SN1
USSPA Primary Temperature Sensor Error

Display shows SN1 and spa may not heat; temperature reading may be erratic.

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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 main temperature sensor, Damaged sensor cable, Corroded sensor connector on control board, Sensor not properly seated in heater tube

How to Fix / Troubleshooting

Safety first: Turn OFF power at the breaker before handling sensors or wiring.

  • Inspect sensor placement:
    • Locate the main temperature sensor on the heater tube and ensure it is fully inserted and secure.
  • Check cable and connector:
    • Follow the sensor cable to the control board and inspect for cuts or abrasions.
    • Unplug and replug the connector to clean contacts.
  • Test sensor resistance:
    • With power OFF, disconnect the sensor and measure resistance with a multimeter.
    • Compare reading to USSPA specifications for the current water temperature.
  • Replace sensor if faulty:
    • If resistance is out of range or unstable, replace with a USSPA-compatible temperature sensor.
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Repair Difficulty

Medium 3/5

Required Part

Water Temperature Sensor
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