On Tue, 14 May 2013 18:51:31 +0100, Jane Frith
wrote:


I have cleaned them out as well as I could -- and removed quite a bit of black
"gunge" which was soluble when rubbed between fingers in water. It appears to
be mould/bacterial growth of some sort. The only thing flowing through the
pipe/machine to that point is mains cold water.

I have asked the legal question in uk.legal.moderated : if I draw the problem
to the Public Water supply company - do they have a legal obligation to check
the water supply quality and check the "gunge" to ascertain what it is.

Of course not. It is mould growing inside your machine because of
detergents you are using. Why on earth should the water company be
expected to do anything about it?

The d-i-y questions: any ideas what the gunge will be

A combination of mould and bacteria growing in the damp atmosphere
inside the machine and feeding on the detergent used in the rinse aid.
More common if you use "ecofriendly" products.

and what could I wash the
pipes equipment tray with in order to dissolve/remove it?

The cure is to pour a kettle full of boiling water through the
dispenser periodically and run the machine empty on its hottest cycle
once a month.