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8. VACUUM PUMPING
General Clause:
Vacuum pumping should be done more than 60 minutes from 2 portions.
One portion at high - pressure side and one portion at low - pressure side.
Be sure the Adaptor good connect to vacuum pump.
The Adaptor can stop oil flow from Vacuum Pump to Cooling Unit HFC-134a, after Manifold Gauge
and Charge Hose vacuum condition.
Be sure the rapir tools which are exclusive use for HFC-134a (except vacuum pump).
Coupler Socket
Valve
close
Charge cylinder
Adaptor
Valve
close
state
1.
Run the vacuum pump for 30 minutes before connecting. This is to resume the vacuum by evaporating
the cleaning liquid which is blent in the pump oil.
2.
Connect repair tools such as control valve, manifold gauge, charge hose, coupler socket, charge cylinder
as shown in the figure.
3.
Connect the adaptor with vacuum pump properly and turn the switch to HFC-134a use.
4.
Run the vacuum pump and open each valve (3 portions) of manifold gauge and check the vacuum.
Note:
1. Check the reading of manifold gauge before use.
2.
If the reading at low-pressure gauge does not reach 760 mmHg while the vacuum pump alone is
running, there is aleakage or something is wrong with the pump, check the rubber packing of hose
and the deterioration of vacuum pump oil.
3.
Check the vacuum level by read the Vacuum Gauge periodicly, if gauge indication over from 0.5 torr,
change the oil vacuum pump and check the packing rubber.
4. For High Pressure
Insert the coupler plug to compressor charge pipe and lock the lever. Then connect the coupler plug
with coupler socket.
For Low Pressure
Inert the coupler plug to dryer charge pipe and lock the lever. Then connect the coupler plug with
coupler socket.
5.
After 2 minutes vacuum pumping, close the valve form manifold gauge and control valve, make sure
the indicator gauge no move.
6.
Open the Valve from manifold gauge and control valve, and one again vacuum pumping more than 60
minutes.
7.
When to finish vacuum pumping, disconnect the coupler Socket at High Pressure and close both
Valve (red and yellow) from manifold Gauge. then stop the vacuum pumping.
Manifol Gauge
Control Valve
state
Valve
open
state
Coupler plug
(one-touch type)
HFC-134a
Valve open state
during vacuum pumping
Valve
close
state
during vacuum pumping
-15-
Coupler plug
(one-touch type)
High Pressure
Gauge
Low Pressure
Gauge
Change Switch
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