If you own or operate specialized 2-step truck wash equipment, you know how important it is to keep your system running smoothly and efficiently. A malfunctioning system can cause delays, customer dissatisfaction, and loss of revenue. That's why you need to know how to troubleshoot your system and fix common problems before they become major issues.

In this blog, you'll learn how to troubleshoot your 2-Step fleet wash system so that you can wash vehicles faster and more effectively while avoiding unnecessary downtime.

How do 2-Step systems work?

While 2-Step washing has been around for decades, in the past few years, 2-Step fleet washing has proven to be the most effective method for high quality brushless cleaning. Coupled with advancements in technology and growth in the fleet washing industry, the demand for 2-step washing systems has boomed.

This is especially true in the mobile fleet washing market, where operators seek to maximize labor efficiency to produce a higher output with a focus on a lower overall cost per wash.

There are several wash methods and a variety of ways to utilize your pressure washing equipment, but using equipment that is specifically made for 2-Step washing typically improves the speed and quality of the wash results.

But all 2-Step methods typically follow the same general process:

Start by applying a Step 1, acidic pre-soak to the surface of the vehicle, let it dwell for a short period of time (30-60) seconds and then apply the Step 2, alkaline soap directly over Step 1, let it dwell for 30–60 seconds. Then rinse it off with water. It’s important to have both the low pH and the high pH because the two different products “attack” different types of dirt and grime on vehicles.

The beauty of the 2-Step washing routine is that it requires much less physical labor, can be applied quickly, and actually neutralizes the truck’s surface — making it the best solution for removing road film. 

As with any piece of pressure washing equipment, your 2-step system will require proper setup and maintenance, especially if you are using aggressive detergents. 

Many 2-step wash systems operate using upstream or downstream Venturi injection methods through a pressure washer. Some 2-step systems may include their own injection system for detergent application, while others may simply connect to your existing injector already installed. Continued development in technology now includes higher pressure downstream 2-step systems, such as the 2-step gun and similar remote systems.

Troubleshooting Your 2-Step System

When using your 2-step system, there is also a chance that you may experience some issues. Below are some common issues whether you’re using upstream or downstream injectors, as well as a 2-step gun, remote, or other valve assembly:

Issue #1: Your System Stopped Drawing Chemicals

Most 2-step systems rely on a Venturi effect to draw chemicals. If your 2-step system is not drawing chemicals, here’s what we suggest:

  1. Check for blockages. Chemical injection tubes can become clogged with chemical residue and raw materials. Chemical injectors and nozzles can also become blocked with debris from your high pressure water line.
    • Can you see through the injector and nozzle? Can you flow liquid or blow air through the lines?

  2. Check your chemical lines. Chemical injection fittings can lose their suction due to air leaks at connection points and tears. Chemical lines can also get kinked at bending points or due to making contact with other surfaces.
    • Do your lines have chemicals in them? Do you see air bubbles?

  3. Check your chemical injector. Chemical injectors typically have a smaller opening on the inlet side and a larger exit point. Verify that your injector is installed in the proper direction. Ensure that the chemical injector and nozzle(s) you’re using are the correct size for your pressure washer & 2-step system. Look for signs of corrosion or deterioration of the components due to chemicals. Ensure the smaller injector orifice is not blocked or loose.
    • Is the arrow on the injector pointed WITH the direction of flow? Did you provide your supplier with your GPM/PSI? Have you replaced the injector?

  4. Inspect check valves. Many chemical injectors as well as 2-step systems & chemical lines are equipped with check valve(s) to prevent backflow. These can become stuck in a “closed” position to prevent chemical draw OR become stuck in the “open” position allowing water to backflow through your chemical lines.
    • Do your chemical lines remain primed? Can you flow liquid or blow air through the lines with the direction of flow?

  5. Inspect your bypass system (if applicable). 2-step guns and remote systems may be equipped with a water bypass system for the chemical injector using a high pressure valve. If your high pressure valve fails to open and/or close or if your bypass system is not sized properly, you may not draw chemicals.
    • Do you notice a change in flow/pressure when utilizing your bypass? Do you notice suction with your injector or chemical lines while in use?


