Too much draft or user error?

[Hinker25]

Hey all, wondering if I have a draft issue. Stove was new in July it is a hearthstone castleton. Used it this weekend. Heats house great but feel like I am not getting the optimal efficiency. Chimney is also new this year and it is installed on the main floor of a ranch style house with 8 foot ceiling. Chimeny is mostly vertical except for 2 bends to get away from the middle ridge of the roof.

My issue is fairly active flames even with air control closed as much as possible. I start a fire and engage the catalyst after the thermometer is in the active region. Turn air control down to low in a few steps. Initial wood burns down over a few hours and time for a reload. Open bypass and put large splits in fairly tight. Close door with air control open to get them charred. Close air down again all the way and engage cat.

At this point the secondary is active for quite a while and can see flames coming up from wood in middle of chamber for at least an hour before it slows down and the cat thermometer goes into the too hot range so I open the bypass to help it cool down.

It's been 2 hours since I did a reload and cat is engaged and air lowered all the way and have wispy flame but mostly glowing embers. It looks like most of the wood is consumed already. I feel like I am doing something wrong especially since the cat gets too hot after the reload with air lowest setting. There is no damper installed.

 

[Hinker25]

Here is a picture of the firebox 3 hours after adding 3 large hardwood splits. After I added them I turned air to half right away and the after they were starting to catch I turned air to low and engaged catalytic. It ran really well for 3 hours but I checked back and now it was like this with cat thermometer right on edge of too hot.

 

[begreen]

Doesn't look bad. A new cat is going to run hot for the first several fires.

 

[Kvic]

I just experienced the same thing last weekend with a Buck stove installed in July. Don't know how I missed this, as I was scouring the forum looking for answers. I didn't do a reload on my first burn, but the cat got close to the max temp range but eventually dropped. On the second one did a reload and had flames similar to yours but about 30 minutes after the reload and cat got toward 1600 deg. Talk about pucker factor.

I opened the bypass as well to help cool it down, but a response from Highbeam on my thread said not to do that as it could cause damage to the bypass opening.

Looks like fun in store for both of us learning new cat stoves.

 

[GM80NY]

I would like to bump this. Tonight is the second night I've had a similar experience.

I loaded 6 splits. 3 on the bottom N to S and then 3 more E to W. Air fully out. I leave the bypass open until I get some decent flames. When CAT gage is in Active. Then engage the CAT and let it run for a little while. Manual says it also cleans the CAT to let it run for 20 mins on high. Anyway I lower the air to just above the Med-Low area and after a while the flames stop and I can see wood is going to red coal stage but the CAT temp keeps climbing. I don't want it to go into the too hot area. I close the air fully until things sort of stabilize and then it runs fine but it gets kinda scary since you're supposed to not run it in the too hot area. I can totally tell when the CAT is getting close to the line just by (cast iron) smell and how heat radiates out of the front.

I also can look into the top from the front and you can see the CAT is glowing red. I have some pictures but I mean its just mostly blackness but you can see the red line in the top.

The other thing is I am not sure how accurate the cat gage is. You can make it go down just by cracking a window and having cold air blow on it. I don't use anything currently to monitor temps other than the CAT gage. I do shut the lights off to see if anything is glowing but only thing I've seen red is the CAT.

UPDATE 21:55: so with the air fully closed I'm about 1/4 inch below the nono line on the CAT and flames are just dancing in the top like normal. I may wait a bit and open the air slightly now. Finally can go to sleep. Anyone ever hear their chimney make noises every so often? I assume its the rapid heating and cooling.

 

[begreen]

I would like to bump this. Tonight is the second night I've had a similar experience.

I loaded 6 splits. 3 on the bottom N to S and then 3 more E to W. Air fully out. I leave the bypass open until I get some decent flames. When CAT gage is in Active. Then engage the CAT and let it run for a little while. Manual says it also cleans the CAT to let it run for 20 mins on high. Anyway I lower the air to just above the Med-Low area and after a while the flames stop and I can see wood is going to red coal stage but the CAT temp keeps climbing. I don't want it to go into the too hot area. I close the air fully until things sort of stabilize and then it runs fine but it gets kinda scary since you're supposed to not run it in the too hot area. I can totally tell when the CAT is getting close to the line just by (cast iron) smell and how heat radiates out of the front.

I also can look into the top from the front and you can see the CAT is glowing red. I have some pictures but I mean its just mostly blackness but you can see the red line in the top.

The other thing is I am not sure how accurate the cat gage is. You can make it go down just by cracking a window and having cold air blow on it. I don't use anything currently to monitor temps other than the CAT gage. I do shut the lights off to see if anything is glowing but only thing I've seen red is the CAT.

UPDATE 21:55: so with the air fully closed I'm about 1/4 inch below the nono line on the CAT and flames are just dancing in the top like normal. I may wait a bit and open the air slightly now. Finally can go to sleep. Anyone ever hear their chimney make noises every so often? I assume its the rapid heating and cooling.

