Clark's Remarks

If It Ain’t Broke, (Sometimes) Fix It!

Planned replacement is best utilized in IT. Our industry can use many of the same criteria in designing a replacement program for mechanical equipment and controls.

“If it ain’t broke, don’t fix it!” How many times have we heard that expression? And yet how often is that our advice to our clients? Can you imagine a HVAC service company telling a customer to ignore an obviously frayed and brittle V-belt and not replace it until it breaks? In some industries, a failure can be catastrophic, so replacement before failure is a standard best practice. In our industry, however, it is rare. Why is that?


Most probably would agree it’s a matter of cost. Yet, often, there’s a higher cost associated with allowing equipment to fail. In the case of manufacturing, for instance, the cost can be thousands of dollars an hour. Often, however, the cost is more than economic, with morale, reputation, relationships, comfort, and even health at stake. Consider the repercussions of an air-conditioning failure in a critical application such as a data center or hospital operating room.

Often, the solution to avoiding downtime is to stock critical or long-lead-time parts that commonly fail, but that’s not very practical for expensive components or components with a limited shelf life. When there is a failure, then, owners end up paying for overnight delivery and weekend (premium labor rate) installation of an aftermarket part, often with a shorter warranty period. How many times should they go through that before they replace the unit?

Justification for a planned replacement obviously requires an economic advantage (i.e., an overall cost lower than that of an unexpected replacement). Also, it should provide an improvement in overall reliability. In other words, a planned replacement must reduce the likelihood of system or equipment failure. Preventive maintenance (PM)—generally planned or scheduled maintenance—is widely accepted in the HVAC industry. For larger or more sophisticated systems, a condition-based maintenance program also may be in place. Key to any equipment-maintenance or replacement program is a vigorous PM program. PM long has been recognized to not only extend the useful economic life of equipment, but improve efficiency. And there is real value in reducing unplanned service incidents, whether self-performed or outsourced. ASHRAE considers maintenance management important enough that it devotes much of Chapter 39 of 2011 ASHRAE Handbook—HVAC Applications to the subject.

Planned replacement arguably is best utilized in the information-technology world. With computer technology advancing at such a rapid pace, staying ahead of obsolescence—not just equipment failure—requires a formal plan for ongoing replacement. Our industry can use many of the same criteria, such as implementing an adequate budget strategy and installation scheduling to avoid areas being without necessary equipment at critical times, in designing a replacement program for mechanical equipment and controls. Who will be responsible for developing and managing a planned replacement program—whether an individual or a department—also must be given careful consideration.

The bottom line? Sometimes spending ahead of time helps the bottom line!

Discuss this Blog Entry 1

on Dec 11, 2013

Larry, Please explain this to 98% of the clients. To engineers, this is preaching to the choir ... in most cases. I was talking to some investors about maintance the other day. They don't care. When it breaks, they fix it. NOW, if this was made a requirement in LEED/Green buildings in order to maintain certification, then we could make some headway in educating people. How long did it take for VFDs to become "standard" and how often is it STILL misapplied?

Please or Register to post comments.

What's Clark's Remarks?

The thoughts and musings of Lawrence (Larry) Clark, principal of Sustainable Performance Solutions LLC.


Lawrence (Larry) Clark, QCxP, GGP, LEED AP+

A member of HPAC Engineering’s Editorial Advisory Board, Lawrence (Larry) Clark, QCxP, GGP, LEED AP+, is principal of Sustainable Performance Solutions LLC, a South Florida-based engineering...
Blog Archive

Sponsored Introduction Continue on to (or wait seconds) ×