How to Use: Trash pumps

While using a trash pump may be a straightforward operation, knowing what your pump can do – as well as knowing what it can’t – means more productive performance from a piece of equipment to which you may not have given much thought. Keep these tips in mind to make your pump work harder for you.

Purchase vs. rental – If you’re considering adding a trash pump to your yard, look at your usage time as well as the types of jobs on which you are using the pump. If the same pump will be used in frequently in ongoing applications, such as a 3-inch trash pump that is useful for a variety of jobs, purchasing the pump would be a cost-effective decision. If you’re looking at limited usage time, however, or a need for different types and sizes of pumps, the rental option will save money.

Check your solids content – While centrifugal trash pumps are designed to pump water containing solids, the traditional volume of solid material this type pump can handle in a liquid is 10 to 25 percent, says Mark Conrardy, sales engineering manager, Wacker. “Generally, if the water contains more than 25 percent solids, you need a diaphragm pump or some type of positive displacement pump to move these materials,” he says. “A centrifugal trash pump will begin to plug up in these conditions.”

When pumping muddy water, switch to a diaphragm pump when the muddy water no longer flows through the hose, says Pam Meyer, equipment sales manager, Subaru Robin. As long as the material flows properly, a trash pump can handle just about anything, she says. “As long as the material fits through the strainer, there are no limits on what a trash pump can handle. The strainer will limit the particle’s size, but trash pumps are built to handle anything from sticks to stones to concrete chips.”

Avoid pumping corrosive material, gasoline or other fuels through your trash pump – they will create mechanical problems as well as safety issues. Also check the water temperature. Hot water has a high vapor pressure, and the suction may cause the water to boil, creating cavitation that could damage the pump’s impeller. Conrardy recommends using caution when water temperatures reach 115 degrees Fahrenheit.

Don’t underestimate suction lift height – Because of specific gravity and the effects of atmospheric pressure, you can only pump water from no more than 26 feet down. However, this measurement applies only to pumps used at sea level, Meyer says. For above sea level operation, subtract 2 feet from the 26-foot depth for every 1,000 feet above sea level. If you fail to make this calculation, your pumping volume will be lowered or the pump will fail to function entirely. Above 12,000 feet, place the pump at water level or slightly below so the pump can act as a siphon. See the chart above for atmospheric pressure corrections.

One of the most common mistakes users make involves using too much suction hose or pipe, according to Jim Widrick, sales manager, Gorman-Rupp. “Using too much suction hose creates a high friction loss factor,” he says. “Many times this leads to suction cavitation – the most destructive thing a pump can experience.”

Higher lifts result in lower pump output. Ideally, you should place the pump as close as possible to the water. The closer the pump, the more gallons per minute produced. In situations where you can’t place the pump lower in the site, use a larger submersible pump, Conrardy says.

Perform routine maintenance – Prolonging the life of your pump begins before you even make the purchase, Meyer says. “A number of components have a direct impact on how long a unit will keep pumping. This will save money in the long run, not just in replacement parts, but in the cost of downtime spent on a pump that does not handle well.

First, look for a high quality engine. Not only will this prolong the pump’s life, but lessen maintenance issues, as well. Quality components are also key. Look for a well-made impeller and high quality mechanical seals. A worn seal may allow air to enter the pump and interfere with operation. Pumps that frequently handle debris will last longer when equipped with a wear plate that will protect the unit’s impeller. Replacing a worn wear plate costs less than replacing the impeller.

Not only will preventive maintenance extend a pump’s service life, it will enhance the pump’s performance. Taking care of the pump will help ensure you are pumping efficiently and productively. Monitor the hoses for holes or worn couplings, maintain the seals and follow the maintenance schedule the pump manufacturer provides.

Follow safety recommendations – Check to see that your pump’s engine has a spark arrestor, which will prevent a spark from igniting once the engine gets hot. Check the pump’s temperature before opening the unit. If it’s heated, let the pump cool before you try to perform any maintenance work.

If your pump isn’t performing properly, resist the urge to strike the flywheel to get it to move. Doing so may cause the flywheel to shatter during operation.