by Patrick Prayne
December 17, 2011

OEM pumps and parts outperform replicated products, and can save thousands per year in operating costs. 

Industrial process managers who purchase and maintain pumps are familiar with a marketing tug of war. On one side are the manufacturers of well-known pump brands who claim their products offer higher quality with a lower cost of ownership. On the other side are replicators who make pumps and parts that cost less out of the box and claim to perform just as well as the OEM products.

Studies by the Hydraulic Institute show that purchase price of a medium-sized ANSI pump is only 10 percent of the life-cycle cost of a pump, with energy, maintenance and downtime costs accounting for nearly 70 percent. In many cases, the initial purchase price is the most heavily weighted factor in purchasing decisions.

This may be especially true for process pumps that conform to the ASME B73.1 specification, commonly known as the ANSI standard. Most ANSI pumps can look similar, even to the eyes of a skilled engineer—and because they are the world's most common process pump, with tens of thousands sold each year, it may seem reasonable to assume that replicated ANSI pumps and parts are likely to perform as well as those from OEMs.

To test this, engineers at an OEM pump company recently conducted a comparison of a popular OEM pump to pumps of identical size from non-OEM suppliers. The results showed that when it comes to purchasing pumps, the short-term gain of a lower purchase price equals long-term pain in performance. In every test:

  • Non-OEM pumps failed to match the OEM pump performance for flow, head and efficiency.
  • Non-OEM pumps performed an average of 10.25 percent lower in efficiency than the OEM counterpart.
  • Non-OEM pumps did not perform in accordance with their own published performance curves, and therefore did not conform to the ASME standard.
  • At a standard electricity cost of 7.6 cents per kilowatt hour, the lower efficiency of the non-OEM pumps would translate into wasted energy costs of at least $1,100 per year per pump, and as much as $3,700 per year on a medium-sized pump, based on continuous operation.

Customers report that OEM pumps and parts also require less maintenance and reduce downtime, which further contribute to the lower operating costs for OEM pumps. This article provides details on the tests, and examples from two customers who switched to using only OEM pumps and parts. Together, they show that OEM claims to lower the total cost of ownership are not simply marketing hype but a fact that can be verified by controlled testing.

Test Methodology

Performance tests were conducted on four sizes of ANSI pumps:

  • 1x1.5-6 (1-in. discharge flange, 1.5-in. suction flange, 6-in. impeller)
  • 1x1.5-8
  • 1.5x3-13
  • 2x3-6

The testing was performed in accordance with ASME B73.1 and Hydraulic Institute Standard 1.6, Level A, which includes guidelines and uniform procedures for testing, recording data and acceptance criteria for centrifugal pumps. Level A testing uses clean water and involves monitoring the rate of flow, system head, input power and pump speed. Level A acceptance criteria states that “no minus tolerances or margin shall be allowed with respect to rate of flow, total head or efficiency at the rated or specified conditions.”

Each pump was tested as-received, with only the impeller clearance being set per the product installation, operation and maintenance (IOM) manual.

While the size of the differential varied, the OEM pumps outperformed their non-OEM counterparts in every measure on every test. A close-up look at the results for two of the pump sizes tested provides a snapshot of typical findings.

1x1.5-8 Test—OEM Pump Is 17 Percent More Efficient                                          

At 3,550 rpm, the OEM pump produced a flow of 150 gpm, a total dynamic head (TDH) of 271 ft, with an efficiency of 61.1 percent.

For the non-OEM pump operating at the same speed and flow, the TDH was only 229 ft, which is 15 percent lower. It was operating at an efficiency of 50.7 percent, which is 17 percent lower than the OEM of the same size.

OEM Pump is 8 percent more efficient

The 1.5 x 3-13 pumps also were tested at a speed of 3,550 rpm. The OEM pump produced a flow of 484 gpm, TDH of 492 ft, and an efficiency of 55.3 percent. For the non-OEM pump operating at the same speed and flow, the TDH was only 459 ft, which is 7 percent lower; and an efficiency of 51.1 percent, which is nearly 8 percent lower.

Small Differences Yield Big Energy Savings

An efficiency delta of less than 10 percent may not sound like a lot, but it translates into major differences in energy costs.
Consider the 1.5x3-13 pump comparison, in a pumping application requiring a flow of 484 gpm at 459 ft—the actual performance result of the non-OEM pump at 3,550 rpm. The OEM pump would produce the same flow and head using a smaller impeller, using 8 percent less power, saving 8.3 hp (or 6.2 kW).

According to the U.S. Department of Energy, in August 2008 the average price of electricity in the North American industrial market was just under eight cents per kilowatt per hour—$0.076 on average, ranging from $0.066 in the Midwest to $0.138 in New England. At the average price, the energy costs in this application would be more than $3,700 lower per year with the OEM pump compared to the non-OEM pump.