Daikin REYQ72-432XAYCU, Service Manual

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SiUS371901EB Check
Part 6 Service Diagnosis 428
4.7 Vacuuming and Dehydration Procedure
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 –100.7 kPaG (–14.6 psiG, 5 Torr, –755
mmHgG).

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 –100.7 kPaG (–14.6
psiG) or less.
 If the degree of vacuum does not reach –100.7 kPaG (–14.6 psiG) 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 –100.7 kPaG (–14.6 psiG) 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 –100.7 kPaG (–14.6 psiG) 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 0.05 MPaG (7.3 psiG).
3. Vacuuming and dehydration
 Conduct vacuuming and dehydration for a period of 1 hour or more. If the degree of vacuum
does not reach –100.7 kPaG (–14.6 psiG) 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 –100.7 kPaG (–14.6 psiG) 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.
CHECK 8