INVENTOR V7LI-12WiFiR/U7RS-12, Installation Manual, Page: 30 / 152

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8
Air Evacuation
Safety Precautions
Evacuation Instructions
CAUTION
• Use a vacuum pump with a gauge reading low-
er than -0.1 MPa and an air discharge capacity
above 40L/min.
• The outdoor unit does not need vacuuming.
DO NOT open the outdoor unit’s gas and liquid
stop valves.
• Ensure that the Compound Meter reads -0.1
MPa or below after 2 hours. If after three hours
of operation and the gauge reading is still above
-0.1 MPa, check if there is a gas leak or water
inside the pipe. If there is no leakage, perform
another evacuation for 1 or 2 hours.
• DO NOT use refrigerant gas to evacuate the
system.
Before using a manifold gauge and a vacuum
pump, read their operation manuals to make
sure you know how to use them properly.
Manifold Gauge
Compound gauge
-76cmHg
Low pressure valve
Charge hose
Pressure gauge
Flare nut
Cap
Valve stem
Valve body
High pressure valve
Charge hose
Vacuum pump
Low pressure valve
Fig. 9.1
Fig. 9.2
1. Connect the manifold gauge’s charge hose
to the service port on the outdoor unit’s low
pressure valve.
2. Connect the manifold gauge’s charge hose
from the to the vacuum pump.
3. Open the Low Pressure side of the manifold
gauge.Keep the High Pressure side closed.
4. Turn on the vacuum pump to evacuate the
system.
5. Run the vacuum for at least 15 minutes, or
until the Compound Meter reads -76cmHG
(-1x105Pa).
6. Close the manifold gauge’s Low Pressure
valve and turn off the vacuum pump.
7. Wait for 5 minutes, then check that there has
been no change in system pressure.
8. Insert hexagonal wrench into the packed valve
(high pressure valve) and open the valve by
turning the wrench 1/4 counterclockwise. Lis-
ten for gas to exit the system, then close the
valve after 5 seconds.
12. Tighten valve caps by hand, then tighten it
using the proper tool.
9. Watch the Pressure Gauge for one minute to
make sure that there is no change in pressure. It
should read slightly higher than the atmospher-
ic pressure.
10. Remove the charge hose from the service port.
11. Using hexagonal wrench, fully open both the
high pressure and low pressure valves.
NOTE: If there is no change in system pres-
sure, unscrew the cap from the packed valve
(high pressure valve). If there is a change in
system pressure, there may be a gas leak.
OPEN VALVE STEMS GENTLY
When opening valve stems, turn the hexago-
nal wrench until it hits against the stopper. DO
NOT try to force the valve to open further.