Why is it important to ensure that bearings are wet before starting a water-lubricated pump?

• A. To reduce friction
• B. To prevent overheating
• C. To prevent bearing damage due to dry start
• D. To improve seal alignment

Answer: (C)

A lubricating film must be present at startup to keep bearing surfaces separated. Water-lubricated bearings rely on a thin film of water to prevent metal-to-metal contact. If the bearings aren’t wetted before starting, the first spins cause dry contact, generating high friction and heat that can score or damage the bearing races and rollers. Pre-wetting ensures the water film exists from the very first revolution, reducing wear and the risk of damage, while also helping to keep startup torque and initial heating in check.