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  1. #1

    Mitsubishi 4 Zone ductless split condenser fan runs continuosly

    I Installed a Four zone ductless split approx. 3 months and spent several hours on the phone with

    Mitsubishi tech support, and problem still exist. Heres some history on what happened. After the system was installed I had all four evaporators calling for cooling. As the last zone satisfied, the

    outdoor condenser fan continued to run. I checked the amp draw to make sure the compressor wasnt running which it was not. I then went inside and turned off one zone at a time, went back

    out to the condensing unit and the fan continued to run until all evaporators were turned off. I called Mitsubishi Tech Support and explained the problem to them. After checking several things

    for the phone tech he tells me it must be a faulty PC Board. After driving 1 1/2 hours and spending almost $80.00 on a New PC Board I installed it and the problem is still there. The

    following day I call Tech Support again and the phone tech tells me it must be the power board because it communicates with the PC Board. I drive 1 1/2 Hours again, spend $50.00 ,I then

    install the Power Board and Guess what? The problem still exists. The phone techs then tells me he would like me to go out to the job site were I installed this and check several things for him. I

    Finally found the time to go out to the job site and I was on the phone for 1 1/2 hours with the phone tech checking several components, Jumping out sensors, putting sensors in ice water,

    remove control wires from each unit while powered up. Guess what? The phone tech tells me he still doesnt understand why this is happening but he will send the information to Japan. The next

    day he tells me he would like me to change out the condenser fan motor and if that doesnt work then he would like me to change the PC board again. I told him Im pretty discourage and Im sick

    of replacing parts. I refused to replace anything else at this point. Im wondering if all of these units are doing this. The four Zone ductless splits are new for mitsubishi. The phone tech told me

    he has a three zone at there lab and the condenser fan shuts off when the zones satisfy. He also told me the three zone is the same as the four zone with the exception of an extra terminal strip.

    I find that hard to believe. The condensing unit is a MXZ-4A36NA and the Evaporators are three MSZ-A09NA and one MSZ-A15NA. If any one could please shed some light on this problem I would

    really appreciate it. Thanks

  2. #2
    Join Date
    Sep 2008
    Location
    Yes, I mentioned it before, Georgia.
    Posts
    13
    the fan is supposed to run. the guys you are talking to, should tell you that. i have installed quite a few, for server rooms, and what not. the compressor will shut down, normally. yet, the fan will stay engaged. these guys, are made to run, even if it is 14deg
    outside.

  3. #3
    It only makes sense that the fan would shut down when all zones satisfy. These units are made to be very efficient. I have worked on several single zone units and the condenser fan shuts off when the zone satifies. Ive seen the condenser fan motor slow down and the compressor idle along under a low load condition. The phone tech told me they had a three zone in the shop and the condenser fan shuts off when the zones satisfy. On this Problem child the condenser fan actually picks up speed when the last zone satifies. I wish I knew someone with a four zone!

  4. #4
    Join Date
    May 2001
    Location
    Western Wa
    Posts
    1,834
    I ran into a Mitsubishi single zone unit where the full speed fan switch and the high pressure cutout were switched, apparently from the factory. I was seeing high pressure cutouts on hot days when the fan wasn't ramping up to full speed.

    You might want to prowl around and see if all the little plugs are landed in the right place.
    God Bless our Veterans

    God Bless the USA

  5. #5
    Thanks alot guys

  6. #6
    THanks for all your help guys

  7. #7
    Join Date
    Dec 2005
    Location
    San Jose, CA
    Posts
    465
    Verify the valves are open!!

  8. #8
    Join Date
    Dec 2005
    Location
    San Jose, CA
    Posts
    465
    Verify the valves are open!!

  9. #9
    Join Date
    Sep 2008
    Location
    Central PA.
    Posts
    4
    Has anyone had many bad experiences with these Mitsubishi quads? Today, I just sold a job that has (4) MXZ-4A36NA quads with different indoor sizes and (1) double - total of 18 zones. I'm hanging my neck out there that everything will go in and work as planned. I've had good experiences with Sanyo, but their quad just didn't seem good for this application. It doesn't sound like Misubishi has great product support from reading below.

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