| After extract N2 gas for pressure/leak test,
vacuum test to be carried out for leakage detection and |
| drying of system with vacuum pump. If ambient
temperature is below |
| 5°C, system to be heated to prevent water freezing
in the system. Especially, the place where |
| moisture can remain in the system is to be heated
partially. |
| Keep ambient temperature above 16°C as far as
possible to speed up the evaporation of moisture. |
|
| "CAUTION"
|
Do
not attempt dehydration if ambient temperature is below 5°C |
|
Moisture
may freeze in the system. |
| |
|
| 1. |
Vacuum pump to be connected to liquid charging
valve with connector. |
| 2. |
Vacuum indicator to be installed between the
charging valve and the suction valve of the |
| |
vacuum pump. |
| 3. |
Lubricating oil of the vacuum pump to be fresh
and clean. And to be confirmed suitable quantity |
| |
of oil before start-up. |
| 4. |
Vacuum dehydration to be carried out after oil
charging in crank-case of the compressor so as |
| |
to dehydrate Iubricationg oil. |
| 5. |
Open compressor stop valve and all stop valve
in the system. Close all valves and connections |
| |
to atmosphere. |
| |
Be sure to open expansion valve, solenoid valve,
pressure regulating valve and all valves which |
| |
are connected to the high and low sides of system
and allow the pump to draw a vacuum on |
| |
entire system. |
| 6. |
Open shut-off valve in pump suction line, start
vacuum and open charging valve and suction |
| |
side stop valve of compressor. |
| 7. |
Vacuum pump to be operated until the vacuum
indicator indicates high vacuum so that the |
| |
moisture contained in lubricating oil in the
refrigerating system can be sufficiently evaporated an |
| |
extracted |
| 8. |
Continue dehydrating until a vacuum of 50 mm
hg absolute pressure in reached on vacuum |
| |
indicator. |
| 9. |
When dehydration is completed, hold vacuum for
minimum twelve(12) hours and observe vacuum |
| |
indicator reading continuously and ascertain
that the pressure rising rate in the system is 1mm Hg |
| |
per one hour or less. |
| 10. |
If system holds vacuum, disconnect indicator
and connect a refrigerant, R-134a bottle to . |
| |
charging connection. The system is now ready
for charging and operation |
