Measuring HVAC Airflow and Static Pressure: If You’re Not Collecting Data, You’re Just Guessing
Simply replacing HVAC equipment will not correct airflow performance issues. Rather, clearly identifying static pressure problems and correcting ductwork anomalies will. But to find the problems afflicting an HVAC system, you first need to know where to look and how. If you’re not collecting data you’re just guessing.
As static pressure increases, airflow will decrease. Almost all HVAC manufacturers design equipment to operate at a .5 TSP (total static pressure). Many residential HVAC systems usually operate at a higher TSP due to ductwork returns being undersized and supply ductwork having excessive flex ductwork runs, kinks, closed dampers etc., In fact, the average residential TSP is about .87.
In comparing static pressure with the manufacturer’s blower motor performance chart, HVAC contractors will often find that systems will be moving 100-250 CFM less than what is required. What this means is if a system is not moving the right amount of air at the right velocity, there will be a direct impact on suction, discharge pressure, sub-cooling, superheat, and across the heat exchanger. Without the right temperature rise, be prepared for heat exchanger failure. That is why taking a simple static pressure map of a few readings with a digital manometer on every service call is so important. It only takes a few minutes and will tell you everything about the system’s airflow. Many identified problems can be fairly easily corrected by either repairing or replacing sections of ductwork, correcting flex ductwork problems, opening dampers, etc., to deliver proper airflow throughout a home.
E.P. Homiek Sheet Metal & HVAC Supply hosts Testing, Adjusting and Balancing (TAB) seminars several times a year at our Lakewood and Union locations, bringing attention to HVAC equipment and the tight air flow and static pressure design tolerances at which they must operate. We will be announcing upcoming seminar dates in the near future.
About E.P. Homiek
E.P. Homiek Sheet Metal Fabrication & HVAC Supply, with two convenient locations in Lakewood, NJ and Union, NJ, provides one- to two-day turnaround on all residential and light commercial ductwork, as well as one- to two-hour emergency fabrication service, rapid delivery, and competitive prices. HVAC parts, supplies, and equipment lines include Goodman, Honeywell, Bryant, Bradford White, Crown Boiler, Daikin, Weil-McLain, Sea Breeze, Generac, Fantech, ZM, A.O. Smith, Hart & Cooley, Malco, Mueller, and many more.
