Daikin VRV RXYQ72-384XAYCA, Service Manual

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Check SiUS342004EB
365 Part 6 Service Diagnosis
4.7 Vacuuming and Dehydration Procedure
CHECK 8
Conduct vacuuming and dehydration in the piping system following the procedure for Normal
vacuuming and dehydration described below.
Furthermore, if moisture may get mixed in the piping system, follow the procedure for Special
vacuuming and dehydration described below.
Normal vacuuming and dehydration
1. Vacuuming and dehydration

Use a vacuum pump that enables vacuuming up to 500 microns.

Connect manifold gauges to the service ports of liquid pipe and gas pipe and run the
vacuum pump for a period of 2 or more hours to conduct evacuation to 500 microns.

If the degree of vacuum does not reach 500 microns or less even though evacuation is
conducted for a period of 2 hours, moisture will have entered the system or refrigerant
leakage will have been caused. In this case, conduct evacuation for a period of another 1
hour.

If the degree of vacuum does not reach 500 microns or less even though evacuation is
conducted for a period of 3 hours, conduct the leak tests.
2. Leaving in vacuum state

Leave the compressor at the degree of vacuum of 500 microns or less for a period of 1 hour
or more, and then check to be sure that the vacuum gauge reading does not rise. (If the
reading rises, moisture may have remained in the system or refrigerant leakage may have
been caused.)
3. Additional refrigerant charge

Purge air from the manifold gauge connection hoses, and then charge a necessary amount
of refrigerant.
Special vacuuming and dehydration
Use this procedure if moisture may get into the piping, such as construction during the rainy season
(dew condensation may occur, or rainwater may enter the piping during construction work).
1. Vacuuming and dehydration

Follow the same procedure as that for normal vacuuming and dehydration described above.
2. Vacuum break

Pressurize with nitrogen gas up to 375,000 microns.
3. Vacuuming and dehydration

Conduct vacuuming and dehydration for a period of 1 hour or more. If the degree of vacuum
does not reach 500 microns or less even though evacuation is conducted for a period of 2
hours or more, repeat vacuum break - vacuuming and dehydration.
4. Leaving in vacuum state

Leave the compressor at the degree of vacuum of 500 microns or less for a period of 1 hour
or more, and then check to be sure that the vacuum gauge reading does not rise.
5. Additional refrigerant charge

Purge air from the manifold gauge connection hoses, and then charge a necessary amount
of refrigerant.