Issue #2: Inconsistent Cleaning Performance

Familiarize yourself with the many factors that affect cleaning performance. If you are experiencing inconsistent cleaning performance without any significant changes in temperature, vehicle conditions, or water quality, we suggest:

  1. Check your chemical draw rate & dilutions. Changes in your chemical draw rate through your injector can impact cleaning performance. This is due to drawing more or less than the expected amount of cleaning solution. These changes can be caused by the issues listed in the section above.
    • Did you measure the exact dilution rate for your chemical injector for potential changes?

  2. Check your detergents and ratios. Detergents are sold at many strengths and with a variety of raw material ingredients. Some chemicals may also settle or have different viscosity due to concentration and may not draw properly.
    • Did you check your chemical draw rate prior to purchasing/mixing detergents? Did you check for settling at the bottom of your tanks?

  3. Check your chemical metering system (if applicable). Some 2-step systems can be adjusted using chemical metering valves, proportioning tips, or the adjustment collar/screw on the injector. Due to corrosion, blockage, or improper sizing, these metering systems can change and affect performance.
    • Did you measure your draw rate before & after using a metering system? Do you notice changes in your chemical usage?


Issue #3: Changes in Spray Volume and Pressure
2-step injection systems are used in conjunction with the pressure washer and utilize the high pressure hose, wand, and spray nozzles for cleaning performance. If you are noticing changes in your water spray volume or cleaning pressure, we suggest:

  1. Check your nozzle(s) for damage. Corrosion or damage to your nozzle can influence the size of the opening. Blockages in your nozzles due to debris from your water line or blowback could also influence the volume of water and application pressure. Any of these could affect performance or cause inconsistency.
    • Do you notice a difference in the spray pattern? Do you feel more or less water flow & pressure? Have you changed the nozzle?

  2. Check the size of your nozzle(s). Improper nozzle sizes too large or too small can affect your spray volume, pressure, and cleaning performance. Different 2-step systems may also require unique nozzle sizes for your pressure washer.
    • Did you provide your supplier with your GPM/PSI? Did you change machines or purchase replacement parts elsewhere?

Issue #4: Intermittent Chemical Draw

With some 2-step systems, it is not uncommon to experience small bursts of soap as you change detergents or switch to rinse. This is often due to a small amount of chemical in the injector lines past the shutoff, as well as the remaining chemical in your high pressure line prior to rinsing water. If you experience intermittent chemical draw or continuous small bursts of soap, we suggest:

  1. Check your shut-off valves/solenoids. If using valves with shutoffs on a 2-step gun or manual system, check to ensure there are no leaks or fractures in the valve structure. If using a remote shutoff system, check the solenoids to ensure they are sealing completely.
    • Do you notice chemical leaks or chemical lines losing prime? Have you replaced valves or solenoid seals?

  2. Check chemical injector. The smaller inlet orifice of the chemical injector could become blocked by debris. The orifice could also become loose due to pressure & vibrations. Both of these issues can cause intermittent soap draw.
    • Do you see anything blocking the opening of your chemical injector? Have you tightened and/or replaced the orifice insert on the injector?

Issue #5: Switching Between Detergents

When changing between detergents using 2-step systems, these assemblies will switch soaps with manual valves and/or remote solenoids. If you are experiencing issues with switching soaps or not drawing one of your detergents, we suggest:

  1. Check your remote transmitter (if applicable). Remote systems may not switch soaps or may shut off if out of range and without direct signal. Systems may also have timed shut-off or solenoids may not function properly if overheated.
    • Did you check the batteries on your remote transmitter? Do you have an obstructed signal? Does the manufacturer have programming information?

  2. Check your shut-off valves/solenoids. If using valves with shutoffs on a 2-step gun or manual system, check to ensure there are no air leaks or blockage in the valve structure. If using a remote shutoff system, check the solenoids to ensure they are opening completely. Corrosive chemicals may also deteriorate the function of one valve quicker than the other.
    • Do you notice chemical lines losing prime? Have you flushed your system with water? Have you replaced valves or solenoid seals? 

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