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  1. #1
    Join Date
    Mar 2003
    Posts
    41

    Confused

    ok,,need some help on this one, i have just installed a bryant 3 ton heat pump and air handler in a town house,(new construction) when i first fired the unit it ran for several hours then blew the 5 amp fuse in the air handler,i checked all my connections and replaced the fuse,,it ran for about two hours then blew the fuse again,,i replaced the stat thinking maybe it was bad,,now the fuse is blowing as soon as i turn power on,,,i pulled the stat ran a wire from the stat up to the air handler bypassing the one in the wall,,when i turned power on display came on at 5 mins air handler came on and at call for outdoor unit it blew the fuse,,so i re mounted the stat and now ran a wire from the air handler out the window down to the heat pump,, units ran for two hours then blew the fuse,,so at this point ive been chasing wires and i cant find a short,,i replaced the defrost board and the board in the air handler,,did then one at a time and both times units ran for two hours each time then blew the fuse !#@$&!$#@*!^%(@!_!+!!!!! dont know what to do next,,,,could it be a short in the reversing valve coil? compressor contactor or in the contactores them selfs ????? cant seem to figure out why im getting a two hour run before it blows,,amp draw on the 24volt power wire never got over 0.16 any ideas????????????

  2. #2
    Join Date
    Nov 2004
    Location
    Naples, Fla.
    Posts
    1,403
    Well - short of gremlins, you've missed something.

    Itermittent problems are allways a challenge. You'll need to replicate the fault.

    Be sure 1st ALL your connections are 100% correct - do'nt assume it, unwire all the controls & start over.

    1) Try in just 1st stage ht
    2) Try 2nd stage ht
    3) Try cooling
    4) Try defrost

  3. #3
    Join Date
    Mar 2003
    Posts
    41
    thanks,,ive checked all my connections,,i was the first person i blamed,,in fact when i replaced the stat i wired the common and fan backwards((hurry hurry hurry)))) i think tommorow im going to start by disconnecting the reversing valve and seeing how long i can get it to run,,one way or the other it will be the cause or eliminated as the trouble

  4. #4
    Join Date
    Jan 2005
    Posts
    123

    some wiring fun

    stupid question here Is the transformer tapped for the right voltage?? If its 208 incoming and tapped for 240, you could be getting the wiring to warm up a little and cause some extra resistance, also is tstat wire small gauge? sometimes that and an incorrect tapped transformer can add up to some fun after a few hours of running.

    Just a suggestion.....................

  5. #5
    Join Date
    Mar 2003
    Posts
    41
    thanks backbeat,,i will check into that,,thats a good question,,,trust me at this point ,, i have 30 more of theses to rough in,,i have other jobs to finish and a new 24 unit project starting tomorrow, the more i mess with this to more i fall behind eles where,, im thinking of buying a new unit,, if it solves my troubles great,,tell my factory rep i want a refund if it dont solve my trouble i will use it on the next set,,,, am i lazy ?? or just tired and cold !!!LOL or both or all three

  6. #6
    Join Date
    Jan 2004
    Location
    Texas
    Posts
    127
    yea chech the primary line voltage to transformer and wire in correct tap.you could be having inrushes of too much voltage blowing fuse. (power surge or spike) I recomend the short-pro-tool if locating low volt shorts, in the
    meantime install something called the ressetable fuse.
    R-270 for a 40va system R-500 for a 75va 24 volt system.

  7. #7
    Join Date
    May 2003
    Location
    Sarasota. Fl
    Posts
    1,266
    The fuse is blown as soon as the call for cooling came?

    Look at the wires in the condenser.

    Look at the wires for the Low?High pressure switches....etc

    A wire is probably "skinned" or frayed and touching something.

    The unit could be vibrating the wires around during run time......then that "skinned" part of the wire touches a refrigerant line due to the vibration....and pop.

    If that wire is now laying on it at start up, it would blow as soon as you put power to it.

    That would explain different length`s in run time before the 5 amp fuse blows.


    Atleast thats what happened to me last week.(3 moth old equipment)

    Pain in the @#$ to find.
    It is the job of thinking people not to be on the side of the executioners.

    ~Albert Camus

  8. #8
    Join Date
    Mar 2003
    Posts
    41
    thanks for the input ,,i will check into that,,i have traced a bunch of the wires in the outdoor unit and cant seem to find one that is frayed,,thats what got me to wondering if i had a coil heating up,,,i had my amp probe clamed around the 24 volt power wire and it never went over 0.16 while it was running,,

  9. #9
    Join Date
    Mar 2003
    Posts
    41
    AAHHHHHH!!!!!!!! !!@^!*!!&*!@*@!*@*&**%*%@$*$*!!!! STILL BLOWING AFTER 2 HOURS OF RUN TIME!!!!!!!!!found small burn in defrost wiring thought it might be it,,,and i was wrong!!LOL

  10. #10
    Join Date
    Jan 2004
    Location
    Texas
    Posts
    127
    You said it was new construction right? if you dont think its a power supply problem you must have a intermitent short. Check your ground voltage and locate that short pro tool & reset fuse at Insco. Distributing in Texas...

    [Edited by acg on 01-26-2005 at 09:16 PM]

  11. #11
    Join Date
    Nov 2003
    Location
    Wisconsin
    Posts
    458
    Betcha got a shorted contactor coil in the ODU. Check it out and let us know.

  12. #12
    Join Date
    Dec 2004
    Posts
    441
    New construction did you say? Start ohming out your stat wires, sheetrock screws......

  13. #13
    Join Date
    Mar 2003
    Posts
    41
    yes it is new constr. i have cheked all my wires,,its been running on emer. heat since yesterday afternoon,,the short is in the outdoor unit and at this point ive turned it over to my factory rep,,,ive lost enough time and have other jobs to take care of,so i put it on them,,,the head man is going to check it out and either fix it or replace it,,i have a cool rep,,hes been a great asset to my company in my first year in buss.

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