Our Diplomat 8322 is about 2 1/2 -3 years old. It has just developed a fault-coinciding with having our tap replaced- but seemingly just a coincidence?

It seems to not be cleaning properly/not filling properly? The soap tablet is not melting so I assume the water is not filling properly.
It heats up, the electrics are working, the sprays are fine. salt etc.....
It is also making a noise unlike usual, a chugging noise. What could be the problem?

set, January 2010