Communication between the head and the Auraton 200 TRA controller and error signals In order to save the battery, the Auraton 200 TRA controller communicates with the head every 2 minutes. Immediately after the Auraton 200 TRAcontroller logs into the head, the two devices are synchronized the process takes about one minute. The synchronization process is not indicated in anyway but is necessary for proper operation of the set. Communication maybe disturbed if the Auraton 200 TRA is reset (for example in order to replace the battery. The head indicates interrupted communication after 6 minutes with a LED diode blinking every 8 s. After a maximum of 4 hours, the head should automatically synchronize itself with the Auraton 200 TRA controller. This time can be reduced to 2 minutes if, after the reset of the Auraton 200 TRA controller, the tab is taken off from the head and reinstalled after 3 [s]. Even after communication between the head and the Auraton 200 TRA controller is interrupted, the user should not experience any deteriorated adjustment of temperature. In such a case, the head stabilizes the temperature of the radiator on the level that was required earlier in order to maintain the temperature in the room.