Understanding Catalytic Stove Combustion - Is mine working right?

[Boomstick Bruce]

Hi all,

I purchased a Hearthstone Heritage IV catalytic wood stove. I've just started to proper use it and despite absolutely loving it so far, I am still unsure as to if I'm working it properly and if (heaven's forbid) I might not have a problem with my catalyst...

I've been reading a lot about operating wood stoves and catalytic combustion in general and I can't really square everything I'm reading with the way my stove operates. Here's what I understand from my searches :

1-You don't want your fire to start smoldering. You want to maintain a proper burn, otherwise your fire will generate a lot of smoke and you'll get a lot of creosote buildup.

2-A catalyst will basically "burn" the smoke/gases generated by the fire. Because of this there will be much less creosote buildup in the flu and the stove will emit a lot less pollution. It also has the added benefit of having to burn less wood to achieve the same heat output.

Now here's my issue :

My Heritage IV burns perfectly as long as its in the normal operating mode. When the stove reaches the proper temperature range (as indicated on the catalytic probe) and I shut the bypass door (and in so doing activate the catalyst), all the flames in my stove tend to die out within 1-3 minutes. If I open the bypass door and stop the catalyst, the flames return in about 1-3 minutes. The embers remain regardless.

A couple of times now, I tried pushing the heat up, loading wood, activating the catatlyst and then going to bed. As mentioned, the flames die out and only the embers remain. But the following morning, there's nothing left in the stove. Slowly but surely all the wood burned. When I did the same thing and checked on the stove periodically, I noticed that the temperature on the probe would rise, despite an absence of flame.

I called the store where I purchased it and explained that I have no prior experience with catalytic stoves and therefore don't really know what to expect from a catalytic combustion. The vendor says that I should push the temperature even higher (to about 2/3 into the catalytic combustion range), open the air controls to maximum and then activate the catalyst. He says that a catalyst acts like a damper and therefore the fire will normaly slow down, but I should still see flames. I asked him if there are any other probes that I could get aftermarket that would be more precise in indicating when to activate the catalyst. He said that Hearthstone designed the probe specifically for my stove and that I shouldn't replace it.

But that kind of begs the question.... if Hearthstone designed the probe specially for the stove, why wouldn't the catalystic combustion start as soon as the stove reaches the temp. indicated on the probe? I don't quite understand why I whould have to reach 2/3 into the indicated catalytic range before the catalyst actually kicks in...

So yeah, for all I know, I don't even have a problem to solve here.

My reasonning was that since a catalyst burns the smoke/gases, there might not be an issue. Because of its damping effect, the flames would normally die out. But because the smoke would be burned away, there's no problem with a smoldering fire.

But I'm also thinking that should I have a problem with the catalyst, it might be acting as TOO much of a damper and cutting off any circulation, therefore killing the fire. I've barely burned half a cord of wood so far so I can't imagine that the catalyst would be clogged but, heh... i wouldn't really know. And I'm thinking if that were the case, even the embers would eventually die out. But the stoves always burns through all the wood.

So yeah.... what gives? I just want to make sure I'm not clogging up the catalyst or generating massive creosote buildup by allowing the flames to die out and the fire to smolder.

Many thanks for any help you all can give!

Cheers!

 

[kennyp2339]

Question, when you wake up is the house cold or warm? If you shut the damper in the daylight and let the cat do its own thing then check the chimney an hour later is there any smoke coming out of it?
There was a poster here not to long ago that also complained that they were having issues with flames going out when they engaged the by-pass, unsure what the end result was though.
Also check your wood supply, buy a meter, take a room temp split, re-split it and test the fresh face, should be under 20% to rule moist wood as the source of your issues.
Also how long of a chimney run to do have, when the by-pass in open and you open the loading door, do you get any smoke roll out?

 

[stoveliker]

Check your cat temperature gauge every hour after you close the bypass (to check now, obviously not always needed...). If it remains in the active area, you're good.
That is, the wood is smoldering, and the cat is eating the smoke. Indeed, see if smoke exits the chimney.

If you need more heat, increase the air control. I.e. provide more air to the fire. This will increase the burn rate (decrease the time until the wood is gone), and in doing so create more flames.

How tall is your chimney? If short, even an open air control might result in smoldering.

 

[Woodsplitter67]

I second the test your wood. Most new people here have subpar wood that makes issues for the new user. The weekend is here so I would burn during the day and engage the cat wait 15 minutes and check your chimney to see what is coming out. Smoke is a darker gray and will not disappear right away. If the cat is running and the stove is operating as it should, then what comes out the chimney is a white almost steam looking color and it will dissipate like around 10ft from the cap. Take some notes on how your operating the stove and where the probe reads. Once you getting running right you can replicate how you operated it.

 

[kennyp2339]

I don't quite understand why I whould have to reach 2/3 into the indicated catalytic range before the catalyst actually kicks in...

I believe the dealer is basically telling you to let the fire get more situated before engaging that cat, figure in the basic fire growth stage of the burn, a fire can double its size every 30sec so if it takes another 15min from active cat range to 2/3 range then the fire had a real good chance to get seated well.

 

[gthomas785]

It sounds like your stove is working correctly and your wood may be a bit damp.

 

[whatyousmokin]

I have the Heritage 8024 cat stove and am a rookie at operating it, so take my experience for what it's worth. What I have observed is if I am burning with the cat activated and it's operating in mid-range, I need to play around with the air flow to maintain visible flames. If I push the air control all the way to the right (reducing air flow) I lose flames but the wood glows bright (and will eventually all burn to ash by morning). If I push the air control a little to the left (opening it up) with the wood glowing bright, the flames return. If I have the air flow exactly where I think it should be, the flame "dances' in what seems like slow motion; I have read flames like that are referred to as "northern lights". Again, I am a rookie at this and the more experience I gain, I may change my approach as to how I operate this beautiful stove most efficiently.

And your reasoning here is pretty much my thoughts too: (I will often turn air down all the way at night and let it burn down with no visible flame--it is good and hot and operating just fine)
"My reasonning was that since a catalyst burns the smoke/gases, there might not be an issue. Because of its damping effect, the flames would normally die out. But because the smoke would be burned away, there's no problem with a smoldering fire."

 

[begreen]

I asked him if there are any other probes that I could get aftermarket that would be more precise in indicating when to activate the catalyst. He said that Hearthstone designed the probe specifically for my stove and that I shouldn't replace it.

The main thing specific is the probe length. A Condar catalytic probe thermometer can be bought by matching the probe length.