S-17B Ground Test; S-17D Operation Test; Testing Crankcase Heater (Optional Item) - Daikin DCH048 Series Service Instructions Manual

SERVICING

S-17B GROUND TEST

If fuse, circuit breaker, ground fault protective device,
etc., has tripped, this is a strong indication that an
electrical problem exists and must be found and cor-
rected. The circuit protective device rating must be
checked, and its maximum rating should coincide with
that marked on the equipment nameplate.
With the terminal protective cover in place, it is accept-
able to replace the fuse or reset the circuit breaker ONE
TIME ONLY to see if it was just a nuisance opening. If
it opens again, DO NOT continue to reset.
WARNING
Disconnect ALL power before servicing.
Disconnect all power to unit, making sure that all
power legs are open.
1. DO NOT remove protective terminal cover. Discon-
nect the three leads going to the compressor termi-
nals at the nearest point to the compressor.
2. Identify the leads and using a Megger, Hi-Potential
Ground Tester, or other suitable instrument which
puts out a voltage between 300 and 1500 volts, check
for a ground separately between each of the three
leads and ground (such as an unpainted tube on the
compressor). Do not use a low voltage output
instrument such as a volt-ohmmeter.
HI-POT
COMPRESSOR GROUND TEST
3. If a ground is indicated, then carefully remove the
compressor terminal protective cover and inspect for
loose leads or insulation breaks in the lead wires.
4. If no visual problems indicated, carefully remove the
leads at the compressor terminals.
WARNING
Damage can occur to the glass embedded terminals if
the leads are not properly removed. This can result in
terminal and hot oil discharging.
Carefully retest for ground, directly between com-
pressor terminals and ground.
5. If ground is indicated, replace the compressor.
24

S-17D 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 this unit. 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 discon-
nected 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.
S-18 TESTING CRANKCASE HEATER (OP-
TIONAL ITEM)
Note: Not all compressors use crankcase heaters.
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 accumu-
lation 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.
WARNING
Disconnect ALL power before servicing.
1. Disconnect the heater lead in wires.
2. Using an ohmmeter, check heater continuity - should test
continuous. If not, replace.