The device is equipped with a filter maintenance indicator, which has the task of alerting the user to the filter replacement or maintenance. After 300 hours of operation, the filter maintenance indication button flashes. This means that the pre-filters need to be cleaned, see paragraph Device maintenance. After performing maintenance, the indicator must be reset by holding down the button for about 5 seconds.
After 4500 hours of operation, the filter maintenance indication button flashes. In this case, the combined filters must be replaced. After replacement, the indicator must be reset by holding down the button for about 5 seconds.
TIP: The current operating time since the last reset can be displayed by briefly pressing the filter maintenance button once. The first number that appears on the display means the order of thousands, the second number that appears after a while means hundreds, tens and units of hours. E.g. if the first number is 1 and the next number is 358, it means that the device has been in operation for 1358 hours since the last reset of the indicator.