I did exactly that on a new Thetford Nano Eco.
I didn't have enough room for another raw water pump
, so I added a couple of diodes to the supply line from my salt water anchor
washdown circuit to energize the pump
during flush. I also added a tee for the flush water.
My washdown pump is a 6 gpm/60 psi unit and the one supplied by Thetford is only 3 gpm, so I inquired about the ability of the head
to be able to evacuate water above the input rate !
They assured me it would work
fine if I was able to do the electrical
end of my plan.
It works without any problems.