Why is cooling poor even when the fan runs?

Possible causes include wrong direction, clogged filters, insufficient airflow, short-circuited ducting or trapped hot air. Check both intake and exhaust. 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.