After erection of air conditioning plant onboard
and finished refrigerant pipe work prior to application |
of insulation, pressure/leak test to be performed
as follow procedure. |
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1. |
Close suction valve and discharge valve of compressor. |
2. |
Open other valves installed on the refrigerant
pipe line. |
3. |
Low pressure switch to be isolated from the
suction line during this test and ensure that |
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expansion valves, pressure switches and etc.
containing bellows or diaphragms are isolated |
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from the rest of the plant during the test. |
4. |
Charge N2 gas into entire system through charge
valve until the pressure rises up to the test |
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pressure of 11kg/cm² G. for low pressure side. |
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(From expansion valve to compressor suction
stop valve) |
5. |
Close stop valve just before the expansion valve
on the liquid line to separate high pressure |
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line from low pressure line. |
6. |
Further charge dry N2 gas until the pressure
rises up to the test pressure of 21 kg/cm² G. for |
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high pressure side. (From compressor discharge
stop valve to manual stop valve installed just |
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ahead expansion valve) |
7. |
Keep this condition for twelve(12) hours and
check the pressure drop at the end of this test. |
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The pressure drop should not exceed 0.35 kg/cm² with following temp. correction |
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P = Po - P(To/T)
0.35 kg/cm2 |
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here, |
P
= Pressure drop (kg/cm²) |
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Po
= Initial pressure (kg/cm²) |
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To
= Initial temperature
(°K) |
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T
= Temperature at end of test
(°K) |
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8. |
In case of pressure drop exceeds 0.35 kg/cm²,
every joint to be checked by halide torch detector |
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or soap water. If leakage is detected, the test should be
repeated after the leak part repaired. |