Results 1 to 6 of 6
  1. #1
    Join Date
    Sep 2017
    Location
    United States
    Age
    31
    Posts
    1
    Rep Power
    0

    Mitsubishi city multi VRF incorrect daisy chain



    New guy here, I've been contracted by a company to fix a botched VRF install, besides multiple leaks I've already found they daisy chained the communications wire incorrectly instead of indoor unit to indoor unit they ran all indoor units to the condenser. All of the wires were ran under ground and the house is nearing its final inspection and they cannot not run new wire.

    My question is will the below set up work. I am unable to test the system as is due to the fact that they will not have power to the building for another two weeks.


    IDU 1 --- Condenser --- IDU 2


    This system is a part of the S series M/N PUMY-P60NKMU



  2. #2
    Join Date
    Sep 2010
    Location
    Dorset
    Age
    69
    Posts
    210
    Rep Power
    10

    Re: Mitsubishi city multi VRF incorrect daisy chain

    I would suggest a large junction box where you can reconnect the wiring tails to correct the bad wiring.

    I hope that the hidden data cabling is not run alongside any power cablibg.
    Brian, retired in Devon.

  3. #3
    Join Date
    Dec 2008
    Location
    UK
    Posts
    501
    Rep Power
    16

    Re: Mitsubishi city multi VRF incorrect daisy chain

    The problem is going to be trying to create a series daisy chain from each air handler when only one set of cables has been run from each air handler.
    Trying to get the communication to operate through a star point is going to be fraught with problems and it is likely to cause random Comms errors and not necessarily just when first powered up.
    Mobile A/C at its best, see avatar.

  4. #4
    Join Date
    Sep 2010
    Location
    Dorset
    Age
    69
    Posts
    210
    Rep Power
    10

    Re: Mitsubishi city multi VRF incorrect daisy chain

    Sorry, what I meant was to create the daisy chain by connecting the wires as pairs from one unit to the next.
    Brian, retired in Devon.

  5. #5
    Join Date
    Dec 2008
    Location
    UK
    Posts
    501
    Rep Power
    16

    Re: Mitsubishi city multi VRF incorrect daisy chain

    Make sure that you keep the polarity the same on each pair of wires as sometimes crossing them over can cause spurious Comms errors as well.
    The only problem might be potential interference due to the extended cable runs. Try to keep the junction point away from mains sources.
    Mobile A/C at its best, see avatar.

  6. #6
    Join Date
    Feb 2011
    Location
    England
    Posts
    23
    Rep Power
    0

    Re: Mitsubishi city multi VRF incorrect daisy chain

    Best option would be to use 1 of the cables from the condenser to 1 of the indoor units and then run new interconnecting cables between each indoor unit. You could use the condenser as a star point but this could cause comms issues.

Tags for this Thread

Posting Permissions

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