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bryant furnace fuse

hoops
hoops Member Posts: 7
have bryant furn model 986ta48080v17a....circuit board hk42fz064......with 100 percent of power off to unit it blows 3 amp fuse instant insertes....the fuse is correct amp...thxs

Comments

  • mattmia2
    mattmia2 Member Posts: 7,191
    what thermostat is connected to it? is anything else connected to the thermostat? an external transformer or separate cooling?
  • hoops
    hoops Member Posts: 7
    digital thermostat....no batteries....guess direct wired......cooling/heating is zoned
  • JUGHNE
    JUGHNE Member Posts: 10,315
    Zone motors.....where do they get their power?

    If you remove that power supply does the fuse still blow?
    mattmia2
  • hoops
    hoops Member Posts: 7
    don't know but with all power off and fuse still blowing wouldn't that have to be something that stores energy like a capacitor........very low tech here
  • ratio
    ratio Member Posts: 3,336
    It would have to be either power isn't completely off after all or a cross connect to something that isn't unpowered.
  • HomerJSmith
    HomerJSmith Member Posts: 1,926
    Is this something new or is it always happening from the installation?
  • hoops
    hoops Member Posts: 7
    "Just started not previous issue....main breaker off
  • Jamie Hall
    Jamie Hall Member Posts: 20,473
    I hate to say this, but fuses just don't blow all by themselves. Somewhere that fuse is getting power, and it would be well to find out where before you get powered yourself.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    mattmia2
  • hoops
    hoops Member Posts: 7
    No worry as not poking around myself....has to be a bad capacitor  or diode maybe
    SuperTech
  • mattmia2
    mattmia2 Member Posts: 7,191
    You turned off the service disconnects for the house and it is still blowing? Is there a separate meter for an AC condenser?

    If all of the power is off for the house it has to be a current through a water/cable tv/phone/gas service from a bad neutral from a neighbor or the utility finding its way back through your neutral.
  • Jamie Hall
    Jamie Hall Member Posts: 20,473
    A capacitor will not blow a fuse, unless it is a very large capacitor. A diode is not an energy source, and can't possibly blow a fuse by itself.

    There must be an energy source somewhere still connected. If you've really turned off the service disconnect and it still blows, you have far more serious electrical problems than a blown fuse. You need a good electrician in there, yesterday morning, to find and fix the problem.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    ratio
  • JUGHNE
    JUGHNE Member Posts: 10,315
    You turned off the main breaker to the entire house or the "main" breaker for the furnace??
  • hoops
    hoops Member Posts: 7
    Turned off breaker that controls ac/heat.  Thermostat doesn't have batteries but I think direct wired.  Could that be a source or a bad circuit board
  • Jamie Hall
    Jamie Hall Member Posts: 20,473
    If you turned off only the breaker that serves the ac/heat, that should have killed ALL the power to the system -- and the fuse would have no reason to blow.

    Therefore, you still have an electrical problem, and you still need an electrician, and the sooner the better.

    You also may have a problem with the thermostat being mis-wired, although if you didn't change anything in the wiring that seems unlikely, You may also have a problem with the control board -- but that should be off with the breaker off.

    Is there a separate transformer for the thermostat? If so, how is that powered? Besides the obvious -- it should be on the same breaker, and if it is the culprit it needs to be reconnected properly -- it could contribute, depending somewhat on exactly what the blown fuse protects.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hoops
    hoops Member Posts: 7
    Appreciate the input guys......going to get electrician to check things out as suggested.....will update later.....once again thxs
  • JUGHNE
    JUGHNE Member Posts: 10,315
    Zone control power supply still on??
  • HVACNUT
    HVACNUT Member Posts: 4,865
    Is there a humidifier with its own transformer that's not on the same circuit as the furnace?
    JUGHNE