This Blog was posted by Smithson Valley Services Air Conditioning. We serve the Texas Hill Country, including Blanco | Bulverde | Canyon Lake | Fisher | Kendalia | New Braunfels | North San Antonio | Sattler | Sisterdale | Smithson Valley | Spring Branch | Startzville

On-Site Variable Air Volume Controls Training

Isn’t it Time You Gave Your Building A Tune-up? On-Site VAV Controls Training

No matter how long you’ve been in the HVAC business, there is always more to learn. Just when you think you’re getting close, you run into something new you’ve never seen before. Control systems are the same way. They are enhanced, upgraded, and modified all the time. The shear quantity of different system configurations and the different types of controls that can be put on them often confuse. This ultimately leads to some system performance problems in many buildings today. Service mechanics and building operators find it tough to keep up with all the design concepts and changes.

A system that highlights this syndrome is Variable Air Volume (VAV). It enjoys the growing popularity of being one of the most energy-efficient systems, but at the same time, it takes the bad rap of being a poor operating system. Problems can result from many areas like design, balancing, controls, filters, operators, etc.

We specialize in training mechanics and technicians to troubleshoot and properly calibrate automatic temperature controls and set up the VAV terminal units. The quality of a system’s performance often depends on the knowledge level of the people who operate it. So, if the people servicing or operating a VAV system do not know the system or how the controls work, they crank on the controller knobs to correct problems. Often, they turn into adjustments that have nothing to do with the problem and destroy the efficiency of a perfectly calibrated system. Understanding the theory and the calibration of components is essential to a well-tuned system. We conduct on-site, hands-on training sessions to show “how to’s” of calibrating components in a VAV system to achieve peak
performance.

Many perceived control problems are mechanical problems. Problems might include a simple flex duct blown off a collar up to a clogged airflow sensor. But, because of a mechanic’s lack of training, they begin turning screws and pushing slides on controllers because the symptom is assumed to be a control problem (let’s say the zone is too hot). After someone fiddles with the controls, the zone could still
be too hot. Needless to say, in any VAV system, there are many knobs to twist. This attempt to get the zone temperature back in control could result in a building full of tweaked knobs! By cranking on these knobs, the controls go out of calibration, resulting in energy waste and a building out of control. Before tweaking any knobs, consider training your technicians in the proper troubleshooting of VAV systems.

Even with Direct Digital Controls (DDC) becoming popular, most older jobs still use pneumatic controls to operate the VAV boxes. Today, there are more than 200 different types of VAV boxes. Manufacturers like Metal Air, Temp Master, Titus, and Trane, to name a few. There are also many varieties. These boxes can be pressure-dependent or pressure independent, including auxiliary fans which are parallel or series flow fans. Boxes might have heating; if they do, it could be electricity, hot water, or even steam. The valves could be Normally Open or Normally closed; thermostats can be Direct Acting or Reverse Acting . . . well, you get the idea – a wide variety of configurations. This is one of the big contributors to the confusion in VAV systems, which is made clearer in training.

Proper calibration of controls can be the single most important item in reaching the most energy-efficient system possible. Simple thermostat calibration and volume reset control settings should be performed yearly for the first step in a productive preventative maintenance program. These and other simple, “real world” step-by-step calibration instructions and training are available through
our company’s HVAC services.