Airwell YEVFD Series, Service Manual

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■ The refrigerant pipe should be clean. The nitrogen should flow under the pressure of about 0.5Mpa and when
charging the nitrogen, stop up the end of the pipe by hand to enhance the pressure in the pipe, then loose the
hand (meanwhile stop up the other end).
■ When connecting the pipes, close the valves fully.
■ When welding the valve and the pipes, use the wet cloth to cool down the valve and the
pipes.
1st side
hand
2nd side
source valve
0.2MPa
B. Leakage test
1. The outdoor unit has been executed the leakage test in the factory. The pipe should be executed leakage test
individually and forbidden to test after connecting with stop valve.
2. Refer to the below figure to charge the nitrogen into the unit to take a test. Never use the chlorin, oxygen,
flammable gas in the leakage test. Apply pressure both on the gas pipe and the liquid pipe.
3. Apply the pressure step by step to the target pressure.
a. Apply the pressure to 0.5MPa for more than 5 minutes, confirm if pressure goes down.
b. Apply the pressure to 1.5MPa for more than 5 minutes, confirm if pressure goes down.
c. Apply the pressure to the target pressure (4.15MPa), record the temp. and the pressure.
d. Leave it at 4.15MPa for over 1 day, if pressure does not go down, the test is passed. Meanwhile, when the
temp. changes for 1degree, pressure will change 0.01MPa as well. Correct the pressure.
e. After confirmation of a~d, if pressure goes down, there is leakage. Check the brazing position, flared position
by laying on the soap. modify the leakage point and take another leakage test.
4. After leakage test, must execute the evacuation.
nitrogen
Hi handle
gauge manifold
Hi
to indoor
Lo
Lo handle
C. Evacuation
Evacute at the check valve of liquid stop valve and both sides of the gas stop valve. The oil equalization pipe also
must be vacuum (executed at the oil equalization pipe check valve respectively).
Operation procedure:
Leakage test passed
Leave it for over 1
hour, vacuum pointer
does not arise.
After reaching -100.7KPa or
less (below -755mmHg), let
the vacuum pump running
continuously for over 1hour.
Charge refrigerant
Evacuation begins
Check vacuum
Evacuation ends
If vacuum pointer arises, it shows there is water or leakage in the system, please check and modify it, and then
evacuate again.
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