A defect found at the factory costs a day to fix. The same defect found after installation costs a week, a service flight and an argument about who pays. That asymmetry is the whole case for a factory acceptance test.
What the test covers
The standard protocol runs four checks: vacuum decay on the empty chamber, refrigeration pull-down and hold, shelf temperature mapping at three setpoints, and a full cycle with a representative load.
Documentation is reviewed in the same session: as-built drawings, P&ID, electrical schematic, calibration certificates, test records and manuals in the ordered language.
The three tests worth watching
Vacuum decay. Watch the gauge rather than reading the result afterwards. A machine that holds pressure on the day will hold it in the customer's plant.
Shelf mapping. Ask for the map at the coldest setpoint, not only at ambient. Uniformity at +20 °C is easy; at −45 °C it is not.
The full cycle. Not a partial run. Watch the stage transitions and look at the product at the end. Cut a piece open.
What to look at with your own eyes
Pipework: joint count, bend quality, insulation continuity. Control cabinet: labelling, terminal torque, cable routing, earthing. Door and seal: alignment, compression, latch effort. Chamber interior: weld finish, corner treatment, drain slope. Nameplate and markings against the order.
Documents to take away
Vacuum decay and pull-down records for the serial number. Shelf uniformity map. Calibration certificates, all in date. Final cycle trend file, exported rather than photographed. As-built drawings, signed. Spare parts list and packing list.
Open items are normal
A test with zero findings usually means the test was too easy. What matters is that every open item is written down with an owner, a closure date and a verification method. Release the balance payment against the closed list, not against an assurance.
If you cannot travel
Ask for a live video test with the camera on the screen and on the machine, and insist the trend files are emailed during the session rather than afterwards. A recording is better than nothing; a live call with questions is better than a recording.
What JIAXIN provides
A written protocol in advance, with acceptance criteria per test, and a signed report at the end listing results and open items. Where a customer brings their own product, the final cycle runs on that material and the trend is labelled accordingly.
