Topside control displays OH or OHH and spa immediately shuts down; water in the spa feels excessively hot, often above 108°F (42°C).

Safety first: Turn off power at the GFCI breaker and allow the spa water to cool below 100°F before working on it. Do not use the spa until the cause is corrected.

• Step 1 – Power reset: Turn off the spa at the GFCI breaker for 5–10 minutes, then restore power. If OH clears and does not return, monitor temperature for several hours.
• Step 2 – Verify water temperature: Use an independent thermometer in the spa water. If the actual temperature is normal (around setpoint) but the display shows very high, suspect a faulty high-limit or temperature sensor.
• Step 3 – Check circulation and flow: Remove and clean the filter cartridges used in your Vita Spa (rinse thoroughly). Run the spa with filters removed for 10–15 minutes. If OH does not return, replace clogged filters.
• Step 4 – Inspect heater area: With power OFF, open the equipment bay. Check the heater manifold on the Vita Spa pack for kinks, closed slice valves, or debris in the suction/return lines that could trap hot water.
• Step 5 – Sensor testing: Locate the high-limit sensor and temperature sensor plugged into the Vita Spa control pack. Inspect for corrosion or loose connections. If you have a multimeter and the service manual, compare sensor resistance to temperature charts; replace any sensor that is out of spec.
• Step 6 – Control board relay: If the spa continues to heat with the heater indicator off, the heater relay on the control board may be welded closed. This is a serious fault; disconnect power and have the control board or entire pack serviced or replaced by a qualified technician.