Hitachi RAM-90QH5, Service Manual, Page: 16 / 83

– 15 –
Fig. 6-1
Fig. 6-2
Fig. 6-3
Lo Hi
Stop valve
Charge hose A Charge hose B
Stop
valve
Vacuum pump adapter
Valve cap
Valve cap
Valve cap of valve core
Valve cap
Valve core
Valve cap of
valve core
Stopper
O-Ring
Pipe
Pipe
Seal cap
Flare nut
Spindle
When the meter reaches -101KPa (-76cmHg) during
pumping, fully tighten the shuttle.
Air purging by vacuum pump
Closed
Vacuum pump
R410A
Manifold valve
Be sure the stop valve is always fully opened.
The refrigerant channel is opened so that the refrigerant
will flow from the outdoor unit into the indoor unit.
Meter showing pressure
Remove the valve cap from the service valves located at both the
large and small pipe rims
➤
Connect the charging hose A to the large service valve.
After connecting the vacuum suction pump adaptor, connect the
charging hose B to the adaptor.
During relocation or re-installed, there is a possibility of electric-powered
valve to be closed. Should the electric-powered valve be closed, even
with air purging being conducted, certain amount of air is still trapped
within that area, hence, there is a need to open up the electric-powered
valve to do an air purging. Under such circumstances, before using
the vacuum-suction pump, the main power supply (LN terminal) should
be connected to enable a complete opening up of the valve. After
connecting the power supply for approximately 90 seconds, the valve
will be fully opened, after which disconnect the power supply and start
using the vacuum suction pump.
(Refer to “Power Supply Terminal Connections” in regards to the LN
terminal)
CAUTION: Ingress of air during the operating cycle may cause increase
in pressure and other breakdowns.
Switch off the outdoor unit’s power supply
Shut the manifold valve handle Hi, handle Lo need to be open and
operate the vacuum pump for approximately 60 minutes.
Upon a full shut of manifold valve handle Lo, the vacuum pump can
be stopped.
Check to ensure that there is no gas leakage.
After removing the charging hose A, rotate the service valve spindles
in an anti-clockwise direction to fully open for both valves.
Reinstall the cap nuts to their original positions and tighten them to
their specified torque.
Disconnect the charge hose from the service valve.
Tighten the valve cap of valve core.
[Torque 12.3 - 15.7 N·m (125 - 160 kgf·cm)]
Fix the valve cap to the spindles of each large and small dia. pipe
side service valves.
Tighten the valve cap of the spindle.
[Torque 19.6 - 24.5 N·m (200 - 250 kgf·cm)]
4. Air purging by using vacuum pump
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!
CAUTION
1. Be sure to use the vacuum pump, vacuum pump adapter and manifold gauge and refer to their instruction manuals beforehand.
2. Ascertain that the vacuum pump is filled with oil to the level designated on the oil gauge.
3. After closed the ball valve of charge hose, it should be disconnected at service port side and refrigerant cylinder side at first.
Next, after discharging the remained gas in the charge hose by opening the ball valve a little, disconnect it at manifold gauge side. You
can prevent sudden release of refrigerant by connecting the ball valve to service port. And you can work more safety.