Gas powered diaphragm pumps question

So I’m considering building my own setup due to head flow issues. I’ve had multiple houses and roofs cause me issues because my hose had to go straight up 40’ before I even got to the house.

I’m thinking of buying a pump with my upcoming commercial cleaning check and charging the engine to my account at a local shop.

My question is am I understanding correctly that when I let off the hose the flow needs somewhere to go? And if that’s the case what’s the best way to ensure I get no chemical going back to the tank so I can also use my water tank for my pressure washer? Cheap radio solenoid valve on the SH and surfactant?

Rinse time:

  1. Turn off the lines with the remote.
  2. Keep spraying till just water.
  3. Then if I let off only water goes back in my tank?

Just trying to make sure I got this correct.

Not sure if that will work or not. I had mine plumbed by a professional and even having it in my possession it is fairly complicated to follow. I have a water tank as well as an sh tank. The pump is connected to a blending manifold. It recirculates through a 12’ length of 3/4 hose. Thats the one coming out the bottom and wrapped around the base of machine. It loops back into the downward part of the plumbing

This is set up differently as your power washer because with your power washer when you’re off the trigger it dumps it to the tank. With your gas pump when you come off the trigger that water just recirculates in how ever many feet of hose you put. He had 12’ I probably got about the same. You can stay off the trigger for a bit but it does get warm and you need to pull the trigger for a second.

Looks like that does eventually dump back into a tank.

Im pretty sure youre looking at the suction line. It looks like his recirculates in the red hose wrapped around the rear of the proportioner

No sit it has a bypass loop