Is it just the empty water light that's on all the time?
Just the empty water light is on as well as the on light
Ok when this happens the water chamber is full of water at the bottom. So its either blocked in there or the drain pump is faulty.
To access this you need to remove the plastic trim on the front at the bottom.
From there you will see the drain pump. Take it out and give the water chamber a good clean out and clear the pump as well.
Then refit the pump and cover and retry the dryer and see how it goes. If it does it again then its more then likely the pump at fault and will need to be replaced.
But if you need anymore info just get back to me.