About The Piping Length - Daikin VRV IV+ Installer And User Reference Manual

18.1.5 About the piping length

REYQ8~20+REMQ5U7Y1B
VRV IV+ heat recovery
4P561154-1A – 2020.10
Make sure the piping installation does not exceed the maximum allowable pipe
length, the allowable level difference, and the allowable length after branching. To
illustrate the piping length requirements, 6 cases are discussed in the chapters
below. They describe both standard and non-standard outdoor unit combinations
with VRV DX indoor units, Hydrobox units and/or air handling units (AHU).
Definitions
Term
Actual piping length
Equivalent piping length
Total piping length
Equivalent length of the piping accessories
Accessory
Refnet joint
Refnet header
Single BS1Q100~160
Single BS1Q25
Multi BS4~16Q14
Allowable height difference
Term
H1
H2
H3
H4
(a) If single outdoor units or standard multi-outdoor combinations >20 HP are
connected to only VRV DX indoor units, then the height difference between indoor
units (= H2) can be increased from 15 to 30 m. However, this limits the allowable
maximum length of the longest pipe (see
4
units" [ 76]).
(b) The allowable height difference is 50 m in case the outdoor unit is positioned higher
than the indoor unit, and 40 m in case the outdoor unit is positioned lower than the
indoor unit. If only VRV DX indoor units are used, the allowable height difference
between outdoor and indoor units may be extended to 90 m, without the need of
an additional option kit. In this case, make sure all conditions below are met:
Pipe length between outdoor and
indoor units
Pipe length between outdoor and
indoor units, including the equivalent
length of the piping accessories
Total piping length, from the outdoor to
all indoor units
Definition
Height difference
between outdoor and
indoor units
Height difference
between indoor units
Height difference
between outdoor units
Height difference
between EKEXV‑kits and
AHU units.
"Connection with only VRV DX indoor
18 Piping installation
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Definition
Equivalent length
0.5 m
1 m
4 m
6 m
4 m
Height difference (m)
(b)
50/40
15
(a)
30
5
5
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