Carrier 38QUS018DS2-2 Installationshandbuch Seite 21

8. AIR EVACUATION
8.1 Safety Precautions
CAUTION
• Use a vacuum pump with a gauge reading
lower than -0.1MPa and an air discharge
capacity above 40L/min.
• The outdoor unit does not need to be
vacuumed. DO NOT open the outdoor unit's
gas and liquid stop valves.
• Ensure that the Compound Meter reads
-0.1MPa or below after 2 hours. If after three
hours 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 leak, perform
another evacuation for 1 or 2 hours.
DO NOT use refrigerant gas to evacuate the
•
system.
8.2 Evacuation Instructions
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
Low pressure valve
Fig. 8.1
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.
Pressure gauge
High pressure valve
Charge hose
Vacuum pump
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 1/4
counterclockwise. Listen for gas to exit
the system, then close the valve after 5
seconds.
Fig. 8.2
Valve body
Valve stem
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 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.
8.3 OPEN VALVE STEMS GENTLY
When opening the 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.
13.If the outdoor unit uses all vacuum
valves, and the vacuum position is
at the main valve, the system is not
connected with the indoor unit. The
valve must be tightened with a
screw nut. Check for gas leaks
beforeoperation to prevent leakage.
Flare nut
Cap
Fig. 8.3
GB-20 7