Johnson Controls (H, Engineering Manual

Page: 70 / 124

OUTDOOR UNITS
2-48
TC-16006
A header branch can be used with a line branch at the three pipes segment and two pipes segment.
A header branch can also be used after the second branch. Do not connect a line branch to a header
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branch to the farthest indoor unit is within 131.2 ft (40m).
Line Branch
Header Branch
Within 131.2 ft
Within 131.2 ft
Header Branch
Line Branch
Line Branch
Indoor Unit
x
The number of indoor units connectable to outdoor unit is as follows:
Comply with the following conditions when installing the unit.
x
A maximum total capacity and a minimum total capacity against the nominal outdoor unit capacity can be
obtained by combination of the indoor units.
NOTES:
1. For a system under which all the indoor units are supposed to operate simultaneously, the total indoor
unit capacity should be less than outdoor unit capacity. Otherwise, it may cause a decrease of operating
performance and operating limit in overload operation.
2. For the system under which all the indoor units are not supposed to operate simultaneously, the total
indoor unit capacity is available 100% or more against the outdoor unit capacity. Refer to Table 2.2 “System
Combination” (Section 2.13) for detail.
3. When operating the outdoor unit in cold area with temperatures of 14
o
F (-10
o
C), or under the high heating
load conditions, the total indoor unit capacity should be 100% or less against the outdoor unit capacity
and the total piping length should be 984.3ft (300m) or less.
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or more. Make sure to select appropriate indoor units when installing indoor units where cold draft
may occur during heating operation. If installing indoor units in such places, refer to the recommended
number of connectable indoor units.
5. When installing an Energy Recovery Ventilation (ERV) unit, the additional load must be considered when
calculating the maximum units that can be attached.
Outdoor Unit Capacity (MBH) 72 96 144 168 192 288
Maximum Number of Connectable I.U. 15 16 31 30 33 50
Recommended Number of Connectable I.U. 10 10 18 18 18 32