HL
Caldera Spas
High-Limit Trip / Overtemperature at Heater
Display shows “HL” or “HIL”; spa shuts down heater and possibly pumps.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Blocked filter or suction, Air lock causing localized heater overheating, Failing high-limit sensor, Stuck heater relay on IQ control board
How to Fix / Troubleshooting
Safety first: Turn off power at the GFCI breaker and allow the spa water to cool.
- Open cover: Remove the spa cover to help the water cool more quickly.
- Clean filter and check flow: Remove and clean the filter cartridge. Ensure all jets and valves are open and that you feel strong flow from the jets when pumps run.
- Bleed air: Loosen heater and pump unions to purge trapped air, then retighten.
- Reset and monitor: Restore power and monitor operation. If HL returns quickly, the high-limit sensor or heater relay may be faulty.
- Sensor replacement: Replace the high-limit thermistor if it is reading incorrectly or intermittently tripping without true overheating.
Persistent HL errors with normal water temperature indicate a control or sensor issue that should be diagnosed by a spa technician.
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Repair Difficulty
Hard
4/5
Required Part
Heater Assembly
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