Hitachi RASC-10HNPE, Service Manual, Page: 39 / 306

3.
Piping work and refrigerant charge
3 Piping work and refrigerant charge
SMGB0091 rev.2 - 11/2015 29
3
Index
3.1 Piping work connection considerations .................................................................................................30
3.1.1 Copper pipes and sizes ................................................................................................................................. 30
3.1.2 Pipe connection ............................................................................................................................................. 31
3.1.3 Insulation ....................................................................................................................................................... 31
3.1.4 Three principles on refrigerant piping work ................................................................................................... 32
3.1.5 Suspension of refrigerant piping .................................................................................................................... 33
3.1.6 Brazing work .................................................................................................................................................. 33
3.2 Piping connection for RASC unit ...........................................................................................................34
3.3 Refrigerant piping range ........................................................................................................................38
3.3.1 Refrigerant piping length ............................................................................................................................... 38
3.3.2 Piping system (Header branch installation) ................................................................................................... 38
3.3.3 Piping system (Line branch installation) ........................................................................................................ 41
3.3.4 Combinations of piping size and piping length .............................................................................................. 42
3.3.5 Refrigerant piping size and multikit/distributor selection ............................................................................... 43
3.3.6 Considerations when installing distributors ................................................................................................... 47
3.4 Refrigerant charge.................................................................................................................................48
3.4.1 Refrigerant charge amount ............................................................................................................................ 48
3.4.2 Refrigerant charge procedure ....................................................................................................................... 50
3.4.3 Caution of the pressure by check joint .......................................................................................................... 51
3.4.4 Pump down refrigerant .................................................................................................................................. 51
3.5 Caution in case of refrigerant leakage...................................................................................................52
3.5.1 Maximum permitted concentration of HFCs .................................................................................................. 52
3.5.2 Calculation of refrigerant concentration ......................................................................................................... 52
3.5.3 Countermeasure for refrigerant leakage ....................................................................................................... 52
3.6 Compatibility with the piping of current installations where R22 or R407C is used ..............................54
3.6.1 Installation procedure for existing pipes ........................................................................................................ 54
3.6.2 When the existing air conditioner is a product of another manufacturer ....................................................... 55
3.6.3 Permissible range for existing air-conditioning pipes .................................................................................... 55
3.6.4 Selection of the renewal kit model ................................................................................................................. 55
3.7 Drainage and drain pipe installation ......................................................................................................57