SN2
QCA Spas
High-Limit or Secondary Sensor Error
Display shows SN2, spa may shut down or run with limited functions, heater may be 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
Failed high-limit sensor, Broken sensor wiring, Incorrect sensor resistance, Corroded connector on control board
How to Fix / Troubleshooting
Safety: Turn off power before working inside the equipment bay.
- Identify secondary sensor: On many QCA Spas packs, the SN2 sensor is the high-limit sensor on the heater tube. Confirm by tracing the labeled wires.
- Check continuity: Using a multimeter (with power OFF), measure resistance across the sensor leads and compare to manufacturer specs for the current water temperature. Infinite or zero resistance indicates failure.
- Replace sensor: If readings are out of range, replace the high-limit sensor with a QCA-compatible part. Ensure the new sensor is properly seated and sealed.
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Repair Difficulty
Hard
4/5
Required Part
High-Limit Sensor
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