Help me diagnose a Buck 27000 blower problem.

[Samjo]

Howdy folks....new guy lookin' for advice.

The Buck 27000 insert was installed in 1979. It's one of the earlier models, because the thermostat used to be located at the rear.

Over the years, I've replaced the motor a couple of times, most recently in the winter of 2009. Last year, I replaced the thermostat, with the new three puck style, mounted in the front.

Here's what she's doing.

When I build a fire, she works fine. Kicks on like it should, but if the fire gets hot enough that it should jump to high speed, then the motor quits altogether. If I let the fire die, as the temp comes down, it will kick back on and start blowing again, on what I think is medium speed.

My first thought was that there was a problem with the High speed thermostat puck, but here's where I get confused. When it knocks off, the manual switch will not work either. Shouldn't the manual switch override the thermostat all together?

Last night...just as a test, I built the fire, and flipped the switch to manual and let it run. Sure enough...when the fire got good and hot, the motor stopped. Flipping the switch back and forth at this point did nothing.

I've looked again at my wiring, after I downloaded the diagram, and I'm fairly certain I have it wired correctly. The only mistake I see with the installation, is that I might have it mounted just a little low. The instructions I downloaded last night says it should me mounted 2 1/2" down from the top of the stove, mine's probably 4" down. Must have missed that on the first install.

It's flat against the fire box, so I don't think that little bit of distance is causing the problem.

Do these motors have some kind of over heat protection built into them that would cause it to knock off?

Do you think the motor's going bad again?

I don't really know how to test it, even if I pull it back out, cause it's gotta be pretty hot for it to knock off.

I'm open for suggestions on what steps to take to figure this out.

I'm about ready to wire it to a 4 position manual rotary switch, and make it manual operation, but I really don't want to do that.

Any ideas?

Thanks in advance for the help.

Sam

 

[begreen]

Did you check with Buck to make sure that this snapdisk set it ok to use with your motor. It probably is, but it doesn't hurt to ask. If so, the perhaps you have connected to the wrong leg of the switches? Or the assembly is upside down?

Can you post a picture of the snap switches in place?

 

[rwhite]

Almost sounds like you have a normally closed disc that opens when hot.

 

[Samjo]

I took a pic with my cell phone....but you really can't see much with the intake grate in place. I have to get up pretty early tomorrow....so I don't want to take the time to take it off tonight. Here's a pic off the net of the exact thermostat unit I have. It's mounted with the red/low sensor on the bottom, and the white one to the top.

I haven't talked to Buck...never even considered that the thermostat might not match to the motor. The motor is three speed, and the thermostat is for three speed, so I guess I just took for granted they'd all be the same.

Let me know if I need to remove the grate, and get a detailed pic of my actual unit.....I can do that tomorrow.

Thanks for the quick response.

http://www.maconspas.com/sitebuildercontent/sitebuilderpictures/Buck_Stove/Buck3-speed.gif

 

[rwhite]

IIRC snapdiscs parts #'s should start with an "L" or an "F". Which is limit or fan. The last 3 #'s are the cut out temps for an "L" switch and the cut in temp for a "F" switch. You should have "F" switches on a wood stove.

 

[begreen]

Yes, I think the motor is wired to the wrong contacts on snapdisk 2 and maybe also 3. A clear photo of the actual wiring may help sort this out. Note there are both normally open and normally closed contacts on snap disk 2 & 3. Also, per service sales website, they recommend replacing the wiring harness when updating the thermostatic disk assembly.
http://www.servicesales.com/buck-stove-repairs-i-9.html

Here's the wiring diagram:

 

[central_scrutinizer]

First, check to see if the thermostat and motor are wired properly by following the wiring diagram. Now, if the motor is cutting out when the switch is in the manual position, this means that the motor is overheating. The motor has a thermal protector in it and will shut off when it gets too hot, then come back on when it cools down. The solution here is replacing the motor. Just to rule out the thermostat, you may want to test it. I have a little rig that I hook the thermostats to and heath them up. Different colored lights come on as the individual disks close. You may have to test each one individually with a meter. I still think it is the motor. You can try to oil the motor with transmission fluid, putting a few drops in each end. You will see half-round openings where the end caps of the motor attach to the body of the motor. You will need to un-mount the motor to get to the front oil port near the shaft. It is tucked too far into the motor housing to get to without taking it off. Oiling the motor may get you by for a while. Then again, it may not. I thing the thermostat position should be fine where you have it. Good luck!

