![]() But never use an anemometer or a balometer or such.įor some reason also, every company I have used dosen't do duct layouts, they come in and measure the new home, do a load calc and then start installing the duct work after. They have however measured static pressure. I have spoke of this and they companies that I told me they don't have the equipment to do this. After the job is complete, they pack up and there gone. It would be good to get an expert to test and balance all the duct work but in the area that I am in for some reason, no one seems to want to do that or has the test equipment. There are balometers made that do well measuring residential grill outputs. If you're dying of curiosity, find a TAB outfit (testing and balancing) to test the output of every grill in your house using a balometer. You'd be better off finding a BPI or Comfort Institute certified HVAC tech (or someone familiar with those principles and knows how to apply it) who can measure actual airflow through your system. Thanks for you time folks!!!Don't expect to find 1200 CFM at every grill. I asked this from the HVAC company but they really didn't answer my question. Now I use an air hood (balometer) at the grills or a hot wire velocimeter (anemometer) inserted into the duct. I have tried to use velocimeter grill readings, and gave up, too many variables and too much guesswork compared to other methods. For a 4x10 grill, maybe middle left, middle, and middle right averaged will work. So you must average the velocity readings if the velocity is not the same. Another problem is that many grills will not have the same velocity across the whole grill, one side will be higher than the other. The grill manufacturer will publish the net area of the grill. ![]() ![]() So a 4x10 grill with a free area of 24 sq.in. One problem is what is the actual area of the grill? A 4x10 grill doesn't have a net area of 40 square inches, it may only have a free area of 24 square inches, depends on the grill. The velocimeter itself will be accurate as described by TIF, for one location of measurement. It is difficult to use velocimeter readings at grills to get readings accurate within normal tolerance of +/- 10%. The supply vents are 4"x10" in the floor area. My main question is how can I measure the CFM from the velocity readings? The meter will show velocity (ft/min) and CFM, but measurments have to be inputed in the device to measure the CFM. And also to balance the airflow when we get done with the flooring and install the vents.įor instance I just had a 3 ton system installed and I am assuming that the system air displacement is 1200 cfm for the system. The last company sized the supply duct work a little different, and the pressure dosen't fell like I am used to, and anyway I bought a TIF 3220 to check the CFM of the system to satisfy myself. He recently retired and I have just started using another company. I build houses for a living and have been using the same HVAC guy for years. I am new to this forum and I'll tell you about me and what I have going on. If you have any problems with the registration process or your account login, please contact support. We suggest not registering using an AT&T, BellSouth, AOL or Yahoo email address. Gain access to our free AOP (Ask a Professional) Section to get real answers for your questions.Īll this and much more is available to you absolutely free when you register for an account, so join our community today today!.Post photos, respond to polls and access other special features.Participate in over 40 different forums and search/browse from nearly 3 million posts.As a registered Guest you will be able to: To gain full access to our forums you must register for a free account. You are currently viewing as a NON-REGISTERED guest which gives you limited access to view discussions Welcome to, a non-DIY site and the ultimate Source for HVAC Information & Knowledge Sharing for the industry professional! Here you can join over 150,000 HVAC Professionals & enthusiasts from around the world discussing all things related to HVAC/R.By continuing to use the website, you consent to our use of cookies. To learn about our use of cookies and how you can manage your cookie settings, please see our Cookie Policy. We use cookies to improve your website experience.
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