How to Choose Chemical Injector Use in a Pressure Washer: Upstream or Downstream

Chemical injectors are just what they sound like: an apparatus that injects chemicals (into a pressure washer). Essentially, there are two types of chemical injectors: upstream and downstream. Knowing the difference between an upstream and a downstream chemical injector, or the advantages and disadvantages of both upstream and downstream chemical injectors, means you're informed and ready to make the best use of either type of chemical injector while pressure washing.

How to Choose Chemical Injector Use in a Pressure Washer: Upstream

An upstream chemical injector simply means the injector functions prior to the pressure washer water pump. Usually, the way a pressure washer is setup that includes a chemical injector goes: water hose inlet coupler or connection, and then the chemical injector, and then the pressure washer water pump.

One advantage to using an upstream chemical injector is the ability to use high pressure to apply whatever chemicals you're using while pressure washing. This obviously means you can eliminate a lot of time whilst applying chemicals compared to using low pressure to apply chemicals on a pressure washing job or task.

The main disadvantage, and it is a big one, is an upstream chemical injector pushes chemicals through the water pump on the pressure washer. Chemicals, particularly oft used bleach (sodium hypochlorite), speed up deterioration of the internal metal and rubber parts in the water pump.

You must make it a point to run clear water through the water pump and the entire pressure washer system, for that matter, every single time you're finish using the upstream chemical injector. When choosing to use an upstream chemical injector, be very efficient about using the chemical injector. Use the chemical injector and then use fresh water afterward to clean the pressure washer system.

How to Choose Chemical Injector Use in a Pressure Washer: Downstream

While choosing to use an upstream chemical injector for its speed in applying chemicals is advantageous, like a two-edged sword it can be a disadvantageous if you waste more than make use of those same chemicals. This is where choosing a downstream chemical injector for use in a pressure washer may be your choice, since using a downstream chemical injector means you have to apply chemicals with low pressure. Yes, using low pressure means taking more time to apply chemicals, but it's still much faster than by hand or pump sprayer.

A downstream chemical injector in a pressure washer simply means the injector is inline after the water pump on the pressure washer. The pressure washer setup that includes a downstream chemical injector goes: water hose connection or coupler, and then the water pump, and then the chemical injector.

The main advantage to choosing to use a downstream chemical injector is the inverse to why an upstream chemical injector is a disadvantage: the chemicals don't pass through the water pump and therefore don't cause harm to it. Still, chemicals are passing through the rest of the pressure hoses, particularly, and therefore you need to use fresh water through the pressure washer to clear the chemicals out of the system.d

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