Method for operating a liquid-to-air heat exchanger device, in which air flows through at least one first flow channel at least in a first passive heat exchanger stage, which flow channel comprises plate fins, and a liquid flows through at least one second flow channel which is separated from the at least one first flow channel by a thermally passive separating wall, the method comprising the following steps: determining the dew point temperature of the ambient air; determining whether the dew point temperature of the ambient air is higher than the temperature of the liquid, and if this is the case operating the heat exchanger device in an operating mode designated as pulsed operation according to the following steps: allowing the liquid to flow through the first heat exchanger stage during a predetermined period of time; preventing that the liquid flows through the first heat exchanger stage, and measuring and monitoring the temperature of the air after exiting of the air from the first heat exchanger stage, wherein the temperature of the air measured after exiting the first heat exchanger stage indicates a first temperature increase, remains subsequently at an approximately constant level for a specific period of time, and then shows a second temperature increase; detecting the second temperature increase and terminating the preventing that liquid flows through the first heat exchanger stage once the second temperature increase was detected, and repeating these steps as long as the dew point temperature of the ambient air is higher than the temperature of the liquid. determining the dew point temperature of the ambient air; determining whether the dew point temperature of the ambient air is higher than the temperature of the liquid, and if this is the case operating the heat exchanger device in an operating mode designated as pulsed operation according to the following steps: allowing the liquid to flow through the first heat exchanger stage during a predetermined period of time; preventing that the liquid flows through the first heat exchanger stage, and measuring and monitoring the temperature of the air after exiting of the air from the first heat exchanger stage, wherein the temperature of the air measured after exiting the first heat exchanger stage indicates a first temperature increase, remains subsequently at an approximately constant level for a specific period of time, and then shows a second temperature increase; detecting the second temperature increase and terminating the preventing that liquid flows through the first heat exchanger stage once the second temperature increase was detected, and repeating these steps as long as the dew point temperature of the ambient air is higher than the temperature of the liquid. allowing the liquid to flow through the first heat exchanger stage during a predetermined period of time; preventing that the liquid flows through the first heat exchanger stage, and measuring and monitoring the temperature of the air after exiting of the air from the first heat exchanger stage, wherein the temperature of the air measured after exiting the first heat exchanger stage indicates a first temperature increase, remains subsequently at an approximately constant level for a specific period of time, and then shows a second temperature increase; detecting the second temperature increase and terminating the preventing that liquid flows through the first heat exchanger stage once the second temperature increase was detected, and repeating these steps as long as the dew point temperature of the ambient air is higher than the temperature of the liquid.