–17–
■Refrigerant pipe length
Single
Simultaneous twin
Outdoor unit
Allowable pipe length (m) Height difference (m)
Total length Indoor-outdoor H
Minimum Maximum Indoor unit: Upper Outdoor unit: Upper
GP56
3503030
GP80
Outdoor unit
Pipe diameter (mm)
Number of bent portions
Gas side Liquid side
GP56 12.7 6.4 10 or less
GP80 15.9 9.5 10 or less
Outdoor unit
Allowable pipe length (m) Height difference (m)
Total length
•
1
+
2
•
1
+
3
Maximum
Branch piping
•
2
•
3
Maximum
Branch piping
•
3
-
2
Maximum
Indoor-outdoor H
Indoor-indoor
(Δh)
Indoor unit:
Upper
Outdoor unit:
Upper
GP80 50 15 10 30 30 0.5
Outdoor unit
Pipe diameter (mm)
Number of bent
portions
Main pipe Branch piping
Gas side Liquid side Gas side Liquid side
GP80 15.9 9.5 12.7 6.4 10 or less
Outdoor unit
Indoor unit
Figure of single
Outdoor unit
Indoor unit
Figure of simultaneous twin
Indoor unit
6 Air purging
■Airtight test
After completing the refrigerant piping work, perform an airtight test. Connect a nitrogen gas cylinder and
pressurize the pipes with nitrogen gas as follows to conduct the airtight test.
Gas leak check
Step 1....Pressurize to 0.5 MPa (5 kg/cm
2
G) for 5 minutes or longer.
Step 2....Pressurize to 1.5 MPa (15 kg/cm
2
G) for 5 minutes or longer.
Step 3....Pressurize to 4.15 MPa (42 kg/cm
2
G) for 24 hours. ................ Micro leaks can be discovered.
(However, note that when the ambient temperature differs during pressurization and after 24 hours, the pressure
will change by approximately 0.01 MPa (0.1 kg/cm
2
G) per 1°C, so this should be compensated.)
* After the airtight test is completed, evacuate the nitrogen gas.
If the pressure drops in steps 1 through 3, check the connections for leakage.
Check for leaks with leak detector manufactured specially for HFC refrigerant to perform the R32 gas leak
inspection, take steps to fix the leaks such as brazing the pipes again and tightening the flare nuts, and then
perform the airtight test again.
V
L
V
H
High pressure gauge
Gauge manifold
Low pressure gauge
Nitrogen gas
Charge port
Pressure reducing
valve
Never use oxygen, flammable gas, or noxious
gas for the airtight test.
Major leaks can be discovered.
33-EN 34-EN
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