Display shows LOC or a lock icon, and buttons do not respond.

Safety first: No electrical work is required for this issue.

• Unlock panel: Refer to your Master Spas manual. Commonly, press and hold specific buttons (e.g., Temp Up and Temp Down together for 3–5 seconds) to toggle the lock.
• Check for stuck buttons: Inspect the topside panel for moisture under the overlay or physically stuck keys. Gently press around the edges to free them.
• Dry panel: If moisture is present, power off the spa and allow the panel to dry. In some cases, the topside control panel must be replaced.