P5417009-rev.6
13
The number of indoor units that can be connected to an outdoor unit is defined in Table 3.2.
Comply with the following conditions when installing the unit.
A maximum and minimum total capacity as opposed to the nominal outdoor unit capacity can be obtained
through combination of indoor units.
Model: (H,Y)VAHR_B(3,4)2S
Outdoor Unit
Capacity
(MBH)
Minimum Capacity at
Individual Operation
(MBH)
Maximum Number
of Connectable I.U.
Recommended
Number of
Connected I.U.
Connectable Indoor Unit
Capacity Ratio
Maximum
2,3,4,5
Minimum
72
6
1
15
8
130%
70%
96
20
8
130%
65%
120
26
8
130%
60%
144
26
10
130%
55%
168
36
12
130%
55%
192
40
14
130%
55%
216
46
18
130%
60%
240
52
18
130%
60%
264
56
20
130%
55%
288
59
20
130%
55%
312
64
22
130%
55%
336
64
24
130%
55%
360
64
28
130%
55%
384
64
30
130%
55%
408
64
30
130%
55%
432
64
30
130%
55%
1. When the outdoor air temperature is 23
o
F (-5
o
C) or less during the outdoor unit cooling operation, the minimum
connectable indoor unit capacity is 18 MBH. A snow protection hood or low ambient kit (optional part) should be
installed.
2. When the outdoor air temperature is 109
o
F (43
o
C) or warmer during the outdoor unit cooling operation, the maximum
connectable indoor unit capacity ratio is 100%.
3. When the outdoor air temperature is 14
o
F (-10
o
C) or less, or under the high heating load conditions, the total indoor
unit capacity should be less than 100% of the outdoor unit capacity, and the total piping length should be less than
984 ft (300m).
4. When the number of connected indoor unit (I.U.) is within the recommended, the maximum connectable indoor unit
capacity ratio is available up to 150%.
5. There are some limitations of the Height Difference between Outdoor Units and Indoor Units.
Refer to Section 6.5 “Piping Size and Multi-kit Selection”, for details.
Table 3.2 System Combination
NOTICE:
The connectable indoor unit capacity ratio can be calculated as follows:
Connectable Indoor Unit Capacity Ratio = Total Indoor Unit Capacity / Total Outdoor Unit Capacity
In a system where all the indoor units operate simultaneously, the total indoor unit capacity should be less than the
outdoor unit capacity. Otherwise, a decrease in operating performance and an increase in the operating limit can result
in an overload.
In a system where all the indoor units do not operate simultaneously, the total indoor unit capacity is available up to
150% against the outdoor unit capacity.
The air flow volume for indoor units of 6 and 8 MBH is set higher than that for indoor units of 12 MBH or more.
Make sure to select appropriate indoor units for installation where a cold draft may occur during heating operation.
If installing indoor units in such locations, refer to the recommended number of indoor units as shown in above table
that can be connected.