PREVOST LE MIRAGE XLII BUS SHELLS, Руководство по обслуживанию

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Section 22: HEATING AND AIR CONDITIONING
PA1564
36
VAPOR-PRESSURE
TEMPERATURE PRESSURE
°F °C psi kPa
190 87.8 433.6 2989.7
200 93.3 485.0 3344.1
210 98.9 540.3 3725.4
9.11 TORCH BRAZING
Use an electrode containing 35% silver.
CAUTION
When using heat near a valve, wrap with a rag
saturated with water to prevent overheating of
vital parts.
DANGER
Before welding any part of refrigeration
system, make sure the area is well ventilated.
9.12 LEAK TESTING
Some methods such as nitrogen pressure and
soap, and electronic sniffer can be used for leak
testing. However, the most common method
used is a "Halide" torch consisting of an
acetylene tank, a burner and a suction test
hose. Proceed as follows:
DANGER
Do not inhale fumes from leak detector.
The flow of acetylene to the burner causes
suction in the test line. Any gas refrigerant
present will be drawn through the hose and into
the burner where it decomposes into free acids.
These acids come in contact with the hot copper
reaction plate in the burner, causing color
reaction in the flame. A small concentration is
indicated by a green tint and a large
concentration by an intense blue. Do not
confuse this change in color with the change
caused by shutting off the air supply through the
hose by holding the end too close to an object.
The procedure for testing is:
1. Adjust flame so that the top of the cone is
approximately level or within one-half inch
above the plate.
2. Probe end of suction test tube around all
joints, valves, etc. When a leak has been
found at a soldered joint, this section of the
system must be pumped down. Do not
solder as pressure will force hot solder out.
If the system is empty, it is more
economical to put in just enough R-134a to
produce about 15 psi (103 kPa). The
pressure can be raised to about 150 psi
(1034 kPa) with dry nitrogen.
NOTE
This gas is put into the suction and discharge
shutoff valves at the compressor. The receiver
valves must be opened. If no leaks are found,
dump this mixture, evacuate the system and
fill with refrigerant.
10. SMALL HVAC SYSTEM - AIR
CONDITIONING COMPONENTS
10.1 COMPRESSOR
Consult the SANDEN SD Compressor Service
Manual included at the end of this section.
WARNING
Read the cautionary information in the
SANDEN SD Compressor Service Manual
included at the end of this section.
10.2 COMPRESSOR REMOVAL
10.2.1 When the compressor is operational
* Perform the “OIL RETURN OPERATION”
(Refer to paragraph 10.5).