Having Problems With Your Downstream Injector? Let Us Help!

Having a downstream injector fail on you can be a pretty common problem these days and we wanted to take a minute to explain a few things that you will want to double check before you toss the injector into the garbage, plus also give you some tips on how you can repair your injector.

Follow along as we break down the actions that you can take to keep your crew soft-washing with a pressure washer using a downstream injection system. We also explain what a downstream injector is and how exactly it works!

A downstream injector is a very handy tool that is used to "inject" chemicals or soaps into the flow of water after the pump on your pressure washer. When using an injector you will be able to safely add and spray chemicals or soaps onto a surface at a lower pressure to assist in cleaning without the risk of damaging your pressure washer pump. This is possible because the chemicals enter the high pressure hose after the pump via injection. To read more about how this all works be sure to read our blog "How To Soft Wash In Canada".

There are 2 common problems that you may encounter when using a downstream injector. 

  1. Your injector will "NOT" draw soap
  2. Your injector will "NOT STOP" drawing soap.

First start by trouble shooting items that you should check off your list before you start taking your injector apart. Be sure to double check all of these suggestions first.

1. Make sure that all of your connections are good and air tight by visually inspecting and double checking everything with the proper wrenches. This includes all of the nozzles on you JROD or DTH-4 (4 Nozzle Holders). It also includes the fitting on your hoses and the injector itself. Make sure they are air tight as the injector works on a Venturi system which means a vacuum or suction needs to be created in order for the ball inside of the injector to shift and allow soap or chemicals to enter the high pressure line. A loose fitting could prevent the ball from shifting properly and make you think that the injector is not working properly. 

2. Make sure that the arrow on the injector points in the same direction as the water is flowing. So at the outlet of your pressure washer where you would normally hook up your high pressure hose is where the water would be leaving the pump and heading down the line towards the gun. Since that is the direction that the water is flowing then that is the way you will want the arrow on the injector to point as well.

3. Make sure that the hose on the injector is fully submerged in your mix tank. One pro tip is to cut a pice of 1/2" irrigation tubing that is a few inches taller than your mix tank and use that to help keep the hose at the bottom of the bucket and stop the hose from curling.

4. Make sure that the injector that you are using is properly rated for the pressure washer that you are using. 

  • 1.8 works with 2-3GPM machines
  • 2.1 works with 3-5GPM machines
  • 2.3 works with 6-8GPM machines

5. Next you need to check your nozzle size.

  • 3-5GPM use a 30-40 orifice size 
  • 8GPM use a 40-60 orifice

***Using nozzle sizes too small will create too much pressure for the Venturi effect to happen and will not allow the suction to take place***

6. Make sure that you are not using too much pressure hose. Keeping your hose as short as possible may help with the process. 50, 100, 150 foot lengths are fine but 200 or 250 feet may stop the Venturi action for happening.

7. Double check and make sure that the injection isn't actually happening and you just don't know it. Take a black sharpie pen and make a mark of your mix level and then use the injector like normal. Wait at least 5 minutes and see if the tank is slowly going down. Since injection only sucks a small amount of mix at one time it can often fool you into thinking you are not drawing anything when in fact you actually are.

8. If you have tried all of these recommendations and you are positive that the injector is still not working then you will want to try the following:

Take the hose off the barbs on the injector and use an O-Ring Pick Kit to push through the top barb as seen in the picture below and ensure that the ball and spring inside of the injector is able to freely move. The area inside the barb should be clean and free of debris. You can soak the injector, ball, spring, and barb in household cleaning vinegar for a few hours to clean any mineral deposits or rust from the inside of it. Then, re-assemble and check it's operation again. They often become seized if they sit for long periods of time or they do not get flushed with water or Agent Halt after each use. 

If the problem still persist then you should purchase the injector rebuild kit or purchase a new injector. It is also very important to always make sure you have a few extra injectors on you at all times to avoid any possible down time. We hope this post will help you understand injectors and the injection process a little bit better and if you have any additional tips or questions please feel free to leave us a comment. 










1 comment

  • My question is can i remove the chemical injector completely from my machine . I know the water gets chocked off through the injector, would i still get normal performance if i just hook the quick disconnect to the pump. My injector has actually been removed and lost so im wandering if i can bypass it?


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