What should be done if an integrated purifier is noisy?

Noise mainly comes from the fan, excessive air velocity, duct resonance, unstable mounting or insufficient sound attenuation; first match airflow and pressure correctly, then use vibration isolation, silencers and secure ducting. Do not reduce noise by blocking inlets or blindly lowering airflow, as this causes fume leakage. 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.