Installation Instructions

16
Airtight test
After the refrigerant piping has finished, execute an airtight test. For an airtight test, connect a nitrogen gas bomb as
shown in the figure below, and apply pressure.
• Be sure to apply pressure from the service ports of the packed valves (or ball valves) at liquid side, discharge gas
side, and suction gas side.
• An air tight test can be only performed to the service ports at liquid side, discharge gas side, and suction gas side
of the outdoor unit.
• Close fully valves at liquid side, discharge gas side, and suction gas side. As there is possibility that nitrogen gas
enters in the refrigerant cycle, re-tighten the valve rods before applying pressure.
(Re-tightening of the valve rods are unnecessary for valves at discharge gas side because they are ball valves.)
• For each refrigerant line, apply pressure gradually with steps at liquid side, discharge gas side, and suction gas
side.
Be sure to apply pressure to suction gas side, discharge gas side, and liquid side.
REQUIREMENT
Never use “Oxygen”, “Flammable gas” and “Noxious gas” in an airtight test.
 
 
STEP 1 : Apply pressure 0.3MPa (3.0kg/cm
2
G) for 3 minutes or more.
Available to detect a gross leakage
STEP 2 : Apply pressure 1.5MPa (15kg/cm
2
G) for 3 minutes or more.
STEP 3 : Apply pressure 3.73MPa (38kg/cm
2
G) for approx. 24 hours. Available to detect slow leakage
• Check pressure down.
No pressure down: Accepted Pressure down: Check the leaked position.
However, if there is difference of ambient temp. between when pressure has been applied and when
24 hours passed, pressure changes by approx. 0.01MPa (0.1kg/cm²G) per 1°C. Correct the pressure.
Leaked position check
When a pressure-down is detected in STEP 1, STEP 2, or STEP 3, check the leakage at the connecting points.
Check leakage with hearing sense, feeler, foaming agent, etc, and perform re-brazing or re-tightening of flare if
leakage is detected.


VL VH
Connected to indoor unit
Packed valve fully closed
(Gas side)
Outdoor unit
Low-
pressure
gauge
High-
pressure
gauge
Gauge
manifold
Brazed
Service port
Ø6.4
Copper pipe
Ø6.4
Copper pipe
Fully closed
Reducing
valve
Nitrogen gas
Ball valve fully closed
(Liquid side)
Service port
Main pipe