Vacuum Dry Procedure - York R-410A Technical & Service Manual

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3) Vacuum dry procedure

There are two methods of vacuum dry due to different construction environment:
common vacuum dry, special vacuum dry.
Common vacuum dry procedure
Vacuum dry (for the first time)---connect the all-purpose detector to the inlet of liquid
pipe and gas pipe, and run the vacuum pump more than two hours (the vacuum pump should be
below -755mmHg)
If the pump can't achieve below -755mmHg after pumping 2 hours, moisture or leakage
point will still exist in the pipe. At this time, it should be pumped 1 hour more.
If the pump can't achieve -755mmHg after pumping 3 hours, please check if there's some
leakage points.
Vacuum placement test: place 1 hour when it achieves -755mmHg, pass if the vacuum
watch shows no rising. If it rises, it shows there's moisture or leakage point.
Vacuuming from liquid pipe and gas pipe at the same time.
Sketch map of common vacuum dry procedure.
Special vacuum dry procedure
This vacuum dry method is used in the following conditions:
- There's moisture when flushing the refrigerant pipe.
- Rainwater may enter into the pipe.
Vacuum dry for the first time 2h pumping
Vacuum destroy for the second time Fill nitrogen to 0.5Kgf/cm2 because nitrogen is for
drying gas, it has vacuum drying effect during vacuum destroy. But if the moisture is too much,
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Installation