Display shows OH or OHH and spa shuts down, pumps may run briefly then stop

Safety first: Turn off power at the GFCI breaker. Do not use the spa until the overheat condition is resolved.

Steps to address OH/OHH:

• Remove the cover and let the spa cool: Leave the cover open for several hours to allow heat to escape. Verify water temperature with a thermometer.
• Check water level and filters: Ensure water is above all skimmer openings. Remove the Strong Spas filter cartridges and run the spa briefly (with power restored) without filters to see if OH clears. Dirty or collapsed filters are a common cause.
• Bleed air from pumps: With power OFF, loosen the pump union on the primary jet pump and circulation pump (if equipped) just enough to let trapped air escape, then retighten. Re-energize and check for normal flow.
• Verify all jets and valves are open: Make sure diverter valves and slice valves are fully open and that jets are not all closed, which can restrict flow through the heater.
• Observe pump operation: With power ON, confirm that the circulation pump or low-speed pump runs steadily when heating is called for. If the pump stops but the heater indicator remains on, a stuck heater relay or control board fault is possible.
• Inspect sensors: If OH appears immediately on startup with cool water, the temperature or high-limit sensor may be faulty and should be tested or replaced as a set.

When to call a technician: If OH persists after cleaning filters, bleeding air, and verifying flow, or if the heater continues to heat with pumps off, a professional should test the heater relay and control pack.