Constant Snap Disc Fan Issues

[scfa99]

Alright I'm on my 3rd snap disc fan since 05. I have a quad 7100 and the fan is wired into a switch on the wall that allows you to run it constantly or you can flip the switch down into the "off" position which then has the fan kick on when the stove gets up to temperature. this feature is really nice and allows me to let it run at night without fear of overfiring and it shuts off once the stove cools down. now the problem is that since we've had the quad it never works in the off position for more than a couple of weeks. it then stops working for long periods of time and then starts working again. the dealer has been out a few times and I think they've replaced the snap disc a couple times. not positive since i wasn't there and my wife doesn't ask questions.

they've been out twice this year, first in the fall and again just a couple of weeks ago they replaced it for sure. it worked properly for a week and then poof, it won't turn on no matter what the temp, i even got it up to 500+ surface temp for a few hours and it wouldn't kick on. then the next day it kicked on when it got up to 200.

anyone have any ideas on what it could be?

 

[kenny chaos]

Alright I'm on my 3rd snap disc fan since 05. I have a quad 7100 and the fan is wired into a switch on the wall that allows you to run it constantly or you can flip the switch down into the "off" position which then has the fan kick on when the stove gets up to temperature. ?

That makes no sense. A snap switch will only work when up to temp.
It can't do both as you claim.

 

[Corey]

Hard to say...intermittent troubles can sometimes be the result of a bad connection. Next time it's acting up, try tapping the switch likc czar says, or if you've got a volt meter, see if there is voltage to the snap switch. If you can really dig into it, identify which side of the snap disk is the 120V side and which is the motor side and see if you've got voltage from each side to ground.

If you have no power to the 120V side, then something is wrong with your wall switch or wires back that way. If you've got power on the 120V side, but not on the motor side, something's wrong with the snap switch. If you've got power on the 120V side and on the motor side, but the motor is still not working, then you've got an issue with the wires from the snap switch to the motor or a bad connection at the motor, or the motor itself. You could then check for voltage at your wall switch and/or motor to further nail down the cause.

Edit PS: Kenny, if you've got a three-way switch on the wall, it can send power directly to the motor to run it all the time, or send power to the snap switch in which case the motor will only turn on when it's up to temp. I've got my blower set up this way, so it's entirely possible and actually works pretty well.

 

[kenny chaos]

Edit PS: Kenny, if you've got a three-way switch on the wall, it can send power directly to the motor to run it all the time, or send power to the snap switch in which case the motor will only turn on when it's up to temp. I've got my blower set up this way, so it's entirely possible and actually works pretty well.

Ohhh. Okay. Thank-you.

 

[raybonz]

Alright I'm on my 3rd snap disc fan since 05. I have a quad 7100 and the fan is wired into a switch on the wall that allows you to run it constantly or you can flip the switch down into the "off" position which then has the fan kick on when the stove gets up to temperature. this feature is really nice and allows me to let it run at night without fear of overfiring and it shuts off once the stove cools down. now the problem is that since we've had the quad it never works in the off position for more than a couple of weeks. it then stops working for long periods of time and then starts working again. the dealer has been out a few times and I think they've replaced the snap disc a couple times. not positive since i wasn't there and my wife doesn't ask questions.

they've been out twice this year, first in the fall and again just a couple of weeks ago they replaced it for sure. it worked properly for a week and then poof, it won't turn on no matter what the temp, i even got it up to 500+ surface temp for a few hours and it wouldn't kick on. then the next day it kicked on when it got up to 200.

anyone have any ideas on what it could be?

Just a guess that the contacts are arcing when opening and closing the load causing the contacts to fail.. You could have the snap t-stat pull in a relay when then applies power directly to the motor via the relay contacts pretty much eliminating any arcing contacts.. I would also check that the snap switch is actually seeing the heat where it is mounted.. If the area is hot then you can also try applying heat sink compound the where the switch contacts the stove to enhance heat tranfer..

Ray

 

[DAKSY]

anyone have any ideas on what it could be?

I'm willing to bet it's the snap-disk...
HHT had a LOT of problems with the disks in the Northstar system &
while I don't know for a fact, I'd guess they probably use the same set-up
in the quad in order to keep inventory down...
Fortunately, the double switch system allowed you to override the disk so you could turn the blowers on...
The originals in the Northstar used to melt, so they ended up with a new design...
See if your dealer can get you one from a Northstar, it may be more durable...

 

[Jags]

Or forget the whole mess and go with a stove stat. Been running one for many years flawlessly.

 

[73blazer]

I have a manufactured in fall of '08 NorthStar, and my disc is working pretty good.
I do notice, when alot of ash builds up, it takes the disc much longer to kick on, sometimes not for hours.
After a tip from someone here, I started scraping away the ashes in the center and getting only red hot coals in the center strip area, and the disc works as it should when I keep that.
I went looking for a solution the first day it didn't turn on for a couple hours (well, I kept the bypass on), I had just started a fire on a large ash bed, and that wasn't working at all. Until I got those ashes out of there, it wasn't coming on. Chimney temp (I have a thermo behind the front plate stuck to the chimney, so I peer in the top grate area and can read it) was up to 650, and it still didn't kick on until I got those ashes out of there.
Not saying it's your issue, yours sound a little more dire, but you might check how much ashes your letting build up in the center portion there. The disc is underneath the firebrick, under the steel door under there, so add some insulating ashes on top of that, and I can see how that happens.
I do like that 3rd party stove stat switch though.

 

[jtp10181]

SCFA, its possible the contacts fell off the disc or are metled and need to be replaced. If you take the center bricks out there is an access plate with two screws in it. Pop that up and the snap disc is mounted to the bottom of it. I have also seen when replaced sometimes people do not get it in there right so its not toughing to bottom of the plate, check that also. If you have BOTH the switch and speed control off you will not have any live power at the connectors on the snap switch.

 

[scfa99]

First I'd like to thank everyone for all the replies/advice.

Cozy heat is correct, I do have a 3 way connection I forgot to mention that in my original post.

I think I found the solution. 73blazer's post really got me to thinking and made alot of sense why the snap disc would suddenly start working for a few days and stop again. Per the instructions from the dealer I usually leave a good base of ash in the firebox and rarely ever do a full clean out. So the center area where the disc is located usually has an inch to 3 inches of ash. So thinking back to when the fan worked in the past its usually after I do a full clean out of the firebox. So this am I still had a lot of hot coal but I scooped as much ash out as I could and then clear out the middle section. Threw a couple of splits on, turned the wall switch to the down position (automatic) and came back a few minutes later and it was running.

I'll give it a week to see if its definitely the fix but my gut tells me it is. Thanks again everyone.

 

[jtp10181]

Hmmm... I thought I told you the trick about cleaning the ash from the center when you realod on a different post.... maybe not. That was my first guess but I was assuming that you already knew that