
necessary repairs before starting the unit.
6. While the water is circulating, adjust the water
fl
ow
and check the water pressure drops through the
evaporator. Refer to “water-system
fl
ow rates” and
“water-system pressure drop”.
7. Adjust the
fl
ow switch on the evaporator piping for
proper operation.
8. Stop the water pump. The unit is now ready for
startup as described “Startup procedures”
-
To shut the unit down for a short time, use the following
procedure:
1. Press the STOP key on the TD7. The compressors
will continue to operate and, after unloading for 20
seconds, will stop when the compressor contactors
de-energize.
2. Stop the water circulation by turning off the chilled
water pump at least one minute after the stop of the
compressors.
-
The unit will start normally, provided the following con-
ditions exist:
1. The controller receives a call for cooling and the dif-
ferential-to-start is above the setpoint.
2. All system operating interlocks and safety circuits are
satis
fi
ed.
The following procedure is to be followed if the system
is to be taken out of service for an extended period of
time (i.e. seasonal shutdown):
1. Test the unit for refrigerant leaks and repair as neces-
sary.
2. Open the unit main electrical disconnect and unit-
mounted disconnect (if installed) and lock in the
“OPEN” position.
3. Disconnect the evaporator heater, to avoid burn out
of heater.
4. Open the electrical disconnect switches for the
chilled-water pump. Lock the switches in the
“OPEN”position
5. Close all chilled-water supply valves. Drain the water
from the evaporator.
6. At least every three months (quarterly), check the re-
frigerant pressure in the unit to verify the refrigerant
charge integrity.
-
Follow the 3.1 Start Up to start the unit, Only after pass
through the procedure of 2.2 Check Procedure, steps 1 to
15.
Pre-Start Chekout
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