AUX-DC inverter ARV outdoor unit individual series technical manual
106
Note:
1. Under the normal air pressure, the boiling point of water (steam temperature) is 100℃, but the pressure in
vacuum pump pipe is near vacuum, this makes the boiling point lower to below the outside air
temperature, and the water in the pipe is evaporated.
2. After the vacuuming process of R410A refrigerant circulation system is complete, vacuum pump will
stoprunning. As a result of suction in the in the air conditioning system, vacuum pump lubricant will seep
back intothe system. Thissituation will also occur if vacuum pump suddenly stops during operation. It
willcause different oils mix, leading to system malfunction, therefore it is recommended to use one-way
valve toprevent reverse flow of oil in vacuum pump.
Example:When the ambient temperature is 7.2℃, vacuuming can be carried out under -752mmHg.
3.8.3 Operation procedure
There are two vacuum drying methods: common and special.
Ordinary vacuum drying
1. Connect the pressure gauge to the infusing mouth of gas and liquid pipe, keep vacuum pump running
for atleast 2 hours, ensures vacuum degree o is below -14.6PSI(-755mmHg).
2. If the vacuum degree is not below -14.6PSI(-755mmHg) after 2 hours of drying, system will continue
dryingfor 1 hour.
3. If the vacuum degree is not be below -14.6PSI(-755mmHg) after 3 hours of drying, check the system
forleaks.
4. Vacuum placement test: when the vacuum degree reaches -14.6PSI(-755mmHg), keep for 1 hour. If
thevacuum gauge indicator does not increase, the process is complete. If the vacuum gauge
increases, itindicates of moisture or a leak.
5. Vacuum drying shall be conducted from liquid and gas pipe simultaneously. There are a lot of
functionalparts like valves, which could shut down the gas flow midway.
Special vacuum drying
Special vacuum drying method shall be adopted when:
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