'Just had F-12 on my Hotpoint Aquarius washing machine. Problem was due to water not draining. Power off. My machine has access plate at bottom on the back. The water drain is held onto the drum via a jubilee clip and when i took it off the drain was clogged with hair, sweet wrappers, money, hair bobbles Once cleared, put back as was - machine now running ok.'
I found this posted on another website i got the same problem, hope this is helpful
Asum, July 2009