Catalytic Combustor Health?

First post here. Been lurking, reading, and learning for a few months. Thanks for all the knowledge transfer.

Curious on your thoughts on the catalyst from our new wood stove. Stove was installed this past September. I'm new to a wood stove, but have been a long time burner in an open fireplace (which I'm also SMRT enough to know the techniques are not the same). Since it's currently 70 in New England, we haven't had consistent cold days. I actually cut the grass this past weekend in shorts and a tshirt. But over the last two months I was able to complete all of our break in fires. And was able to have 3 day long fires with stove top temps consistent about 500-550 with the Catalyst engaged for about 8-10 hours. The Catalyst temperature gauge also was within range for these burns. Stove is a Vermont Castings Defiant and I'm burning red oak that has been seasoned 3-4 years.

While it's been warm I decided to check out the catalyst after my first couple of fires. I immediately saw that there were a few pieces of the honeycomb missing. After removing the catalyst from the stove, I reached into the back chamber and found those missing pieces on the bottom (which are laying aside of the catalyst in the picture). By my count I'm missing 3 pieces - two were found intact. One was found broken in two pieces.

Do I press on and do nothing? Meaning, next cold day light a fire and heat my house like I didn't see it.

Do I try to reinsert these into missing locations? They seem very brittle and I suspect they will break.

Do I replace this catalyst? I'm under warranty and my assumption is they will replace the catalyst one time.

Thanks in advance!

 

There's no real way of fixing this, other than getting a new Cat. (at least to my knowledge) However, it's perfectly useable as is. It was possibly damaged in shipping, or installation. I'm not familiar with your exact stove and they've changed over the years, but if you bought the stove brand new I wonder if the pieces broke off during loading wood into the stove? Most cats are protected from taking direct hits from wood being inserted, usually there is some protection of the cat.

I'd would not be surprised if the dealer, would be giving you a new cat for replacement, as it is not really going to have a big or even small negative impact on your heating. The ceramic combustors like that one do deteriorate over time, but usually for much longer periods of time. I have a ceramic cat in my Woodstock Fireview, that I installed in December 2018. All I ever do for maintenance on it is take it out and give it a gentle tap on a wooden railing to get the ash dust out of it. A gentle vacuum might do the same thing. The point is they are somewhat delicate but they need very little maintenance.

The term combuster and/or cat I use interchangeably, I only use combuster here as that may be what Vermont Castings used to call them.

So welcome to the forum from another Massachusetts resident. I was down in Hyannis a month or so ago with my wife for a couple of days. We love the Cape but usually visit in the off-season.

PS please post pics of your stove installation. We LOVE pics!

Feel free for any questions, it takes time to become fully familiar with your stove and getting good burns that will certainly help with your heating bills this winter.

oldhippie aka Steve

 

Welcome to the club!

I'm down to the Cape several times a year. Are you able to get any black locust? I see it all over the area.

 

Nice to see some fellow Massachusetts guys here. Well I generalized my profile location as "Cape Cod", but the truth of it all I'm actually in Pembroke off of Rt 3 which is not even on the Cape. Caught red handed! I'll sulk in my steamahs and hard serve ice cream and my vineyard vines tshirt.

Oldhippie - Thanks for the input here. Very helpful. The cat in this stove sits raised up behind 2 refractory bricks that protect it from wood loading. So I think your theory of possible damage during shipping/installation may be valid. It's good to hear that you have a ceramic cat that has been running since 2018. I'm under the impression this will be a 2-3 year consumable and in this economy - I may buy 10 of them NOW before they rise another 100%. My stove manual recommends a very gentle cleaning.

