hotpoint wt761 diplay error code h20 then f-05?

HI, I have had my washer for just over a year and it's always worked well, but yesterday started displaying h20 after wash had started, so we checked all pipes going to machine, and it was filling with water ok, we checked no kinks in hose. It went off and was ok but did same today, then seemed to be working ok till near end of wash when started displaying f-05.I am thinking there may be some sort of blockage, when looking at manual it says this model has a self cleaning filter. so any ideas? am not very technologically minded!