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HVAC School - For Techs, By Techs

Apr 21, 2022

This podcast is a class that Bryan taught for BTrained in Birmingham, AL. He covers troubleshooting, installation, and commissioning best practices with a focus on the fundamentals.

To be a good troubleshooter, you must be able to find the problem, identify the source of the problem, fix the problem, and optimize performance based on your data, the customer’s comments, and your observations. The Five Pillars of diagnosis aren’t comprehensive diagnostic or charging criteria, but they can help you charge or diagnose a system.

Isolation diagnosis works best for electrical components; you isolate the problem area from the system and see how the system works without the suspected issue. If the system operates normally without the component in question, then we can conclude that our hypothesis about the “problem” part was correct.

Wide-narrow-wide troubleshooting is an approach that allows you to inspect the entire system, zero in on the problem, and optimize the entire system. By starting wide, going narrow, and going wide again, you can troubleshoot holistically.

Installations take place in several phases: pre-planning, planning, demo, installation, and commissioning. Many people place a lot of emphasis on the demo and installation and neglect the conversations and procedures associated with pre-planning, planning, and commissioning.

Bryan also covers:

  • Heuristics and mental shortcuts
  • Evaporation vs. boiling
  • Rules of thumb
  • Head pressure, suction pressure, and compression ratio
  • Energy transfer fundamentals
  • What superheat and subcooling really indicate
  • Restrictions and temperature drop
  • Delta T
  • “Redneck” compressor test
  • Testing circuits
  • Useful measurements and test instrumentation
  • Causes of compressor failure
  • Measuring airflow
  • Low vs. high static pressure
  • Bringing tribal knowledge to building design
  • Ductless systems, ventilating dehumidification, and sensible heat ratio
  • Manual J, attics, and combustion air
  • Radiant barriers and heat transfer
  • Supply relative humidity
  • Dehumidifier configuration and system design
  • Bad envelopes
  • Vented attics
  • Duct upgrades
  • Total effective length and turning vanes
  • Evacuation


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