SN2
Hot Spring
High-Limit Sensor Failure
Display shows “SN2”; spa may shut down or show OH/OHH intermittently.
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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 thermistor, Loose sensor in heater well, Damaged sensor wiring, Control board high-limit circuit fault
How to Fix / Troubleshooting
Safety first: Turn off power at the breaker.
- Locate high-limit sensor: This thermistor is usually mounted on or in the heater manifold, separate from the main water temperature sensor.
- Check mounting: Ensure the sensor is fully inserted and making good thermal contact with the heater housing or water path.
- Inspect wiring: Follow the sensor cable to the IQ control box, checking for damage or loose connectors.
- Replace sensor: If visual checks are fine but SN2 persists, replace the high-limit thermistor with a compatible Hot Spring part.
Continued SN2 errors after sensor replacement point to a control board issue that should be handled by a qualified technician.
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Repair Difficulty
Medium
3/5
Required Part
High-Limit Thermistor
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