DENSO CORPORATION CLASSIC PLUS 26 - Manual (Page 40)

TROUBLESHOOTING AND REPAIR
32
16. Inspection of High Pressure Switch
Check for continuity across both terminals of the
high pressure switch or the J104 connector. With
pressure equalized when the unit is stopped,
there should be continuity across both terminals
and the J104 connector. If there is no continuity
(open circuit), replace the high pressure switch.
Specifications:
Cut off pressure - 29.5kg/cm
2 G (420 PSIG)
Reset pressure - 20.5kg/cm 2 G (291 PSIG)
17. Inspection of Wiring Connection
Refer to the Wiring Diagrams (pg. 40) and check
for connection of each wire.
18. Inspection of Thermistor(s)
Using an Ohmeter, check the resistance value
across the 2-Pin connector. At normal temperature (77˚F, 25˚C) either thermistor (Room or Freeze) should
measure approx. 10,000 or 10k ohms.
19. 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.
20. 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 overheating of flux.