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 handling sensors or control wiring.

• Locate sensor: Find the water temperature sensor threaded into the heater tube or mounted in a sensor well on Dynasty Spas models. It will have a small cable leading to the control pack.
• Inspect wiring: Check for cuts, abrasions, or rodent damage along the sensor cable. Ensure the connector is fully seated on the control board.
• Check seating: Make sure the sensor is fully inserted into the heater tube or well and tightened snugly (do not overtighten plastic threads).
• Replace sensor if needed: If Sn1 persists, replace the temperature sensor with a compatible Dynasty Spas temp sensor kit. Power down, unscrew the old sensor, quickly swap with the new one (water may seep slightly), reconnect wiring, and test.