Display shows HL or HLo, spa shuts down heater and may disable pumps until reset.

Safety first: Turn off power at the breaker before touching any components.

• Allow spa to cool: Remove the cover and let the spa sit until the water temperature drops.
• Check filter and water level: Clean or replace the filter cartridge and ensure the water level is correct.
• Bleed air from heater: With power OFF, loosen the heater unions slightly to release trapped air until a steady stream of water appears, then retighten.
• Inspect circulation pump: Confirm that the circulation pump runs continuously when the spa is in heating/filtration mode. If it is hot to the touch, noisy, or not running, it may be failing.
• Reset power: Turn the breaker back on and monitor the spa. If HL reappears quickly, the high-limit sensor or control board may need replacement.

Because HL involves over-temperature protection, if the error recurs after basic flow checks, have a technician test the heater circuit and sensors.