Daikin VRV IV - 18.1.9 Multiple Outdoor Units: Possible Layouts

18 | Piping installation
Installer and user reference guide
79
RXMLQ8 + RXYLQ10~14T7Y1B*
VRV IV system air conditioner
4P543427-1A – 2020.10
6,7 VRVDX indoor units
Maximum allowable length
▪ Between outdoor unit and indoor unit.
Actual piping length 100m
Example:
a+b+g+l≤100m
Equivalent length
(a)
120m
Total piping length 250m
Example:
a+b+d+g+l+k+c+e+f+h+i+j≤250m
(a)
Assume equivalent piping length of refnet joint=0.5m and refnet header=1m (for
calculation purposes of equivalent piping length, not for refrigerant charge calculations).
▪ Between BP unit and indoor unit.
Indoor unit capacity index Pipe length
<60 2~15m
60 2~12m
71 2~8m
Remark: Minimum allowable length between outdoor unit and first refrigerant
branch kit>5m (the refrigerant noise from the outdoor unit can be transmitted).
Example: a>5m
Maximum allowable height difference
H1 ≤50m (40m) (if outdoor is located below indoor units)
H2 ≤15m
H4 ≤40m
H5 ≤15m
H6 ≤5m
Maximum allowable length after branch
The pipe length from the first refrigerant branch kit to the indoor unit ≤50m.
Example: b+g+l≤50m
If the piping length between the first branch and BP unit or VRVDX indoor unit is
over 20 m, it is necessary to increase the gas and liquid piping size between the
first branch and BP unit or VRVDX indoor unit. If the piping diameter of the sized
up piping exceeds the diameter of the piping before the first branch kit, than the
latter also requires a liquid piping and gas piping size up.
18.1.9 Multiple outdoor units: Possible layouts
▪ The piping between the outdoor units must be routed level or slightly upward to
avoid the risk of oil retention into the piping.