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PRE-START-UP
IMPORTANT: Before beginning Pre-Start-Up or
Start-Up, review Start-Up Checklist at the back of
this book. The Checklist assures proper start-up of a
unit and provides a record of unit condition,
application requirements, system information, and
operation at initial start-up.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage.
Do not attempt to start the condensing unit, even
momentarily, until the following steps have been
completed. Compressor damage may result.
System Check
1. Check all air handler(s) and other equipment auxiliary
components. Consult the manufacturer's instructions
regarding any other equipment connected to the con-
densing unit. If the unit has field-installed accessor-
ies, be sure all are properly installed and correctly
wired. If used, the airflow switch must be properly in-
stalled.
2. Be sure the unit is properly leak checked and dehyd-
rated.
3. Check tightness of all electrical connections.
4. Open the liquid line and suction line service valves.
5. Be sure the unit is properly charged. See "Preliminary
Charge", below.
6. The electrical power source must agree with the unit's
nameplate rating.
7. The crankcase heater must be firmly attached to the
compressor crankcase. Be sure the crankcase is warm
(heater must be on for 24 hours before starting com-
pressor).
Turn On Crankcase Heater — Turn on the crankcase
heater for 24 hours before starting the unit to be sure all
the refrigerant is out of the oil. To energize the crankcase
heater, proceed as follows:
1. Set the space thermostat set point above the space
temperature so there is no demand for cooling.
2. Close the field disconnect.
Preliminary Charge —Before starting the unit, charge
liquid refrigerant into the high side of the system through
the liquid service valve. The amount of refrigerant must
be at least 80% of the operating charge listed in the
Physical Data table (Tables 1A and 1B). Allow high and
low side pressures to equalize before starting compressor.
If pressures do not equalize readily, charge vapor on low
side of system to assure charge in the evaporator. Refer to
GTAC II, Module 5, Charging, Recover, Recycling, and
Reclamation for liquid charging procedures.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage.
Prior to starting compressor, a preliminary charge of
refrigerant
must
be
compressor damage.
START-UP
38AUD Units — The compressor crankcase heater must
be on for 24 hours before start-up. After the heater has
been on for 24 hours, the unit can be started. If no time
elapsed since the preliminary charge step was completed,
it is unnecessary to wait the 24-hour period.
PRELIMINARY CHECKS
1. Check that electric power supply agrees with unit
nameplate data.
2. Verify that the compressor crankcase heater is se-
curely in place.
3. Check that the compressor crankcase heater has been
on at least 24 hours.
4. Recheck for leaks using the procedure outlined in the
Pre-Start-Up section, Leak Test and Dehydration. If
any leaks are detected, repair as required. Evacuate
and dehydrate as described in the Leak Test and De-
hydration section.
5. Ensure that the preliminary charge has been added as
described in the Pre-Start-Up section, Preliminary
Charge.
6. All internal wiring connections must be tight, and all
barriers and covers must be in place.
NOTE: The 38AUD units are factory charged with the
required amount of oil. If recharging in required, use
Emkarate RL 32-3MAF for the 38AUD units.
COMPRESSOR ROTATION — On 3- - phase units with
scroll compressors, it is important to be certain that the
compressor is rotating in the proper direction. 38AUD units
are equipped with a Comfort Alert Diagnostic Module
(CADM). Alert Code 7 indicates reverse power phasing.
To correct phase order:
1. Turn off power to the unit, tag disconnect.
2. Reverse any two of the unit power leads.
3. Reapply power to the compressor, verify correct pres-
sures.
To verify the compressor is rotating in the proper direction:
1. Connect service gages to the suction and liquid pres-
sure fittings.
2. Energize the compressor.
3. The suction pressure should drop and the liquid pres-
sure should rise, as is normal on any start- - up.
17
added to avoid possible
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