What stove is this with? If you want less dramatic fires then load it differently. Criss-cross loading allows a lot of air between the splits encouraging rapid combustion.

 

[neverstop]

I would like to bump this. Tonight is the second night I've had a similar experience.

I loaded 6 splits. 3 on the bottom N to S and then 3 more E to W. Air fully out. I leave the bypass open until I get some decent flames. When CAT gage is in Active. Then engage the CAT and let it run for a little while. Manual says it also cleans the CAT to let it run for 20 mins on high. Anyway I lower the air to just above the Med-Low area and after a while the flames stop and I can see wood is going to red coal stage but the CAT temp keeps climbing. I don't want it to go into the too hot area. I close the air fully until things sort of stabilize and then it runs fine but it gets kinda scary since you're supposed to not run it in the too hot area. I can totally tell when the CAT is getting close to the line just by (cast iron) smell and how heat radiates out of the front.

I also can look into the top from the front and you can see the CAT is glowing red. I have some pictures but I mean its just mostly blackness but you can see the red line in the top.

The other thing is I am not sure how accurate the cat gage is. You can make it go down just by cracking a window and having cold air blow on it. I don't use anything currently to monitor temps other than the CAT gage. I do shut the lights off to see if anything is glowing but only thing I've seen red is the CAT.

UPDATE 21:55: so with the air fully closed I'm about 1/4 inch below the nono line on the CAT and flames are just dancing in the top like normal. I may wait a bit and open the air slightly now. Finally can go to sleep. Anyone ever hear their chimney make noises every so often? I assume its the rapid heating and cooling.

Initial fires with my hearthstone also dae the cat gauge climb very high. A week into burning it doesn't spoke like that anymore.

Your current issue sounds like your shutting down the air too late and too quickly. If you get a good char and quickly snuff the flames out the wood will continue to off gass and the cat is the only thing that will burn off those combustibles instead of primary/secondary flames. The more off gassing the more the cat has to burn, hence the red glow.

Ideally, you want to burn most of the off gassing via secondary combustion and the cat is just there to clean up any remnants. I know with my stoves primary air control 25%-0% does not feel like linear adjustments.

 

[stoveliker]

A note to keep in mind is that closing the air more could increase the temperature on the cat as well; it results in more half-burned gases (due to smoldering) that are precisely the fuel for the cat.
So thinking the cat gets too hot (and new cats often get very hot, but that's normal, and if not persistent for 10s of fires, it should be no problem), and then decreasing the air, can increase the cat temp.

But I would not open the bypass; depending on the stove (brand, design) it could damage things.

 

[Ashful]

A note to keep in mind is that closing the air more could increase the temperature on the cat as well; it results in more half-burned gases (due to smoldering) that are precisely the fuel for the cat.

Yep, this is fine, and not inaccurate to say. But does little good to the guy whose cat temp is spiking. I remember being in exactly this situation with my three old Jotul cat stoves, and never did find a good solution, once in this position. Turn a raging stove down, and cat temp momentarily spikes. Turn it up, and it just runs away even farther, leaving you even more to reign in.

The only solution I found to that problem was prevention, never let it get to the point of getting hot enough to spike the cat temp. It was a bad situation, only eventually solved by selling those stoves, and replacing them with a brand/model that doesn't have such problems.

If I ever owned another cat stove that put me in this situation more than once, my solution would be very quick and simple: sell it.

 

[GM80NY]

Your current issue sounds like your shutting down the air too late and too quickly. If you get a good char and quickly snuff the flames out the wood will continue to off gass and the cat is the only thing that will burn off those combustibles instead of primary/secondary flames. The more off gassing the more the cat has to burn, hence the red glow.

This is pretty much what I suspected. The stove was installed late Feb this year. It happened once earlier in the year and once again last night but this is what I attributed it to.

I am trying to get as long of burn times as possible but the one thing I fight with in my brain is just piling logs on even hot coals next to each other and worried I will snuff the fire out. Still learning getting the best balance here. I don't think it's an issue just a thing to be aware of in the future.

Thanks for all the feedback guys! This should definitely be a warning to any CAT Stove owners I think. There's nothing in the manual that warns about this or any info on how to handle it. I think I've read the section in the manual about loading and starting about 50 times already lol.

 

[GM80NY]

A note to keep in mind is that closing the air more could increase the temperature on the cat as well; it results in more half-burned gases (due to smoldering) that are precisely the fuel for the cat.
So thinking the cat gets too hot (and new cats often get very hot, but that's normal, and if not persistent for 10s of fires, it should be no problem), and then decreasing the air, can increase the cat temp.

But I would not open the bypass; depending on the stove (brand, design) it could damage things.

Yep. I like to engage the CAT as early as possible so when the gage is hanging on the line with the bypass open, if there are good flames a blazing I will just shut the bypass and it will jump into the Active Zone quickly. I will leave the air all the way out for 5 to 10 to also clean anything that built up on the CAT before I lower the air.