I have a Miele G579 dishwasher which I have had from new – some 15 years. There is now not enough water getting into the machine, which I suspect may be due to a blockage or limescale on the inlet side (I have checked the non-return filter and I know the water pressure is high enough). Is there a way to check this and if it is limescale, to correct the problem or, given the age of the machine is it better to replace the machine?