
I - 3
(2) Selecting system header and branch tubing sizes
Outdoor and indoor units are connected together by a pair of headers.
If the maximum tubing length exceeds 90 m (effective length), increase the size of the main tubing for both liquid
and gas by one size. Be careful when selecting tube sizes, as the wrong size may impair performance.
cOutdoor Tubing/Main Tube Size(*1) (*2)
Outdoor tubing Main tubing
Outdoor unit (gross) capacity (kW)
45 56 71 85 90 101 112 116 127 142
Gas tube (mm) φ28.58 (φ31.75) φ31.75 (φ38.1) φ38.1
Liquid tube
(mm)
φ12.7
(φ15.88) φ15.88 (φ19.05) φ19.05 (φ22.22)
(*1) If there are plans for future expansion, choose plumbing sizes according to the total capacity after such expan-
sion. However, if tube size is stepped up 3 levels, expansion is not possible.
(*2) If the maximum tube length exceeds 90 m (or equivalent length), use the figure in parentheses ( ) to size the
main tubing, along with those of the liquid and gas tubes.
However, size the gas tube only up to φ38.1. (A reducer has to be fitted on-site)
dSize of main tubing after branch (*1) (*2)
When indoor unit(s) are connected Main tube after branching
Post-branching indoor unit capacity (kW)*3
– 5.6 – 16.0 – 22.4 – 28.0 – 16.0 – 28.0 – 35.5 – 45.0 – 71.0 – 101.0 Over
101.0
Gas tube
(mm) φ12.7 φ15.88 φ19.05 φ22.22 φ15.88
(φ19.05)
φ22.22
(φ25.4)
φ25.4
(φ28.58) φ28.58 (φ31.75) φ31.75
(φ38.1) φ38.1
Liquid tube
(mm) φ9.52 φ9.52 (φ12.7) φ12.7 (φ15.88) φ15.88
(φ19.05) φ19.05 (φ22.22)
(*1) Select a diameter for the main tubing after a branch that is no larger than that of the header.
(In cases where the main tubing after a branch would have to be larger than the header tubing, select tubing of
the same size, and never exceed the header size.)
(*2) If the maximum tube length exceeds 90 m (or equivalent length), use the figure in parentheses ( ) to size the
main tube after branching, along with those of the liquid and gas tubes.
However, size the gas tube only up to φ38.1.
(*3) “–* *” in the table above means “** kW or less”.
eBranch/Header Tube Selection
Use the following branch tubing sets or tubing sets for branching the system’s main tube and indoor unit tubing.
Capacity after branch
Branch tube size (*1) Branch tube number
Gas tube (mm) Liquid tube (mm) Branch tubing
APR-P160BG APR-P680BG APR-P1350BG
Over 72.8 kW φ31.75 φ19.05 — — ●
Over 45.0 kW to 72.8 kW φ28.58 φ15.88 — ●●
Over 35.5 kW to 45.0 kW φ28.58 φ12.7 — ●●
Over 28.0 kW to 35.5 kW φ25.4 φ12.7 — ●●
Over 22.4 kW to 28.0 kW φ22.22 φ9.52 — ●●
Over 16.0 kW to 28.0 kW φ19.05 φ9.52 ●●●
Over 5.6 kW to 16.0 kW φ15.88 φ9.52 ●●
(*3) ●(*3)
5.6 kW or below φ12.7 (*2) φ9.52 ●●
(*3) ●(*3)
(*1) Make a selection so as not to exceed the main tubing size.
(*2) Even when 5.6 kW or below, make the gas tube diameter φ15.88 if 2 or more indoor units are connected after
branching.
(*3) As the tube diameter for the supplied reducer does not match, another reducer must be provided by the installer.
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