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.
Low pressure gauge
High pressure gauge
Gauge manifold
V
V
L
H
Charge port
Pressure reducing
Gas leak check
2
Step 1 ... Pressurize to 0.5 MPa (5 kg/cm
G) for 5 minutes or longer.
Step 2 ... Pressurize to 1.5 MPa (15 kg/cm
Step 3 ... Pressurize to 4.15 MPa (42 kg/cm
(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
If the pressure drops in steps 1 through 3, check the connections for leakage.
Check for leaks with foaming liquid, etc., take steps to fix the leaks such as brazing the pipes again and tightening
the flare nuts, and then perform the airtight test again.
* After the airtight test is completed, evacuate the nitrogen gas.
Air Purge
With respect to the preservation of the terrestrial
environment, adopt "Vacuum pump" to purge air
(Evacuate air in the connecting pipes) when installing the
unit.
• Do not discharge the refrigerant gas to the
atmosphere to preserve the terrestrial environment.
• Use a vacuum pump to discharge the air (nitrogen,
etc.) that remains in the set. If air remains, the capacity
may decrease.
For the vacuum pump, be sure to use one with a
backflow preventer so that the oil in the pump does not
backflow into the pipe of the air conditioner when the
pump stops.
(If oil in the vacuum pump is put in an air conditioner
including R32, it may cause trouble with the refrigeration
cycle.)
EN-161
CAUTION
Never use oxygen, flammable gas,
or noxious gas for the airtight test.
valve
Nitrogen gas
Major leaks can be discovered.
2
G) for 5 minutes or longer.
2
G) for 24 hours. ................ Micro leaks can be discovered.
2
G) per 1°C, so this should be compensated.)
Compound pressure gauge
–101 kPa
(–76 cmHg)
Handle Low
Charge hose
(For R32 or R410A
only)
Charge port
(Valve core
(Setting pin))
Packed valve at gas side
- 81 -
Vacuum pump
As shown in the figure, connect the charge hose after
the manifold valve is closed completely.
Attach the connecting port of the charge hose with a
projection to push the valve core (setting pin) to the
Loosen the flare nut of the packed valve (Gas side) a
little to check that the air passes through. (*2)
Execute vacuuming until the compound pressure
gauge indicates –101 kPa (–76 cmHg). (*1)
Leave the vacuum pump as it is for 1 or 2 minutes, and
Pressure gauge
check that the indicator of the compound pressure
Gauge manifold valve
Handle High
(Keep fully closed)
Open the valve stem or valve handle fully. (First, at
Charge hose
(For R32 or R410A
only)
Disconnect the charge hose from the charge port.
Vacuum
pump adapter
for backflow
prevention
Tighten the valve and caps of the charge port securely.
(For R32 or
Vacuum
pump
R410A only)
*1
*2
charge port of the set.
Fully open the valves of the outdoor unit. (First fully open
the valve on the liquid side, and then fully open the valve
Open Handle Low fully.
on the gas side.)
* Do not open or close the valves when the ambient
Turn ON the vacuum pump. (*1)
Liquid side
Open the valve with hexagon wrench.
Retighten the flare nut.
Gas side
Ball valve
Close Handle Low completely.
Turn OFF the vacuum pump.
gauge does not return.
liquid side, then gas side)
Use the vacuum pump, vacuum pump adapter, and gauge
manifold correctly referring to the manuals supplied with
each tool before using them.
Check that the vacuum pump oil is filled up to the specified
line of the oil gauge.
When air is not charged, check again whether the connecting
port of the discharge hose, which has a projection to push
the valve core, is firmly connected to the charge port.
How to Open the Valve
temperature is -20°C or less. Doing so may damage
the valve O-rings and result in refrigerant leakage.
Hexagon wrench size
4 mm
Valve unit
Using a minus
screwdriver, turn it
counterclockwise
by 90° until it hits
the stopper. (Full
Charge port
open)
(1)
Flare nut
(2)
EN-162