Spa makes loud banging or knocking noises when the pump runs, especially on high speed.

Safety: Turn off power before tightening any hardware.

• Bleed air: Run the pump on low speed with all jets open to purge air. Briefly open and close air controls to release trapped air.
• Check pump mounting: Tighten pump mounting bolts to the equipment base to reduce vibration.
• Inspect plumbing: Look for pipes that are hitting the cabinet or each other and secure them with clamps or foam.