GREE DC Inverter Multi VRF System II Service Manual
145
6.3 Airtightness test
6.3.1 Importance of airtightness test
The airtightness of VRF system is the leak tightness of the pipeline for refrigerant, which the
guarantee for safe and reliable operation. The leakage of refrigerant may affect the operation of air
conditioner seriously, or even damage compressor and then lead to breakdown of system. Therefore, it
needs to perform the airtightness test. If the there’s gas leakage after the system is installed completely,
because the indoor ceiling decoration are all finished, it’s will be very difficult to find out the leakage point.
Thus, the airtightness test of the system must be finished before finishing indoor decoration.
6.3.2 Operation procedure for the airtightness test
Before ex-factory, cut-off valve for gas pipe and liquid pipe of outdoor unit is turned off. Please
confirm that before operation.
Before testm please smear a little corresponding lubricant oil at and pipe terminal, and use two
wrenches for fixing
Do not allow to connect the pipeline of outdoor unit for test during airtightness test.
The system test pressure for R410A is 4.15MPa (3.0MPa for R22 refrigerant system). Nitrogen must
be used as the medium for the airtightness test and the nitrogen should be dry. Increase pressure slowly
for three steps:
Step 1:Increase pressure slowly to 0.5MPa, stop for 5min and then check the gas leakage. Big
leakage may be found out;
Step 2:Increase pressure slowly to 1.5MPa, stop for 5min to check the airtightness. Small leakage
may be found out;
Step 3:Increase pressure slowly to 4.15MPa for R410A slowly (3.0MPa for R22 refrigerant system),
stop for 5min and perform the strength test. Minor leakage or sand hole may be found. Increase
pressure to test pressurem, keep it for 24h and observe whether the pressure is decreasing. If not, the
pressure is qualified.
6.3.3 Cautions
˄1˅The test manometer range for R410A should be 4.5MPa above (3.5MPa above for R22 refrigerant
system);
˄2˅Record the data on manometerk, ambient temperature and test time at the same time;
˄3˅Pressure modification: when temperature changes 1ć, the temperature will change 0.01MPa
correspondingly.
˄4˅Pressure should be kept the same.
˄5˅If it needs to keep pressure for a long time, decrease the pressire lower than 0.55MPa pr below.
Long-time high pressure can lead to leakage at the welding position, which may cause riskl.
˄6˅Before the airtightness for the pipeline of refrigerant is finished, do not allow to insulate and bundle
the welding positions and connection position of bellmouth of indoor unit.
To Next Page
Loading...
Need help?
General
