Carrier X-POWER Series Service Manual page 115

Carrier service manual
operation. At this moment, different oils will mix, which induce the refrigerant circulating system to
malfunction, so it is recommended to use one-way valve to prevent reverse flow of oil in vacuum pump.
3.3.1.3 Vacuum drying for pipe
Vacuum drying: Use vacuum pump to make the moisture (liquid) in pipeline change into steam, which
will eliminate the moist of the pipeline and keep drying of pipe inner. Under atmospheric pressure,
water's boiling point (steam temperature) is 212℉(100°C), while its boiling point will decline when using
vacuum pump reduce the pipeline pressure to vacuum. When the boiling point declines under outdoor
temperature, moisture in pipe shall be evaporated.
Boiling Point of Water Air Pressure
℉(℃)
(mmHg)
104(40)
86(30)
80.06(26. 7)
75.92(24. 4)
71.96(22. 2)
69.08(20. 6)
3.3.2 Operation procedure for vacuum drying
3.3.2.1 Methods of vacuum drying
By different construction environment, there are two kinds of vacuum drying ways: ordinary vacuum
drying and special vacuum drying.
3.3.2.1.1 Ordinary vacuum drying
1) Firstly, connect the pressure gauge to the infusing mouth of gas pipe and liquid pipe, keep vacuum
pump running for above 2 hours, and it is quality that vacuum degree of vacuum pump is below
-755mmHg.
2) If the vacuum degree of vacuum pump could not be below -755mmHg after 2 hours of drying, system
will continue drying for one hour.
3) If the vacuum degree of vacuum pump could not be below -755mmHg after 3 hours of drying, please
check the system leakage source.
4) Vacuum placement test: when the vacuum degree reaches -755mmH, keep rest for 1 hour. If the
indicator of vacuum gauge does not go up, it is qualified. If going up, it indicates that there is moisture
and leak source.
5) Vacuum drying shall be conduct from liquid pipe and gas pipe simultaneously. There are a lot of
functional parts like valves, which could shut down the gas flow midway.
3.3.2.1.2 Special vacuum drying
This kind of vacuum drying method shall be adopted when:
1) Finding moisture during flushing refrigerant pipe.
2) Conducting construction on rainy day, because rain water might penetrated into pipeline.
3) Construction period is long, and rain water might penetrated into pipeline.
4) Rain water might penetrate into pipeline during construction.
Procedures of special vacuum drying are as follows:
a. The first vacuum drying 2 hours.
b. The second vacuum damage, filling nitrogen to 0.5kgf/cm
Because nitrogen is dry gas, vacuum damage could achieve the effect of vacuum drying, but this
method could not achieve drying thoroughly when there is too much moisture. Therefore, special
attention shall be drawn to prevent the entering of water and the formation of condensate water.
c. The second vacuum drying 1 hour.
Installation
Vacuum Degree
(mmHg)
55 -705
36 -724
25 -735
23 -737
20 -740
18 -742
Boiling Point of Water Air Pressure
℉(℃)
64.04(17. 8)
59(15)
53.06(11. 7)
44.96(7. 2)
32(0)
2
.
R410a DC Inverter 60Hz
Vacuum Degree
(mmHg) (mmHg)
15 -745
13 -747
10 -750
8 -752
5 -755
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