Piping Work And Refrigerant Charge - Hitachi UTOPIA RAS-4HVRP2E Service Manual

3 Piping work and refrigerant charge

Index
3.1 General notes before performing pipe work .......................................................................................... 42
3.1.1 Piping Materials ............................................................................................................................................. 42
3.1.2 Three principles on refrigerant piping work ................................................................................................... 44
3.1.3 Suspension of refrigerant piping .................................................................................................................... 44
3.1.4 Brazing work .................................................................................................................................................. 45
3.2 Piping connection for outdoor unit ......................................................................................................... 46
3.2.1 RAS-3HVRC2 ................................................................................................................................................ 46
3.2.2 RAS-(4-6)H(V)(R/N)(C/P)2E ......................................................................................................................... 47
3.2.3 Outdoor unit stop valve ................................................................................................................................. 50
3.3 Refrigerant piping range ........................................................................................................................ 52
3.3.1 Refrigerant piping length ............................................................................................................................... 52
3.3.2 Piping system for header branch ................................................................................................................... 52
3.3.3 Maximum lenght of refrigerant piping ............................................................................................................ 53
3.3.4 Combinations of piping size and piping length .............................................................................................. 54
3.3.5 Refrigerant piping size and multikit/distributor ............................................................................................... 54
3.3.6 System installation ........................................................................................................................................ 56
3.4 Refrigerant charge................................................................................................................................. 59
3.4.1 Caution of the pressure by check joint .......................................................................................................... 60
3.4.2 Refrigerant charge quantity ........................................................................................................................... 60
3.4.3 Refrigerant charge before shipment (W
3.4.4 Calculation method for the additional refrigerant charge ............................................................................... 61
3.5 Caution in case of refrigerant leakage................................................................................................... 63
3.5.1 Maximum permitted concentration of hydrofluorocarbon (HFC) ................................................................... 63
3.5.2 Calculation of refrigerant concentration ......................................................................................................... 63
3.5.3 Countermeasure for R410A refrigerant leakage ............................................................................................ 64
3.6 Drain piping ........................................................................................................................................... 65
3.6.1 Drain discharging boss .................................................................................................................................. 65
41 SMGB0136 rev.0 - 07/2021
3 .
P i p i n g w o r k a n d r e f r i g e r a n t c h a r g e
(kg)) ............................................................................................... 61
0
3