29
Using
the
vacuum
pump
AIR PURGE
For air purge, evacuate the air in the connecting pipe and indoor unit by using
vacuum pump. For details, please refer to the following procedure.
a. Connect the gauge manifold.
b. Open the low pressure valve and close the high pressure valve of the gauge
manifold completely.
c. Operate the vacuum pump during at least 20 minutes until the pressure
reaches -101Kpa (-760mm Hg).
d. Close the low pressure valve of the gauge manifold and stop the vacuum
pump operation. (If the indicator of gauge manifold is returned
within 1-2minute after stopping the vacuum pump, check the piping
connection leakage)
e. Open both the two-way and three-way valve completely.
f. Close both the two-way and three-way valve caps completely.
g. Remove the gauge manifold and vacuum pump.(During the disconnection,
please be cautious not to lose any refrigerant and oil)
h. Reinstall the valve caps and service port nuts.
Figure 17
When the connection pipe is less than 7.5m, extra amount of refrigerant per meter(If it is impossible to extract proper amount of refrigernat, please keep 7.5m piping
length by making loops or windingd for compressor reliability)
Note that the shorter connection pipe, the better the performance of system.
The maximum allowable length of the connection pipe is 40m and the maximum allowable elevation between indoor unit and outdoor unit should be less than 20m.
ø15.88mm
45 g/m
(14.5 _
7.5) x 45 = 315 g
ø19.05mm
60 g/m
(14.5 _
7.5) x 60 = 420 g
Connecting pipe Size
Extra charge amount
Example for 14.5m pipe
Refrigerant charging
•
In case of refrigerant charging due to refrigerant leak or service refer to the nameplate on the outdoor unit.
•
When the upward gas line is long, oil trap shall be installed every 10m in order to return oil to compressor.
CAUTION