Also available with a case. See the kit here!
The high quality bearings in the testo 417 yield nearly "friction-free" rotation for direct measurement of air velocity with an NTC sensor used to determine air temperature. The vanes cover all the measured area - no airflow is lost between the vane and outer ring.
The 4" head averages true flow over its entire area, not just responding to local stray eddies. Just input the duct cross-sectional OPEN area (from 0.2 sq. in. to over 107 sq. ft. (15,498 sq. in.)) to see accurate, real-time CFM calculations. Simply toggle between velocity, CFM, and temperature readings on the clear, back lit display. Simply tap the ON/OFF key when the unit it is ON to toggle the back-light.
Flow direction is indicated by an arrow in the display. timed or multi-point averages are easily accomplished with all parameters and calculations. Min-Max values can also be displayed. The "Hold" function freezes current readings in the display making data recording easy.
The primary advantages of vane anemometers are speed, accuracy, and ease of use. Vane anemometers do not require air density compensation due to air temperature, humidity, or atmospheric pressure. The large vane is ideal for verifying proper velocities from supply and return registers and performing proportional balancing of HVAC systems. This tool should be on every technician's truck.
The CFM displayed across the area being measured depends on the internal calculation:CFM = Velocity (in FPM) x Area (in Sq. Feet)Where the user enters the Area data in square inches and the 417 converts to square feet.
The CFM measuring range across the area of the 4" diameter head is basically 5 to 350 CFMHead area = 0.087 sq ftVelocity range = 50 to 38040 FPMCFM range across 4" head = 50 x 0.087 to 3940 x 0.087 = 4.35 CFM to 343 CFM
1) DETERMINE the OPEN AREA as follows: On RETURNS, the OPEN AREA is the 100% of the full measured area of the grille, as the air is flowing first through the 417 measuring vanes, then into the return duct. On SUPPLIES, the OPEN AREA is the fraction or percentage of the grille that the air passes through, before moving through the 417 measuring vanes. See grille manufacturers product info for open area data **. Then Multiply the Duct dimensions (Height and width) in inches by multiply of the OPEN AREA factor.
FOR EXAMPLE: We have a supply grille that is 6x10 inches with 65% open area. The open area is 6 x 10 x 0.65 = 39 sq inches open area
2) ENTER the OPEN AREA into the 417.Turn ON the 417, after a few seconds the display comes up. PRESS AND HOLD the RETURN ARROW (Hold/Max/Min Key) until a number appears on the display and the in2 label is blinking. Use the UP or DOWN arrows (VOL and MEAN keys) to adjust the number in the display your open area. IN THE EXAMPLE ABOVE adjust it to 39.0
3) EXIT to measuring mode by pressing the RETURN ARROW (Hold/Max/Min Key) 5 times
4) MEASURE: Place the 4" vane into the air stream in front of the grille position it at one corner of the grille, parallel to the grille surface. A) Press the MEAN key TWICE to enter the timed average mode. B) Press the RETURNkey (Hold/Max/Min Key) when you want to start collecting data. C) Keep the 417's measuring head about 1" away from the face of the grille. Move the 417 head across the grille at a rate of about 1 foot (12") over 4 seconds. (note the timer on the 417's screen) D) Be sure to "paint" the entire grille face with head of the 417 to account for total flow through the grille.DO NOT paint any area more than once! E) When you are done covering the entire grille area, press the RETURN key (Hold/Max/Min Key) again to pause the reading on the display.
OPTIONAL: You can measure again (re-paint the entire area) to improve the reading. Just start at step 4B.
5) DISPLAY the average values by pressing the MEAN key. The Timed MEAN icon will flash and the average Feet Per Minute (FPM) will be displayed. Tap the VOL key once to see the Average CFM for this test. Tap the VOL key again to see the Average Temperature for this test. Tapping the VOL key continues rotating thru these three results.
NOTE: BE SURE to record the data, as there is NO memory storage in the 417. Once you tap the MEAN key again, the data is gone.
6) CLEAR the data and prepare for another measurement by tapping the MEAN key ** One manufacturer's data books give open area factors of from 71% to 75% for one type of floor diffuser (depending on size), 66% to 75% for another model and 65% to 75% for another model. While a heavy duty, dual shutter floor grille from the same manufacturer has a range of 48% to 52% open area factor. Generally speaking, the larger the grille dimension, the small the open area factor.
Testo 417 Data Sheet