What happens when a commercial oven fan fails?

Please verify the following points and require itemized written supplier responses:（commercial oven oven-fan） A failed fan reduces circulation, creates uneven temperatures, lengthens baking time and may cause noise or a hot motor. Stop using the oven if the fan does not turn, makes abnormal noise or rubs against the housing. 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.