MikeInMa - thanks for the welcome. I don't have any Black Locust - I have about 8 cords of red/white oak split and stacked in varying degrees of aging. One of the primary reasons for installing this wood stove is that my Wood Hoarding had increased to a level that my 1st floor fireplace was not going to consume (maybe 10-15 fires in there all year around for the ambiance and a little heat if you sit on the hearth). Plus cost of oil, a cold basement without heat where I work remotely, and our 2-3 week long yearly power outages. All the Nor'Easters that have blown through here the last few years take at least 1 tree every year on our property. And we cut down about 32 a few years back (a few Oaks but mostly 100 foot Pine trees with nasty leans toward the house). The Pine went to the wood chips. Throw in all of the hardwood I've cut, hauled, split, and stacked from the neighbors - it's an Oak hoard here. I do have a good friend who grew up around Hyannis and his family still owns and operates a large tree farm that specializes in mature tree movement and installations. I'll ask him if he has any leads. Have Saw, will travel!

Anyway - here's some pictures of our basement install. There's an even longer story as to why there is a Class A chimney aside of my multi-flue chimney. Stop by sometime on your way to ACTUAL CAPE COD and we'll share a bourbon and tell stories.



Lawn Chaney III (aka Lon)

 

Welcome to the FHC Lawn Chaney III
Just a hint throw an @ in front of name and it gives member an alert

I want to hear the story on the chimney

 

Canadian border VT PROOF that this site is educational

 

Do it!

 

Welcome Lawn Chaney great group of guys here always ready to help. I am over in Fairhaven if you ever need a place to cut give me a shout. We have 23 acres of mostly red oak many dead standing and blowdowns. As far as your stove goes I would definitely see if they will send you a replacement. If they do keep using the one you have as it looks ok . Then you will have a spare.

 

Thank you all for the warm welcome and opinions. Hope you all had a nice Thanksgiving.

I wanted to update as I took the catalyst out recently and see that it has gotten worse. Picture below.

As mentioned this is my first season, so admittedly lots to learn but things seem to have been going "decently" from my unexperienced but well read brain. Couple facts here to help baseline your opinions and feedback: Wood is red and white oak which has been minimally seasoned 2 years with a max of 4 years stacked and under top cover (we also have a regular fireplace on our 1st floor and I had a ton of wood). I just ordered a moisture meter so I can look at that more closely but I'm expecting (hoping) to see <20. My general operation is to light using top down and allow the firebox to fully engage and build some embers before closing bypass. STT is typically 550-650 before closing bypass (manual says once STT says 450 close down, but I have found this to be too early and too cool for Catalyst to light off). Reload currently is happening 4-6 hours with about 4-5 splits (larger in first, smaller on top). After reload, running stove with bypass open and primary air between 50-100% open for about 20 minutes, then closing bypass if flue temps and STT are up. I'm only burning on days when I am able to work from home and pay attention. So typically lighting a fire around 5-6am, with a reload around noon, then letting stove go out before bedtime (8-9pm). I'm not burning overnight as I'm just not experienced enough and the oil burner can take over from there while we sleep at a cooler temperature. Chimney pictures are above (about 30 feet of Class A). Stove picture is above too (VC Defiant Cat-C).

Couple questions for ya'll.......
1. Is it safe to assume that because the cells have fallen from that specific row, I'm experiencing something like a domino effect? Meaning, one cell fell out from that area and now it's weaker there, so neighboring cells are going to just keep falling from that row? Any predictions whether that will travel to other rows? What would be wise to look for in terms of performance issues?

2. While the stove is under warranty, I'm not getting anywhere with my local dealer I bought this stove from (completely expected - which is part of the reason we have a Class A aside of that multi-flue chimney). Because I'm just going to eat it and buy a new catalyst - considering going to a Steel catalyst instead of a Ceramic as Condar appears to provide some preferences on their website about this. Any guidance/thoughts/experience/preferences over one or the other? Is this a reasonable idea?

3. Now the question I'm dreading asking - rake me over the coals if you will. My manual says cells typically fall as a result of thermal shock. This could be attributed by loading with wet wood (again, don't think this is it, but I'll rule that out). Also could be due to excessive temperatures in the catalyst. I have experienced this only once thus far where the catalyst temperature probe approached the top end of the "operate catalyst range". I was able to control that by opening the primary and burning off more in the fire box which brought the catalyst temperature down. Any reason to think the damage I've experienced to this ceramic catalyst are a direct result of operator performance? Feel free to ask additional questions and I'll answer, but from my summary of operation above, anything in general you'd recommend changing?

