Display shows SNS, SN2, or SNB, and the spa shuts down the heater.

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

Shorted sensor leads, water intrusion into the sensor head, incorrect sensor type installed, control board misreading sensor resistance.

Safety first: Disconnect power at the breaker before working on the sensors.

1. Identify the sensor:
- SNS or SN2 often refers to the high-limit or secondary sensor.
2. Inspect the sensor and wiring:
- Check for moisture around the sensor head and cable entry.
- Look for crushed or pinched cable segments.
3. Reseat the connector:
- Unplug the sensor from the control board and reconnect it firmly.
4. Replace the sensor:
- If SNS persists, replace the affected sensor with the correct Wellis part number.
5. Control board check:
- If a new sensor does not clear SNS, the control board’s sensor circuit may be shorted. Have a technician test and replace the board if necessary.

Medium 3/5

High-Limit Sensor

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