How should an old restaurant be retrofitted with a purifier?

First inspect burners, hood, airflow, ducting, power supply, fan static pressure and discharge point, then decide whether to replace the purifier or modify the hood and fan. Simply adding a purifier to old ducting may increase resistance and weaken suction. Checklist: 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.