Daikin VRV Plus Series General Information Manual page 145

Si33-003.book Page 141 Monday, June 25, 2001 9:06 AM
SiE33-003
5. Pipe Connection
Note: Refrigerant Pipe Flushing
Flushing removes foreign particles from the inside of pipes by means of nitroren gas pressure.
<Three main effects>
1. Removes oxidized film inside copper pipes generated by insufficient charging of nitrogen gas during
2. Removes foreign particles and moisture that entered pipes due to inadequate preparation.
3. Confirms connection of pipes between indoor and outdoor units (for both liquid and gas pipes).
<Procedure>
1. Mount a pressure reducing valve on the nitrogen cylinder.
2. Connect the charge hose of the pressure reducing valve to the service port of the liquid pipe of outdoor
3. Mount a blind plug on indoor unit (B). Do not mount a blind plug on unit A.
4. Open the main valve of the nitrogen cylinder, and adjust the pressure reducing valve until the pressure
5. Make sure that the nitrogen gas is released through the liquid pipe of unit A.
6. Flushing
*
7. Close the main valve of the nitrogen cylinder.
8. Repeat the same procedure for unit B.
9. After completing the flushing for the liquid pipes, conduct flushing for the gas pipes.
Installation Manual
Apply ether or ester oil around the flare portions before connecting.
Only proceed with brazing after carrying out "Refrigerant pipe flushing" (note) or while releasing
nitrogen into the refrigerant piping (note).
If brazing is done without "Refrigerant pipe flushing" or without nitrogen being released into the piping, a
thick oxidized film will form on the inside of the piping, affecting the valves and compressors in the
refrigerant system, and making normal operation difficult.
brazing.
* Be sure to use a nitrogen gas. (Use of oxygen gas prohibited.)
unit.
becomes 0.5 MPa.
Close the pipe end with the palm of the hand.
When the pressure becomes high, move the hand quickly.
(1st flushing)
Close the pipe end with the palm of the hand again.
(Conduct the 2nd flushing.)
During the flushing process, place a clean cloth at the pipe end, and check the content and amount of
the removed foreign particles. If even a small amount of moisture is found, be sure to remove all
moisture from inside the pipe.
Procedure
(1) Conduct flushing using a nitrogen gas (until no moisture comes out).
(2) Conduct vacuum drying.
1
3
10
4
2
A B
6
5
7
8
9
13
15
1. Pressure reducing valve
2. Gas pipe
3. Outdoor unit
11 12
4. Liquid pipe
5. Gas pipe
6. Liquid pipe
7. Blind plug (Brass)
8. Flare nut
9. Copper pipe
10.Main valve
11 Primary side
12.Secondary side:0.5MPa
14
13.Nitrogen gas
14.Pressure reducing valve
15.Pressure: 0.5 MPa
Fig. 14
(V0862)
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Refrigerant Piping
141