HVAC contractors share tips for servicing variable refrigerant flow systems
As the American market becomes more familiar with variable refrigerant flow (VRF) systems, it’s discovering firsthand the technology’s ability to deliver exceptional comfort with lower life cycle costs.
Additionally, contractors are touting the ability to perform maintenance on systems individually, allowing them to fix a problem without disrupting the comfort delivered to the remainder of the facility.
According to a study by the Pacific Northwest National Laboratory for the General Services Administration (GSA), regular maintenance on VRF systems consists of changing filters and cleaning coils for the fan coil units. Additionally, maintenance of the compressor unit is minimal, allowing significant maintenance savings for that part of the system compared to chilled water and hot water plant equipment.
“VRF systems don’t require service like competing technologies,” said Matthew Kuntz, vice president of Jupiter-Tequesta Air Conditioning, Plumbing & Electric Inc. in Tequesta, Florida. “The time needed to perform maintenance on a VRF system versus the other options is far less from a labor and materials standpoint. If you’re only maintaining one or two condensing units versus one per traditional air handler, you can see how the time savings adds up fast.”
However, regular maintenance is still important, Kuntz noted. “Like any mechanical system, semiannual maintenance is very important to maintain the life cycle of any system. The main reasons systems fail is from lack of maintenance. So maintenance is ultra-important.”
Dominic Freschi, owner of Freschi Service Experts in Antioch, California, said periodic maintenance is necessary on all HVAC systems.
“It’s no more or less so with VRF systems,” he explained. “Maintenance helps ensure the longevity, efficiency, and reliability of the system.”
Rick Boucher, technical advisor at Comfort Supply Inc. in Pittsburgh, said regular maintenance is actually critical for VRF systems.
“Some people tend to neglect regular maintenance because VRF systems tend to be very reliable,” Boucher said. “System performance and energy efficiency are the first to go without regular maintenance. This affects the customers’ bottom lines and their perception of the product and the contractor.”
According to Freschi, a common problem he observes with VRF systems stems from installation errors.
“The most common issue we see is contractors not following standard industry practices during the installation process. It’s important for consumers to hire reputable contractors. There are no specific common failure points of VRF equipment. They are as reliable as any HVAC system, provided the equipment is installed and maintained properly.”
Kuntz agreed, saying he runs into very few problems with VRF systems.
“Power surges cause the most issues,” he explained. “Probably the most common cause of failure on a VRF system occurs on the circuit boards.”
Boucher said a lack of filter maintenance is “probably the single most common maintenance-related problem on VRF systems.”
“The total static pressure on these systems is typically less than that of a traditional system,” Boucher continued. “This leads to greater performance issues and loss of energy efficiency. Refrigerant leaks in the system are probably a close second. Mechanical failures are also common causes of failure. All of these issues are absolutely preventable when caught early on through regular maintenance. It starts with proper installation techniques. With regular maintenance, refrigerant leaks can be identified and repairs can be made before system efficiency is affected greatly. Our most successful contractors make use of our tools, like the Mitsubishi Maintenance Tool, for logging and checking system performance. This helps identify issues before they become critical.”
So, what are some best practices when it comes to VRF maintenance?
Freschi noted it is imperative for contractors to follow manufacturers’ installation guidelines. “They also need to pressure-test and evacuate the refrigerant system to ensure the field-installed piping is sound,” he added.
Kuntz said his technicians follow a list of best practices that includes making sure all parts of the system are free from dust and buildup. “We also make sure they are bonded for electrical surges to prevent issues during storms.”
“The most successful contractors we work with offer regular maintenance to their customers from day one,” Boucher added. “Communicating the benefits to the customer is a skill that can and should be taught to all contractors.”