First, the use of external mechanical vacuum pump for vacuum leakage test this method is generally used in small cold storage equipment, the specific operating steps are as follows:

1, counterclockwise rotation under the suction shut-off valve channel fine teeth screw plug, clockwise suction shut-off valve rod circle, is the suction valve is in a three-way state;

2, with a three-way repair valve and vacuum pressure gauge of the flexible receiver will be vacuum pump and suction shut-off valve on the multi-preferences connected to a good;

3, open all the valves in the system (including solenoid valves and manual valves, etc.)

4, turn on the vacuum pump power supply, vacuum the system until the vacuum pressure gauge reading reaches -0.1mpa, appropriate time after the suction shut-off valve lever counterclockwise rotation exit and screwed tightly;

5, keep 18-24h, if the vacuum degree remains unchanged, choose to consider the refrigeration system vacuum test qualified.

Second, machine room air conditioning using the system compressor for self-financing vacuum test for larger refrigeration systems usually use this method of vacuum test, using the system. compressor for self-evacuation of the vacuum, the specific operating steps are as follows:

1, first of all, the exhaust valve shut-off valve stem clockwise spin to the end, is the system in the compressor exhaust port to lose circulation channel.

2, counterclockwise turn down the exhaust valve shut-off valve multi-channel fine tooth screw plug, so that the exhaust port of an atmospheric connection.

3, open all the valves in the system.

4, short the contacts of the low-pressure relay, the temporary giant clam protection function (when it must be restored).

5, start the compressor, so that the air in the system discharged into the atmosphere (compressor suction valve should be opened slowly, a side of the system gas can not be discharged in time, resulting in exhaust pressure is too high and cause high pressure protection, etc.)

6, observe the low-pressure end of the vacuum gauge, until the vacuum pressure gauge reading reaches -0.1mpa, after an appropriate period of time will be the exhaust shut-off valve rod rotating out and screwed tight.

7, keep 18-24H, such as machine room air conditioning vacuum does not change that is qualified. Test should be noted: (1) the pressure lubrication of the compressor refrigeration system for vacuum, should be the oil pressure relay contact to do temporary forced connection; (2) self-financing vacuum time can not be too long, otherwise the moving parts of the compressor for a long time in the higher temperatures are prone to greater wear and tear and metal fatigue; (3) in the self-evacuation vacuum test, can be connected to the mouth of the distributor a hose, will be inserted into the oil at the other end of the hose The other end of the hose can be inserted into the oil, and the bubbles on the surface of the oil can be observed to be overflowing. If there is no bubble overflow in a longer period of time, the vacuum can be customized, no change in the vacuum degree after 24H qualified. If the bubble for a long time more than, can first close the compressor suction valve, Jane is the compressor itself is not leaking, such as the oil is not in the bubble, that the compressor itself is not leaking, the other parts of the system is leaking, bubbles continue to produce, indicating that the compressor leakage, which is often caused by the shaft seal is not tight.

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