As I read it , Mike pumps water from the fresh tank straight to the hot box , then onto the wand .
I always thought it an overcomplication to pump to the accumulator, so that the TM engine can then pump to the hx/ wand .
My plan is to mount an electric pump on the van wall , along with a hot box , then have the slideout engine /blower clamped to the van floor , fabrication/powder coating of frame is free if you know the right welder.
Just need the pump spec and to know about the bits after the blower.