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Black Bart capacitor info needed

Post in 'Classic Wood Stove Forums (prior to approx. 1993)' started by uaw239gm, Jan 31, 2012.

  1. uaw239gm

    uaw239gm New Member

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    Newbie here. I have an old Black Bart which was working fine up to a month ago so I've been trying to troubleshoot the thing before throwing money away. The writing on the blower capacitor is all but gone. The only remaining info is 370 VAC. Without the ratings on this thing I can't test to see if it's bad before moving on to the next thing. Does anyone know what the uf rating is for this capacitor? I've tried several online venders with only dead silence from them. Thanks to anyone taking the time to read this post!

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  2. Jags

    Jags Moderate Moderator Staff Member

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    Typically when a capacitor dies, it shorts (as opposed to a resistor that opens). Take your reading and see if it would be abnormally low for a capacitor of the size your looking at.
  3. begreen

    begreen Mooderator Staff Member

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    Maybe take the blower to a local motor shop where they will have multiple start capacitors.

    Or... is this the part? I googled Black Bart stove parts and got lots of links. I'd give them a call and ask for the cap rating.

    http://www.servicesales.com/black-bart-stove-parts-c-20.html

    PS: I'm surprised to see a start cap on a motor this small. It seems like a replacement motor might not need one.
  4. bja105

    bja105 Member

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    Its a run cap, not a start cap.

    Typically, they fail open, not shorted. When the top "pops," from the oil overheating, it opens the internal contacts. None of which matters, since it sounds like the OP's meter checks capacitance.

    The manufacturer probably doesn't have specs on the cap, just a replacement part number, but it doesn't hurt to ask. Just make sure the motor wasn't superseded by one calling for a different capacitor.

    The motor should have the run cap data on its data plate, but you may need to remove a belly band to read it.

    If all else fails, and I need a new capacitor but don't know the proper value, I grab my box-o-capacitors and make an educated guess. If I think I need a 10uf, I'll grab 5, 7.7, 10, 12.5, and 15, and try each one, measuring amp draw on the motor's common. The cap that gives the lowest amp draw at full speed is the winner. You probably don't have a box of capacitors, though.

    Why do you suspect a run cap? Classic run cap problem on a blower is slow start up with a distinct 60 cycle hum pulsing at shortening intervals. It also will draw high amps, at or above rating plate.
  5. uaw239gm

    uaw239gm New Member

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    I'm no Einstein when it comes to repairs of this nature, just a single Mom fixing things myself out of financial necessity. I try and start with the little stuff first, in this case the thermo-disc and move on until I have eliminated each thing, one by one. Before the blower stopped working, I noticed that the blower speed was slow and unresponsive to the rheostat. Since the blower fan is on the back of the insert where I can not get to it, my hope was that something else went bad that I could replace. Removing this unit is not an option for me, both physically and lack of knowledge and I not going to just start replacing parts since most of them are rather pricey, as in the capacitor ....cheapest I've found is $29 + shipping, kind of much for a fairly ordinary single pole capacitor. Any additional help is greatly appreciated.
    PS I by-passed the rheostat and thermo-disc with an electric cord, running it through the capacitor, and all I got out of the motor was a hum. I forced my arm into the side space, barely reaching my fingers around the back to make sure that the blades would spin, but not with the power on........too scary for me since I can't see what I'm doing!
  6. Jags

    Jags Moderate Moderator Staff Member

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    This is gonna be a tough one without the ability to pull the insert. Even if it is the run cap, do you have the ability to change that out without pulling the insert??
  7. bja105

    bja105 Member

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    Did the blower wheel spin freely, and keep spinning after you let it go.

    If your meter reads capacitance, what was it? If it only reads resistance, you can't test a capacitor.
    Did you ohm out the windings?
    On blowers, almost every time I 'fixed' it by changing out the run cap, I had to go back and change the motor, too. If you are sure the motor is getting proper voltage and not running, you may as well skip the intermediate steps and change out the motor and run cap.
  8. uaw239gm

    uaw239gm New Member

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    The rheostat and capacitor are mounted on the front right side removable trim panel. My boiler guy tested the capacitor and basically told me that if it's a 5 uf it's good but if it's a 10 it's bad. I can spin the blower fan with my fingers but without being able to see it, I don't know how well it's spinning since touching it makes it stop. I'm thinking that it's a lost cause and I'll just have to live without using the thing. I actually pondered the possibility of mounting a smaller fan on one or both of the sides and just disconnecting the rear mounted one. I'm not sure if I have enough clearance for this or if it's even a good idea. I think I'm just burnt out on being a home owner..... 25 years of fixing things has me worn out.. anyone wanna buy a house cheap? LOL

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