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  1. #1
    Join Date
    May 2005
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    Getting ready to start drywalling. Is there a problem with using new a/c system while house is under construction? I have individual returns. Is there a way to temporarily filter them or shouldn't I worry about that? There will be a filter at the air handlers, but I'm worried about the duct system before that point.

  2. #2
    Join Date
    Apr 2005
    Richmond, Virginia
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    YES, no matter how well you try to filter the dust, it will collect on the coil. I see this all the time in commercial buildings. I've seen GC turn on the roof top unit before any windows are installed! I can't tell you how many times I've gone to clean a new evap coil right after the building opens. It's gotten to the point where I've started to take out the control board in some units to prevent the GC from starting units. I've also voided the warrenty in some cases where the GC had another mechanical contractor buddy come in and start the unit so his guys could stay cool in the summer.
    Sean Cantrell

  3. #3
    Join Date
    Jul 2005
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    Yes, drywall dust is very light and will find its way into everywhere. When we absolutely have to have AC for the workers' or HO's comfort (remodeling), we put filters on the returns AND supply registers. We take out the grilles and tape pleated filters to the floor/wall/ceiling. You can use pleated paper for a one-time job. If you do this for a living, you can use washable K&N.

  4. #4
    Join Date
    Jun 2003
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    I know it's hot, but don't do it. That A/C system would have to be completely cleaned.
    If everything was always done "by the book"....the book would never change.

  5. #5
    Join Date
    Dec 2004
    Derby City
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    As you can gather from the advice given, ideally, you would not operate the system at all. Realistically though, you may need to have the a/c in operation in order to finish out, i.e. paint, drywall, etc. I would also agree, that the returns be filtered at the openings, and changed frequently during use of the system during this time. Same applies for the filter at the unit. Reality dictates that if the system can be operated, it will probably be run.

    Believe it or not, comfort would not be my concern. But sometimes in order for the drywall mud to set properly, paint to cure properly, etc. it is necessary to have the space conditioned.

    Another option is to have the contractor provide a complete duct cleaning and servicing of the equipment upon completion of construction, or better yet, you have someone of your choosing come in and do so, and he pays for the call.

    I would belive that the contractor (HVAC) has a vested interest in the equipment being in the best possible working condition upon completion of the house construction. For no other reason than to avoid warranty calls down the road, they want to be sure the system is clean and operating properly.

    In MOST commercial applications, there are stipulations in the specifications that outline temporary heating and cooling during construction. I can tell you that the majority of the time, this is provided by the equipment that is part of the permanent installation. Would I prefer that it not be run? Absolutely. Will it be run? Probably.

    Again, these are suggestions. Even if the system were not run, I would request that the system be cleaned and serviced as the drywall dust and other debris can still settle in the duct system and on equipment surfaces.
    Everyone has a purpose in life..........even if it's to be a bad example.

    Seek first to understand, before seeking to be understood.

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