4. And then one additional question - I've read through quite a few discussions in the forum about Black Glass on an EPA Stove and see this answered both ways. Some say it's a problem. Some say it's just an expected thing with EPA stoves. Let's open it up to the floor again - I am getting black glass typically on the left and right most sections of the glass. Not down the middle. I would call this soot as it's very easily wiped off using the wet paper towel and ash method before start up in the morning. I do plan to check out the inside of my pipe from the bottom of the Tee in the next few days just to take a look. But what say you? black glass in an EPA stove - be concerned? or just deal with it? 2nd picture below shows my glass situation. This is at a reload of only a few splits and letting temperatures rise. This does remove some of the black glass but it still requires a clean next morning.

Thanks,
Lon

 

I was surprised about the "thermal shock" thing. But thinking about it, if you're going from a not engaged cat, that is definitely warmed up, but maybe nowhere near the "550-650'F" of your STT when you engage the cat. Sounds to me like they are suggesting to not engage that high. Maybe they have seen this happen in the past and decided it's high heat causing this physical reaction. Are you saying that when you engage at 450'F the stove goes into a decreased temp mode and the fire goes out? Is it possible that you engage at 450'F and just give it some time, like 20~30 minutes for the cat to gets fully up to temp. Can you see the cat in this stove or are you going by watching the temp gauge on the stove top? 550-650'F is quite high for engagement.

I'm wondering if the actual catalyst "nest" or frame of where those Cat boxes sit has a physical change in shape/size due to the high increase in heat and then putting pressure on the cat causing the breaking of the ceramic. I've been burning with a catalytic stove since 1985 with my Consolidated Dutch West, and then later with a VC Resolute, and not had problems with the Cat. However, the cast iron inner parts of the Resolute did need replacement once which I chalked up to an overfiring.

The Cats do take a bit of time to get fully engaged, and they aren't always bright orange when they are still doing their job.

As for the glass, neither of my stoves glass that is always clean. My Fireview does a similar thing to what your seeing where the glass stays clean in the middle but the edges on both sides, not so much. I think the "air wash" isn't perfect or something like that. You're wood is probably fine.

If you do buy a new Cat, I'd be thinking Stainless Steel given the luck you've had with this one. (and I'm the guy that has a ceramic in my Fireview) But before you go buy another one, it would be good if you could come to resolve the start up/cat engagement phase with the one you have.

It would be great if you could get some input from others who have one of these VC stoves like yours. Have you found ny other owners?

 

If the Cat is still functioning (clean exhaust plume when up to cruising speed?), I would stuff it back in and continue on. Grab another Cat for peace of mind. Possible that your damaged Cat may be attributed to stove operation you are still figuring out. Normal! Unfortunate collateral damage.
The thermal shock damage is commonly thought to be from opening the loading door without opening the bypass first and letting the Cat cool. 1000F Cat meets 70F room temp air. Ouch.
Do you have a key damper installed? 30' of class A may be enough to make a key damper worth considering. Window glass getting dirty like yours is common also on many make/models. No worries.

 

So weird that all the cells are in one row. I wonder what vendor they source those from. VC has changed hands and I've lost track of them. There was a time in the 70s here in New England where they were the gorilla in the market. Defiants were everyplace! When I had a resolute, I loved the top loading feature. Do they still have that feature?

That is one long chimney you got there. I do wonder if that has some impact on the cold-start issue with the Cat being difficult to take off. Maybe the draft is too much? We were hearing a guy last year who was having all sorts of cold-start issues on his AS and he had a very tall flue.

 

Thanks for some feedback. And for showing grace! We were not home for a few days while with family so sorry for delay.

There is not a damper on that flue. Will keep this in mind if issues continue.

This defiant does have top load feature which was probably why we chose it over what was available in stock for us to buy. Plus a basement install so we wanted a big stove. I have recently been cutting wood at 20-24 inches because it fits. I only open front doors for cleaning and initial start up. Cooked a nice beef stew a few nights ago on the griddle. I do however think trying to keep it clean/dry/rust free may be a long term battle.

Oldhippie In reading through your feedback I’m thinking about this all wrong. I’m looking for catalyst to reach the “operate catalyst” range on my probe thermometer almost too immediately after closing bypass. Manual says to close bypass damper at 450 STT as long as a sufficient ember bed is established. Because I hit 450 relatively quickly on STT and there isn’t a huge bed depending on how much I have in the stove, I have been feeling like this is too early to close. Letting that fire get even hotter and Probably waiting another 20-30 minutes. In your suggestion of closing and giving the catalyst 20-30 minutes to sufficiently warm, it would give the catalyst time to gradually warm instead of eating all that heat at the same moment. Will try this on next startup.

moresnow Thanks for “normalizing” it. A good friend a long time burner told me after install - “wood stoves are for thinkers”, and I’m an over analyzer for sure. My exhaust plume is very clean once up to cruising - only really seeing the heat vapor. My basement has a walk out that I can just easily pop out of to see my pipe and that is part of my operation. My theory on thermal shock was not that I was thinking I was giving the catalyst too cold of a blast, but that I was giving it too much heat out of the gate. Will close bypass sooner next startup.

I did find a guy in another forum with the same stove and about 23 feet of chimney. He disintegrated 2 ceramic cats in his first season. Then switched to steel and it got instantly better.

I’m going to get a steel replacement but keep running this ceramic cat. Will post an updated picture after a few more weeks. Let’s see what happens.

 

In your suggestion of closing and giving the catalyst 20-30 minutes to sufficiently warm, it would give the catalyst time to gradually warm instead of eating all that heat at the same moment. Will try this on next startup.

Yes, get to temp, say 375 to 400'F, then engage CAT, give the cat time to get up to high heat, 500 or something. But just as importantly, look for the flue temp gauge to drop equally slowly down to the 250~300'F range. No turbo charge in these devices, they just take a bit of time to go up and come down. ...and the watched pot doesn't boil kind of thing just puts us into a frenzy.

I've had both ceramic and stainless steel. I've never had one of the ceramics fail me for very long periods of time. Here are some pics of my ceramic that has been almost 24X7X365 since December 2018, so 4 plus full years. The minor small-cell imperfections are probably caused by my tapping the entire CAT on my deck railing to clear out the ash dust. This really isn't much as the Fireview has a nice fairly fine stainless steel screen between the Cat and the firebox. Note: This cat goes to 700'F pretty regularly on the top of my Soapstone Fireview, that's saying it's not pampered.

 

24/7/365? You burn all summer too?

 

I can't trust all my lingo that my 'puter finishes words for me. Yeah, I don't burn after Mid March usually and haven't really started 24X7 yet this year. 45'F here today on the NH/MA border.

 

Here you are guiding me and they start ripping on you! this past hot summer we had I knew you weren’t burning in. 60 today down on the south shore of MA.

 

Crazy weather, but it's not snow and 45', so not burning. I think I burn more oil in shoulder seasons than I do in the dead of winter. Plus I keep buying a season pass for Mt Wachusett as I love to ski midweek. I'm ready for winter.

 

I took my wife to Wachusett about 8 years ago for her first ski day ever. Great little beginner area there to the left of lodge. I'm hopeful for 1 ski day this year, baby #3 is coming in 4 weeks. Another reason I'm hopeful to get stove operation stable as we're going to be hunkered down for the winter. Let's be warm!

 

Every stove and install takes a learning/experimenting phase to get it down to a standard process and settings. Hanging around FHC helped get me through a big learning curve, first going to a Catalytic from my old Smoke Dragon, and then going to learning the Absolute Steel and they hybrid technology.

Between the learning and then also getting on the 2-year plan and now the 3-year plan, it's become much more of a fun hobby than a chore.
Having really good wood makes all the difference.