Free tool

Nitrogen pressure test

Temperature moves the gauge as much as a small leak does. Enter what you charged to and the temp now, and see what a tight system should read.

How it works. Gay-Lussac's law: at a fixed volume, absolute pressure follows absolute temperature (P1/T1 = P2/T2). Gauge pressure is turned into PSIA (+14.7) and °F into °Rankine (+459.67) for the math.

For a line set that runs both inside and outside, take a temp at each spot and use the two-point test. Always follow the equipment maker's test pressure and hold time.

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