- THE MAGAZINE
The majority of new cleaning technicians coming into the business today that are using hot-water extraction (HWE) systems start out with a scrub wand as their primary carpet-cleaning tool.
Economics and a lack of familiarity with other tools, including the various rotary-type heads on the market, usually dictate that the wand will be the most common tool for newcomers. To use an old and oft-stated phrase, this isn't rocket science. Learning to use the wand effectively is not difficult, but there are several very common mistakes made by newbies as they develop their techniques and hone their skills as on-site cleaners.
The most common problem is streaking. Failing to provide sufficient overlap from clean to dirty, resulting in streaks that run the same direction as the wand movement, is usually the culprit. The proper technique is to overlap 1 to 2 inches.
Sometimes the streaking runs crosswise to the direction of wand movement. A close look at wand design reveals the cause: the actual point at which the rinse solution hits the carpet is about 1 to 2 inches behind the point at which the vacuum head contacts the carpet surface. The streaking is the result of the tech changing the direction of wand movement (i.e. from to to fro) at the same time the solution valve is closed. This results in a wet area about 1 to 2 inches wide running crosswise to the direction of the wand movement that causes a wicking or browning condition to develop. The proper technique is to close the solution-flow valve and continue the wand movement another 2 to 3 inches in the same direction to pick up that wet spot, and bada bing! With proper technique the carpet dries evenly and leaves no crosswise streak.
But technique is only one piece of the puzzle. The cleaner has little control over wand design, and only in the sense that he or she selects the wand to use. Designers and engineers control such critical areas as the number of jets and distance from jet to floor surface. And the little numbers engraved on the jets really do mean something. Each jet has specific characteristics, and those numbers tell you what those characteristics are.
The first two or three numbers, which will be between 15 and 110, indicate the angle of spread of the spray pattern leaving the jet at 40 PSI. Increasing PSI will not appreciably increase spray angle. Lower numbers equal a narrow spray pattern; higher numbers indicate a wider spray. Since the spray is triangle-shaped, the distance between the jet and the floor will control the width of the spray pattern at impact. On a single-jet wand, if the jet is too close to the floor the spray will not be able to spread enough to ensure coverage from one edge of the wand to the other. In this case, the operator will have to pay close attention to wanding procedures, allowing enough overlap on strokes to be certain that all soil is removed and no clean or dirty streaks are left behind.
On a multi-jet wand, the spray from each jet must spread enough to intersect with the spray from the adjoining jets. This means that the solution pressure must be high enough to get sufficient spray-spread to achieve this intersecting of sprays. If the spray from the adjoining jets does not intersect, the result will be clean, or dirty, streaks.
Here again, it is the operator's challenge to ensure proper soil removal leaving no clean or dirty streaks. And keep in mind that jet spacing, which may be suitable for a low commercial carpet, may not work so well on a high-pile saxony. The wand head may be pulled down into a saxony by vacuum, moving the jets closer to the carpet surface. Under these circumstances there may not be sufficient spread of the solution spray to allow intersection of the separate sprays.
The last two numbers will indicate the amount of solution passing through the jet at 40 PSI. This number is expressed in 1/10 gallon per minute (GPM), so a tip with the last two numbers being 06 will pass 6/10 GPM, or about 75 ounces, at 40 PSI.
As water pressure increases, water flow increases. That same tip will pass 1.6 GPM at 300 PSI. That's a lot of water! Changing to a smaller tip, such as a 04, will reduce the gallons per minute being passed, in this case from 1.6 GPM to 1.1 GPM at 300 PSI. Reducing flow will generally increase water temperature, but will reduce the rinsing and soil-removal ability of the cleaning process. More passes may be required to remove all soils, but drying time may compress from the use of less water. Reducing solution pressure will have a similar effect. The 06 tip that passed 1.6 GPM at 300 PSI will pass 1.3 GPM at 200 PSI. If reduced GPM is your desire, e.g. when cleaning olefin berbers, reducing pressure is the easiest route to take.
Viewed from a broader angle, it becomes apparent that, while streaking may be affected by mechanical conditions, prevention is actually an operator function. Whether factors such as poor design, poor jet selection or clogged jets contribute to the problem, in the end it is the operator's job to inspect his or her equipment regularly to detect such problems. It is generally the technician's job to correct these conditions, and it is certainly the technician's responsibility to adjust wanding patterns to conditions to eliminate any streaks that may develop. The technician should be constantly monitoring the cleaned carpet to make sure that no streaking is present.
Remember, wands are only tools; they cannot think. The onus is on the operator to take in the situation, making adjustments as they are required, and provide a satisfactory, completed operation. This will result in a win-win: Happy client smiling as she shuts the door behind you, the happy cleaner smiling all the way to the bank!
Until next month, see ya!