This type of problem on a condensor dryer is often caused by water not being fully cleared from the condensor area up into the water container. The excess water held within the unit causes condensation in places that shouldn't have it - e.g the heating elements. Please see this thread (below) for advice on resolving the problem on an Indesit that won't clear water - mine also caused the electricity to be tripped frequently before I found the problem with water held within the sump. I understand the Hoover is a similar design - no guarantess it will cure your problem, but worth a try?.
http://www.howtomendit.com/answers.php?id=216747
Martin
February 2009