Piping Work And Refrigerant Charge - Hitachi RAS-8FSXNS2E Installation & Operation Manual

Piping work and refrigerant charge

3.1 Connection kit selection ..................................................................................13
3.2 Pipe size selection............................................................................................13
3.2.1 Size of pipes (Ø mm) ..............................................................................14
3.2.2 Examples ................................................................................................24
3.3 Pipe connection ...............................................................................................25
3.3.1 Precautions for the installation of the outdoor unit .............................26
3.3.2 Piping direction ......................................................................................32
3.3.3 Piping connection ..................................................................................34
3.3.4 Stop valve ...............................................................................................34
3.4 Connection scenarios ......................................................................................39
3.5 Air-Tight Test ....................................................................................................41
3.5.1 Tightening check of stop valves ............................................................41
3.5.2 Air-tight test method .............................................................................42
3.5.3 Insulation work ......................................................................................43
3.6 Vacuuming .......................................................................................................43
3.6.1 Basic Method ........................................................................................43
3.6.2 Triple Evacuation Method .....................................................................44
3.7 Charging work ..................................................................................................44
3.7.1 Maximum permitted concentration of hydrofluorcarbon (HFC)
refrigerant ..............................................................................................45
PMML0628 rev.0 - 05/2023
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