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  1. #1

    Manual J and Manual D?

    Quote Originally Posted by HVAC_HUSKER View Post
    He would need to do A manual j and manual d for the whole house including addition... Not just adding duct and some dampers.. The whole dust system will more than likely need to be redesigned or you may need to upgrade system size. This is what manual j will tell you. Then you will have a option to use manual dampers and balance system properly or you do a complete zoning system... You can't do both.. But as long as its designed properly then system should thrive..
    what is manual J and manual D??

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,328
    manual J is a method of determining a structures heat loss and gain. manual D is a method of determining the total equivalent length of a duct system to determine what friction rate loss to use on a duculator.
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    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Both are critical to properly sizing, designing and installing a complete HVAC system. Anything short, is just varying degrees of guesswork or a matter of simply throwing it together.

    IF the transmission died in your car, would you want them to use a mfg specific service manual and procedures, or just throw it together because they are "all about the same".

  4. #4
    Join Date
    Aug 2009
    Location
    Beatrice, NE
    Posts
    2,288
    A couple of books from the bible of the HVAC world.

  5. #5
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,006

    kls-ccc; Great Statement...

    Quote Originally Posted by kls-ccc View Post
    A couple of books from the bible of the HVAC world.
    When doing the Manual J heat-gain/heat loss, look at fixing those areas that allow too much gain or loss; as if you can reduce the equipment size that will help the existing duct system to work better.

    Though you'll still need to run a Manual D so you know the system is going to work properly. Far too many never check airflow at all...

  6. #6
    thnx guys,..this site is helpin me lot...a couple of mnths earlier i was nt even knowin d HVAC full form, somebudy askd me n i told him it mayb high voltage alternating current..hehe...bt now m learning day by day n also implementing it my project

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