Tackling HVAC Deferred Maintenance

Work toward optimizing HVAC systems by implementing these practical solutions.

By Alan L. Wozniak, CIAQP, CIEC
From the December 2019 Issue

deferred maintenance
This HVAC technician is performing steam cleaning for coils in the HVAC system. (Photo: Pure Air Controls)

Deferred maintenance is a serious problem that often goes overlooked. While taking this approach may seem to save money, in reality, the hidden costs of deferred maintenance compound over time. Did you know that a Pacific Partners Consulting Group study showed $1 saved now costs $4 in capex later? Well, this is especially true for the HVAC system.

Putting off routine maintenance of the HVAC system impacts building operations and occupant safety. When one area of the system gets compromised, other parts are affected too. Let’s take a look at how these key areas create a chain reaction that leads to higher operating costs.

Indoor Air Quality (IAQ) Suffers

The main function of the HVAC system is to exchange air in a building and regulate comfort. Filters are responsible for keeping the air clean. If filters are not regularly changed, these become clogged. This restricts airflow and static pressure. So, particulates then find other ways into the air handling unit. This happens through gaps in the filter housing or worse, holes in the cabinet itself.

Particulates build up on the inside components of air handling units—the walls, blower motor housing, drain pan, and especially the evaporator coils. When coils get dirty, airflow and static pressure are again compromised. So, it is harder to regulate the temperature and humidity, or comfort, in the building.

This buildup also gets damp and becomes a food source for bacteria and fungi. When microbes spread so do foul odors, mold spores, and allergens. Then, building occupants could suffer from headaches, sinus congestion, and eye irritation. Or worse, they might experience allergen and asthma attacks.

Productivity Goes Down

It’s been proven that deferred maintenance causes indoor air quality issues that affect building occupants. Recent studies from Harvard/State University of New York found a correlation between indoor air quality and cognitive functions. This adds up to losses in productivity and an increase in sick days. The United States Centers for Disease Control estimates a loss of $60 billion dollars a year in productivity due to poor indoor air quality.

Energy Costs Rise

Deferring HVAC maintenance also degrades energy efficiency. Consider that 3/16 inch of fouling on the evaporator coils drops their efficiency by more than 20%. Dirty coils restrict airflow and static pressure, as well as altering the heat transfer rate. This makes the blower motor run longer in order to achieve the desired thermal set point. The change in heat transfer also compromises set points in the chilled water system which, in turn, further decreases energy efficiency.

System Failure

HVAC units under constant stress fail, plain and simple. Motors running longer wear out belts, bearings, and bushings. Clogged drain pans overflow and cause structural damage. Wiring might overheat or short circuit that could result in fires. Cooling lines crack and leak.

This causes flooding with a chilled water system. In a condenser system cracked lines cause gas leaks that present a safety issue to occupants. Each of these scenarios create major disruptions to operations. Not to mention the steady stream of work orders and additional costs to fix them.

What Can Be Done?

deferred maintenance
HVAC technicians are performing coil cleanliness verification testing. (Photo: Pure Air Controls)

Most think preventive maintenance programs are expensive. But, HVAC deferred maintenance really adds up in the long run. It’s like Benjamin Franklin once said, “An ounce of prevention is worth a pound of cure.” So, what are some practical things to do that keep HVAC systems optimized?

Mechanical Inventory

Believe it or not, many organizations do not keep a detailed inventory of their HVAC systems. This data often varies from building to building. A good inventory provides insights into the specifications, age, and history of equipment. This is helpful for routine maintenance, as well as planning for restoration or replacement. If you don’t have an inventory of HVAC equipment or it’s incomplete, now is the time to create or improve this information. This can be accomplished in a variety of ways including using a manual accounting ledger or with software solutions, of which there are plenty to choose from. It all depends on your organization’s technology needs and budget.

Conduct cleanliness and performance tests to report on the condition of HVAC units. These HVAC health assessments provide visibility for prioritizing and planning maintenance. This is especially useful when there are many air handler units in a facility or across a campus of buildings.

It helps identify and prevent potential problems. This service is an important step in recovering from deferred maintenance. Static pressure testing (both upstream and downstream from the coils), as well as airflow testing in cubic feet per minute can be conducted on a semi-annual or even quarterly schedule to ensure optimal operating conditions.

Air Handling Unit & Coil Cleaning

Routine cleaning of air handling units is important for good indoor air quality and energy efficiency. Conventional chemical spray methods do help with surficial cleaning and some odor control. However, steam cleaning methods use high temperature and low pressure to deep clean and disinfect equipment. There are many case studies and white papers that demonstrate pure steam coil cleaning effectively optimizes building health and equipment performance.

deferred maintenance
Before and After (top and bottom): Large Coils shown here “before and after” steam cleaning process. (Photos: Pure Air Controls)

Depending on the use of the facility and outcome of routine testing it is recommended that coils are cleaned on an annual basis. Products such as antimicrobial bio-enzyme treatments generally offer protection for up to one year.

Duct Cleaning

Cleaning ductwork after periods of deferred maintenance requires extra care. Be sure that the duct cleaning is focused on indoor air quality and engineered to prevent cross contamination. The process must clean every component associated with the duct system. This includes VAV terminals and reheat coils that are often ignored or are not written into the specification. It is also recommended to hire NADCA (National Air Duct Cleaners Association)-certified duct cleaning professionals. Duct cleaning should be considered on an annual or bi-annual basis. Of course, this depends on the building use. Again, routine HVAC system testing will provide visibility into duct cleanliness.

HVAC Restoration

Some building owners and managers think they need to replace all aging HVAC equipment. This is simply not true. The mechanical inventory and an HVAC assessment provides data for restoration or replacement. HVAC restoration is viable option that is much less than the cost of replacement. A total restoration should include steam cleaning along with specialized coatings, pan liners, and insulation.

Before and After (top and bottom: VAV terminal coils in this HVAC system underwent a duct cleaning. (Photos: Pure Air Controls)

Other upgrades such as ECM fan array retrofits can greatly increase the energy efficiency and longevity of HVAC equipment. ECM, or DC, fan motors operate in tandem with one another and are variable speed. These replace the AC motor and giant blower wheel. Multiple ECM fans are configured in a wall to provide the same cubic feet per minute as the old blower. If one of the ECM fans fail, the others in the array make up the difference until the fan can be replaced. Finally, with restoration there is no need for redesign, disruption, temporary cooling, and equipment disposal.

HVAC systems are key to maintaining optimized building operations and occupant health. There are quite a few cost-effective solutions available to routinely manage HVAC cleanliness and performance. It should be incumbent upon facility executives to make these into best practices, so that HVAC deferred maintenance becomes a thing of the past.

Wozniak is the CEO for Pure Air Control Services, Inc. Since 1984 Pure Air Control Services has performed IAQ and HVAC restoration services across over 600 million square feet in more than 12,000 buildings worldwide.

Do you have a comment? Share your thoughts in the Comments section below or send an e-mail to the Editor at acosgrove@groupc.com.

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