RE: How do you measure system airflow?
So much of what we do requires either measuring or approximating airflow measurement on the entire system (over the evaporator coil) what method or methods do you use?
If you absolutely had to get a system air measurement within 5% of reality on every call what method would you use?
I’d love one of those new Testo 440 setups. I used to do it based on Total External Static, however since I’ve gotten a hot wire anemometer that’s my go to now, using a timed-average traverse. I’ve compared results of static testing vs. hot wire and seems that my hot wire give me more repeatable results with greater accuracy. My static results tend be 8-10% higher than actual delivered CFM (probably because of no air density corrections that are built into the hot wire). If you would’ve said within a 10% accuracy, then I would say Total External Static. I would also add that testing with a hot-wire does not mean you shouldn’t also compare Total External Static, when commissioning, for equipment profiling.