Heat exchangers

The connections between a furnace and duct system are rarely considered as a cause of cracked heat exchangers. Commonly repeated mistakes with return and supply duct connections significantly impact airflow and the length of time before you’re back for repairs. Let’s look at some these issues that may be killing airflow and the heat exchangers …
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CO - What Do You Know?

Many HVAC professionals assume the leading cause of carbon monoxide (CO) poisoning is a cracked heat exchanger. This assumption leads to inaccurate test methods that pass on from technician to technician. They try to assure customer safety, but unknowingly rely on misinformation. No one wins in this scenario — both the contractor and customer have …
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Avoid sharp turns

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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Carbon monoxide (CO) poisoning is one of those scary issues that most HVAC professionals hope to never encounter. As with many frightening things we want to avoid, this doesn’t make those issues go away. The threat is very real even though contractors often turn a blind eye to it. With all the stories and reports …
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HVAC Airflow and leaf blowing -- the common denominator

Let’s talk airflow. We live back in the woods on a half-acre with fifteen 100-foot tall oak trees. For years I’ve imagined sharing leaf blowing airflow lessons with my fellow airheads. Let’s take a look at the mad airflow skills you can master while blowing leaves. Fascinating Statistics “If you don’t measure, you’re just guessing.” …
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Benchmarking

Responses from an article on benchmarking that ran in Contracting Business.com magazine’s Hotmail email newsletter nearly a year ago continue to appear in my inbox. This new field evaluation and test method is being included in progressive service and maintenance agreements throughout the industry. It is proving as beneficial to customers as it is for …
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Flex duct cost savings

Flex duct versus metallic duct: for decades many considered duct material the key to how well an HVAC system delivers airflow to the conditioned space. You should start paying closer attention to this discussion. Events unfolding over the next few months could ultimately determine how much flexible duct you will be allowed to use when …
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When it comes to duct work, there’s lots of discussion  kicking around about them being substantially undersized. Here’s a two-minute test that can check the size and performance of your duct system. The instruments are inexpensive and it takes less than 10 minutes to learn to do. Tons of Air Static pressure is a measurement …
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Airflow has its own Bermuda Triangle

Airflow. It’s in our ventilation sytems. It’s the media through which our weather works. Off the South-Eastern coast of the United States, bounded by Miami (in Florida), San Juan (in Puerto Rico), and the north-Atlantic island of Bermuda, is an area known as the Bermuda Triangle. For years many ships and planes inexplicably disappeared when …
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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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