Complete Guide to the Suttner ST-164 Dual Foam Injector

The Suttner ST-164 is the next evolution in professional downstream injection—offering a dual chemical draw system that streamlines your wash process without sacrificing performance. Designed for users who frequently switch between two soaps (like Chem-X Stars + Stripes) or alternate between a pre-soak and a degreaser, this injector simplifies chemical management and maximizes efficiency.

Whether you're operating a fixed bay, mobile rig, or industrial wash station, the ST-164 is engineered to give you fast transitions and consistent foam output—all with a single high-quality injector.

What Is the ST-164 Dual Foam Injector?

The Suttner ST-164 is a dual-line downstream chemical injector, meaning it allows you to switch between two separate chemical sources without swapping lines, nozzles, or equipment. It's built for high-pressure systems and designed to operate with hot or cold water in a wide range of flow rates.

This injector shines in systems using touchless wash processes or setups that require multiple chemical stages with zero downtime.

Key Features

Dual chemical draw ports – independently labeled and color-coded (usually red and blue)
Rotary selector knob – choose between Chemical A, Chemical B, or Water Rinse
Rated up to 4,000 PSI
Flow range: 2.0–5.0 GPM
Stainless steel ball and spring for corrosion resistance
Brass and nickel-plated housing for durability
Adjustable metering on both chemical ports
Compatible with hot water up to 180°F

How It Works

The ST-164 uses a selector valve to control which of the two chemical ports is active:

Position 1: Draws from the red (Chemical A) side
Position 2: Draws from the blue (Chemical B) side
Center Position: Fully shut off—no chemical draw, just high-pressure rinse

It relies on downstream pressure differentials created by a low-pressure nozzle, foamer, or soap gun to activate the suction process and pull chemical into the line.

How to Set Up the ST-164

Install After the Pump:
The ST-164 must be plumbed into the high-pressure line downstream of the pump. It can be mounted inline or with quick connects.
Attach Chemical Pickup Tubes:
Connect each pickup port (red and blue) to separate chemical containers. Use weighted filters and check valves to prevent backflow and contamination.
Connect Your Soap Nozzle or Foamer:
Use a Chem-X Chrome Cannon 2.0, Freedom Foamer Lance, or QC Soap Nozzle with a large enough orifice to activate the injector.
Adjust Your Ratios:
Fine-tune chemical draw on each port using the metering adjustment screws located on both sides of the unit.
Select Your Soap or Rinse:
Simply rotate the selector knob to switch between Chemical A, Chemical B, or a rinse cycle.

Why Choose the ST-164 Over the ST-160?

Feature	ST-160	ST-164
Chemical Inputs	1	2
Chemical Selection	Fixed	Selectable (Red / Blue / Off)
Best Use Case	Single soap or degreaser	Multi-stage or touchless wash
Flexibility	Moderate	High – switch instantly on the fly
Metering Control	Single	Dual (individual control)

If your workflow includes alternating between Stars + Stripes, or switching from a degreaser to a ceramic soap, the ST-164 saves time and reduces error by keeping both products pre-loaded and ready to go.

Best Practices

Label your pickup tubes clearly to avoid chemical confusion
Flush with clean water regularly, especially after using high-viscosity products
Use enlarged orifice soap nozzles for proper injector activation
Mount the ST-164 in a visible, accessible location to quickly rotate the selector during a wash
Use a check valve or Mezzo Valve upstream if combining with a multi-gun setup or lance system

Ideal Pairings

Pair your ST-164 with:

Chem-X Stars (Red) and Stripes (Blue)
Snake Oil (Red) and Heavy Duty Degreaser (Blue)
Old Glory (Red) and Eagle Guard (Blue)

This setup is especially popular for:

Commercial fleets
Touchless wash bays
Trailer washouts
Industrial cleaning
Mobile rigs handling multiple surface types

Maintenance Tips

Inspect metering screws and selector knob monthly for buildup
Replace pickup tubes when they become brittle or discolored
Lubricate O-rings and seals during seasonal tune-ups
Keep your check valves clean to avoid cross contamination

Final Thoughts

The Suttner ST-164 Dual Foam Injector is built for professionals who demand speed, flexibility, and precision. If you’re tired of swapping tubes, wasting time between chemical stages, or risking cross-contamination, the ST-164 is your all-in-one solution.

With Chem-X soaps designed specifically for downstream foam systems, you can count on rich, effective foam every time—with zero hassle and maximum control.