Air bubbles constantly come from some jets even when air controls are closed.

Safety: Turn off power before removing air control valves.

• Operate air controls: Turn each air control knob fully clockwise to close and counter‑clockwise to open. If one does not change bubble output, it may be stuck.
• Inspect air valves: Remove the suspect air control from the shell and check for broken internal parts. Replace if damaged.
• Check air lines: In the equipment bay, inspect clear air tubing and check valves for cracks or disconnections.