Troubleshooting — Engineering 101
Do you have what it takes to solve and correct HVAC mysteries?
Back in July 2007, I wrote in this column on how troubleshooting can be a niche business, and it certainly has been for me over the years. As someone who used to design HVAC systems, along with a variety of other HVAC-related business opportunities, I have always found troubleshooting to be a fun thing to do. After all, hindsight is 20/20, so looking at a situation after the fact can bring a new perspective to the issue at-hand.
Sure, it takes years of experience to reach a point in your professional experience to take on this role, but once you get there, being contracted to resolve problematic HVAC issues and concerns is a great opportunity. At the same time, troubleshooting is not something any engineer can do, and I believe the skill level to do so requires the following:
Be proficient in HVAC design, construction, and operation and maintenance;
Be a good listener; listen-listen-listen;
Perception is reality but don’t believe everything you hear;
Experience with quality control steps helps prevent one from jumping to the solution based on his or her years of experience; and
Applying what I call Engineering 101 — collecting basic data and analyzing it before solution plans can be formatted.
Engineering 101 in my world is:
Long before the project kickoff, have a standardized checklist of things to do and questions to ask;
Ask questions and document these comments and/or perceptions;
Review record drawings and automatic temperature control record documents, too;
Review the original basis of design and design criteria if available and, if not available, document what is now believed to be the original basis of design; and
Create a system flow diagram based on the above. If the problematic system is an air system, collect and review the following:
- Past and/or current air balancing report(s);
- Review the equipment submittals and, in particular, the fan curve(s);
- Inspect the installation and document observations using a camera to capture existing conditions (a picture can be worth 1,000 words); and
- Review the fan curve and compare it to the air balancer’s report as well as the design criteria.
With this basic data at hand, one can begin to analyze the questions raised and assess whether the concern is a design issue, an installation issue, the result of a lack of commissioning, a change in basis of design, or some other issue. Wherever the direction this data collection and analysis takes the troubleshooter, having fundamentally sound facts, calculations, and reasoning will lead one to a solution plan that may include further test data collection and then recommended corrections before recommissioning or retro-commissioning the system(s).
Problematic HVAC installations arise from mistakes made by the designer or the contractor, but more often than not, new construction issues and concerns occur because the system wasn’t commissioned. If the problematic project is an existing HVAC installation, it may still be that the original system never got commissioned, or it may be the use of the facility has changed over the years so the basis of design and original design intent is in conflict with the current system operation.
Other reasons existing HVAC systems become problematic is that the automatic control set points, equipment schedules, etc. have been changed. Maybe the automatic control system had been switched over to manual operation sometime in the past and has remained in this manual mode of operation. For some reason, individuals often believe they can operate a building better themselves than the computers that are specifically assigned to do that job.
Another issue that often gets blended in with the HVAC problem is the question, “Who is at fault?” Some people are more focused on “who could have done this,” which delays the problem solving process until the individual can indentify the culprit. This is silly because of the amount of time and conversation that is wasted while the HVAC system continues to be problematic.
When troubleshooting an HVAC system, this problem solver should make sure this “Who done it” theme is put aside and that his or her attention is focused on the system. One can always return to this question if required, but in the meantime, it will contribute nothing to troubleshooting the problem.
Next month, I’ll continue discussing this topic, shifting our focus to waterside HVAC systems.