Display shows OHH and spa immediately shuts down heating and pumps to protect from extreme overheat.

Safety first: Turn off power at the GFCI breaker. Do not attempt to use the spa until the water has cooled and the fault is corrected.

• Cool the spa: Remove the cover and allow the water to cool to below normal soaking temperature. You can add cool water to speed the process, but do not drain a very hot tub completely to avoid shell damage.
• Check for flow issues: Inspect and clean the Dynasty Spas filter cartridge. Verify that all slice valves are fully open and that there are no closed jets that could restrict flow.
• Test circulation pump: After cooling, restore power and observe whether the circulation pump starts. If it hums but does not move water, or does not run at all, the circulation pump may have failed and should be replaced.
• Inspect sensors and heater: Check the high-limit sensor on the heater tube for secure mounting and intact wiring. If OHH reappears immediately on startup with cool water, replace the temperature and high-limit sensors. If the heater is energized when it should be off, the control board heater relay is likely defective and requires professional service.