Daikin REQ71B7V3B [10/16] Vacuating
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Daikin REQ71B7V3B [10/16] Vacuating

Daikin REQ71B7V3B [10/16] Vacuating
Installation manual
7
REQ71+100B7V3B + REQ71~125B7W1B
Split System air conditioners
4PW19495-1B
■ Be sure to insulate the liquid and gas-side field piping.
(The highest temperature that the gas-side piping can reach is
around 120°C, so be sure to use insulating material which is
very resistant.) (See figure 8)
1 Compressor
2 Ter minal cover
3 Indoor and outdoor field piping
4 Corking, etc.
5 Insulation material
6 Bolts
A Be carefull with pipe, bolt and outer panel connections
Cautions for flare connection
■ Please refer to the table for the dimensions for processing flares
and for the tightening torques. (Too much tightening will end up
in splitting of the flare.)
■ When connecting the flare nut, apply refrigerating machine oil to
the flare (inside and outside) and first screw the nut 3 or 4 turns
by hand.
Coat here with ether or ester oil.
■ After completing the installation, carry out a gas leak inspection
of the piping connections with nitrogen and such.
Cautions for necessity of a trap
Since there is fear of the oil held inside the riser piping flowing back into
the compressor when stopped and causing liquid compression
phenomenon, or cases of deterioration of oil return, it will be necessary
to provide a trap at an appropriate place in the riser gas piping.
■ Trap installation spacing. (See figure 3)
A Outdoor unit
B Indoor unit
C Gas piping
D Liquid piping
E Oiltrap
H Install trap at each difference in height of 15 m.
■ A trap is not necessary when the outdoor unit is installed in a
higher position than the indoor unit.
Cautions for brazing
■ Be sure to carry out a nitrogen blow when brazing.
Brazing without carrying out nitrogen replacement or releasing
nitrogen into the piping will create large quantities of oxidized
film on the inside of the pipes, adversely affecting valves and
compressors in the refrigerating system and preventing normal
operation.
■ When brazing while inserting nitrogen into the piping, nitrogen
must be set to 0.02 MPa with a pressure-reducing valve (=just
enough so that it can be felt on the skin). (See figure 6)
1 Refrigerant piping
2 Part to be brazed
3 Taping
4 Hands valve
5 Pressure-reducing valve
6 Nitrogen
EVACUATING
■ Do not purge the air with refrigerants. Use a vacuum pump to
vacuum the installation. No additional refrigerant is provided for
air purging.
■ Pipes inside the units were checked for leaks by the
manufacturer. The refrigerant pipes fit on site are to be checked
for leaks by the installer.
■ Confirm that the valves are firmly closed before leak test or
vacuuming.
Set up for vacuuming and leak test: (See figure 5)
Procedure for leak test
Leak test must satisfy EN378-2.
NOTE
Any exposed piping may cause condensation or burns
if touched.
Piping
size
Flare nut
tightening torque
A dimensions
for processing
flares (mm)
Flare shape
Ø9.5
32.7~39.9 N•m
(333~407 kgf•cm)
12.8~13.2
Ø15.9
61.8~75.4 N•m
(630~770 kgf•cm)
19.3~19.7
Ø19.1
97.2~118.6 N•m
(989.8~1208 kgf•cm)
23.6~24.0
R=0.4~0.8
45°
±2
90°
±2
A
1 Pressure gauge
2 Nitrogen
3 Refrigerant
4 Weighing machine
5 Vacuum pump
6 Stop valve
1
Evacuate the pipes and check vacuum
(1)
. (No pressure
increase for 1 minute.)
(1) Use a 2-stage vacuum pump with a non return valve which
can evacuate to –100.7 kPa (5 Torr, –755 mm Hg).
Evacuate the system from the liquid and gas pipes by using
a vacuum pump for more than 2 hours and bring the system
to –100.7 kPa. After keeping the system under that condition
for more than one hour, check if the vacuum gauge rises or
not. If it rises, the system may either contain moisture inside
or have leaks.
2
Break the vacuum with a minimum of 2 bar of nitrogen. (Never
pressurize more than 4.15 MPa.)
3
Conduct leak test by applying soap water, etc. to the connecting
part of the pipes.
4
Discharge nitrogen.
5
Evacuate and check vacuum again
(1)
.
6
If vacuum gauge does no longer rise, the stop valves can be
opened.

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