LG ARUM072BTE5 Installation Manual page 112

PRE-COMMISSIONING
Triple Leak / Pressure Check
Triple Leak / Pressure Check Procedure Steps, continued.
4. Perform the leak / pressure check at 150 psig for five (5) minutes (standing pressure check).
5. Perform the leak / pressure check at 300 psig for fifteen (15) minutes (standing pressure check).
6. Perform the leak / pressure check at 550 psig for 24 hours to make sure the piping system is leak-free. After the gauge reading reaches
550 psig, isolate the system by first closing the gauge manifold, then close the nitrogen cylinder valve. Check the flared and brazed con-
nections for leaks by applying a bubble solution to all joints.
The bubble solution should be a solution designed for refrigerant leak testing. Common soap solution should never be used on refrigerant piping as
those contain chemicals that could corrode copper and brass, and cause product malfunction.
7. If the pressure does NOT drop for 24 hours, the system passes the test. See how ambient conditions may affect the pressure test below.
Ambient Conditions and the Leak / Pressure Check
If the ambient temperature changed between the time when pressure was applied and when the pressure drop was checked, adjust
results by factoring in approximately 0.79 psi for each 1°F of temperature difference.
Correction formula: (°F Temperature when pressure was applied - °F Temperature when pressure drop was checked) x 0.79.
Example: When pressure (550 psig) was applied, temperature was 80°F; 24 hours later when pressure drop (540 psig) was checked,
temperature was 68°F.
Thus, (80°F - 68°F) x 0.79 = 9.5 psig.
In this case, the pressure drop of 9.5 psig was due to temperature differences, therefore, there is no leak in the refrigerant piping system.
8. If the pressure drops and it is not due to ambient conditions, there is a leak and it must be found. Remove the bubble solution with a clean
cloth, repair the leak(s), and perform the leak / pressure check again.
9. After the system has been thoroughly tested and no leaks are found, depressurize by loosening the charging hose connector at the nitro-
gen cylinder regulator. When system pressure returns to normal, completely disconnect the charging hose from the cylinder, and release
the nitrogen charge from all refrigerant piping. Wipe off any remaining bubble solution with a clean cloth.
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