Siphon Chem Draw
I was reading this and no one had posted an answer yet.
I had the same type of chemical system on a Steam Genie. We were able to regulate the amount of chemical by the meter, as well as the water valve. The water valve controled how much water flow to the pump, the chemical would siphon directly from the inlet to the machine.
When I cleaned stairs I would have to go back out to the van with my stair tool and reset the amount of chemical I wanted with the WATER VALVE. Opening the valve DECREASED my amount of chemical.
You're using MORE water when using your carpet wand vs your stair tool. Since the water is not evacuating the machine as quickly, your machine is actually drawing the same rate as before. But with the slower evacuation of water with the stair tool, it does increase the amount of chemical/water ratio. What it'll do instead of taking in mostly water, it takes in more chemical. So as I stated before, you have to OPEN the WATER VALVE to increase the amount of water coming in, and it will "decrease" the amount of chemical you're drawing, simply adds more water to the chem/water ratio.
That is one flaw to the siphon system. Not to mention that the chemical is coming in first, than getting pressurized by the cat pump, and then running through any heaters that you may have. If you're running a junk emulsifier/rinse it'll gum the heck out of your machine. Been there, done that.
With LAST STEP chemical injection, the water gets pressurized, heated, and then chemical thrown in right before it gets sent out to the tool you're using.
Hope this made sense and helped.
