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  1. #1
    Join Date
    Aug 2008
    Location
    San Clemente, CA
    Posts
    1,233

    Fujitsu takes a shocking licking and keeps on ticking

    Computer rm down - no cool air

    Never got the straight answer on who done this but someone took the 208 volt power wires and moved them to number 1 & 2 communication terminals as the color of the wires matched up would be my guess. I looked at this roof top unit and went what the f***.

    So as I turn off power and move the power wires to where they belong L1 & L2 I send power to the proper terminals and she is not working. Not to surprised at this point. I pull the lid off and dig into the electronics. Well look at this a blown 5 amp fuse. So now I am digging through the truck and find a 5 amp automotive fuse on a bad CB pulled off a furnace earlier in the day. Put the spade connectors on the 5 amp automotive fuse and she works. Unbelievable if you ask me... What other product can you do this too and not let the factory smoke out.

    Crappy install if you ask me as power was tapped off a 40 amp 3pole disconnect for a package unit 10' away. Illegal for a commercial building not to have 208 volt wire in a conduit. We bid on this install and now I see why we did not get it.

    The only factory thing I see is Fujitsu needs to work on their label integrity as this unit is not that old. I think a couple of years, 410A refrigerant and all.








  2. #2
    Join Date
    Jul 2009
    Location
    Columbia, MD
    Posts
    4,266
    sooooooo......this thing ran like that for how long?

  3. #3
    Join Date
    Nov 2011
    Location
    Long Island, NY
    Posts
    285
    WOW!

    Good to know.

  4. #4
    Join Date
    Jun 2003
    Location
    Chicago, IL
    Posts
    4,497
    Quote Originally Posted by JKopp View Post
    Unbelievable if you ask me... What other product can you do this too and not let the factory smoke out.
    I once wired 480V to the 24V side on a carrier rooftop unit. blew the 24V fuse, blew the 25A 480V fuse, no other damage.

    Its hard to explain how this happened, but for those familiar with Carrier RTUs it has to do with the 24V limit switch in the blower motor.

  5. #5
    Join Date
    Aug 2008
    Location
    San Clemente, CA
    Posts
    1,233
    Quote Originally Posted by gravity View Post
    sooooooo......this thing ran like that for how long?
    I can't imagine it worked wired this way. I think we had a Sparky wannabe messing with it. I never looked it over before this trouble call.

  6. #6
    Join Date
    Mar 2009
    Location
    Mid-Mo
    Posts
    3,596
    That's pretty funny considering it is well labeled. Durrrr. Hard to believe it didn't tear something up.

  7. #7
    Join Date
    Jun 2003
    Location
    Chicago, IL
    Posts
    4,497
    Quote Originally Posted by JKopp View Post
    I can't imagine it worked wired this way.
    actaully it probably did run that way. take a look at the wires. the white wire is just a jumper. the black wire is also just a jumper, but it goes through the fuse. The red wire is the communication wire, and that one looks ok.

    the difference between hooking it up this way and the right way is that the indoor unit now has no fuse protection and the outdoor unit gets its power through that tiny fuse. The outdoor units are so efficient that I suppose its possible that it ran fine for years through that fuse

  8. #8
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,162
    Yes, it worked fine that way.

    Like Craig stated, the 5 amp fuse was protecting the outdoor unit instead of the indoor unit, this is the only difference.

  9. #9
    Join Date
    Aug 2008
    Location
    San Clemente, CA
    Posts
    1,233
    He did have that pussled look when i said someone changed this wiring. Wow, ok then that may make sense as we had some long heat waves roll through the hottest in like 4 years and the fuse finally gave up. Hard to believe the outdoor unit was running on that little 5 amp. Thanks for the insight.

  10. #10
    Join Date
    Aug 2012
    Location
    Vancouver Island, British Columbia
    Posts
    16
    last fujitsu i went and worked on had a TCA of 3.8a, it was a 24k btu with 2 heads both on heat to 88f so it was ramped right up. crazy how efficient they are.

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