SN2
USSPA
High-Limit Sensor Error
Display shows SN2 and spa may shut down heater; high-limit protection may be compromised.
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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 on heater tube, Damaged sensor wiring, Faulty sensor input on control board
How to Fix / Troubleshooting
Safety first: Turn OFF power at the breaker before working on the heater or sensors.
- Locate high-limit sensor:
- Find the high-limit sensor on or near the heater tube.
- Inspect mounting and wiring:
- Ensure the sensor is firmly attached to the heater surface or properly inserted in its well.
- Check wiring for damage and secure connections at the control board.
- Test sensor:
- With power OFF, disconnect and measure resistance; compare to main sensor at same temperature.
- Replace if defective:
- Install a new USSPA-compatible high-limit sensor if readings are out of spec.
- Control board check:
- If a new sensor does not clear SN2, the control board may require replacement.
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Repair Difficulty
Medium
3/5
Required Part
High-Limit Sensor
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