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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Testing HVAC Static Pressure

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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Chances are high that you’ve encountered disastrous equipment replacement jobs you’d love to forget. Whether it’s the customer who now has high humidity issues, or the system that can’t maintain temperature anymore — we’ve all experienced them. Indeed, in many of these occurrences, attention to detail and avoiding bad industry habits helps prevent the occasional …
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Challenge is measuring static pressure on a variable speed fan

Measuring static pressure on air handling equipment that has variable-speed fans can be a challenge to both new and experienced technicians. By addressing a few details, your readings will be consistent when you encounter this blower type. Let’s look at three tips you can use the next time you measure static pressure on a variable-speed …
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Stacked pebbles represent stability in HVAC systems

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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Heat Transfer explained

or So what exactly is combustion energy and heat transfer anyway? This article is based on more than 30 years of field testing, measuring, and auditing equipment performance. Although some of the information requires interpretation, it’s still based on proven field performance. What is Combustion Energy? Combustion is the burning of some kind of fuel …
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Measuring static pressure

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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It is often taught that to diagnose a restrictive air filter is as simple as a visual inspection to see if it’s plugged. Then, if the filter is dirty, replace it. Once this obvious defect is fixed, everything is assumed to work correctly. Could there be more to it? What if the new air filter …
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