Chemical not pulling when using my Hi-Lo fan nozzle. Bear in mind, I’ve used these nozzles for several years now and it worked great halfway through a job and then it just stopped. On high pressure I’m running 3500-3550psi and when I’m using low pressure I’m running below 2000psi. This should be plenty of drop in pressure to pull chemical. I replaced the ball (ceramic), spring and o-ring and no change. I also checked the orifice and it looked great but I changed it as well and still nothing.

It will pull chemical using a 40 tip and/or with no gun at all. Any idea or thought of why the injector is not working using the Hi-Lo nozzle?