Reading Duct Velocity Pressure, CFM and Static with a Testo 510i and a Pitot Tube

This video shows you how to use a Testo 510i with the Testo Smart Probes App and a pitot tube to read duct velocity and CFM. Unlike a static pressure tip, a pitot tube has a hole. That hole accounts for velocity, and additional holes account for static pressure. You get velocity by taking the total pressure and subtracting the static pressure.

Velocity changes at different points of the duct. So, we must perform a duct traverse to read at various points of the duct and average out our readings. Alternatively, you could perform a timed average traverse where software takes readings as you're pulling the pitot tube through the duct. Pitot tubes must be inserted all the way into the duct for the most accurate measurements.

Pitot tubes connect to the Testo 510i with hoses. It is best to make sure that your hoses are 4-8 feet long. Connect the hoses to the static and total pressure ends appropriately. Then, connect the hoses to the Testo 510i ports on the positive and negative sides as appropriate.

When taking duct measurements, think about the duct's anatomy to set up the best possible testing conditions. For example, you'll want to try to stay away from transitions to limit turbulence. It is easy to make holes for a duct traverse in a round duct. Profile your duct in the Testo Smart Probes app and set your testing mode and parameters.

When you insert the pitot tube and are ready for testing, press the "play" button on the Testo Smart Probes App and pull the tube out slowly. In this case, Bryan pulls out the tube in about 13 seconds. After you've finished taking your measurements, the "stop" button on the app will give you your measurements. You can use your airflow and CFM measurements to calculate enthalpy and velocity.

[jimboblio]

Brian, this forms a great intro to the Testo 510i and pitot tube!  Can you tell us the minimum duct  diameter the app permits?

[FooDaki]

bryan i cant thank you enough for you free content, learned more in your videos that my actually trade school

[cubbymcelrath]

Great information Bryan
Thank you guys for your time and effort to better the industry
As a technician and electrician one of the hardest arguments that we get is “it’s working or it’s worked that way for years”
You guys are giving us the knowledge and information to know and act otherwise
Thanks so much

[maazkhan-tcir]

Can u please make a vedio about static pressure and it's importance in Hvac, like it's exact definition, how to maintain, how to measure ? Why it is needed ? Difference between static pressure and external static pressure??

[sincityhvacr]

great videos great explanation thank you for your time with these videos and the podcast, i live in Los Angeles i get stuck in traffic all the time so i always listen to your podcasts
i have a question am going for the refrigeration side am just wondering do u have any podcast about how to adjust pressure switches on refrigeration units ?
thank you

[hangngoaigiare]

236 cfm - 173cfm thats a huge different? can u compare using vane anemometer

[kgainer]

236, 173, and 188 CFM are not in the "same" range", not even close. That's a variance exceeding 25%.

[idrisallen]

Can you re-do this with the testosterone hot wire probe?

[davids]

Which app do you use that shows barometric pressure in PSI? The only ones I can find all show inHG and I can't find a conversion chart that converts inHG to PSI.

[waitjustaminute]

That 8" sure looks like 10" to me

[NOBOX]

This tool sucks, give 50 cfm first try and 4 cfm the next WTH man

[TheZooBrooksAB]

This seems like a dumb system. I can think of a much better way to test airflow.