TROUBLESHOOTING AND REPAIR
32
18. Inspection
In most cases, the probable cause for insufficient cooling is a clogged system, leakage or an incorrect
amount of refrigerant. In such cases, inspect the system according to the following procedure.
A. Inspection of Clogged System
Check the component parts of the refrigerant system, including piping, that could be clogged with
refrigerant. If clogged with refrigerant, only the clogged part is frosted partially. In such a case, change
the part in question.
B. Inspection of Refrigerant Leak
Carefully check all connections, and each component for leaks whenever the refrigerant system is
installed or repaired. Use an electronic gas leak tester to inspect the system.
C. Insufficient Refrigerant
In case the unit is judged to be deficient in cooling capacity, be sure to perform the inspections in
A. and B. to confirm the cause of trouble. After that, charge the system with refrigerant to the specified
amount.
19. Repair of Refrigerant System
In case there is a leak, obstruction, or trouble in the refrigerant system of the Spot Cooling System, replace
or repair the part in question. After replacing any component all connections must be brazed.
A. Proper Brazing Techniques
It is desirable to use a slightly reducing flame. Oxyacetylene is commonly used since it is easy to judge
and adjust the condition of the flame. Unlike gas welding, a secondary flame is used for brazing. It is
necessary to preheat the base metal properly depending on the shape, size or thermal conductivity of
the brazed fitting.
The most important point in flame brazing is to bring the whole brazed fitting to a proper brazing
temperature. Care should be taken to not cause overflow of brazing filler metal, oxidization of brazing
filler metal, or deterioration due to the over-
heating of flux.
•
BRAZED FITTING AND ITS CLEARANCE
In general, the strength of brazing filler metal
is lower than that of the base metal. So, the
shape and clearance of the brazed fitting are
quite important. As for the shape of the
brazed fitting, it is necessary to
maximize its
adhesive area
. The clearance of the brazed
fitting must be minimized to facilitate brazing
filler metal to flow into it by capillary action.
•
CLEANING OF BRAZING FILLER METAL
AND PIPE
When the refrigerant system has been
opened up, exposure to heat may have
caused brazing filler metal to stick to the
inside and outside of the pipe. Brazing filler
metal may also be compounded with oxygen
in the air to form oxide film. Fats and oils
may stick to the pipe from handling. All these
factors will reduce effectiveness of brazing. It
is necessary to eliminate excess brazing filler
Brazed Fitting and Clearance
Summary of Contents for Classic Plus 14
Page 1: ...SERVICE MANUAL CLASSIC PLUS 14 ...
Page 3: ...ii ...
Page 5: ...iv ...
Page 7: ...GENERAL DESCRIPTION 2 ...
Page 46: ...DSCA P N LA990009 0379 ...
