—15—
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.
I. SYSTEM CHECK
1. Check all air handler(s) and other equipment auxil-
iary components. Consult the manufacturer’s instruc-
tions regarding any other equipment connected to the
condensing unit. If unit has field-installed accesso-
ries, be sure all are properly installed and correctly
wired. If used, airflow switch must be properly
installed.
2. Backseat (open) compressor suction and discharge
valves. Now close valves one turn to allow refrigerant
pressure to reach test gages.
3. Open liquid line service valve.
4. Check tightness of all electrical connections.
5. For 576C, 566D units only, compressor oil level
should be visible in sight glass. Refer to Check Com-
pressor Oil Level. Adjust the oil level as required.
Refer to Start-Up, Preliminary Oil Charge section.
No oil should be removed unless the crankcase heater
has been energized for at least 24 hours.
6. Be sure unit is properly leak checked, dehydrated,
and charged. See Preliminary Charge, this page.
7. Electrical power source must agree with nameplate
rating.
8. Crankcase heater must be firmly locked into compres-
sor crankcase. Be sure crankcase is warm (heater
must be on for 24 hours before starting compressor).
9. Be sure compressor floats freely on the mounting
springs and that snubber washers can be moved with
finger pressure. See Compressor Mounting, page 9,
and Fig. 5 for loosening compressor bolts.
II. LEAK TEST AND DEHYDRATION
Leak test the entire refrigerant system using soap bubbles
and/or an electronic leak detector. Evacuate and dehydrate
entire refrigerant system.
III. TURN ON CRANKCASE HEATER
Turn on 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.
3. Turn the fan circuit breaker on. Leave the compres-
sor circuit breakers off. The crankcase heater is now
energized.
IV. 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 added must be at least 80% of the
operating charge listed in the Physical Data table (Tables
1A-1C, pages 6-8). 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, Charg-
ing, Recover, Recycling, and Reclamation for liquid charging
procedures.
START-UP
I. 569D, 566E, 569F UNITS
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 has elapsed since the preliminary
charge step has been completed, it is unnecessary to wait the
24-hour period.
A. Preliminary Checks
1. Ensure that compressor service valves are back-
seated.
2. Verify that each compressor floats freely on its
mounting springs.
3. Check that electric power supply agrees with unit
nameplate data.
4. Verify that compressor crankcase heater is securely
in place.
5. Check that compressor crankcase heater has been on
at least 24 hours.
6. Recheck for leaks using same procedure as previously
outlined in Pre-Start-Up section, Leak Test and
Dehydration.
7. If any leaks are detected, evacuate and dehydrate as
previously outlined in Pre-Start-Up section, Leak
Test and Dehydration.
8. All internal wiring connections must be tight, and all
barriers and covers must be in place.
NOTE: The 569D, 566E, 569F units do not have a compressor
oil level sight glass. These units are factory changed with the
required amount of oil. If recharging is required, use Zerol
150 for the 569F, 569D072, and 569D090. Use Replacement
Components Division Oil (P/N P903-0101) for the 569D120
and 566E150-240.
B. Compressor Rotation
On 3-phase units with scroll compressors, it is important to
be certain compressor is rotating in the proper direction. To
determine whether or not compressor is rotating in the
proper direction:
1. Connect service gages to suction and discharge pres-
sure fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge
pressure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge
pressure does not rise to normal levels:
1. Note that the condenser fan is probably also rotating
in the wrong direction.
2. Turn off power to the unit, tag disconnect.
3. Reverse any two of the unit power leads.
4. Reapply power to the compressor, verify correct
pressures.
The suction and discharge pressure levels should now move
to their normal start-up levels.
CAUTION: Do not attempt to start the condensing
unit, even momentarily, until the following steps have
been completed. Compressor damage may result.
CAUTION: Prior to starting compressor, refriger-
ant equal to operating charge must be added to avoid
possible compressor damage. See Tables 1A-1C.
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