Error f 05 on Hotpoint Aquarius+ WMF740 -Pictures included-?

For about a couple of months the washing machine would make a 'drilling sound' and then beep boises would follow. A h20 message would appear and this would only go away if I press the pause and wait for about 20 seconds and then resume the cycle. This method only works for a couple of minutes untill I have to do the whole procedure again which is tiring. So after googling and looking at similar problems, ive come to realise that it was something got to do with the pressure switch. I opened up the machine and located the pressure switch. Although I have no idea how to clean the tube since its diameter is very small. I then hoped that would fix the problem but now a error f-05 comes up so after looking up the message, I need to clean the pipes but im unexperienced in this field and I dont really know how to clean a pipe even which pipe to clean..
Heres a link to the pictures:http://s1065.photobucket.com/user/mchouhan723/library/washing%20machine