Daikin R407C PLUS, Service Manual

Page: 258 / 267

Si33-105 Precautions in Servicing The Models with New-type Refrigerant
Appendix R407C PLUS Series Heat Recovery System 247
4.2 Notes for Work Procedures
Brazing connections
!
With the new type of refrigerant, much more care must be paid to keep impurities from
coming in. In brazing the pipes, be sure to blow the pipe using nitrogen gas.
!
In any other connecting works, much stricter process control is needed to prevent impurities
from coming into the pipes. For this purpose, take appropriate measures such as covering
the pipes and do the vacuum drying.
Flaring work
!
Chamfer (file) the pipe ends as specified. Be very careful not to allow cuttings to come into
the pipes.
!
To avoid leak, apply a proper amount of refrigerant oil over the inner and outer surfaces of
each flared section. As the refrigerant oil, be sure to use synthetic oil (ether oil, ester oil, alkyl
benzene oil or their mixture).
Charging refrigerant
!
Be sure to charge the new-type refrigerant in liquid phase via the service port of the liquid-
side stop valve (outdoor unit). At this time, give vacuum drying with a vacuum pump. Never
try the air purging.
Air-tightness test
!
Be sure to conduct air-tightness test.
Caution For servicing the models with the new-type refrigerant, strictly follow the above instructions and
precautions. Otherwise the system may get in trouble. For details on handling the new-type
refrigerant and the related work procedures and tools, refer to the Installation/Test Run Manual
published by Daikin.