– 15 –
29-EN 30-EN
WARNING
Never use oxygen, flammable gases, or noxious gases in an airtight test.
V
L
V
H
Connected to indoor unit
To outdoor unit
Gas-side valve
Gas-side
service port
Piping at site
Piping at site
Piping at site
Balance valve
Balance
service port
Liquid-side valve
Liquid-side service port
To gauge manifold
Packed valve details
To
outdoor
unit
To
outdoor
unit
Gas side valve fully closed
Low pressure
gauge
High pressure
gauge
Gauge
manifold
Reducing
valve
Copper
pipe
Nitrogen
gas
Header outdoor unit
Service port
Copper pipe
Service port
Service port
Liquid valve fully closed
Balanced pipe side valve
fully closed
Connected to other follower units
Brazed
Fully
closed
Fully
closed
Main piping
Able to detect a serious leakage
1. Apply pressure 0.3MPa (3.0kg/cm²G) for 5 minutes or more.
2. Apply pressure 1.5MPa (15kg/cm²G) for 5 minutes or more.
Available to detect slow leakage
3. Apply pressure 4.15MPa (42.3kg/cm²G) for approx. 24 hours.
• If there is no pressure decrease after 24 hours, the test is passed.
NOTE
However, if the environmental temperature changes from the moment of applying pressure to 24 hours after that,
the pressure will change by about 0.01MPa (0.1kg/cm²G) per 1°C. Consider the pressure change when checking
the test result.
REQUIREMENT
When pressure decrease is detected in steps 1-3, check the leakage at the connecting points.
Check the leakage using a foaming agent or other measures and seal the leak with re-brazing, flare retightening
or other methods. After sealing, execute an airtight test again.
◆ Allowable length and allowable height difference of refrigerant piping
Item
Allowable
value
Piping section
Piping length
Total extension of pipe
(Liquid pipe, real length)
Below 34HP 300m LA + La + Lb + Lc + L1 + L2 + L3 + L4+
L5 +L6 + L7 + a + b + c + d + e + f + g +
h + i + j
34HP or more 1000m (*6)
Farthest piping Length L (*1)
Equivalent
length
235m
Lc + LA + L1 + L3 + L4 + L5 + L6 + j
Real length 190m
Equivalent length of farthest piping from 1st
branching Li (*1)
90m (*2) L3 + L4 + L5 + L6 + j
Equivalent length of farthest piping between
outdoor units LO
25m LA + Lc(LA + Lb)
Max. equivalent length of main
piping
Equivalent
length
120m (*3)
L1
Real length 100m (*3)
Max. equivalent length of outdoor unit connecting
piping
10m Lc(La, Lb)
Max. real length of indoor unit connecting piping
30m a, b, c, d, e, f, g, h, i, j
Max. equivalent length between branches
50m L2, L3, L4, L5, L6, L7
Difference in
height
Height between indoor and
outdoor units H1
Upper outdoor
unit
70m (*4, *7) –
Lower outdoor
unit
40m (*5) –
Height between indoor units H2
40m –
Height between outdoor units H3
5m –
(*1) : (C) is outdoor unit furthest from the 1st branch and (j) is the indoor unit furthest from the 1st branch.
(*2) : If the height difference (H1) between indoor and outdoor unit exceeds 3m, set 65m or less.
(*3) : If the max. combined outdoor unit capacity is 46HP or more, then max. equivalent length is 70m or less
(real length is 50m or less).
(*4) : If the height difference (H2) between indoor units exceeds 3m, set 50m or less.
(*5) : If the height difference (H2) between indoor units exceeds 3m, set 30m or less.
(*6) : Total charging refrigerant is 140kg or less.
(*7) : Extension up till 90m is possible with conditions below.
- Outdoor Temperature Cooling : 10°C to 52°C (Dry-bulb temp.)
Heating : -5°C to 15.5°C (Wet-bulb temp.)
- Equivalent length of farthest piping from 1st branching Li<50m
- Real length of main piping L1<100m
- Height difference between indoor units H2<3m
- Total capacity of combined indoor units : 90% - 105%
- Single CDU, and up to 20HP
- Minimum capacity of connectable indoor unit : 4HP or Larger
■ Airtightness test
After the refrigerant piping has been finished, execute an airtight test.
For an airtight test, connect a nitrogen gas canister as shown in the figure on this page and apply pressure.
• Be sure to apply pressure from the service ports of the packed valves (or ball valves) at the liquid side, gas side
and balance pipe side.
• An airtight test can only be performed at the service ports at the liquid side, gas side and balance pipe side on
header unit.
• Close the valves fully at the gas side, liquid side and balance pipe side. As there is a possibility that the nitrogen
gas will enter into the cycle of outdoor units, re-tighten the valve rods at the liquid side and balance pipe side
before applying pressure.
(When using MAP10A, MAP12A, MAP140, MAP160, MAP14A, MAP16A, MAP180 or MAP200, you do not have
to re-tighten the liquid side valve rod as their valves at the liquid side are ball valves.)
• For each refrigerant line, apply pressure gradually in steps at the liquid side, gas side and balance pipe side.
Be sure to apply pressure at the gas side, liquid side, and balance pipe side.
1117101401-3_EN.indd 151117101401-3_EN.indd 15 1/18/16 10:32 AM1/18/16 10:32 AM
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