 

[Samjo]

That's the same diagram I downloaded, and have been going by.

I still think I'm wired right, but the only thing that would make me question it is that the "Blue" wire, on my stove looks more White, than blue. The pic below is of the three wires coming from the motor, to the thermostats. Red is obvious....and black looks obvious, but the white has a slight baby blue tint to it. I'm taking for granted that's blue. It looks more white than blue to me. That's the one I sent to the middle snap disc. I can't remember if I purchased a new wiring harness when I bought the thermostats, but I figure I must have, or they probably wouldn't reach.

I didn't change any of the jumpers that came already plugged on to the snap disc....I used the open plugs. The red/white striped wire from the switch, that goes to the High disc is plugged onto the bottom layer, closest to the "C" as the instructions say.

If y'all don't mind...take a look at these two pics, and see where you think I should go from here.

I still don't understand why, even if I did have the wires going to the wrong disc, why flipping the toggle switch to the manual position wouldn't override the thermostats all together. I keep leaning towards the motor getting too hot, and stopping, but it's not but a couple of years old, and I hate to replace it without being sure it's the problem.

I have to run to Macon...so I don't know if I'll get back to this thread tonight or not, but don't think I don't appreciate the suggestions.

Thanks.

http://img.photobucket.com/albums/v415/Samjo/BuckStove006.jpg

http://img.photobucket.com/albums/v415/Samjo/BuckStove008.jpg

 

[Samjo]

Thanks Central....I'm leaning towards the motor myself.

If I have to pull the heater, to get to the motor, I'll go ahead and replace it. Too much trouble to just "Get by for a while".

I might could test the thermostats by building a fire, and checking voltage on each one as the heater heats up. I have a point and shoot thermometer to give me an idea of which one should be hot at a particular temperature.

Alas...that will have to wait till another day....Bosslady says we gotta go.

Thanks again.

 

[central_scrutinizer]

From what I can tell, the wiring looks correct if, indeed, that is the blue wire. I don't know what other wire it could be. Flipping the switch to "manual" does by-pass the thermostat altogether. That is why I think the motor is the problem. Just because it is only two years old doesn't mean that it can't go bad. Why do you think they only put a 1 year warranty on them? haha

I think if you replace the motor you will be in fine shape. I have always thought that you should mount the thermostat in the stove so that the turned-up edge on the bracket is facing toward the front of the stove. To me, this would create a little dam for the air that is being pulled in by the fan and would prevent any cooling between the bottom of the thermodisc and the mounting plate. You are probably fine like it is, and in some cases the thermodiscs are as flush to the plate as they can possible be, just a little added insurance against shutting off and on. Whatever you do, make sure the thermostat is not touching the metal grate thing when you put it back on. You should be okay once you replace the motor. Check your housing gasket and rubber washer while you're at it, you may need to replace them as well.

 

[coltfever]

Here is something you might want to try. Without a fire in the stove take a hair dryer and you can check each one of the thermostat disk with it. Point the dryer at the lower disk which should be low ( 115 F ) after it starts move up to middle one ( 145 F ) then the top disk which should be high (175 F ). You might have to run hair dryer on high heat. You can test it that way without having a fire in your stove. When I bought my stove I went ahead and replaced my fan motor, 3 speed thermostat and wiring harnest with a new one just to be on the safe side even thought the guy I bought my stove from said all works good. Thats how I check mine before using. I enjoy my little Buck 26000 insert. Good luck and happy heating

 

[rwhite]

Could you isolate the high switch? Didn't know if it would be possible to remove and cap (temporarily) the blue wire, hook the black wire to where the blue was, and remove the jumper between the high and med discs?