Sn2
Tuff Spas Secondary / High-Limit Sensor Failure

Display shows Sn2 or SENS2; spa may continue to run but with limited heating or safety shutdowns.

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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

Failed high-limit sensor, Loose sensor in heater tube, Damaged sensor harness, Control board sensor input fault

How to Fix / Troubleshooting

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

  • Step 1 – Identify high-limit sensor: On many Tuff Spas systems, the high-limit sensor is a separate probe on the heater tube or integrated into the heater assembly.
  • Step 2 – Inspect connection: Check the sensor plug at the control pack for corrosion or looseness. Unplug and replug to ensure good contact.
  • Step 3 – Verify mounting: Confirm the sensor is firmly attached to or inserted into the heater tube so it can accurately sense temperature.
  • Step 4 – Replace sensor: If Sn2 remains, replace the high-limit sensor with a Tuff Spas-compatible part. Ensure watertight seals are maintained.

Persistent Sn2 after sensor replacement suggests a control board issue; contact a spa technician for further testing.

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Repair Difficulty

Medium 3/5

Required Part

High-Limit Temperature Sensor
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