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Operation
CAUTION
Compressor Damage!
Compressor crankcase heaters must be energized at least 8 hours
before unit start-up. Failure to do so may result in compressor
mechanical damage.
[ ] After the compressor crankcase heaters have operated a minimum of 8
hours, open the unit circuit breaker, reinstall control circuit fuse (FU) in the
unit control panel, and re-close the circuit breaker.
[ ] The factory-installed evaporator heat tape (HTTB) should be energized
whenever there is water in the unit evaporator. Additional heat tape supplied
in the field requiring its own fused disconnect box should be closed at this
time.
[ ] Reset any control that requires a manual reset.
[ ] Set the water temperature thermostat (WTT) as described on page 46.
Checking Operating Conditions
Once the unit has operated for at least 30 minutes and the system has stabi-
lized, complete the following checklist to ensure proper unit operation.
[ ] Re-check evaporator water flow and pressure drop. These readings
should be stable at proper levels. Refer to "Water System". If pressure differ-
ential drops off, clean all evaporator water supply strainers.
[ ] Measure unit suction and discharge pressures by installing pressure
gauges on the discharge and suction line access ports. Refer to Table 8 for
approximate normal operating pressures.
Note: Many application variables exist which can effect operating pressures;
these include ambient dry bulb temperature. as well as the installation of
such options as head pressure controls or hot gas bypass. Since these vari-
ables can give misleading results, do not use operating pressures as the
sole check of system operation.
[ ] Check compressor amp draw.
[ ] Check electrical power supply.
[ ] Check the liquid line sight glasses/moisture indicators for the presence of
moisture.
Note: Bubbles in the liquid line may indicate either a low refrigerant charge,
or excessive pressure drop in the liquid line. Such a restriction can often be
identified by a noticeable difference in line temperature on either side of the
restricted area. (Frost often forms on the outside of the liquid line at the point
of restriction, as well.) Bubbles are not necessarily a symptom of improper
system operation.
38
CSRA-SVX01A-EN
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