Display shows HL or HLo, spa stops heating and may shut down pumps intermittently.

Safety first: Turn off power at the breaker before bleeding air or opening unions.

• Bleed air from heater and pump: Slightly loosen the unions on the heater and pump until water seeps out and air is released, then retighten. This removes trapped air that can cause hot spots.
• Clean filter and check water level: Ensure proper water level and a clean filter. Run the spa without the filter briefly to test.
• Verify circulation: Confirm that the circulation pump is running and that there is a steady stream from the circulation return jet.
• Reset high-limit (if manual): Press the reset button on the high-limit switch if your heater has one, after the water has cooled.

If HL recurs frequently, the circulation pump or high-limit sensor may need replacement, or the heater may be scaled internally and require professional descaling or replacement.