Your water pump is primed and the liquid is flowing… kind of. One of the more common problems with water pumps is a reduced or lower than expected water flow. When you need to dewater the jobsite, low flow means more downtime for the crew, costing money and putting deadlines at risk. Often, low water flow is less about your water pump and more to do with the situation. Below are a few things to review to troubleshoot water pump problems involving low water flow.

Pump Too Far From The Water Source

The greater the distance a pump has to pull the water, the lower the flow rate will be. Get too far from the water source and the more power is dedicated to ‘sucking’ the water and less to discharging, reducing the flow rate.

Typically, pumps should be with 20 feet of the water source. Depending on the typography, how high the pump is relative to the water, the flow may be reduced at even shorter distances. Your pump has individual specification, so be sure you read the spec and operate within them.

Reduction In Supply Line Diameter

Your pump is designed to operate with a certain diameter input line. In some cases, we have seen people attach a smaller than recommended hose or line (using a reduction couplings). Depending on the intake line you use, it is also possible that the line crimps, or is “sucked in” on itself.

A few things to check.

  • The intake line should be both the recommended size and at least the same size as the discharge line
  • Walk the intake line from the source to the pump and be sure there are no kinks
  • If possible use a rigid intake line. Sometime called a non-collapsible hose.

Intake line obstruction

Anything that impedes the water’s flow into the line will cause a reduction in the flow rate.

Debri blockage is a common problem. With murky water it can be hard to see the intake hose. But, operators should check to be sure there is no debris blocking the intake. The blockage usually happens at the filter as it does it’s job to prevent damage to the water pump. Remove the debri and reposition the hose to start pumping again.

The intake filter or screen can also be the culprit even without debri . While you must ensure the filter is fine enough to prevent damaging solids from entering the pump, too fine a filter for the water pump will restrict the flow right as the water enters the intake. Be sure the filter is proper for the pump.

Improperly Connected Motor

Centrifugal water pumps are designed to operate with the impeller going in one direction. If it is going the opposite direction, the pump will not operate properly. This can happen if the electrical connections to the electric motor is not established correctly. Review the electric motors setup and user instructions to ensure your connections are correct.

Whether you are dewatering a jobsite, irrigating a field or applying your water pump for any other purpose, low flow is an issue. In some cases, like a firefighting pump, it can be a matter of life-or-death. One way to minimize onsite issue it to check all your equipment on a regular basis, replacing worn parts and performing maintenance as needed. But when confronted with low flow rates, follow the above steps and you’ll be able to get your water pump back in action, and your crew back to work.

If you are unable to identify the cause of a poor performing pump, give us a call. We’ll be happy to help you.