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Accepting reports that the DC6000 is rated at 200CFM at any one of the three 2 1/2" ports what air flow rate (ft/min) measured with a cheap anemometer should we see.

A just bought an anemometer and am totally confused by what I see. What should I expect the air flow rate to be with a single port open?

dusty wrote: ↑Sat Nov 26, 2022 12:53 pm Accepting reports that the DC6000 is rated at 200CFM at any one of the three 2 1/2" ports what air flow rate (ft/min) meaured with a cheap anemometer)should be see.

A just bought an anemometer and am totally confused by what I see. What should I expect the air flow rate to be with a single port open?

Dusty,

Did you adjust the area parameter for the anemometer? Most of these instruments ONLY measure air speed (fpm) and then calculate airflow (CFM) based on what area you enter for the measurement. IF you are using 2-1/2" hoses, these have an ID of only 2-1/4". The cross sectional area of this is 0.028 ft² which is what you enter into the anemometer for calculating airflow through a 2-1/2" hose to calculate airflow in CFM units. Also double check units on the anemometer, e.g. inches vs. feet and metric vs. Imperial.

RFGuy wrote: ↑Sat Nov 26, 2022 12:57 pm

dusty wrote: ↑Sat Nov 26, 2022 12:53 pm Accepting reports that the DC6000 is rated at 200CFM at any one of the three 2 1/2" ports what air flow rate (ft/min) meaured with a cheap anemometer)should be see.

A just bought an anemometer and am totally confused by what I see. What should I expect the air flow rate to be with a single port open?

Dusty,

Did you adjust the area parameter for the anemometer? Most of these instruments ONLY measure air speed (fpm) and then calculate airflow (CFM) based on what area you enter for the measurement. IF you are using 2-1/2" hoses, these have an ID of only 2-1/4". The cross sectional area of this is 0.028 ft² which is what you enter into the anemometer for calculating airflow through a 2-1/2" hose to calculate airflow in CFM units. Also double check units on the anemometer, e.g. inches vs. feet and metric vs. Imperial.

This may well be my problem - ignorance. I thought it did when I ordered it but mine does not display CFM. I get air speed only expressed in ft/min, mph, knots/hr, etc. It reads 511.8 ft/min

14.33 CFM ????

WHAT IS THE AREA OF THE FAN APERATURE?

dusty wrote: ↑Sat Nov 26, 2022 2:04 pm This may well be my problem - ignorance. I thought it did when I ordered it but mine does not display CFM. I get air speed only expressed in ft/min, mph, knots/hr, etc. It reads 511.8 ft/min

Dusty,

I am not sure, but I still wonder about the units and how many different types of measurements your anemometer may be capable of. For example, when I zoom in on your picture, I see the unit of "bft" at the top. This is not a standard measurement unit and refers to the Beaufort scale (https://en.wikipedia.org/wiki/Beaufort_scale). What is confusing is that the Beaufort scale has no units, but the display shows ft/min next to it so I am not sure that the 511.8ft/min is correct. Can you try cycling through the "UNIT" button when taking a measurement and see what all of the choices are? Also, if you could scan the instruction manual and post it here, I might be able to help more. I tried looking online and could not find an instruction manual for the AOPUTTRIVER AP-007.

I looked at the Amazon webpage and it is confusing as it lists CFM in several places, but if you look at the comparison chart below it indicates that your model (AP-007) does NOT have CFM calculation, but their AP-866, AP-856 models do. It really doesn't matter for CFM because you can easily calculate it. You just need to find the UNIT setting on your anemometer that corresponds with measuring windspeed in fpm setting, but I question that you are in this mode since it shows the "bft" indicator on the top of the LCD display in your pic. Try cycling through "UNIT" on the device and see how many choices there are.

Honestly, it is easier to just measure airspeed (fpm), so I wouldn't worry that your model doesn't calculate CFM. That way you can switch between measurements such as 2-1/4" port, 4" hose, etc. more easily. Airspeed is always the same, whereas CFM is a calculation based on a particular aperture size. I stopped using the CFM calculation on mine and always do the conversion manually at my computer.

Attached is a PDF of the instruction manual.

The five units are:
M/s, Ft/Min, Knots, Km/h and Mph.

Ft/Min 59-5905 ???

Dusty,

Thanks. Unfortunately the manual doesn't help much because it doesn't talk about the "bft" mode/function. In the pic below you can see that you have some "bft" function turned on for the meter and I can't tell you whether your reading is right or not. I looked up other anemometers. There are many different brands out of China and they basically copy each other, which is why many of them look almost identical externally. I have seen other anemometers (copies of yours or vice-versa) listed where they say things like "6 wind speed units for selection: m/s, km/h, ft/min, knots, mph, bft", so I think that bft is another mode/function on the anemometer. Can you try to change the settings on the anemometer to see if you can get that "bft" on the top of the LCD turned off? If you can do this AND get the units to show "ft/min" then I would be more inclined to believe/trust the measurement you are getting.

I wondered about that. The Beauford Scale, originally from 0-12, was modified to include 13 -17 to facilitate measurements up to 64 knots. I believe this instrument is so annotated to indicate it is capable of those higher speeds. Not certain but will assume that for the moment.

As for my readings - I doubt all of them. I suspect that my testing was haphazard. I need to set up better to ensure good and consistent coupling between the DC6000 hose and the anemometer.

Thanks for your feedback. It has helped.

dusty wrote: ↑Sun Nov 27, 2022 7:58 am I wondered about that. The Beauford Scale, originally from 0-12, was modified to include 13 -17 to facilitate measurements up to 64 knots. I believe this instrument is so annotated to indicate it is capable of those higher speeds. Not certain but will assume that for the moment.

As for my readings - I doubt all of them. I suspect that my testing was haphazard. I need to set up better to ensure good and consistent coupling between the DC6000 hose and the anemometer.

Thanks for your feedback. It has helped.

Dusty,

Yeah, you have to try to seal as much as you can around the sides of the anemometer and whatever you are testing. Either building a wooden/PVC enclosure to attach to it, or using electrical or duct tape to seal around the anemometer housing and the hose/duct that you want to measure from. It doesn't have to be perfect, but you do have to attempt to seal around it a bit to get the best reading.

RFGuy wrote: ↑Sun Nov 27, 2022 8:46 am

dusty wrote: ↑Sun Nov 27, 2022 7:58 am I wondered about that. The Beauford Scale, originally from 0-12, was modified to include 13 -17 to facilitate measurements up to 64 knots. I believe this instrument is so annotated to indicate it is capable of those higher speeds. Not certain but will assume that for the moment.

As for my readings - I doubt all of them. I suspect that my testing was haphazard. I need to set up better to ensure good and consistent coupling between the DC6000 hose and the anemometer.

Thanks for your feedback. It has helped.

Dusty,

Yeah, you have to try to seal as much as you can around the sides of the anemometer and whatever you are testing. Either building a wooden/PVC enclosure to attach to it, or using electrical or duct tape to seal around the anemometer housing and the hose/duct that you want to measure from. It doesn't have to be perfect, but you do have to attempt to seal around it a bit to get the best reading.

Proven to be true!!!

I just took a new set of readings while being much more careful about alignment between the meter and DC port. The ft/mun numbers look more realistic (2350 ft/min which I believe to be about 200 cfm).

Not very scientific but it does make me feel a bit more confident in both the DC and the anemometer. Yes, I know - my quick and easy approach would not pass muster in an engineering review.