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The ABCs of Air Handling Units

Air handling units are often confused with air conditioning units, but they are not the same. If you are responsible for overseeing your commercial property’s HVAC, it helps to have a basic understanding of this unit.

The air conditioning unit is made up of different components and one of them is the air handling unit. Air handling units’ condition and distribute air within a building. They take fresh ambient air from outside, clean it, heat it or cool it, maybe humidify it and then force it through some ductwork around to the designed areas within a building. Most units will have an additional duct run to then pull the used dirty air out of the rooms, back to the AHU, where a fan will discharge it back to atmosphere. Some of this return air might be recirculated back into the fresh air supply to save energy…

In addition to working with your AC unit, an AHU can be paired with a heat pump to help with warming. So it’s clear that the AHU is important in the process of cooling or heating your building and keeping your clients and employees comfortable. There are different types of air handling units based on the size of your HVAC unit, its location and what it can handle.

  • These small, terminal-type AHUs are referred to as fan coil units (FCUs) or blower coil units (BCUs), based on size and capacity. They generally have simple controls and serve a single zone within a building such as a loading dock or maybe a stairwell in a larger building. Although not universal, typical load capabilities for FCUs are 200 to 1200 cfm while BCUs might range from 400 to 3,000 cfm.
  • Slightly larger AHUs selected for outdoor use, located on grade outside or on the roof, are usually referred to as packaged units or rooftop units (RTUs), respectively. In addition to the components noted above, these units will typically have control dampers and serve larger areas or multiple zones within a building. The HVAC load capabilities of these units generally range from a few thousand cfm to tens of thousands. Read full post at CSE Mag…

You’ve probably noticed the rooftop units more than the other types of air handling units but many commercial properties use a combination tailor-made to suit their needs. Now that we have some knowledge of what air handling units are and the types, it’s important to learn how to keep them operating well for a long time.

An air handler maintenance technician will be able to perform the following.

  • Dismantle the air handler unit – Before beginning maintenance, the technician will make sure the A/C unit is turned off outside and the electrical panel at the air handler. Any coolant within the refrigerant lines will be retracted to avoid spills. Next, the refrigerant lines, condensation drain, the fan system and the air handler itself will be removed.
  • Clean the air handler unit – The air handler can then be cleaned with a vacuum and by using an antibacterial/antimicrobial solution. The technician will use a hose to rinse off the coils and then repeat the steps to the fan system.
  • Rebuild the air handler unit – To put the air handler back together, a new insulated duct board will be cut to size and secured with aluminum tape and plastic rib. Each seam can be further sealed with a coat of mastic adhesive cement. Afterward, the technician will replace and reattach the fan system, refrigerant lines and the condensation drain.
  • Give the finishing touches – Make sure your filter is changed at least once a year—more if you have pets and/or your family is prone to seasonal allergies.

So when it’s time for your annual HVAC maintenance, make sure the HVAC technician has not overlooked the air handler unit.

For professional HVAC maintenance services, call Dynamic Heating and Cooling today and speak to an expert HVAC contractor.

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