Faulty carpet washer?

I have used my vax rapide ultimate (carpet washer) today to clean carpets, but when I wanted to use it to do the stairs with the attachment it just flooded the floor with water and solution. Can't understand why and where it is coming from as the water tank doesn't seem to be emptying. Also I have noticed that when I do clean the carpets, the water tank empties very quickly once I press the trigger.