Hello, I’m no fan of complexity, so this is exactly the sort of heater that makes me cringe. 🙁 Still, perhaps it has more accurate temp control when it’s working… As to removing the circular clip that holds the thermistor in place… use a medium small flat screwdriver that fits between the slots in the ring and pry the clip out slowly, using multiple slots to lever from. Rest the screwdriver against the steel port that the element screws into and pry. Done gently, this will remove the clip without damage. From reading the troubleshooting guide, it seems you should be getting an error code of three flashes, indicating the thermistors are not working properly. What code are you seeing now?