How to Fix Pressure Problems on a Waterjetting Job

When something goes wrong with your jetter in the field, these tips will help you diagnose the issue and get back to work

How to Fix Pressure Problems on a Waterjetting Job

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Downtime on a job is a double whammy. It decreases profit margins while also increasing the odds of customer dissatisfaction.

To avoid watching that potential five-star online review go down the drain, it helps if you can diagnose and at least temporarily fix problems with equipment in the field, such as water jetters on drain cleaning jobs.

John McBride, the general manager of Jetters Northwest, and two industry veterans from MyTana Mfg. — Brent Hill, general manager, and Michael Och, operations manager — share common problems that crop up with water jetters and how to resolve them.

Low jetting pressure

This problem often stems from leaks in the discharge system, McBride says. The leaks could result from a variety of causes, ranging from a blown hose to using the wrong size nozzle.

“Sometimes guys just grab a nozzle from another jetter and don’t realize it’s size-specific for certain machines,” he says. “So try putting on multiple nozzles to be sure the problem isn’t the nozzle. Also, check for leaks in the system.”

The problem could stem from the inlet side of the water pump. Debris caught in the strainer between the water tank and the pump is a common culprit.

“If the pump can’t pull water in, it can’t push water out,” McBride says

If a check reveals the strainer is clean, then take a look inside the water tank.

“Sometimes if water is left in the tank, algae and scum can form and wrap around the filters,” he says. “Or if you accidentally leave the lid off the water tank, leaves or other debris can get in. I’ve also seen guys accidentally drop a towel in the tank, too.”

If a blown hose is the cause of the leak, consider using a repair kit for field repairs.

“But you have to be very careful to use the appropriate fittings designed for the hose you’re using, and those kits can cost $1,000 or more,” McBride says.

Sometimes pressure loss stems from a leaking jumper hose, the short section that connects the pump to the actual cleaning hose on the reel. The hose reel usually is equipped with a heavy-duty ball valve that also could be the source of a leak.

“Or the leak could be in the pump itself,” says Och.

Using a hose with a diameter that’s too large for the jetter can also create low-pressure problems; follow manufacturer’s suggestions, Hill says. The other part of that equation is using the right hose with the right nozzle; if paired incorrectly, this can cause low pressure and poor functionality.

“Furthermore, if the machine is spec’d to run 200 feet of 3/8-inch hose and you run 500 feet of hose, it’s not going to perform correctly. The longer the lineal footage of the hose, the lower the pressure at the nozzle head,” says Hill.

Pressure spikes

If you experience erratic spikes of pressure, start the troubleshooting process at the nozzle. Remove it and try flushing water out of the hose to ensure there’s no debris inside it. Then inspect the nozzle, Och says. If a clogged nozzle port or ports are the problem, use nozzle tip cleaners to unclog them.

“Guys normally use two kinds of tools as tips cleaners: an acetylene-torch welding tip or a minifile typically used for performing root canals,” he says. “They come in different sizes that will fit into the orifices on the nozzle and help remove any debris wedged in there. I’d say roughly eight out of 10 times, that’s the issue.”

And no need to worry about damaging the nozzle by poking tools into the ports; most nozzles are either heat-treated or hardened in some fashion or made from materials such as stainless steel.

“You can be pretty aggressive without worrying about making the nozzle ports bigger,” Och says.

Hill says to keep in mind that the holes in the nozzle are drilled at specific angles for different cleaning applications. When using tools to probe those ports, look at the manufacturer’s recommendations so you insert the tools at those angles, he says.

Jetters Northwest sells specific tools for cleaning nozzle ports and includes one such tool with all nozzles it sells. In lieu of those, McBride agrees with Och’s advice and says jetter operators should carry various-sized welding tips for emergency nozzle-port cleanings.

“But you need to be careful,” he says. “If you’re really forcing things, it’s possible to get it stuck in the orifice or even to snap it off. And if that happens, then you’ve lost the nozzle completely.

“I’ve also seen cases where people have tried to drill out clogged orifices with drill bits. If you make a port bigger, you’ve now decreased the level of restriction, which in turn reduces water pressure. It’s important to understand the relationship between flow, restriction and pressure.”

Drops in pump pressure

To understand this issue requires a quick lesson in pumps 101. There are essentially two stages that water goes through inside a water pump: First it travels through a manifold at low pressure, then it passes through the top half of the pumps at high pressure, moves through the jumper hose to the cleaning hose and then to the nozzle, Hill says.

“If your water pump has bad seals or has, say, a cracked piston, the water from the front side of the pump could enter the oil reservoir and make the oil milky when it mixes,” he says. “Then the metal parts in the back of the pump don’t get properly lubricated, which causes a drop in pressure and performance.

“Eventually, the pump will stop working because of damage caused by metal shavings in the oil. There’s no quick field fix for that — you’re either rebuilding or replacing the pump.”

Excessive vibrations

This could be caused by air leaking into the pump’s suction line, McBride says. This can result from the operator accidentally leaving the valve to an antifreeze tank open, for instance, or not enough water in the water tank, which also makes the pump susceptible to sucking in air where it doesn’t belong.

In other instances, an operator might pull off the water-tank strainer cap to inspect it, shake debris out of it and then not notice as the gasket falls out of the cap. That allows air bubbles to enter the water supply.

“This manifests itself through erratic vibrations,” McBride says. “When that occurs, look for anything that might be introducing air into the pump’s inlet.”

Engine won't start

Maybe you’re using old gasoline or the engine is out of gas. Or maybe the battery is dead, Och and McBride say.

An ounce of prevention

Of course, proper maintenance and operation is always critical to maximizing on-the-job performance. For instance, always be sure pump filters are clean so the pump receives sufficient water. In addition, never let a pump run dry, Och says.

“Introducing oxygen wreaks havoc on the guts of the pump. Anytime the engine is turned on and there’s no water flowing through the pump, you’ll burn out all of the O-rings and the seals,” he says.

Using clean water also maximizes performance; dirty water carries tiny grains of debris that can damage the pump.

“Also pay attention to your gauges and listen for abnormal sounds,” Hill says. “If a gauge is showing higher-than-normal pressure, a gas engine isn’t idling at the proper revolutions per minute, or you hear sputtering at the end of the hose, pay attention. Turn off the machine and start inspecting things, starting at the nozzle.”

It also pays to be prepared.

“Carrying a spare hose, cleaning tool or hose repair kit could save your butt on a job,” McBride says. “And it’s crucial to understand your machine and how it works. An ounce of prevention is always worth a pound of cure.”



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