The pro mounts do have a filter fitted, its screwed onto the header tank, behind the jet.
When this filter gets blocked, the machine will over heat.
I have also fitted another filter, inline, before that one.
http://www.worldofclean.co.uk/index.php?productID=334Its also got a filter on the fresh water tank outlet (supply line).
I dont think that any "lumps" could get into the system, but if it was pumping "muddy water" around, that would probably knacker things up.
Did Woodbridge pay for the new bits Red ( water pump etc) ?
Because if the problem was caused by you putting s h i t into the water tank it wouldnt be covered by any warranty, and I would have expected you to have to pay?
Chris