Display shows HL or HLo; spa shuts down heater and sometimes pumps; water may be warm but not excessively hot.

Safety: Turn off power at the GFCI before opening the equipment bay. Do not bypass safety sensors.

• Step 1 – Reset and bleed air: Turn off power, open all jets, and loosen the union fittings on the heater slightly to bleed trapped air until water seeps out, then retighten. Restore power and see if HL clears.
• Step 2 – Clean/replace filters: Remove Vita Spa filter cartridges and rinse thoroughly. Try running the spa without filters for 10–15 minutes. If HL does not return, replace filters with OEM Vita Spa-compatible cartridges.
• Step 3 – Check circulation pump: Confirm the circulation pump is running when the spa calls for heat (you should feel vibration and see water movement at the heater return). If not, check for tripped breakers, stuck slice valves, or a failed circ pump.
• Step 4 – Inspect high-limit sensor: Locate the high-limit sensor on the heater tube. Ensure it is fully seated and its wiring harness is intact. If the sensor body is cracked, corroded, or loose, replace it.
• Step 5 – Persistent HL: If HL returns quickly even with good flow and new filters, the sensor or control board calibration may be faulty. Replace the high-limit sensor first; if the issue persists, have a technician evaluate the Vita Spa control pack.