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VRF fan coil unit - question for HVAC contractors

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I have been told that it is easier to change out an entire VRV fan coil unit, rather than replacing a blower and motor, because the units are so compact and difficult to work on. Has this been the contractors experience? I am an engineer and I am trying to determine whether access needs to be provided to replace the entire unit (which I prefer to do, but the architect/owner wants to minimize access panel size), or it is sufficient just to have enough access space for individual component service and replacement.

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  • GGross
    GGross Member Posts: 1,070
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    It is always a wise idea to allow space to replace equipment, how much will it cost the building owner if there is no way to replace the unit without tearing down walls?. Of course if a motor goes bad it is far easier to just replace the broken part, but at some point there is a good chance the entire system, indoor and outdoor will need to be replaced.

    I'm sure there is no shortage of techs who don't like working on those units, it is relatively new technology for most techs, but swapping the whole unit out because it is too hard to change a motor of all things is just silly, unless these are different than the units I am familiar with
  • ratio
    ratio Member Posts: 3,651
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    How hard it is to work on them depends on how easy access is. Not just an access panel, but obstructions above the ceiling can impede servicing as well, so keep that in mind. I think enough room to get my shoulders through, positioned so that I could see & touch (from above) everything that I'd need to work on, would be the least worst.

    Keep in mind the control panel will likely have tiny dip switches & jumpers that will need to be set, so ready access to that is important. I'm up in the air about ball valves. On the one hand, they'll make it easier to do refrigerant work on the head, but they ain't all that cheap & most of the systems I've worked on will pull over to the side of the road & park if they can't talk to a head, so if you have a leak you've got to shut down the whole thing anyway.

    GGrossDF
  • DF
    DF Member Posts: 7
    edited September 2023
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    I've been told by the manufacturer,  Daiken, that fan and motor replacement on this equipment FDMQ is difficult because of the compact size. Anyone have this experience?
  • pecmsg
    pecmsg Member Posts: 4,883
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    When the install instructions are NOT followed things can and do get crazy. Don't leave required clearances that's not a manufactures issue.
  • GGross
    GGross Member Posts: 1,070
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    DF said:

    I've been told by the manufacturer,  Daiken, that fan and motor replacement on this equipment FDMQ is difficult because of the compact size. Anyone have this experience?

    no first hand experience on that replacement, however if the manufacturer is the one telling you it is difficult to do I would place some stock in that. I would also ask them since they think that replacing the whole unit makes more sense than just replacing a motor, if a motor were to fail under warranty would they warranty a complete unit changeout instead?
    ratioDF
  • ratio
    ratio Member Posts: 3,651
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    Mfgrs only make perfectly awesome equipment. If they're suggesting it's hard, it might be darn near impossible in the field, because I'm sure they do their "testing" on the engineer's desk.

    Put ball valves in. You need access to the controls side for commissioning & air balance, & the entire under side to drop the unit. That door would be like 48x60! You might be able to get away with two doors, one directly underneath & one near the controls side, but honestly I think your best bet is to put a middling access door by the control cabinet, & plan on taking the ceiling out for a replacement.

    Other obstructions will probably bite you on the hiney (I'm at you, Sparky & Mr. Sprinkler Fitter) on a few/some/many heads.

  • pecmsg
    pecmsg Member Posts: 4,883
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    DF said:
    I have been told that it is easier to change out an entire VRV fan coil unit, rather than replacing a blower and motor, because the units are so compact and difficult to work on. Has this been the contractors experience? I am an engineer and I am trying to determine whether access needs to be provided to replace the entire unit (which I prefer to do, but the architect/owner wants to minimize access panel size), or it is sufficient just to have enough access space for individual component service and replacement.
    Who told you that?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,094
    edited September 2023
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    pecmsg said:

    DF said:


    I have been told that it is easier to change out an entire VRV fan coil unit, rather than replacing a blower and motor, because the units are so compact and difficult to work on. Has this been the contractors experience? I am an engineer and I am trying to determine whether access needs to be provided to replace the entire unit (which I prefer to do, but the architect/owner wants to minimize access panel size), or it is sufficient just to have enough access space for individual component service and replacement.


    Who told you that?
    Why did you answer this question with a question?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • pecmsg
    pecmsg Member Posts: 4,883
    edited September 2023
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    I ask a lot of questions. 
    But to answer your question. I highly doubt tech support or the manufacture would make that statement!
  • pecmsg
    pecmsg Member Posts: 4,883
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    and yes
    i still dislike NEST :smile: