Air Purging - Toshiba RAV-GM802ATW-E Installation Manual

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
Charge port
L H
Pressure reducing
Gas leak check
Step 1 ... Pressurize to 0.5 MPa (5 kg/cm
2
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 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.
* 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.)
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CAUTION
Never use oxygen, flammable gas, or noxious
gas for the airtight test.
valve
Nitrogen gas
G) for 5 minutes or longer.
Major leaks can be discovered.
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.)
2
Compound pressure gauge
Pressure gauge
–101 kPa
(–76 cmHg)
Handle Low
Charge hose
(For R32 or
R410A only)
Charge port
Vacuum
(Valve core
(Setting pin))
Packed valve at gas side
– 17 –
Vacuum pump
As shown in the figure, connect the charge hose after the
Attach the connecting port of the charge hose with a
projection to push the valve core (setting pin) to the charge
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
Leave the vacuum pump as it is for 1 or 2 minutes, and check
that the indicator of the compound pressure gauge does not
Open the valve stem or valve handle fully. (First, at liquid
Disconnect the charge hose from the charge port.
Tighten the valve and caps of the charge port securely.
*1 Use the vacuum pump, vacuum pump adapter, and
gauge manifold correctly referring to the manuals
supplied with each tool before using them.
Gauge manifold valve
Check that the vacuum pump oil is filled up to the
specified line of the oil gauge.
Handle High
*2 When air is not charged, check again whether the
(Keep fully closed)
connecting port of the discharge hose, which has a
Charge hose
projection to push the valve core, is firmly connected to
(For R32 or R410A only)
the charge port.
Vacuum pump
adapter for backflow
prevention
(For R32 or R410A
only)
pump
■ How to open the valve
Fully open the valves of the outdoor unit. (First fully
manifold valve is closed completely.
open the valve on the liquid side, and then fully open
the valve on the gas side.)
* Do not open or close the valves when the ambient
port of the set.
Liquid side
Open Handle Low fully.
Open the valve with hexagon wrench.
Hexagon wrench size: 4 mm
Turn ON the vacuum pump. (*1)
Gas side
Service valve
Open the valve with hexagon wrench.
Hexagon wrench size : 5 mm
Retighten the flare nut.
indicates –101 kPa (–76 cmHg). (*1)
Close Handle Low completely.
Turn OFF the vacuum pump.
Valve handling precautions
• Open the valve stem until it strikes the stopper.
return.
• Securely tighten the cap with a torque wrench.
side, then gas side)
temperature is -20°C or less. Doing so may damage
the valve O-rings and result in refrigerant leakage.
Charge port
Valve stem
Valve stem
Valve unit
cap
Flare nut
It is unnecessary to apply further force.
34-EN