Duct Work and Airflow Principles – Part 2 of the Airflow Series

Before we can apply the formulas in Part-1 of our multi-part series, it is important to understand a few more concepts… blower performance, duct performance, and system operating point. Duct Pressures The air pressures in residential ducts are very small. Usually less than 0.025 psi (either positive or negative). Because the pressures are so low,…

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Live HVAC Training Experiment – You’re Invited

Good Morning! I am continuing to experiment with Google Hangouts as a teaching tool. Recently, one of our students mentioned having a chat study session… which we are trying out. Another student asked for an explanation of a schematic diagram found in chapter 31 of our textbook. Google Hangouts let’s us do both. Also the first 9 participants…

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Residential Ductwork Friction Loss and Pressure Drop

Inadequate cooling and heating problems are commonly blamed on the equipment itself when the actual problem is poor/restrictive ductwork. Proper ductwork design is critical for proper heating and cooling performance. As our HVAC equipment becomes more sophisticated deficiencies in the ductwork system design become more critical. The new higher efficiency ECM motors work to try…

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Troubleshoot an HVAC System 24 Volt Problem With Confidence

Control Wiring Troubleshooting – 24 Volt Open Trying to troubleshoot control wiring is sometimes confusing and frustrating. But, if you have a step-by-step procedure it becomes easy and accurate. Below you find a procedure for troubleshooting a 24 volt open in an HVAC system. Symptoms – With 24 volts present one or more control circuits…

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HVAC Troubleshooting

Have you ever been out on a job and just needed a little help? Maybe, you know what’s wrong with the system but just need some reassurance. We have the answer! We have finally designed a mobile friendly website that has everything you need to troubleshoot faster, more accurately, and diagnose with confidence. The HVAC…

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