Air filters create resistance to airflow that can reduce a fan’s ability to move air by up to 50%. You can evaluate the filter’s impact on airflow by measuring the pressure drop over it. It takes less than a minute to do. It is often the diagnostic test that identifies the problem in nearly one …
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What makes modular or two-piece different from their single-piece cousins when it comes to measuring total external static pressure (TESP)? In this article we’ll examine the differences and discuss how to measure TESP correctly. “As-Shipped” The “As-Shipped” idea is helpful when measuring the TESP of two-piece air handlers. So, what do you find when you …
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I hear a lot of reasons for taking static pressure measurements on every service call. One of the most common is that it takes too long — there isn’t enough time on a call to do it. Let’s face it, technicians have a lot of responsibilities and measuring static pressure adds to them. What if …
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Many homeowners across the U.S. live in uncomfortable conditions. Sadly, most are convinced it’s normal. As an HVAC contractor, there are some common steps you can take to deal with their discomfort, and make conditions much more bearable. If you know what to look for, you can easily see the signs. Let’s look at the …
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When replacing HVAC equipment, better service companies offer duct upsize and system performance upgrades as an option to their customers. These upgrades allow the duct system to perform closer to the level of efficiency claimed by the equipment manufacturer. Let’s take a look at the steps necessary to effectively upsize a residential duct system. Why …
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Many technicians get distressed when they measure draft pressure in the flue and discover the reading is zero. Let’s look at three common reasons for zero draft pressure in a flue. We’ll also determine what defect you’re dealing with. Reason #1: Zero Draft from Building Depressurization Building depressurization is probably the most common reason for …
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When testing and diagnosing the operation and performance of an HVAC system, the timing and measurement are critical. Ideally, the system should be calling for full heating or cooling, and fan speed so it can reach a stable operating condition. Let’s take a closer look at what constitutes stable operating conditions so your test data …
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Flex ducts could be in imminent danger. A few months ago, I wrote about a recent proposal to severely limit the use of flexible (flex) ducts. Due to poor installation methods, the International Association of Plumbing and Mechanical Officials (IAPMO) is proposing to limit use of flexible duct to only five feet in length. How …
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Like blood pressure in humans, static pressure impacts HVAC systems, positively or negatively, depending on what that pressure is. We all know that high or low pressure is bad for human health. The same is true when it comes to building static pressure as well. Taking a building’s static pressure lets you “see” the HVAC …
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There is so much more to installing a static pressure testing port than meets the eye. It involves drilling – a scary thing for both your service technicians and homeowner customers. The art of installing these ports involves more than the hardware and technology required to do it. There is a psychology to it. It …
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