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HVAC School - For Techs, By Techs

Feb 16, 2022

Jim Bergmann returns to the HVAC School podcast live from AHR 2022 to discuss a bit about proper system commissioning. He explains the commissioning mindset and some helpful procedures.

Successful system commissioning starts with the mindset. A good commissioning organization broadens its vision; instead of focusing on the appliance, techs and installers focus on the system. Commissioning early on saves time later; you can focus on installs and maintenance instead of callbacks, and your organization can make more money as a result.

When installing and testing new piping, make sure you insulate the tubing properly and keep the lines CLOSED OFF to the atmosphere. Measuring the line set is also critical for weighing the charge properly, as long lines have special considerations.

When doing the decay test, use a quality vacuum rig and try to keep the micron gauge as far away from the pump as possible. Cleaning line sets also helps your vacuum results by getting rid of oil and moisture within the lines.

Flowing nitrogen while brazing and sweeping with nitrogen are two other important installation/commissioning practices. They may seem idealistic, but it’s easy to adopt these practices widely and reduce problematic scale buildup.

Methods for setting airflow have changed over time. Nowadays, the best practice is to take a volumetric flow measurement (such as with a TrueFlow grid).

Jim and Bryan also discuss:

  • Preventing callbacks and warranty returns
  • Evacuation and dehydration
  • Factory practices
  • One-hose evacuation with large hoses
  • Flushing the line sets with pigs
  • Nitrogen flow regulators
  • “Airflow before charging” and metering devices
  • Special considerations for MicroChannel coils


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