Control panel shows E03 and spa shuts down

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.

Possible Causes

Heater overheating due to low flow, Scale buildup in heater, Faulty high-limit sensor, Stuck heater relay

Safety first: Do not use the spa until the cause of overheating is resolved.

1. Allow cooling:
- Turn off and unplug the spa for at least 1–2 hours.
2. Improve water flow:
- Clean or replace the filter cartridge.
- Check for blocked suction/return ports and kinked hoses.
3. Restart and monitor:
- Reconnect power, run filtration, then enable heating.
- Monitor for recurrence of E03.
If E03 recurs: The high-limit sensor or heater assembly may be faulty; professional service is required.

Hard 4/5

High-Limit Temperature Sensor / Thermal Cutoff

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