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Today's tip is to know when it’s time to repair a pump or to replace it. The first step is to understand its performance level. High-efficiency pump systems are designed for specific applications such as water treatment, condensate return, boiler feed water, chiller water in closed systems, water towers in open systems, and chemical proportioning.
Managers and technicians have a number of tools and tactics to gather essential data on pump performance. Technicians can compare baseline readings to subsequent readings to check for wear of the impeller, casing wear plates, and wear rings. Low or erratic pressure differences can indicate loose belts.
Managers must consider both in-house maintenance capabilities and company policy. Some managers opt to repair as long as the pump casing remains in good condition, which can be decades. Technicians simply replace rotating or worn parts as needed, and depending on the in-house maintenance shop, they may be able to make many of the needed parts.
One approach is that optimum service life occurs when cumulative maintenance labor and material costs equal a pump's replacement cost. Managers can use a formula to calculate a pump's optimum service life in hours and can compare optimum hours to actual operating hours.
An hour meter or service-hours recorder attached to the pump can help accurately determine actual hours. The service recorder is the best option because it accumulates operating hours and sorts them into idling hours and hours under load — valuable data for evaluating the effectiveness of the pump design. When actual hours exceed optimum hours, the unit is replaced.
Company financial policy also affects the repair-or-replace decision. Managers must expense parts for rebuilding in the year purchased, but they can capitalize and depreciate replacement pumps over several years. With either option, managers need to watch for upgrade possibilities to newer, more energy-efficient designs. Upgrading the design of a pump or drive can help defray the upfront costs through energy and reliability savings.