Display shows Sn1 or SN1, spa may not heat or may shut down heating cycle.

Safety first: Turn off power at the GFCI breaker before touching any wiring or sensors.

• Locate the temperature sensor: On Lifesmart Spas, the main water temperature sensor is typically threaded into or clipped onto the heater tube connected to the control pack.
• Inspect wiring and connector: Gently unplug the sensor from the control board, check for corrosion or moisture, then reconnect firmly. Ensure the cable is not pinched or damaged.
• Check sensor seating: Make sure the sensor is fully inserted into the heater tube port or firmly clamped to the tube for accurate readings.
• Power cycle the spa: Restore power and see if the Sn1 code clears after a few minutes. If the code returns, the sensor is likely defective.
• Replace the sensor: Drain water below the heater level if necessary. Unscrew or unclip the old thermistor and install a new OEM-compatible Lifesmart temperature sensor, using new O-rings or sealant as required. Refill and test.