Pressure-Pro Low Pressure 4000 PSI Chemical Suction Injector

This is meant to attach to a spray wand that has a female quick connector on the end- so it won't work with the Karcher K3. The filter end goes into a chemical container, and the flow of water picks up the chemical, mixes with it and sprays the mix out through the tip.

Karcher is one of the few brands that will pull from a still water source, Kranzle is another if you're looking for a high-quality unit. This Yard Force unit has it's own water bucket and is handy off-road. You will see them described as "self priming".

This is the Karcher Suction Hose. The video is very informative.

The K3 Follow Me is a good unit for around the house or boat- washing a car or two; cleaning a small to medium size patio, washing off lawn furniture. It's not the best choice for big jobs like cleaning the siding on a large house.

Please remember that the self-priming action depends on a siphon- so you either need gravity from the bottom of a tank (as shown in the video), or if you're trying to pull from a lake you may need to start the siphon by sucking on the hose to get the water started, then adjusting the level of the pressure washer to keep the water flowing.

Neither the Karcher nor the Kranzle unit will "pull" water very far- the closer you can get to the water source the better it will work. If you lose the siphon action, running dry will ruin the Karcher pump, but the Kranzle pump will be fine.

I'm sorry, but I'm not familiar with Reliance pressure washers; we don't sell them.

I hope I've been able to help!

20% is easier to understand in terms of 5 parts water 1 part detergent solution.

This is for in between the pump and high pressure hose so quick connect fittings will be 3/8".

This is not what you would be looking for for your application. This is a low pressure chemical injector as well. I have included two links for you, for your options for high pressure soap. These will both attach to the end of the lance where the colored spray tips usually go. This will also allow you a wider choice in chemicals as nothing will be running through your pressure washer equipment.
Soap Shooter
Foamer

It uses quick connect fitting and will go in between your high pressure hose and pressure washer pump.

Low pressure ensures the detergent sticks to the surface but the stream is usually not very far vs. high pressure which can just bounce off. However, high pressure would be fine for far away applications such as a second story you would need the extra power to reach the detergent to those locations.

The black spray tip needs to be on the end of the lance in order for it to tell the pressure washer you want to siphon the detergent. Also, make sure you have opened the black mesh screen on the end that goes into detergent. If those two things do not solve your problem, please give Pressure Pro a call for additional troubleshooting at (772) 461-4486

This only works properly when used with 3-5 GPM.

You could absolutely use this chemical injector for your task, however, you will have to worry about the chlorine bleach drying out your hose and gun o-rings. This injector attaches to the discharge outlet on your pump, then your hose connects to it.

We carry a high pressure soap injector that can be attached at the end of the wand which would prevent any damage to your hose and gun. I'm posting a link below to the product I am referring to for you to look at:

General Pump Soap Shooter Nozzle