Panasonic U-120MF2U9, Technical Data Manual, Page: 22 / 181

Design of 3WAY VRF SYSTEM
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1. Model Selection and Capacity Calculator
Design of 3WAY VRF SYSTEM
1. Model Selecting and Capacity Calculator
Design of 2WAY SYSTEM
ID 64
L2
L2'
ID 1
ID 3 ID 4
ID 2
ID 63
1st distribution joint
OD 1 OD 2 OD 3
L2 ''
L4
2nd distribution joint
■ Refrigerant Tube
Tubing size increase [Difference
△
L from the first distribution joint between maximum and minimum length]
If the △ L exceeds 131ft. (40m), it is necessary to increase both the liquid tube, suction tube and discharge tube by one size.
Follow the steps below to increase the size.
1. Check the combined indoor units which the L exceeds 131ft. (40m).
Calculate the L of each combined indoor unit after 1st distribution joint (L2 {L2', L2'' ....} -L4).
The L2 ( L2 {L2', L2'' ....} ) indicates the tubing length connected to the farthest indoor unit among each combined indoor
unit from 1st distribution joint. The L4 indicates the tubing length connected from the 1st distribution joint to the nearest
indoor unit among all connected indoor units to the system. If the calculated L exceeds 131ft. (40m), it is necessary to
increase by one size of both the liquid tube, suction tube and discharge tube. Follow the steps to increase the size.
2. Check the total capacity of each combined indoor unit system.
Calculate the total capacity of indoor units from the 1st distribution joint.
Example: L2' L2'': Total capacity of indoor unit 3 and 4
3. Check the portion for increasing the tubing size and length.
Portion to increase the tube by one size: Increase the tubing size to be directed towards the indoor units from the 1st
distribution joint against the indoor unit which the L exceeds 131ft. (40m). Tubing length for sizing up: Tubing length
becomes different according to the total capacity of indoor units.
Total capacity of indoor units and tubing length for sizing up
Total capacity of combined indoor units
Length for sizing up
Less than 76,400 BTU/h (22.4kW) 39ft. (12m)
More than 76,400 BTU/h (22.4kW) and less than 178,600 BTU/h (52.4kW) 66ft. (20m)
More than 178,600 BTU/h (52.4kW) 92ft. (28m)
* The larger the total capacity, the more it is necessary to increase the tubing length for sizing up.
* If the range of size up portion is improper, it is available to extend the length for sizing up until the next distribution joint
is reached.
NOTE:
1. Be sure to use the reducer (field supply) at joint portion between the original tube and the tube increased by one size.
2. If there is the necessity to increase by one size from the original tubing size, there can be only one time effective to
increase by one size even though the portion for sizing up is overlapped.
3. It may sometimes happen that the diameter of tube when sized up becomes wider than that of the main tube LA.
OD stands for outdoor unit.
ID stands for indoor unit.
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*
5: If the tubing length marked “L” (L2 - L4) exceeds 131 ft. (40m), increase the tubing size at the portion after the 1st distribution joint by 1 rank
for the liquid tube, suction tube and discharge tube.
See the section “Refrigerant Tube” as described below.
*6:
7:
If any of the tubing length exceeds 98ft. (30m), increase the size of the tubes (liquid tube, suction tube and discharge tube)
between the distribution tube and solenoid valve kit by 1 rank and also increase the size of the tubes (liquid tube and gas tube)
between the solenoid valve kit and indoor unit by 1 rank.
* However, in the case of the Type 56 solenoid valve kit, it is not necessary to increase the tubes (liquid tube, suction tube and
discharge tube) between the distribution tube and solenoid valve kit by 1 rank.
If the size of suction tubes is ø1-5/8 in. (41.28mm), do not increase the size by 1 rank for the suction tubes.
TD831183-00_北米向け3WAY.indb 6 15/12/17 16:05:07