The danger of the dew point
The cooling air has to be preheated if it is likely that the temperature could fall below the dew point on the cooling elements during the cooling of hot process gases.
Unlike KS, preheating of cooling air is provided with KU. In this case, a partial flow of heated cooling air and fresh air are sucked in together from the cooling air fan.
A pre-selected mixing temperature is regulated prior to entry into the cooling elements by opening or closing the fresh-air valve.