• Installation
•
Systems • Installation
4
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.
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.)
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
2
blowing when brazing is required.
•
Other than brazing, a stricter work control including pipe covering
and drying is required to prevent pipe from intrusion of foreign
matters.
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.
•
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.
Representative tools and devices and interchangeability
Tool name
Work process / Usage
Interchangeability with conventional tool
Pipe cutter
Refrigerant piping work
Pipe cutting
Interchangeable and can be used.
Flaring tool
Pipe flaring
Refrigeration oil
Applying to flared section
Use dedicated ether oil, ester oil, alkyl-benzene oil or mixture of those oils.
Torque wrench
Flare nut jointing
Interchangeable and can be used.
Pipe expander
Pipe expanding in connection of pipe
Pipe bender
Pipe bending
Nitrogen
Air tight test
Oxidation proof for inside pipe
Welder
Pipe brazing
Gauge manifold
From air tight test to refrigerant
additional charging
Refrigerant charging using vacuum and operation check Dedicated gauge is required due to high pressure.
Charging hose
To prevent refrigerant leakage and mixing of foreign matters, dedicated charging hose is required.
Vacuum pump
Vacuum drying
Interchangeable and can be used. (Be strictly sure that oil does not flow in reverse to the unit during pump stop.)
Charging cylinder
Refrigerant additional charging
Not required since charging work conducted with weighing scale.
Weighing scale for refrigerant
charging
Interchangeable and can be used.
Gas leakage detector
Gas leakage check
Dedicated detector is required (Detector for R-134a can be used).
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.
