A missing performance test report can turn a $22,000 screw compressor purchase into a $44,000 commissioning problem. Importers often approve the quotation, then discover during installation that the voltage is wrong, the specific power was never documented, or the warranty covers almost nothing.

Before you transfer the deposit, ask for eight screw compressor supplier documents. Each one forces the seller to put a verifiable number behind the sales claim.

Why Documentation Separates a Real Factory From a Brochure

The local Panrui technical file lists two checks that should appear in any serious supplier file: a 12-hour continuous run test before shipment and a 52°C ambient design point, well above the 40°C level many plants still use. If a seller cannot produce the test record, the “industrial duty” language is unproven.

Also ask for specific power, not just motor power. The Panrui comparison sheet shows two-stage machines listed from 5.9 to 6.5 kW/(m³/min) across 55–90 kW models. A quotation that only shows “90 kW” hides the true operating cost.

Specific power is input kW divided by free air delivery. A lower number means more compressed air from each kilowatt-hour, so it is the most honest way to compare machines of different brands, pressures, and motor ratings.

The 8-Document Package to Request

• Signed quotation: model code, motor power, pressure, free air delivery, voltage and frequency, accessories, and delivery terms.
• Performance data sheet: specific power and free air delivery at each working pressure, with the measurement standard.
• Factory acceptance test record: 12-hour run results, operating temperature, pressure stability, and shutdown/alarm checks.
• Warranty certificate: total term, what is covered, exclusions, and separate terms for the airend and variable-speed drive.
• Export package: commercial invoice, packing list, certificate of origin, shipping marks, and insurance instruction.
• Compliance certificates: the declaration, standards, and test reports required by your customs authority or end customer.
• Installation and maintenance file: commissioning checklist, electrical connection drawing, lubrication schedule, and spare parts list.
• Reference proof: a customer case with before/after kWh, pressure settings, operating hours, or specific-power comparison.

Request dated, signed, and model-specific versions, not only a scanned brochure. A PDF marketing deck is useful for a first pass, but the quotation, test record, and warranty certificate must match the exact model code you are buying.

What Buyers Get Wrong

• Sending a deposit on a one-page quotation without a factory acceptance test schedule.
• Treating a CE mark as automatic compliance in every target market.
• Comparing motor kW instead of specific power at the required pressure.
• Accepting “5-year warranty” without checking which parts, labor, and failure modes are excluded.

Do not accept a document package that was clearly reused from another customer. If the model number, voltage, pressure, or delivery port on the quotation does not match the test record, stop and correct the file before the machine leaves the factory.

Use the Numbers to Negotiate

Compare the specific-power figures before you compare prices. In the same comparison sheet, a 90 kW two-stage machine is listed at 5.9 kW/(m³/min) while a single-stage 90 kW model is listed at 7.0 kW/(m³/min). That is about 15.7% less input power per cubic meter, a difference that matters more than a small discount on the invoice.

For a plant running 6,000 hours per year, every 0.1 kW/(m³/min) of unnecessary specific power becomes a recurring line item on the electricity bill. Ask the supplier to put that number in writing, then hold them to it during commissioning.

Also confirm what the warranty promise means for your market. A five-year whole-machine warranty is only valuable if the supplier states whether it covers the airend, motor, variable-speed drive, labor, freight, and local service response time.

Your Next Step

Get the eight documents before you pay. Start with a rotary screw air compressor model comparison, and if your demand varies across shifts, also request the variable-speed data sheet. Send your operating hours, pressure, and local voltage to the Panrui team, and ask for the full document package with your first quotation.