Daikin VRV System R-22 PLUS Series Manual page 148

Si33-102.book Page 146 Tuesday, June 26, 2001 3:18 PM
Refrigerant Piping
5. Pipe Connection Apply the refrigerant 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.
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
brazing.
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.
* Be sure to use a nitrogen gas. (Use of oxygen gas prohibited.)
2. Connect the charge hose of the pressure reducing valve to the service port of the liquid pipe of outdoor
unit.
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
becomes 0.5 MPa.
5. Make sure that the nitrogen gas is released through the liquid pipe of unit A.
6. Flushing
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.
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.
Gas pipe
A
146
Pressure reducing valv e (Regulator)
Outdoor unit
Liquid pipe
Main valve
B
Gas pipe Liquid pipe
Nitrogen
gas
Blind plug (Brass)
Flare nut
Copper pipe
: http://splitoff.ru/tehn-doc.html
SiE33-102
Pressure: 0.5 MPa
Primary side
Secondary
side:0.5MPa
Pressure
reducing
valve
(Regulator)
(V1889)
Installation Manual