SN2
Caldera Spas
High-Limit Temperature Sensor Fault
Display shows “SN2” and spa may shut down or stop heating.
Advertisements
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.
Advertisements
Possible Causes
Failed high-limit thermistor, Loose or oxidized connector at IQ control board, Damaged sensor cable, Sensor not fully seated in heater well
How to Fix / Troubleshooting
Safety first: Turn off power at the GFCI breaker.
- Access control box: Remove the equipment door and IQ control box cover. Locate the high-limit sensor connector (often labeled or color-coded differently from the main sensor).
- Inspect connection: Disconnect and reconnect the sensor plug several times to wipe oxidation from the contacts. Check for moisture or corrosion.
- Verify sensor placement: Confirm the high-limit sensor is fully inserted into its well on the heater tube and secured with its clip.
- Restart spa: Restore power and monitor the display. If “SN2” clears and does not return, continue to observe operation.
- Replace if needed: If the error returns, replace the high-limit thermistor with a Caldera-compatible part, following the original routing and securing the cable.
Advertisements
Repair Difficulty
Medium
3/5
Required Part
High-Limit Thermistor
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements