S-18D Operation Test; S-18E Checking 3-Phase Scroll Compressor Rotation - Daikin DAR09 Service Instructions Manual

SERVICING
1. Operate the system and measure compressor current. Cycle
the unloader ON and OFF at 10 second intervals. The com-
pressor amperage should go up or down at least 25 percent.
2. If step one does not give the expected results, shut unit off.
Apply 18 to 28 volt ac to the unloader molded plug leads and
listen for a click as the solenoid pulls in. Remove power and
listen for another click as the unloader returns to its original
position.
3. If clicks can't be heard, shut off power and remove the con-
trol circuit molded plug from the compressor and measure
the unloader coil resistance. The resistance should be 32 to
60 ohms, depending on compressor temperature.
4. Next check the molded plug.
a. Voltage check: Apply control voltage to the plug wires
(18 to 28 volt ac). The measured dc voltage at the female
connectors in the plug should be around 15 to 27 vdc.
b. Resistance check: Measure the resistance from the end
of one molded plug lead to either of the two female connec-
tors in the plug. One of the connectors should read close to
zero ohms while the other should read infinity. Repeat with
other wire. The same female connector as before should
read zero while the other connector again reads infinity.
Reverse polarity on the ohmmeter leads and repeat. The
female connector that read infinity previously should now
read close to zero ohms.
c. Replace plug if either of these test methods doesn't
show the desired results.

S-18D OPERATION TEST

If the voltage, capacitor, overload and motor winding test fail to
show the cause for failure:
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing. Multiple power sources
may be present. Failure to do so may
cause property damage, personal injury
or death.
1. Remove unit wiring from disconnect switch and wire a test
cord to the disconnect switch.
NOTE: The wire size of the test cord must equal the line wire
size and the fuse must be of the proper size and type.
2. With the protective terminal cover in place, use the three
leads to the compressor terminals that were disconnected
at the nearest point to the compressor and connect the
common, start and run clips to the respective leads.
3. Connect good capacitors of the right MFD and voltage rating
into the circuit as shown.
4. With power ON, close the switch.
WARNING
Line Voltage now present.
a. If the compressor starts and continues to run, the cause for
failure is somewhere else in the system.
b. If the compressor fails to start - replace.
COPELAND COMPRESSOR
03 A
YEAR
MONTH
S-18E CHECKING 3-PHASE SCROLL
COMPRESSOR ROTATION
Verify the proper rotation of Copeland scroll compressors as
follows:
NOTE: The compressor may run backwards (noisy operation) for
1 or 2 seconds at shutdown. This is normal and does not harm
the compressor.
1. Install gauges and verify that the suction pressure drops
while the discharge pressure increases.
2. Listen for normal compressor sound levels. Reverse rotation
results in elevated or unusual sound levels.
3. Reverse rotation will result in substantially reduced amp
draw from tabulated values.
To correct improper rotation, switch any two power supply leads
at the outdoor unit contactor.
The 3-phase scroll compressors are direction of rotation sen-
sitive. They will rotate in either direction depending on the
phasing of the power. There is no negative impact on durability
caused by operating 3-phase compressors in reversed rotation.
The compressor's internal protector will trip, de-energizing the
compressor. Continued operation of 3-phase scroll compressors
with the rotation reversed will contribute to compressor failure.
All 3-phase scroll compressors should be checked for correct
phase rotation.
S-18 TESTING CRANKCASE HEATER
(OPTIONAL ITEM)
The crankcase heater must be energized a minimum of four (4)
hours before the condensing unit is operated.
Crankcase heaters are used to prevent migration or accumula-
tion of refrigerant in the compressor crankcase during the off
cycles and prevents liquid slugging or oil pumping on start up.
A crankcase heater will not prevent compressor damage due to a
floodback or over charge condition.
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