Hayward PowerFlo pump makes a rattling or clattering noise, especially at startup or when air is present.

Safety first: Turn off the pump before opening lids or valves.

• Check water level: Ensure the pool water level is high enough to keep the skimmer from drawing air.
• Clean baskets: Empty and clean the skimmer and PowerFlo pump baskets to restore full suction.
• Inspect suction fittings: Check all suction-side connections, hoses, and unions for air leaks. Tighten clamps and unions, and replace cracked hoses.
• Prime the pump: Fill the PowerFlo strainer housing with water, reinstall the lid with a lubricated O-ring, and restart the pump. Listen for reduction in noise as air is purged.