by pass into the fresh tank until the thermostat kicks in, then disconect the flow switch and have a second uploader after the burner so when you stop triggering the wand it diverts so much water back to the freshtank. this stops water sitting in a hot burner ( which will send the water temp through the rooffor 2-4seconds when you trigger the wand again)
see its not as easy as it sounds building T/Ms 
I have got a theory to solve this .
What do you think about having a recirculating system involving the usual supply fresh water hose going to the pump and then onto the hot box , then to the wand , at the wand have a Y- piece so that flow can go to the wand
if the trigger is depressed , if the trigger is not depressed , water would flow down a return hose back into the fresh water tank , eventually on a big job the hot box stat would cut out.
Can the dual pumps take heat through them?
I know there would be hose management issues and extra cost issues .
Jason you are suggesting what I said, I've put in bold our similar statements, but you have a point after a while the freshwater tank will heat up to a temp that is too hot for the pump but its very rare
