They are quite a nice unit, Albert. From personal experience...they DO run forever when maintained...Heat is not amazing...but they have upgraded the heating system...I popped my heat exchangers on the unit (sound familiar, Albert?) so I used a little giant heater...pump out worked great for the 3 or so years that I used the unit.
The waste tank has a wash out system...never a funky tank smell...I just ran one more hose into the house for the pump out water...It provided a real good marketing opportunity when folks would ask what is that terrible black water?
I am sure that
Prochem got there idea for a 4 cylinder water cooled truckmount from the Organic Compounds Fox Unit...as they were making them prior to Prochem.
The only negative thing I found on the pump-out design...One time I was cleaning for a family...the ancient Dad had Alzheimers...when I went to retrieve the hose from a toilet...Gramps was in there...peeing on it! Oh well!
Paul Brown is a good source for buying one of these units...he sells them.