Regarding the issue of creating negative pressure and maintaining pressure in chillers
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I need help regarding the issue of adding R22 during the initial testing of chiller units (using water at 5-10 degrees) and brine units (using brine at -15 degrees). The units have already been tested for leaks, and a vacuum level of -0.94 MPA was achieved. The question is: what is the acceptable pressure drop over 24 hours of holding the pressure at this level? I have achieved a negative pressure of -0.94 MPA, and after 24 hours, the pressure has dropped to -0.80 MPA. Is this normal? Thank you to the experienced experts for helping with this question. It would be great if you could also tell me how long it takes to achieve a negative pressure by vacuuming. Thank you!
It depends on the complexity of your system. Generally, maintaining a pressure level with a change of no more than 5% is considered normal. If you conduct a pressure test for 24 hours and the value remains at -0.8, that’s quite good. The specific regulations can be found in the standards for pressure vessels