SN2
Freeflow Spas High-Limit Sensor Failure

SN2 error displayed; spa may run but heater is disabled.

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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 high-limit sensor, Loose sensor in heater tube, Corroded connector at control board, Overheat damage to sensor from dry-fire event

How to Fix / Troubleshooting

Safety first: Shut off power at the breaker before opening the control box.

  • 1. Identify high-limit sensor: Typically a second sensor on the heater tube, separate from the main temperature sensor.
  • 2. Inspect wiring and plug: Ensure the high-limit sensor connector is firmly attached to the control board and free of corrosion or water intrusion.
  • 3. Check sensor mounting: Confirm the sensor is properly seated in the heater tube or well and not loose or hanging.
  • 4. Reset and test: Restore power and monitor the display. If SN2 reappears quickly, the sensor is likely faulty.

Because the high-limit sensor is a critical safety device, replace it with the correct Freeflow-compatible part. If a dry-fire or severe overheat occurred, have a technician inspect the heater and wiring as well.

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Repair Difficulty

Medium 3/5

Required Part

High-Limit Sensor
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