29
Section C - Components, cont’d.
The start capacitor must be manually discharged. Using
an AC voltmeter set at the 500 volt scale or higher, connect
meter leads to the terminals of the capacitor. Next, discon-
nect the wires to the capacitor. Set the dial-type VOM to
the highest ohm scale and connect the probes to the ca-
pacitor terminals. The reading should rapidly move toward
continuity and slowly return to infinity. Next, reverse the
leads and repeat the procedure. If there is no reading or a
prolonged reading, replace the start capacitor.
C5. PTCR Device or Start Relay
The positive temperature coefficient resistor, or PTCR has
replaced the compressor start relay and the start capacitor
on some models. It should be checked in two different ways:
First check continuity. Turn the air conditioner circuit breaker
to OFF. Disconnect the PTCR from the circuit. Check for
continuity. If there is no continuity, replace PTCR.
This is an energized circuit. Shock can occur
if not tested properly. Testing to be done by a
qualified service technician.
The second check to take is an amperage reading. Clamp
an ammeter around the wire from the PTCR to the capaci-
tor. Turn the air conditioner circuit breaker to ON and start
the air conditioner. When the compressor starts, there will
be an amperage reading for approximately one second or
less. If there is no reading, or if there is a prolonged read-
ing, the PTCR or start relay is faulty and must be replaced.
FIG. C8
C5. Compressor
To check compressor, turn the air conditioner circuit breaker
to OFF. Disconnect the wires from the COMMON, START
and RUN terminals. With the ohm meter set on the lowest
ohm scale, check for continuity between all three termi-
nals. Lack of continuity between any of the terminals indi-
cates faulty windings in the compressor, and the compres-
sor should be replaced. Next, scrape some paint off the
casing of the compressor and check for continuity between
each terminal and the casing. If a reading is obtained, the
windings are shorted to the casing and compressor must
be replaced.
FIG. C9
Manual
Compliments
of
Northwest
RV
Supply
Printed
From
http://www.nwrvsupply.com
