Review: Calculated Industries 4090 Sheet Metal/HVAC Pro Review
Quick Facts
Model: 4090 Sheet Metal/HVAC Pro
Company: Calculated Industries
Years: approx. 2004 - Present*
Memory Register: 1 independent memory, 3 general memory registers
Battery: 2 x LR44 batteries
Screen: 8 digits with alpha numeric prompts, 12 digit accuracy
Logic: AOS (Algebraic), Chain
Price: retails about $89.95; iOS and Android app available for $29.99; used calculators can be found for less
Web Page from Calculated Industries: https://www.calculated.com/mobile/prd722/Sheet-Metal-HVAC-Pro.html
If you purchase it out of the box, either by repackage or retail, both an Armadillo Case and a hard slide cover come with the calculator. In the box set has a full user's manual, which is really nice and gives an extensive amount of examples and details.
History
The Sheet Metal/HVAC Pro was exclusive to the International Training Institute (ITI)(https://www.sheetmetal-iti.org/) until 2021, when Calculated Industries made the calculator available to the Public (7 seconds into this video: https://www.youtube.com/watch?v=wzmB8UAEjls).
I purchased a used Sheet Metal/HVAC Pro which is why you see the ITI logo in the pictures. I am very confident both versions have the substantially the same amount of functions.
Features
* Trigonometry and Right Triangles
* Square, Square Root, Cube, Cube Root
* Fan Laws
* Circle and Arc Calculations
* Column and Cone Calculations
* VP (velocity pressure)/FPM (feet per minute) conversions
* Offset calculations
* Stairs, Hip/Valleys, Jack
* And one of the best known features to come with Calculated Industries industry calculators: feet-inch-fraction and meter-millimeter calculations. Fractions of inches can be set from 1/2" to 1/64". I usually work with 1/16".
I think this is the only calculator from Calculator Industries to have a exponent (10^xx) key (x 10^y), allow for numbers to be entered using scientific notation. The maximum number is 9.999999 * 10^76.
Trigonometry
The only angle unit the trigonometric functions work with is degrees. Two unique features that come with the Sheet Metal/HVAC Pro are the ArcK constant and the Law of Cosines function.
An ArcK constant, which is equal to π/180 ≈ 0.017453. This constant is helpful for circle arc calculations.
The Law of Cosines function where given the lengths of three sides A, B, and C, calculate the angle measurements of each of the angle and the area of the triangle using Heron's formula. This is one of my favorite features of the Sheet Metal/HVAC Pro, as going through the User Guide a lot of pipe work involves determining lengths and angles of triangles.
There are four keys that deal with right triangles, the multi-purpose [ x (Run) ], [ y (Rise) ], [ r (Diag) ], and [ θ (Pitch) ] keys. Enter the given knowns and then just press the remaining keys to solve for the missing parameters.
Fan Laws
The A and A new (which represent the CFM - cubic feet per minute), and the B and B new registers deal with the three fan laws. The B and B new parameters change depending on which fan law is used.
Fan Law 1: B and B new represent RPM (revolutions per minute)
Fan Law 2: B and B new represent SP (static pressure)
Fan Law 3: B and B new represent BHP (brake horsepower)
Stairs and Roofs
The Sheet Metal/HVAC Pro has the stair, hip valley, and jack rafter calculations, the same as the construction calculators Construction Pro 5 and the Construction Master Pro. You can set the default riser height of the stairs, as well as calculate the number of required risers, stairs, the tread width, the stringer length. The HVAC Pro also works with roofs: rafter length, pitch, jack rafters including irregular jacks.
Offset Calculations
The offset calculations on the Sheet Metal/HVAC Pro slightly differ from the offset calculations offered on the Pipe Trades Pro. The offset deal with sheet metals, and the calculations included are:
* centerline radius
* wrapper length
* throat and heel radius
Verdict
As always, Calculated Industries offers quality calculators that are specific to industrial needs and the Sheet Metal/HVAC Pro is no exception. The key quality is great, the display has helpful prompts, and the Armadillo cases given solid protection. I'm happy that this calculator is now available to the public.
Eddie
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