This article emphasizes the importance of proactive maintenance for HVAC systems amidst rising costs for utilities, labor, and equipment. It argues that effective maintenance begins during the design phase, where equipment accessibility and ease of maintenance must be prioritized. This involves ensuring that systems are not only easy to reach but also well-ventilated and protected from elements that could cause damage. Once systems are operational, it’s crucial to establish performance baselines through monitoring key metrics such as flow rates, temperatures, motor amperage, and vibrations. The article also highlights the significance of regular visual, audible, and measurable checks to detect early signs of wear or malfunction. It concludes that, while manufacturers’ guidelines are important, a tailored maintenance approach is necessary to extend equipment lifespan, improve efficiency, and reduce long-term costs.
Is Your HVAC System Telling You Something?
With the rapidly increasing costs of utilities, labor and equipment, it is imperative now more than ever for HVAC plant owners and operators to have a proactive maintenance program in place to maximize the useful life and efficiency of their equipment.
This does not begin when the various systems are brought online for the first time. Rather, it’s during the design phase that considerations must be made for the maintainability of equipment and various components.
Critical to the process is accessibility. Equipment with access situated in notso-ideal locations won’t be observed as often as equipment situated to be conducive to inspection and maintenance. The old adage, “The squeaky wheel gets the grease,” has no place when it comes to equipment maintenance, as it’s usually too late at that point and failure is impending.
Though designers and contractors would prefer systems to be sited in a building’s lobby or great room for all to marvel at, that’s usually never the case. Instead, systems are relegated to the bowels or roof of buildings, only to be visited and tended to by the most diligent of staff – the maintenance department.
The modern marvels that provide us comfort and improved environmental quality are true works of art – not a building’s paintings, sculptures and surface treatments that we find instead in these public areas. But I digress.
We’re then left with having to make the most of areas assigned for siting equipment. Not only is accessibility critical, but so is the ability to ventilate, attenuate vibration, attenuate sound (a form of vibration) and minimize exposure to elements and contaminants that may promote corrosion and wear.
Now that a new system has been designed, built and commissioned, it’s time to throw the switch and bring them online. Just because the equipment is shiny and new (and under the contractor’s warranty), this is not the time to be complacent. It’s the ideal time to establish baselines against which to compare future operating characteristics.
These characteristics can be broken down into three categories: measurables, audibles and visuals.
MEASURABLES
The commissioning report or final test and balance report contains a wealth of information against which to judge future performance and determine if the symptoms or deviations are indicative of possible component failure or require deeper investigation.
Variations of fluid (air or water) flow rates, temperatures and pressures are fundamental indicators that operation is not as designed. Increased fouling rate of air filters may indicate an unforeseen source of room or outside air contamination which may be addressable or may prompt an increase in filter replacement frequency.
Regular lubricant testing will establish trends which may preempt the premature failure of internal components of rotating equipment. Amperage recording of motors and actuators is a clear indicator of whether a component is operating nominally or is working harder to maintain setpoints.
Thermal or infrared radiation measurement guns, also known as FLIR thermal cameras, allow the plant operator to quickly scan the plant and check for abnormal equipment temperatures. Hot electrical panels may be an indication of connection or current issues within.
Elevated motor temperatures, if not addressed, may lead to winding damage and eventual motor failure. Areas of insulation of pipe and ductwork showing to be hotter/cooler than adjacent insulation may indicate leakage or insulation failure.
Regular testing and verification of PH, free oxygen and additives in chilled and condenser water distribution systems prevents pipe and control valve corrosion from within and minimizes fluid flow friction.
Pressure gauges and thermometers give the plant operator instant feedback of the system condition; however, they must be periodically verified as to their accuracy. The constant cycling and vibrations to which these analogue gauges are subject has a degrading effect on accuracy. In many cases the gauges present are from the original installation.
Incorporating a test port or Pete’s Plug adjacent to these gauges allows for the insertion of a calibrated gauge or probe to confirm their accuracy and, therefore, provide confidence that the observed measurement is a true indication of the system condition.
AUDIBLES
Our hearing is an incredible tool. The sounds of fans, compressors, pumps or the HVAC plant in general are unique and an attentive operator will notice subtleties in pitch and amplitude of sounds made by the machinery. These audible variations should lead to a deeper investigation as to their cause.
There is a limit to what the human ear can discern, however, and instrumentation should be used to measure and record critical equipment vibration signatures. Over time, trends will be established which may preempt component failure.
VISUALS
Beyond the obvious status indicator lamps of equipment control panels there are many visual clues that may indicate potential issues with the HVAC plant systems.
Discoloration of equipment panels is an indication of overheating. Staining of ceiling or wall surfaces is a clear indicator of fluid leaks of piping or failed insulation of concealed systems. Pealing or flaking paint may indicate the beginnings of corrosion. Spalling of concrete is a symptom of reinforcement corrosion within the support structure.
We’ve all witnessed how the warm, humid and saline environment of Hawai’i propagates corrosion and if left unchecked will grow to the point of compromising the equipment function and support assemblies.
ADAPT
The operation and maintenance manual prepared and provided by the installing contractor in a culmination of all equipment data sheets includes recommended maintenance procedures and frequencies recommended by the respective manufacturers.
To avoid warranty issues, these recommendations need to be adhered to but are not the sole basis upon which to establish an effective preventative maintenance program.
Like ourselves, HVAC systems develop areas that require more attention than others as they age. It’s delusional to assume systems will have an infinite lifespan, so plant operators must strive to maximize a system’s or component’s useful life and operational efficiency while also minimizing costs.
