Display shows SN1 or SENS1 and spa will not heat; temperature reading may be erratic or show dashes.

Safety first: Turn off power at the GFCI breaker before accessing the control pack or sensors.

• Power reset: Turn breaker OFF for 60 seconds, then ON. If SN1 returns immediately, continue.
• Locate temperature sensor: Open the equipment bay and find the sensor leads entering the Balboa-style control pack. They are usually labeled TEMP or SENSOR.
• Check connections: Gently unplug the temp sensor connector from the control board, inspect for corrosion or moisture, dry if needed, and reconnect firmly.
• Inspect cable: Follow the sensor cable to the heater manifold or sensor well. Look for cuts, pinches, or rodent damage. If damaged, replace the sensor.
• Compare water temperature: Use a separate thermometer in the spa water. If the displayed temperature is far off or shows error, the sensor is likely defective and should be replaced with a matching Passion Spas-compatible probe.

If replacing the temperature sensor does not clear SN1, the sensor input on the control board may be damaged and the control pack may require replacement.