect and the unit-mounted
disconnect (if installed), and lock in
the “Open“ position.
C
CA
AU
UT
TIIO
ON
N
Lock the disconnects on the “Open“
position to prevent accidental start-
up and damage to the system when
it has been set up for extended
shutdown.
At least every three months, check
the pressure in the unit to verify that
the refrigerant charge is intact.
System restart after extended
shutdown
• Follow the procedures below to
restart the unit after an extended
shutdown:
• Verify that the liquid-line service
valves, oil line, and compressor
discharge service valves are open.
C
CA
AU
UT
TIIO
ON
N
To prevent damage to the
compressor, be sure that all
refrigerant valves are open before
starting the unit.
• Check the oil-separator oil level.
See the Maintenance paragraph.
• Fill the evaporator- and condenser-
water circuits. Refer to Table 4 for
evaporator- and condenser-water
content. Vent the system while it is
being filled. Open the vents on the
tops of the evaporator and
condenser during filling and close
them when filling is completed.
C
CA
AU
UT
TIIO
ON
N
Do not use untreated or improperly
treated water. Equipment damage
may occur.
• Close the fused disconnect
switches that provide power to the
chilled-water pump and the
condenser-water pump.
• Start both the evaporator- and
condenser-water pumps and, while
water is circulating, inspect all
piping for leakage. Make any
necessary repairs before starting
the unit.
• While the water is circulating,
adjust the water flows and check
the water pressure drops through
the evaporator and the condenser.
Refer to “Water System Flow
Rates“ and “Water System
Pressure Drop.“
• Adjust the flow switch (s) on the
evaporator piping and the
condenser piping (if installed) for
proper operation.
• Stop both water pumps. The unit is
now ready for the start-up
procedure.
Unit Shutdown
Procedures
