3 Piping work and refrigerant charge
Compatibility with the piping of current installations where R22 or R407C is used
SMGB0091 rev.2 - 11/2015
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3.6 Compatibility with the piping of current installations where R22 or
R407C is used
This chapter describes the works in piping for compatibility with the piping of current installations where R22 or
R407C is used. (Contact your Hitachi dealer for specific support on your installation).
The new RASC-HNPE series is compatible with those installations that have been operating with R22 or R407C. This
allows installing the RASC units, which operate with R410A, without having to change piping installation.
3.6.1 Installation procedure for existing pipes
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N O T E
•
For systems with several indoor units, branch pipes shall be changed to Hitachi-specified model for RASC-HNPE series (R410A).
•
Existing RASC and indoor units for R22 or R407C can not be used.
1
Recover refrigerant (R22 or R407C):
a.
Compressor of the existing unit is working
Pump down. Perform refrigerant recovery operation of existing air conditioner without stopping during 30 minutes
in cooling mode.
b.
Compressor of the existing unit is not working
Recover refrigerant with a refrigerant recovery device.
2
Remove existing air conditioning system (RASC and indoor unit).
3
For the existing pipes, proceed with one of the following operations:
a.
Clean the existing piping.
b.
Install renewal kit (optional accessory).
4
Install the new unit of the RASC series.
5
Vacuum process.
6
Refrigerant charge (R410A)
Follow the normal process described in order to determine whether additional refrigerant charge is necessary.
!
C A U T I O N
Recovering R22 and R407C is mandatory to remove an existing air conditioner and piping. Do not vent into the atmosphere.
Conditions to use existing pipes with cleaning process
After the piping cleaning process, follow the normal installation process as if they corresponded to a new installation,
considering all the restrictions and limitations. Special atention is required with regard to the piping thickness for R410A.
Conditions to use existing pipes without cleaning process
A Renewal Kit (sold separately) can be used even in cases where there is a history of compressor failure, allowing
diversion to existing piping without cleaning. Thus, the burden of installation works at renewal can be reduced.
Existing pipes can be used without cleaning if the following conditions are satisfied:
1
The renewal kit shall be installed. (mandatory)
2
Maximum piping length shall be 50 m (If the pipe is longer than 50m, existing pipes can be used if cleaning is
performed).
3
The capacity of the new unit must be equivalent to the one previously installed.
4
Existing pipes shall be free of corrosion, cracks, scratches or deformations.
5
Dirt inside the pipes shall not be noticeable.
6
The specifications of piping, flare nuts, gaskets, etc. shall be compliant.
7
Flare shall be reprocessed.
8
Piping airtightness and vacuuming shall be ensured in the same way as with new piping.