How can a reliable commercial oven manufacturer be checked?

Please verify the following points and require itemized written supplier responses:（commercial oven oven-manufacturer） Check samples, temperature tests, production capacity, parts supply, warranty, export documents and customer cases rather than price alone. A small trial order helps verify packaging, damage, heating, after-sales response and batch consistency. Define capacity, accuracy, materials and operating environment before requesting quotes on a uniform basis. Request specification sheets, test reports, certificates, maintenance manuals and spare-part lists. During acceptance, verify appearance, dimensions, functions, safety protection and packaging, and keep test records. Do not compare unit price alone; include customization, freight, spare parts, after-sales support and downtime risk. Keep written records of inquiries, confirmations, FAT, acceptance and warranty commitments.