Display shows E02 and heating stops; bubbles may still work but water does not heat.

Safety first: Disconnect the spa from power before opening the control box or touching internal wiring.

• Power cycle: Unplug the spa for at least 5 minutes, then reconnect and check if E02 clears. Temporary glitches can cause sensor errors.
• Inspect sensor cable:
  • Locate the water temperature sensor where it enters the heater housing or plumbing.
  • Follow the cable to the control box and check for cuts, pinches, or rodent damage.
  • Ensure the connector is fully seated and free of corrosion or moisture.
• Check sensor seating:
  • Verify the sensor probe is fully inserted into its well on the heater tube or manifold.
  • If it is loose or pulled out, reseat it firmly.
• Replace the sensor if suspect:
  • If the cable insulation is brittle, cracked, or the probe is corroded, replace with a compatible Avenli water temperature sensor (NTC).
  • Match the connector type and length to the original part.
• If E02 persists: The temperature input circuit on the main control PCB may be defective. This typically requires replacement of the control box assembly by a qualified technician.