Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 22

Thread: indoor unit disconnect

  1. #11
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    36,758
    Quote Originally Posted by wwhitney View Post
    How about 440.8? It says "An air-conditioning or refrigerating system shall be considered to be a single machine under the provisions of 430.87, Exception, and 430.112, Exception.
    The motors shall be permitted to be located remotely from each other."

    Cheers, Wayne
    I think that would only apply to a situation where multiple motors (or even other loads within that machine) are all disconnected by the same branch circuit device. A typical "mini split" may fit in this description, but the typical central air unit is two separate units supplied by two separate branch circuits, though they do work together as one system.
    I live for today, I'm just a day behind.

  2. #12
    Join Date
    Jun 2004
    Location
    Cherry Valley NY, Seattle, WA
    Posts
    4,315
    Quote Originally Posted by kwired View Post
    If it doesn't have a hermetic compressor it isn't covered by 440, it tells us this in 440.1
    thanks
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  3. #13
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    33,165
    IMO, the air handler is a motor and falls under 430. I have never seen an air handler on a ducted system that did not require a disconnect. No way is the motor is not more than 1/8 hp.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  4. #14
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    33,165
    It is really no different than a gas furnace so either way 422, 424 or 430 will still require a disconnect
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  5. #15
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    36,758
    Quote Originally Posted by Dennis Alwon View Post
    IMO, the air handler is a motor and falls under 430. I have never seen an air handler on a ducted system that did not require a disconnect. No way is the motor is not more than 1/8 hp.
    Traditional North American marketed air handlers you likely won't find with that small of a motor.

    I did connect a VRF system in a school building a couple years ago, most the air handlers were not "ducted units" but there were a couple that were. They were less then 300 VA rated. There were some higher volume air handlers used on that system also - those did draw enough we needed to add a disconnect.

    I disagree that it is a motor - it is a motor operated appliance. 422 can send you to 430 for certain things though.
    I live for today, I'm just a day behind.

  6. #16
    Join Date
    Feb 2003
    Location
    Somewhere over the rainbow
    Posts
    3,279
    Quote Originally Posted by Dennis Alwon View Post
    so either way 422, 424 or 430 will still require a disconnect
    It is really no different than a gas furnace
    But you can work on the indoor unit as a separate appliance and it is an independent unit than the condenser.

    The indoor unit of a heat pump will turn off when the outdoor unit's disconnect is turned off. One can not service/troubleshoot the indoor unit without the outdoor power being on. So it is part of an outdoor unit. Also, 422 allows the disconnect to be off site as long as it is lockable in the off position.

    So if 422 allows the off site lockable disconnect (even for more than 1/8 HP ) does 440 have the authority to overrule it?
    Edward
    The only thing I know, is the progressive discovery of my ignorance


  7. #17
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    36,758
    Quote Originally Posted by edward View Post
    But you can work on the indoor unit as a separate appliance and it is an independent unit than the condenser.

    The indoor unit of a heat pump will turn off when the outdoor unit's disconnect is turned off. One can not service/troubleshoot the indoor unit without the outdoor power being on. So it is part of an outdoor unit. Also, 422 allows the disconnect to be off site as long as it is lockable in the off position.

    So if 422 allows the off site lockable disconnect (even for more than 1/8 HP ) does 440 have the authority to overrule it?
    Almost always the other way, especially traditional North American marketed units. Indoor unit sends a control signal to the outdoor unit to tell it to run.
    I live for today, I'm just a day behind.

  8. #18
    Join Date
    Feb 2003
    Location
    Somewhere over the rainbow
    Posts
    3,279
    Quote Originally Posted by kwired View Post
    Almost always the other way, especially traditional North American marketed units. Indoor unit sends a control signal to the outdoor unit to tell it to run.
    What did I say that contradicts your statement?
    Edward
    The only thing I know, is the progressive discovery of my ignorance


  9. #19
    Join Date
    Jul 2005
    Location
    Tennessee
    Posts
    15,973
    Quote Originally Posted by edward View Post
    But you can work on the indoor unit as a separate appliance and it is an independent unit than the condenser.

    The indoor unit of a heat pump will turn off when the outdoor unit's disconnect is turned off. One can not service/troubleshoot the indoor unit without the outdoor power being on. So it is part of an outdoor unit. Also, 422 allows the disconnect to be off site as long as it is lockable in the off position.

    So if 422 allows the off site lockable disconnect (even for more than 1/8 HP ) does 440 have the authority to overrule it?
    I don't think 440 would trump it as no compressor is involved . Since a motor (controller) is involved 430.102 would require an in-sight. IMO, starting with the change in '11, 422.31(C) clarifies a in-sight disconnect is required.
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

  10. #20
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    36,758
    Quote Originally Posted by edward View Post
    What did I say that contradicts your statement?
    You said "The indoor unit of a heat pump will turn off when the outdoor unit's disconnect is turned off." Not true for the majority of the units. You will still have indoor unit running and will still have 24 volts to the contactor coil of the outdoor unit because the control power comes from the indoor unit. The compressor will stop and you won't get any heat/cooling from the refrigerant but the indoor blower and any back up heat still function.
    I live for today, I'm just a day behind.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •