Daikin VRV Series - Precautions for Group Control System or Two User Interface Control System; Energy Saving and Optimum Operation

12
3P184443-12N English
Not recommended but in case of emergency:
You must use a torque wrench but if one is not available, you may follow the installation method
described below.
When you keep tightening the are nut with a spanner, there is a point where the tightening torque
suddenly increases. From that position, further tighten the are nut at the angle shown below:
Pipe size Further tightening angle Recommended arm length of tool
ø1/4” 60 – 90 degrees Approx. 6 in.
ø1/2” 30 – 60 degrees Approx. 10 in.
Aftertheworkisnished,makesuretocheckthatthereisnogasleak.
CAUTION
CAUTION TO BE TAKEN WHEN BRAZING REFRIGERANT PIPING
Do not use ux when brazing refrigerant piping. Therefore, use the phosphor copper brazing ller metal
(B-Cu93P-710/795:ISO 3677) which does not require ux.
Flux has extremely harmful inuence on refrigerant piping systems. For instance, if the chlorine based
ux is used, it will cause pipe corrosion or, in particular, if the ux contains uorine, it will damage the
refrigerant oil.
• Before brazing eld refrigerant piping, nitrogen gas shall be blown through the piping to expel air from
the piping.
If brazing is done without nitrogen gas blowing, a large amount of oxide lm develops inside the piping,
and could cause system malfunction.
• When brazing the refrigerant piping, only begin brazing after having carried out nitrogen substitution
or while inserting nitrogen into the refrigerant piping. Once this is done, connect the indoor unit with a
ared connection.
• Nitrogen should be set to 2.9 psig with a pressure-reducing valve if brazing while inserting nitrogen into
the piping. (Refer to Fig.15)
Refrigerant piping
Part to be
brazed
Taping
Nitrogen
Pressure-reducing valve
Nitrogen
Hand valve
Fig. 15
• Make absolutely sure to execute thermal insulation works on the pipe-connecting section after
checking gas leakage by thoroughly studying the following gure and using the attached insulation for
tting (8) and (9). Fasten both ends with the clamps (4). (Refer to Fig. 16)
• Wrap the sealing pad (11) only around the insulation for the joints on the gas piping side.
(Refer to Fig. 16)