Representative Tools And Devices And Interchangeability; Joint Brazing; Flaring - Daikin VRV System Installation Manual

Introduction
Procedure and tools for refrigerant piping work
Tools
• Several dedicated tools are required for the installation work of R-407C models. Some conventional tools can be used except tools actually used to
install R-22 models.

Representative tools and devices and interchangeability

Tool name
Pipe cutter Refrigerant piping work
Flaring tool
Refrigeration oil
Torque wrench
Pipe expander
Pipe bender
Nitrogen Air tight test
Welder
Gauge manifold From air tight test to refrigerant
additional charging
Charging hose
Vacuum pump Vacuum drying
Charging cylinder Refrigerant additional charging
Weighing scale for refrigerant
charging
Gas leakage detector
Precautions for installation work
Caution to be taken when brazing refrigerant piping
• "Do not use flux when brazing copper-to-copper refrigerant piping. (Particularly for the HFC refrigerant piping) Therefore, use the phosphor copper
brazing filler metal (BCuP) which does not require flux."
(Flux has extremely harmful influence on refrigerant piping systems. For instance, if the chlorine based flux is used, it will cause pipe corrosion or, in
particular, if the flux contains fluorine, it will damage the refrigerant oil. The use of flux is strictly forbidden since the cleaning on site is impossible.)
NOTE
1 Keep in mind that if the phosphor copper brazing filler metal is used and the brazing temperature and the heating time exceed a certain point,
the phosphor changes into the gaseous state (e.g. BCuP -1 to 5 : between 700 and 800°C) which causes pin holes and results in refrigerant
leakage.

Joint brazing

• Since stricter caution should be necessary for R-407C to prevent
intrusion of foreign matters into the refrigerant piping line, be sure to
conduct N blowing when brazing is required.
2

Flaring

• Make sure to conduct chamfering (filing) at cut section, since a large
wall thickness of pipe results large burr. Be aware of no cutting chips
left inside pipe.
4
• Installation
Work process / Usage
Pipe cutting
Pipe flaring
Applying to flared section
Flare nut jointing
Pipe expanding in connection of pipe
Pipe bending
Oxidation proof for inside pipe
Pipe brazing
Refrigerant charging using vacuum and operation check Dedicated gauge is required due to high pressure.
Gas leakage check
• Systems • Installation
Interchangeability with conventional tool
Interchangeable and can be used.
Use dedicated ether oil, ester oil, alkyl-benzene oil or mixture of those oils.
Interchangeable and can be used.
To prevent refrigerant leakage and mixing of foreign matters, dedicated charging hose is required.
Interchangeable and can be used. (Be strictly sure that oil does not flow in reverse to the unit during pump stop.)
Not required since charging work conducted with weighing scale.
Interchangeable and can be used.
Dedicated detector is required (Detector for R-134a can be used).
• Other than brazing, a stricter work control including pipe covering
and drying is required to prevent pipe from intrusion of foreign
matters.
• Apply appropriate amount of refrigeration oil on outer / inner surface
of flared section to prevent leakage. Make sure to use synthetic oil
(ether oil, ester oil, archi-benzene oil or mixture of those oils) as
refrigeration oil.