18 | Piping installation
Installer and user reference guide
70
REYQ8~20+REMQ5U7Y1B
VRV IV+ heat recovery
4P561154-1A – 2020.10
18 Piping installation
In this chapter
18.1 Preparing refrigerant piping ................................................................................................................................................... 70
18.1.1 Refrigerant piping requirements ........................................................................................................................... 70
18.1.2 Refrigerant piping insulation.................................................................................................................................. 71
18.1.3 To select the piping size......................................................................................................................................... 71
18.1.4 To select refrigerant branch kits............................................................................................................................ 74
18.1.5 About the piping length ......................................................................................................................................... 75
18.1.6 Single outdoor units and standard multi-outdoor-unit combinations >20 HP..................................................... 76
18.1.7 Standard multi-outdoor-unit combinations ≤20 HP and free multi-outdoor-unit combinations........................ 79
18.1.8 Multiple outdoor units: Possible layouts............................................................................................................... 81
18.2 Connecting the refrigerant piping.......................................................................................................................................... 83
18.2.1 About connecting the refrigerant piping............................................................................................................... 83
18.2.2 Precautions when connecting the refrigerant piping............................................................................................ 83
18.2.3 Multiple outdoor units: Knockout holes................................................................................................................ 84
18.2.4 To route the refrigerant piping.............................................................................................................................. 84
18.2.5 To connect the refrigerant piping to the outdoor unit ......................................................................................... 85
18.2.6 To connect the multi connection piping kit........................................................................................................... 86
18.2.7 To connect the refrigerant branching kit .............................................................................................................. 86
18.2.8 To protect against contamination ......................................................................................................................... 87
18.2.9 To braze the pipe end ............................................................................................................................................ 88
18.2.10 Using the stop valve and service port.................................................................................................................... 88
18.2.11 To remove the spun pipes ..................................................................................................................................... 91
18.3 Checking the refrigerant piping.............................................................................................................................................. 92
18.3.1 About checking the refrigerant piping................................................................................................................... 92
18.3.2 Checking refrigerant piping: General guidelines ................................................................................................... 93
18.3.3 Checking refrigerant piping: Setup ........................................................................................................................ 94
18.3.4 To perform a leak test............................................................................................................................................ 94
18.3.5 To perform vacuum drying .................................................................................................................................... 95
18.3.6 To insulate the refrigerant piping .......................................................................................................................... 95
18.4 Charging refrigerant ............................................................................................................................................................... 96
18.4.1 Precautions when charging refrigerant ................................................................................................................. 96
18.4.2 About charging refrigerant .................................................................................................................................... 97
18.4.3 To determine the additional refrigerant amount.................................................................................................. 98
18.4.4 To charge refrigerant: Flow chart .......................................................................................................................... 100
18.4.5 To charge refrigerant ............................................................................................................................................. 102
18.4.6 Step 6a: To automatically charge refrigerant........................................................................................................ 104
18.4.7 Step 6b: To manually charge refrigerant............................................................................................................... 106
18.4.8 Error codes when charging refrigerant.................................................................................................................. 107
18.4.9 Checks after charging refrigerant .......................................................................................................................... 107
18.4.10 To fix the fluorinated greenhouse gases label....................................................................................................... 108
18.1 Preparing refrigerant piping
18.1.1 Refrigerant piping requirements
NOTICE
The refrigerant R410A requires strict cautions for keeping the system clean, dry and
tight.
▪ Clean and dry: foreign materials (including mineral oils or moisture) should be
prevented from getting mixed into the system.
▪ Tight: R410A does not contain any chlorine, does not destroy the ozone layer,
and does not reduce earth's protection against harmful ultraviolet radiation.
R410A can contribute to the greenhouse effect if it is released. Therefore pay
special attention to check the tightness of the installation.
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