Pressure Test Checker
Left it on nitrogen overnight and the gauge has dropped? Most of that is usually the weather. Put in what you read at each end and see how much of it temperature accounts for.
When you left it
When you came back
Held for
Needs all four figures. A part-filled answer here is the one that gets believed.
Standing vacuum
Pulling down to 500 microns — 0.67 mBar, 0.5 Torr — proves the pump works. What it does after you isolate it is what tells you about the system.
Pressure follows temperature — the gas law, at constant volume. This separates the part of a change the weather explains from the part it doesn't. It never passes or fails a test: it can't see a gauge left in the sun, a probe reading the wrong air, or nitrogen still settling. That call stays yours.
Record it against the job instead
On a job, the same check saves with the pressures, hold times and the working — and prints on the commissioning paperwork.
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