U.S. Department of Energy - Energy Efficiency and Renewable Energy

Federal Energy Management Program – Operations and Maintenance

Pump Maintenance

The importance of pumps to the daily operation of buildings and processes necessitates a proactive maintenance program. Most pump maintenance activities center on checking packing and mechanical seals for leakage, performing preventive or predictive maintenance activities on bearings, assuring proper alignment, and validating proper motor condition and function.

Basic Measures to Improve Pump Efficiency

  1. Shut down unnecessary pumps.
  2. Restore internal clearances if performance has changed.
  3. Trim or change impellers if head is larger than necessary.
  4. Control by throttle instead of running wide-open or bypassing flow.
  5. Replace oversized pumps.
  6. Use multiple pumps instead of one large one.
  7. Use a small booster pump.
  8. Change the speed of a pump for the most efficient match of horsepower requirements with output.

Pump Efficiency Actions
Large Horsepower Pumps (25 HP or greater)

Here are some actions to take to improve pump efficiency. (Listed in order of decreasing potential for efficiency.)

  1. Excessive pump maintenance — this is often associated with one of the following:
    • Oversized pumps that are heavily throttled.
    • Pumps in cavitation.
    • Badly worn pumps.
    • Pumps that are misapplied for the present operation.
  2. Any pump system with large flow or pressure variations. When normal flows or pressures are less than 75% of their maximum, energy is probably being wasted from excessive throttling, large bypass flows, or operation of unneeded pumps.
  3. Bypassed flow, either from a control system or deadhead protection orifices, is wasted energy.
  4. Throttled control valves. The pressure drop across a control valve represents wasted energy that is proportional to the pressure drop and flow.
  5. Fixed throttle operation. Pumps throttled at a constant head and flow indicate excessive capacity.
  6. Noisy pumps or valves. A noisy pump generally indicates cavitation from heavy throttling or excessive flow. Noisy control valves or bypass valves usually mean a higher pressure drop with a corresponding high energy loss.
  7. A multiple pump system. Energy is commonly lost from bypassing excess capacity, running unneeded pumps, maintaining excess pressure, or having a large flow increment between pumps.
  8. Changes from design conditions. Changes in plant operating conditions (expansions, shutdowns, etc.) can cause pumps that were previously well applied to operate at reduced efficiency.
  9. A flow-flow, high-pressure user. Such users may require operation of the entire system at high pressure.
  10. Pumps with known overcapacity. Overcapacity wastes energy because more flow is pumped at a higher pressure than required.

Maintenance Checklist