Testo 410 Question

[model m-man]

When using the 410 to check supply vent cfm's, do you use the vent opening size or the duct size for the conversion from fpm to cfm?

Any other uses you guy's have came up with?

[jim bergmann]

Use the free opening of the register for the measurement

More than CFM, you should be concerned with velocity. The velocity is the speed and the CFM the volume.

Air velocity should be measured and recorded at each registers part of the commissioning procedure on every job. While no technician can look at register and determine the CFM delivery required without knowledge of the design requirements, he or she can determine if the velocity is substantial enough to produce proper volume and throw, yet low enough that noise is not present. While a vane anemometer is typically not the tool of choice for measuring air volume at a register, it does provide invaluable information when performing balancing on the system.

On a properly designed system, each register will have equal terminal velocity (FPM), and the volume of air (CFM) will be a function of the register size. Each register should be sized to produce the proper volume velocity and throw required to properly mix the supplied air with that in the room. Low air velocity will result in stratification, and high velocity will result in objectionable noise.

Air velocities in residences typically are typically lower than that of hotels offices or stores due to background noise that overcomes that generated by airflow at the registers. Air velocity should also be high enough in main and branch ducts that dust does not settle and accumulate in the duct work and is instead carried through to where it can be removed by the air filtration system.

It is critical that velocity in each section of the ducting system be considered and designed for to achieve proper operation. When evaluation register performance, a timed mean traverse should be performed to calculate average velocity, and if desired CFM. When calculating the CFM, the K-factor of the grill or free area established to determine the actual CFM produced at the grill.

See the attachment

[beachtech]

When using the 410 to check supply vent cfm's, do you use the vent opening size or the duct size for the conversion from fpm to cfm?

Any other uses you guy's have came up with?

its best to take several readings acroos the surface of the register, add and then divide by number of readings and that will give you the average for that particular one :)

most returns i take 5-10 redings across the grill diagonally and on supplies i take 3-4 depending upon size :) its more accurate this way IMO

[jim bergmann]

No need for a 5-10 point traverse with the 410, it has a mean timed traverse function, as you move it across the grill it is taking a reading every 1/2 second then averages all of the readings. :D

[beachtech]

No need for a 5-10 point traverse with the 410, it has a mean timed traverse function, as you move it across the grill it is taking a reading every 1/2 second then averages all of the readings. :D

SOLD!!! my next tool!! and that thing isn't very expensive at 209 that includes WB temp :)

[weber]

SOLD!!! my next tool!! and that thing isn't very expensive at 209 that includes WB temp :)

The 410-2 has the wet bulb feature, this thing will even calc wind chill!

[model m-man]

Thank's Jim.

[DeHeatify]

Yes, thanks to the OP for the question and Jim for the answer. I have a 410-1 and found it very easy to use to read fpm for the grill in my son's room. Have been looking for other uses for it!