Chiller Challenge: Repair or Replace?

By Thomas Bakane, P.E.

The question of whether to repair or replace a chiller or cooling tower sometimes yields an expensive answer. To justify this capital investment, maintenance and engineering managers often compile a model of life-cycle costs to calculate a payback period for the up-front cost.

This model can be as complicated as a chiller itself, and many factors are difficult to translate into dollar figures. Buying new systems larger than existing ones might never have a payback period. But managers must carefully consider many factors beyond the first cost before deciding whether to replace or repair these systems.

Examining Life
The industry standard for chiller service life depends on the type of chiller, the degree of routine maintenance, and the unit’s loading and run-time hours. Even assuming average run conditions and adherence to recommended maintenance, typical service lives differ greatly. Small scroll chillers can last up to 10 years. Properly maintained screw chillers can have a performance life of 15-20 years. Water-cooled centrifugal chillers have been known to last more than 25 years.

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