Sounds silly, but you wouldn't be operating in EC would you. You need the airconditioning system to dry the incoming air. Make sure you are not operating in EC as that cuts out the AC.
The recirculation is controlled by a button with an arrow that goes in a little circle attaching the head to the tail. You should have one of those buttons since the recirculation is recommended for various operating conditions. If the AC is operating it should be able to dry the recirculated air but if you do have that button make sure you're not operating in that mode.