Keystone bypass damper?

[RailProf]

Hi all,

We have a Keystone that we bought new and had installed back in 2010. Changed the cat from the older ceramic one to a newer stainless steel one about 3 years ago. We love it! It's a great little stove and serves us well here in the Missouri Ozarks. It won't quite heat the house on cold and cloudy days, but works very well for our variable weather where it's 20 one day and 55 the next.

I've noticed it's been showing visible smoke, even when operating well with the cat on and damper closed. Changed the cat from the older ceramic one to a newer stainless steel one about 3 years ago. After a close look yesterday during a cleaning, the bypass damper isn't fully shutting all the way. It's leaving a small gap, 1/4 to 1/8 of an inch. This gap lets some smoke through, but not enough to really affect heat output. After a good cleaning I got the gap smaller, about 1/16 but it still won't fully close. I plan to do a very thorough cleaning after the season is over or during the first really nice spell in March, but should I plan on replacing anything? New gasket at least? Anyone have anything similar happen?

 

[Kamiobi]

Hi all,

We have a Keystone that we bought new and had installed back in 2010. Changed the cat from the older ceramic one to a newer stainless steel one about 3 years ago. We love it! It's a great little stove and serves us well here in the Missouri Ozarks. It won't quite heat the house on cold and cloudy days, but works very well for our variable weather where it's 20 one day and 55 the next.

I've noticed it's been showing visible smoke, even when operating well with the cat on and damper closed. Changed the cat from the older ceramic one to a newer stainless steel one about 3 years ago. After a close look yesterday during a cleaning, the bypass damper isn't fully shutting all the way. It's leaving a small gap, 1/4 to 1/8 of an inch. This gap lets some smoke through, but not enough to really affect heat output. After a good cleaning I got the gap smaller, about 1/16 but it still won't fully close. I plan to do a very thorough cleaning after the season is over or during the first really nice spell in March, but should I plan on replacing anything? New gasket at least? Anyone have anything similar happen?

Look at the manual and you can see how to adjust the damper door. It can also get warped if you have overfirred it. If that is the case, you may have to replace it.

 

[DBoon]

I'll have to check my bypass damper out when I clean the stove in the spring. I've found that the lever can accept a little harder "push" to close it - not sure if that closes a small gap or not. Maybe that is why I see a little smoke during a really hot burn?

 

[Woody Stover]

I'll have to check my bypass damper out when I clean the stove in the spring. I've found that the lever can accept a little harder "push" to close it - not sure if that closes a small gap or not. Maybe that is why I see a little smoke during a really hot burn?

Yes, it should require a somewhat firm pull of the lever, and you should feel it "cam down" as it compresses the gasket.
After 12 years, it's definitely due for a new gasket. I'd just go ahead and get the kit and do all the gaskets.

Look at the manual and you can see how to adjust the damper door. It can also get warped if you have overfirred it. If that is the case, you may have to replace it.

Yeah, if you have a raging fire in the box when ramping up a new load, either the bypass door or the bypass frame might be warped.
If not, the gasket instructions are here, under "Gasket Maintenance Kit."

Keystone 204 Maintenance Documents

Interior Exploded View Exploded View Diagram (Stone) Frame Exploded View External Exploded View Catalytic Combustor Replacement Combustor Scoop Replacement Bypass Cover Replacement Bypass Frame Replacement Bypass Lift Guide Replacement Door Knob and Latch Replaceme

www.woodstove.com

 

[Woody Stover]

If you do the glass gasket, keep track of which sides of the windows are in and out. They may have coatings on one side but I'm not really sure in the case of the Ks. I just remember changing mine, seeing that was the case on some stoves, then not remembering how well I kept track.
You could email Woodstock for clarification..

 

[DBoon]

it should require a somewhat firm pull of the lever, and you should feel it "cam down" as it compresses the gasket.

OK, good to know. I'll have to give it the harder pull and see if that changes how my stove burns once I get another load in there.

 

[Woody Stover]

OK, good to know. I'll have to give it the harder pull and see if that changes how my stove burns once I get another load in there.

It's not too hard to adjust, if need be.
I changed my gasket a while back, and cam-down is really a bit too tight. I should tweak the tension because if that area gets a bit hotter than normal burning in a load, some metal expands and the cam-down requires what I consider a bit too hard of a pull. I think I overshot it some, tensioning it to be kind of firm after I installed the gasket when the stove was dead cold.
If your bypass door isn't camming and closing tightly, that could definitely be contributing to more smoke than you want to see in the plume. You don't even have to wait for the next reload; At the end of the current load when the stove has cooled some, try giving it a firmer pull and see if it's camming down. I'd think it was adjusted right when they put the stove together, so I'm guessing it might be working, you just need a firmer pull.

 

[DBoon]

My stove has been taking some time off with my being away and now warmer weather. It will definitely get a workout starting on Thursday night or Friday morning, so we'll run some experiments with the bypass pulled closed a little bit "harder" and see what happens to any smoke coming out the chimney at the peak burn temperature.

 

[DBoon]

The Keystone is back running again with the colder weather, and I've discovered the cam action on the bypass that Woody Stover mentioned earlier. I don't think that was all of my problem with "smoke blowing past the cat" but it seems to be part of it.

I think the presence of a wetter wood also creates some localized dark (cold) spots in the cat that cools it down and allows smoke to pass - I will need to observe that more.

I'm not sure if I'll be recreating my 650 degree F stovetop conditions again anytime soon with warmer weather expected and with my increased knowledge of how to shut the stove down earlier and on a larger coal bed, which gives me more control to flatten the burn cycle and eliminate the faster temperature rise and bigger peak in temperature, which might have led to higher exhaust temperatures and velocities, potentially not giving the cat enough time to burn through all of the smoke.