Sn1
Tuff Spas Primary Temperature Sensor Failure

Display shows Sn1 or SENS1; spa may shut down heater or run erratically.

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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

Open or shorted temp sensor, Damaged sensor cable, Corroded sensor connector at control board, Sensor not fully seated in Tuff Spas heater well

How to Fix / Troubleshooting

Safety: Turn off power at the GFCI breaker before accessing the control pack.

  • Step 1 – Locate temp sensor: The primary temperature sensor is usually threaded or inserted into the heater tube or a sensor well on the Tuff Spas control pack.
  • Step 2 – Inspect wiring: Follow the sensor cable to the control board. Check for cuts, abrasions, or rodent damage. Reseat the connector firmly.
  • Step 3 – Check seating: Ensure the sensor bulb is fully inserted into the heater tube or well and tightened snugly (do not overtighten plastic threads).
  • Step 4 – Replace sensor if needed: If Sn1 persists, replace the temperature sensor with the correct part for your Tuff Spas model. Power must remain off during replacement.

If a new sensor does not clear Sn1, the control board’s sensor circuit may be faulty and require professional diagnosis.

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Repair Difficulty

Medium 3/5

Required Part

Temperature Sensor
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