Display shows SE or SENSOR and spa may shut down or behave erratically.

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

• 1. Inspect all sensors: Locate the temperature and hi-limit sensors on the heater manifold. Follow their cables to the control board and verify each connector is fully seated and free of corrosion.
• 2. Check for damage: Look for cuts, abrasions, or rodent damage along the sensor cables. Replace any visibly damaged harnesses.
• 3. Confirm correct parts: If a sensor was recently replaced, verify that a PDC Spas-compatible sensor with the correct resistance curve was installed. Incorrect sensors can trigger SE errors.
• 4. Power reset: After reseating connectors, turn power ON and observe whether SE returns.

Call a technician if: SE persists after checking wiring and replacing suspect sensors. The control board may have a failed sensor input circuit and will likely need professional replacement.