Midea MOB01-09HFN8-QRD6GW, Installation Manual

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Air Evacuation
9
Safety Precautions
CAUTION
than -0.1MPa 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.
or below after 2 hours. If after three hours of
operation and the gauge reading is still above
-0.1MPa, 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.
Evacuation Instructions
Before using manifold gauge and vacuum pump, read their
operation manuals to familiarize yourself with how to use
them properly.
Manifold Gauge
Compound gauge
-76cmHg
Low pressure valve
High pressure valve
Charge hose Charge hose
Vacuum pump
Pressure gauge
Low pressure valve
Fig. 9.1
1. Connect the charge hose of the manifold gauge to
service port on the outdoor unit’s low pressure valve.
2. Connect another charge hose from the manifold gauge
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
NOTE: If there is no change in system pressure, unscrew
the cap from the packed valve (high pressure valve). If
there is a change in system pressure, there may be a gas
leak.
8. Insert hexagonal wrench into the packed valve (high
pressure valve) and open the valve by turning the
wrench in a 1/4 counterclockwise turn. Listen for gas to
exit the system, then close the valve after 5 seconds.
Flare nut
Cap
Valve body
Valve stem
Fig. 9.2
9. Watch the Pressure Gauge for one minute to make sure
that there is no change in pressure. The Pressure Gauge
should read slightly higher than atmospheric pressure.
10. Remove the charge hose from the service port.
11. Using hexagonal wrench, fully open both the high
pressure and low pressure valves.
OPEN VALVE STEMS GENTLY
When opening valve stems, turn the hexagonal wrench
until it hits against the stopper.
DO NOT try to force the
valve to open further.
12. Tighten valve caps by hand, then tighten it using the
proper tool.
Air
E
vacuation
turn off the vacuum pump.
change in system pressure.
7. Wait for 5 minutes, then check that there has been no
Gauge
reads -76cmHG (-1x105Pa).
6. Close the Low Pressure side of the manifold gauge, and
• Use a vacuum pump with a gauge reading lower
• Ensure that the Compound Meter reads -0.1MPa
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