Display shows Sn1 or SN1; spa may not heat or may shut down; temperature reading may be erratic.

Safety: Disconnect power at the GFCI before touching any wiring.

• Step 1 – Visual inspection: Locate the primary temperature sensor on the heater tube. Check for cracks, swelling, or water intrusion at the sensor body and cable.
• Step 2 – Check connections: Unplug the sensor from the Vita Spa control board and inspect the pins for corrosion or bent contacts. Clean gently and reseat firmly.
• Step 3 – Resistance test: Using a multimeter, measure resistance across the sensor leads and compare to the Vita Spa temperature/resistance chart (typically around 10kΩ at 77°F). If reading is far off or unstable, replace the sensor.
• Step 4 – Replace sensor: If faulty, remove the old sensor from the heater tube and install a new OEM Vita Spa temperature sensor, ensuring proper insertion depth and sealing.
• Step 5 – Control board check: If a new sensor does not clear Sn1, the sensor input on the control board may be defective and the pack may need replacement.