How should I test temperature differences between decks in a commercial oven?

Place calibrated probes at the center and corners, then compare readings at empty, half, and full load after stabilization. The purchase decision should use the actual recipe, load, and duty cycle rather than a catalogue maximum. At acceptance, repeat the agreed test with production-equivalent material and compare the result with the contractual tolerance. These records make the technical promise measurable and reduce disagreement when the machine arrives at the buyer’s site. For repeat orders, preserve the approved configuration so a later machine is built to the same practical performance basis and documented settings.