Service manual

13
1. Most all electronic leak detectors are very sensitive
and are field reliable. A word of warning – do not
“give it a whiff of refrigerant” as a test to see if it is
working because its sensitivity and life expectancy
diminishes as it is exposed to refrigerant.
Always use this instrument as a final leak test. It
will find the very small leaks that take several weeks
to cause trouble but will cause a burn out if not
repaired.
2. With an electronic leak detector, a leak is sometimes
difficult to pinpoint – you can find the general area
of the leak, but not its exact location. A soap bubble
type leak detector will show its exact location.
9. Brazing Equipment
For all brazing work, you need a torch type that burns with a
soft flame that is easy to control and is hot enough for brazing
refrigerant tubes. The easiest and most satisfactory brazing
rod to use is Sil Fos or Stay Silv – 15% silver. This rod can
be used to blend with any brazing rod that exists on today’s
units.
CAUTION
Always have a dry powder fire
extinguisher with you (not in your truck)
while you are brazing.
10. Gauge Manifold
Gauge manifold sets are used for checking pressures,
evacuating and recharging the a/c.
Basically a gauge manifold consists of a compound gauge and
a high pressure gauge mounted on a manifold with hand
valves to isolate the common (center) connection or open it to
either side as desired.
Connecting the gauge manifold to the system is necessary to
read the suction pressure and head pressure, and to
intelligently analyze a system for malfunction. Any service
technician will naturally hesitate to connect his gauges
because to do so involves opening a hermetic system.
The R-22 that is in the system will have to be released to a
refrigerant recovery system (see equipment manufacturer’s
guide for system access information).
V. SERVICE PROBLEMS AND
THEIR SOLUTIONS
When a recreational vehicle owner calls for service on his air
conditioner, let him explain exactly what has happened; when
the air conditioner first gave him trouble, what is sounded
like, how hot was the weather, what time was it, etc. He is a
rich source of information. Listen to everything he says. You
will compliment him and he will help you to identify the
problem.
Always be alert for a customer who has been working on his
own equipment. Check all wiring and visually inspect all
motors, fans, capacitors, dampers, tubing, etc.
When a Service Technician gets all the information he can
from the customer, he then examines the equipment for more
facts that might lead to the cause of the problem (always be on
the alert for loose or burned wires, smoke stains, kinked or
broken tubes, oil stains, etc. - those things which would
obviously cause a malfunction or would indicate a
malfunction).
After he gets all the available information together, he starts
asking himself questions:
“What causes has the information eliminated and why?” (For
instance, if the compressor is running, that eliminates a
tripped circuit breaker as the cause of the problem.)
“What are the possible causes?”
“Which of the possible causes are the most probable ones?”
“How should I check them out?”
For each of his questions, he expects an answer. Since there is
no one else around qualified to answer his questions, he must
supply the answers himself.
As his questions and answers eliminate the possible causes one
by one, he will soon identify the reason for the malfunction.
Then he can repair it.
ISOLATE THE PROBLEM – THE SOLUTION IS SIMPLE.
Problem
1. Nothing runs.
The customer turns the selector switch to the “Cool” position
and the thermostat to a low temperature (below room
temperature) and nothing happens. This is surely a serious
problem, but it is usually the easiest to correct.
Question: “What are the possible causes?”
Answer:
1. “The power supply could be dead.” Check for open circuit breaker or
fuse at service panel. Check for 115 volts domestic USA models or
240 volts export/overseas models between hot line (black) and neutral
(white) at power entrance at unit.