Refrigerant Piping; Selection Of Piping Material - Daikin VRV II Series Design, Installation & Testing Instructions

Si39-303

6. Refrigerant Piping

Caution After completing installation, be sure to open the valve.
(See 6-6 Additional refrigerant charge for details) (Operating the unit with the valve shut will
break the compressor.)
Use R410A to add refrigerant. (The R410A refrigerant cylinder has a pink stripe painted around
it.)
All field piping must be installed by a licensed refrigeration technician and must comply with
relevant local and national regulations.
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 filter 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.)
!
Notes:
!
6.1

Selection of Piping Material

1. Foreign materials inside pipes (including oils for fabrication) must be 30mg/10m or less.
2. Use the following material specification for refrigerant pipping:
3. Make sure to use the particular branches of piping that have been selected referring to
Installation Manual
Use R410A only when adding refrigerant.
Installation tools:
Make sure to use installation tools (gauge manifold charge hose, etc.) that are exclusively
used for R410A installations to withstand the pressure and to prevent foreign materials (e.g.
mineral oils such as SUNISO and moisture) from mixing into the system.
(The screw specifications differ for R410A and R407C.)
Vacuum pump (use a 2-stage vacuum pump with a non-return valve):
1.Make sure the pump oil does not flow oppositely into the system while the pump is not
working.
2.Use a vacuum pump which can evacuate to –100.7 kPa (5Torr, –755mmHg).
•
Construction material: Phosphoric acid deoxidized seamless copper for refrigerant.
•
Size: Determine the proper size referring to chapter "Example of connection".
•
The wall thickness of the refrigerant piping should comply with relevant local and national
regulations. For R410A the design pressure is 3.8 MPa.
chapter "Example of connection".

Refrigerant Piping

167