Avoid These Manual J Mistakes That KILL Your Calculations

In this video, we're going to discuss how to avoid mistakes when doing manual calculations. By following these tips, you'll be able to minimize the chances of making careless mistakes that can lead to system design errors.

Even if you've got a strong math background, there are still things you can do to improve your calculations. In this video, we're going to discuss some common mistakes that people make when doing manual calculations, and how to avoid them. By following these tips, you'll be able to keep your calculations error-free and ensure maximum system design efficiency!

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[QnQoooo]

R values doesnt seems to impact the load too much, really little difference between R 11 to R 15(wall).

[ChristianThunder]

Hi Chris, excellent job with these videos. I’m learning a lot, you’re a great teacher!

I have a question for you.

I recently had new construction built for me and the Manuel J included a Carrier brand system and specs for the report, which is what the Manuel S also included or recommended.

But my builder installed a Comfort Aire handler and Rheem condensers.

The builders choice of equipment was not included on the Manuel J or S, is this problematic?

I am having issues with my upstairs system. It’s running consistently on warmer days and has very poor air flow compared to the downstairs system which is .5 tons larger.

I’m thinking they undersized the upstairs unit but I’m a novice with a Manuel J report trying to find the problem.

Any advice would be appreciated, and thank you for taking the time to make these informative videos!

[Gutter-Snipe]

I would have to respectfully disagree about indoor design temp. customer expectation is paramount. We are after all a customer service industry. Example: my manufacture does say I can offer as low as 68 degrees indoor design temp (COOLING), I can sell that as a you have to live with it or find some one else. As a sales and design man the first 2 questions I ask is what temp do you like in the summer and what temp do you like in the winter< can i meet the clients expectation some way? so if a client says i like 68 in the summer and i too like 68. if you design a system with 75 degree indoor temp and the client is unhappy and finds that fact out you just might find your self on the loosing end of an expensive lawsuit. I know if I got a bug in my but I would gladly pay an attorney to abuse some one with expensive litigation. take away Government/ code mandated indoor temp do not, DO NOT hold up in court. threaten a code official with the liability if the system does not meet customers expectation, have then put it in writing why it failed. easiest code meeting ruling in the contractors favor you"ll ever see.