Jetter

6 Things to Consider Before You Jet a Pipe

High-pressure water cleaning systems have become the tool of choice for maintaining sanitary sewer systems, because of their effectiveness in dealing with grease and sludge, along with their ability to partner with pipe inspection cameras. However, before you fire up your jetter and go off to battle underground monsters, there are six things to keep in mind.

1.    What the heck is down there?

  •  Jetters do a great job on soft stoppages like grease, sand sludge, and even ice. However, when it comes to roots, they are not the preferred tool for the job. If you’re not sure what is happening in the line, you can try to send an inspection camera down to take a look, but if the line is blocked you won’t be able to see much. Remember, cameras can’t see underwater any better than you can. So how can you tell what the blockage is?

  •  First, if the line in question has anything to do with food service, there is a better than even chance that grease is the problem. Using your powers of deduction, you can conclude that blockages in lines leading from restaurants, multi-family dwellings, and any kind of institution involving food service (schools, nursing homes) are likely to be made by grease and maybe rags. The same is true if the pipe in question originates in a factory or industrial facility that flushes lubricants, solvents, or any type of organic material down the drain. Also depending on where you are, sand can be a persistent problem.

 2.    Shake, Rattle, and Roll

  •  Does your jetter unit have a way to vibrate the hose while it is in the pipe? The vibration function is used to break up the surface friction between the hose and the pipe, so you don’t get the hose stuck. One of the first things contractors noticed when they invented jetting some 40 years ago, was that when you connect a hydraulic hose and rear facing nozzle to a pressure washer and shove it down a pipe, there is a chance of getting the hose stuck. And anytime that happens it’s the beginning of a long day, because you’re going to need to get the excavator out. That is why every legitimate manufacturer of high-pressure jetters today has a feature that allows you to vibrate the hose while in use.

 3.    Yes, size matters

  •  Are you using the correct size of hose for the pipe, you are trying to clear? Another excellent way to get your hose stuck in a pipe is by using the wrong size hose, which is surprisingly easy to do. When working with high-pressure water, the philosophy is to use the largest hose that will fit into the pipe. This is because hoses with a larger inside diameter don’t have as much pressure loss due to water friction. All things being equal, the larger the hose, the more pressure at the nozzle. The more pressure at the nozzle the easier it is to do the job.

 4.    Check your water

  •  Since high-pressure water is doing the work down the line, it makes sense that you have enough of it. If you happen to be using a large device with a holding tank, such as a trailer jetter, your only challenge is to make sure the tank doesn’t run dry. Most of these units have an automatic shut-off that keeps this you from making this mistake. However, if you are using a jetter that draws water from a garden hose, a little more attention is required. Most municipal and well water systems in North America deliver approximately 5-6 gallons a minute in flow, but it is recommended that you make no assumptions. Get a 2-gallon bucket and measure how much time it takes to fill it. If you’re close, don’t take the chance, because you could accidentally starve the pump of water and cause cavitation. Cavitation is the second most popular way to kill your pump, so pay attention to details.

 5.    It don’t mean a thing if you don’t have that swing

  •  Keep your hose moving. The preferred technique for jetting a line is to work the hose back and forth: push the hose 2 feet forward, then pull it back a foot, then push forward 2 feet and back a foot. The maximum cleaning action comes when you pull back the hose, not pushing it. As you pull back, the angle of water flow exiting the nozzle scours the sides of the pipe, magnifying your cleaning efforts. If you keep the hose moving, you’ll do a better job and do it in less time.

  •  There is another reason to keep it moving. Because of the fluid dynamics of high-pressure water flow, turbulence can cause vortices to form just behind the nozzle when you are doing the job. These vortices, if stationary for any length of time, can suck sand, loose dirt, grease, or sludge in behind the nozzle, causing it to plug up and trap the hose down in the pipe. Getting your hose stuck in the pipe, no matter what the cause, is a bad thing. Digging it up is usually the only viable option. Again, very time consuming.

 6.    Don’t freeze up

  •  Statistically, freezing is the number one way to kill your pump. If you live in a place with four seasons, you’ll find it surprisingly difficult to keep your pump from freezing when you are doing work on a frigid day. The damage can take place before, during, or after the job, and can affect your hose as well as your pump. If your unit has an antifreeze tank, please get in the habit of using it whenever temperatures are close to freezing. If your unit does not have this feature, introduce antifreeze to keep it from freezing when you are driving to and from the job. Just disconnect the hose that runs from the output valve to the hose reel swivel. Then pour antifreeze into the inlet as you start the motor on the unit, which will draw the fluid through the pump. When you notice antifreeze exiting the output valve, turn off the motor. Then, using an air compressor to blow the water out of the hose (remove the nozzle). Make sure this has been done before you drive to the job, and again before going back to the shop. During the job, limit the amount of time the units sits without water flowing through the pump. Turn the unit on frequently, running water through the bypass system to keep it warm. If you make it someone’s job to pay attention to the pump, then you’ll improve the odds of it surviving till spring.

  •  You probably noticed that most of the points can be summarized by “paying attention to what you are doing” and “do your homework”. Jetters are fantastic tools for our industry, able to address most modern sewer line problems better than other tools at our disposal. But, like everything else in life, greater power comes hand in hand with greater responsibility. If you sweat the details, a jetter is an incredibly versatile and profitable tool that can transform your sewer maintenance program.

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May 2019 Risk and Safety Newsletter

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