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Commercial HVAC Troubleshooting

December 12, 2012 | 2 comments

Your commercial building’s HVAC system does more than keep temperatures consistent – it can affect tenant/occupant satisfaction, productivity levels, tenant/occupant health and wellbeing, and energy bills.

 HVAC maintenance is a crucial part of ensuring that the system functions properly and efficiently. But even the most well-maintained equipment will present challenges to facilities managers.

To help you with HVAC troubleshooting, check out this list of three common commercial HVAC problems and how to solve them:

Problem #1: Odors or Poor IAQ

Complaints of odors or poor indoor air quality (IAQ) can indicate something as simple as a dirty air filter, or something as problematic as a gas leak. The most common causes of odors from the HVAC system include parts overheating, debris melting on the heat exchanger after being pulled into ductwork, dirty air filters, and condensed water that has become stagnant. Check for these items first, and correct them; if you can’t find the source of the odor, it may be time to call a professional.

Problem #2: Inconsistent Airflow

Cracks or holes in ductwork can be difficult to see, but they may be the cause of varying temperatures from room to room. Leaking ductwork can also cause sudden jumps in energy bills if temperatures are being adjusted to make up for the lack of airflow. Look for cracking, separating, or sagging ductwork; if you see any of these things, your ductwork is leaking. (If your ductwork is insulated, dirty spots on the insulation can also indicate leaks.) A U.S. Department of Energy report states that a typical duct system can lose as much as 25% to 40% of the air produced by an HVAC system. Much of this loss can be corrected if leaks are fixed. Because it can be hard to identify all the sources of leakage, it’s recommended that an HVAC professional locate and fix the problems.

Problem #3: Losing Efficiency

If your HVAC system doesn’t seem to be as efficient as it once was, don’t assume you need to replace it or perform a massive retrofit. Pacific Gas & Electric (PG&E) completed a study showing that the efficiency of a 10-ton package unit can be improved by up to 16% through cleaning the evaporator and condenser coils. Plan to clean the coils twice a year.

Another PG&E study found that, upon looking at 13 HVAC units, not one of them had properly operating dampers, which can increase utility consumption and negatively affect IAQ. Dampers keep the compressor from running when the outside air temperature is below a certain point. If they aren’t clean and well-lubricated, they stick, which robs the unit of free cooling potential or overloads the cooling coil with too much hot outside air. Check a few times a year to make sure the dampers are operating properly.

 Have you experienced any of these HVAC problems?  How did you fix them?


  1. Joel
    December 14, 2012

    Nice write up. I have personally witnessed all three problems in my 3 years as HVAC manager for a pharma company. We found ductwork that was totally separated and then wrapped over with insulation, and a return that was broken inside the wall and caused positive pressure in the wall relative to the aseptic suite. Mold, missing and broken supply fan fins, broken dampers pushed down into ductwork, etc. Many of these issues were found upon qualifying the system and inspecting the ductwork and drawings. Companies should pay a little extra up front to have the systems inspected, it will save money in the short and long run.

  2. Vista
    October 23, 2013

    Hi Joel, glad you agree with this! It’s amazing what you find behind-the-scenes that can affect efficiency.

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