You can try a few things: Check if the outlet is working and if the plug is properly connected. Make sure the temperature sensor is making good contact with the radiator. Is the radiator warm enough (at least 33 degrees)? If not, bleeding or adjusting the flow temperature of the boiler might help. The SpeedComfort only works automatically when the radiator is warmer than 33 degrees at the temperature sensor. Want to test if the temperature sensor is working properly? Connect the SpeedComfort without the temperature sensor and plug the adapter into a power source. The fans should start running immediately. You can also test the sensor by holding it against a glass of hot tea or a heated knife. Once the sensor detects a temperature of 33 degrees or higher, the fans should start working. If you're still having trouble, feel free to contact us!