A little background on myself... I'm mechanical engineering student doing my third 6-month coop as a mechanical design engineer. I worked as a tech/engineer for Siemens last year, so I have some field experience with controls, but am a little foggy.
I've been asking around my office about VAV box minimum airflows, but can never get a straight answer. We use a 40% rule of thumb for boxes with reheat, and 25-40%(depending on who you ask) for cooling only boxes. I know the lower limit for a VAV box (from box manf.) is based on the velocity transducer in the controls. I also know that a minimum can go below this and still work fine. It might hunt a little more, and is more likely to have problems, but will work.
What is a realistic minimum for a box? How low can you actually go and have the unit still control for typical pneumatic and DDC setups?
Thanks in advance..