Friedrich KM21J30 Manuel D’Utilisation
Page 8
COMPONENTS OPERATION & TESTING
WARNING
DISCONNECT ELECTRICAL POWER TO
UNIT BEFORE SERVICING OR TESTING
COMPRESSORS
Compressors are single phase, 15 or 230/208 volt, de-
pending on the model unit. All compressor motors are
permanent split capacitor type using only a running ca-
pacitor across the start and run terminal.
pending on the model unit. All compressor motors are
permanent split capacitor type using only a running ca-
pacitor across the start and run terminal.
All compressors are internally spring mounted and ex-
ternally mounted on rubber isolators.
ternally mounted on rubber isolators.
COMPRESSOR WINDING TEST (See Figure 1)
Remove compressor terminal box cover and disconnect
wires from terminals. Using an ohmmeter, check conti-
nuity across the following:
wires from terminals. Using an ohmmeter, check conti-
nuity across the following:
1.
Terminal “C” and “S” - no continuity - open wind-
ing - replace compressor.
ing - replace compressor.
2.
Terminal “C” and “R” - no continuity - open wind-
ing - replace compressor.
ing - replace compressor.
3.
Terminal “R” and “S” - no continuity - open wind-
ing - replace compressor.
ing - replace compressor.
Figure 1:
Compressor Winding Test
GROUND TEST
Use an ohmmeter set on its highest scale. Touch one
lead to the compressor body (clean point of contact as
a good connection is a must) and the other probe in
turn to each compressor terminal (see Figure 2.) If a
reading is obtained, the compressor is grounded and
must be replaced.
lead to the compressor body (clean point of contact as
a good connection is a must) and the other probe in
turn to each compressor terminal (see Figure 2.) If a
reading is obtained, the compressor is grounded and
must be replaced.
Figure 2:
Typical Ground Test
CHECKING COMPRESSOR EFFICIENCY
The reason for compressor inefficiency is normally due
to broken or damaged suction and/or discharge valves,
reducing the ability of the compressor to pump refriger-
ant gas.
to broken or damaged suction and/or discharge valves,
reducing the ability of the compressor to pump refriger-
ant gas.
This condition can be checked as follows:
1.
Install a piercing valve on the suction and dis-
charge or liquid process tube.
charge or liquid process tube.
2.
Attach gauges to the high and low sides of the
system.
system.
3.
Start the system and run a “cooling or heating
performance test.”
performance test.”
If test shows:
A. Below normal high side pressure.
B. Above normal low side pressure.
C. Low temperature difference across coil.
The compressor valves are faulty - replace the
compressor.
compressor.
THERMAL OVERLOAD (External)
Some compressors are equipped with an external over-
load which is located in the compressor terminal box
adjacent to the compressor body (see Figure 3.)
load which is located in the compressor terminal box
adjacent to the compressor body (see Figure 3.)