Buck 91 wiring question

Kyle Baker

Member
Nov 12, 2013
2
Terre Haute, IN
I recently purchased and installed a used Buck 91 (2010) I'm using as an insert. On first burn, the blower burnt up so I purchased and installed a new one. The previous owner had replaced the blower already, he put in an older three speed motor and rheostat, but did not have the three speed thermostat. Right now I have the blower hooked directly to the power, but I'd like to get it working with the rheostat and thermostat. The thermostat is in the stove (was not wired). The rheostat is three speed, so I assume I need to purchase a two wire rheostat? The stove did not come with a manual, and the wiring diagram for the new 91s does not help as I do not have the on/off/auto switch on my model. So looking for some advice on wiring this one up. I've contacted Buck, but still waiting for a response.

Thanks
 

begreen

Mooderator
Staff member
Nov 18, 2005
84,238
South Puget Sound, WA
Not sure about your model, but many Bucks do not use a rheostat for speed control. Instead there are 3 thermostatic snap switches that control the speed for high, medium and low speeds. They are wired to respective windings on the 3 speed motor.
Buck Switch.jpg
 

Woody Stover

Minister of Fire
Dec 25, 2010
12,160
Southern IN

begreen

Mooderator
Staff member
Nov 18, 2005
84,238
South Puget Sound, WA
Thanks Woody. I was wondering if they had changed configs. The OP said his stove had a 3 speed motor which would require the older config to use the motor speeds properly. I'm not sure if the windings on the 3 speed motor would heat up excessively at low speed using a VF speed controller which I believe is mistakenly called a rheostat on the diagram.
 

Kyle Baker

Member
Nov 12, 2013
2
Terre Haute, IN
Thanks to all for the replies. The blown motor was the three speed motor, but the guy I bought it from said this was not the original motor. The stove did not have the three speed thermostat, so best guess is the original owner found a deal on this three speed motor and rheostat and threw them in there. My dealer suggests the same as Woody above, going back to original, though I don't have a spot for the on/off switch on the side. I could mount it near the rheostat. The new motor is not a three speed.
 
Last edited:

begreen

Mooderator
Staff member
Nov 18, 2005
84,238
South Puget Sound, WA
With the proper motor you might be able to use a Broan bath fan speed control that has an on/off switch wired in. Just be sure it is rated correctly for the load.
 

coltfever

Burning Hunk
Jan 4, 2011
146
Middle Tennessee
I never liked using rheostat so I made this change as soon as i got my Buck 91 and it works great. The wiring is simple and was taken off the diagram like you were looking at on Woody's input. As you will see in picture at the right is what come with the stove. I ordered a 3 speed motor from Buck supplier and picked up a 3 speed switch at Lowes and placed where the rheostat was mounted. I wish my drawing was better where you could see how it is wired. Used the same thermostat and on/off auto/manual switch. You can see mounted on the grill. My reason for doing this change is because fan is smooth and quite on low speed. Some motors tend to have a hum noise when running on lowest rheostat speed and I dont care to listen to.
 

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