What do you consider high temps? I shoot for 650 STT with the air open about 10%.
2022/23 VC Owner thread
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Just found this while reading through
"Avoid using a full load of very dry wood in the firebox, such as dry slab wood or wood with below 14% moisture content"
On the 2nd page my my manual it shay that wood should be at 20%.
If you can not control griddle temps that sounds like an air leak to me.... or a flapper that is too far open.
Use a cell phone taped to a stick taking a video. You'll eventually get where to put it and then adjust the air control to see what it's doing. If it is properly closing then your draft is too high you will need a key damper. And that may not even solve your problem, you may need to chop your house in half and shorten your chimney. Ha.
I can get 650 STT but it takes more than 10% air and if I have much wood in the box there's no way as cat temps go to 1600 easy. What are you measuring STT with? Are you monitoring cat temps with a probe?
Thanks for this schematic - I want to share a couple insights I take from it. (Mostly stolen from other years VC owners threads.)
I’ll propose this as steady-state “design intent” operation….
An amount of unburned fuel (offgas, CO, etc) comes in to the catalyst burn chamber. If primary is fully closed, from the schematic, this amount of fuel is set by the amount of secondary air coming forward into the burn chamber and the flow through the EPA hole(s). Assuming complete combustion in the catalyst, we get the catalyst exit temperature. Subtract whatever heat is shed to the room and we arrive at a flue temperature. Flue temperature sets the draft that keeps the machine running.
If we introduce a small perturbation (a split crumbles and unleashes a slug of fuel). Catalyst burns it up, flue temperature rises, draft rises. Now. This is where the design-intent magic happens. When the draft increases, it pulls a small amount of additional fuel (flow through the six or so small holes) and a large amount of additional secondary air, diluting the catalyst exit temperature, lowering flue temp, reducing draft. Back to equilibrium state.
If you want to raise the equilibrium temperature, you open the primary air to send more fuel, higher cat temps, higher flue temps. Eventually the higher draft pulls enough dilution air through the secondary to stop the temperature rise and establish a new equilibrium.
So. Possible cures for runaway catalyst. People in previous years have had success blocking the EPA holes or putting screws in the secondary-go-forward holes. Those didn’t work for you. A guy could increase heat transfer off the back wall with a blower and lower flue temps/draft/fuel to cat. Your flue temp mysteriously never moves. You could put a super restrictive damper in and try to reduce flow that way….that didn’t work. I have one new idea.
So. The primary air is connected to a coil that responds to temperature, however. It’s not catalyst exit temperature, or flue temperature, or even griddle temperature. From your schematic, I think it’s the temperature of the air in the right primary air manifold (or at least influenced by it). If there is a lot of room temperature air moving though the primary air manifold, maybe the coil never gets hot enough to firmly seat the flap. On my encore-2040-cat-c, the flap appears to seat at about half the lever travel. IDK what it’s doing for the rest of the travel other than adding tension to the wire, maybe seating the flap more firmly. Your Defiant manual calls for it to barely seat when cold at full closed. Presumably it came this way and you’ve diligently rebuilt it that way twice. If your primary flap can’t fully seat because it’s always pulling air through the air manifold and cooling the coil, I think it could explain all your past and current issues.
You’re not using anything less than 50% lever travel except for startup anyways, maybe you could try to rig it to shut earlier?
Sorry for the novel but to quote Mr Spock:
If you eliminate the impossible, whatever remains, however improbable, must be the truth.
dmccoole
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I found this video on cleaning an Encore VC. Regarding the glass, I have to get my encore very hot to burn off most of the glass but the sides and edges are caked solid and certainly not cleanable. This guys glass and edges are almost spotless, it's like he has only ever had one small quick fire, like after the first break-in fire.
Is anyone else's glass and edges this clean after burning?
I am appreciating the cold temps finally, as I can run the stove and not worry about adjusting it so much.
Is anyone else's glass and edges this clean after burning?
I am appreciating the cold temps finally, as I can run the stove and not worry about adjusting it so much.
Mine looks like that after burning. Every once I'm a while it is a little fogged and I just run it on full air and it's clear. I'll share some pics tomorrow
He also ran that stove overnight with the bypass open which would not darken the glass nearly as much as if you ran it on low with the cat engaged
These guys must get paid by the word! That's a pretty dirty pipe if he cleans as often as he talks about. What brush and rods are those? That's what I was asking in the gear forum about cleaning through the stove.
I have a whole different issue from you. I monitor my CAT temps with an Auber probe. With my STT in the 600's my CAT temp is typically around 700-800. My issue is my CAT won't stay lit/hot enough.
He said in the video that the brush was from cleaning out a dryer vent. If you want to sweep the chimney yourself look in to the SootEater system. I have one and use it every month or so.
My best days I have completely clear glass. Maybe behind the andirons Ill have a dark spot.
Worst days, completely black with thick black creosote that would require a wire brush on a drill to clean off.
Most of this is solved by burning hotter.
Sometimes in the morning I might have some darkening toward the top, I'll throw a couple smaller splits in to rebuild an already ok coal bed and that goes away for the most part. Then I can either reload fully or just throw in a couple pieces to keep the stove going a bit during the warmer days. I usually opt to just keep a couple of pieces at a time when it's warmer/sunny out (above 40 deg), then do a 1/2 - 3/4 load in the evening, then a full load before bed.
I dont know why but the sound that makes really freaks me out. I do own one, and do use it, but really want to try something else. I know these things are harsh on the pipes. On my chimney I had bits of cement getting knocked out so I had to stop using it, and use a brush top down when it's nice and warm/sunny outside. It's good for me to get up there every now and again anyway so I can inspect my roof , flashing, pipe boots etc.
With primary air closed I highest I saw from a magnetic thermocouple was 658 and there was a distinct hot metal smell in the house.
Yea you get that smell the first couple times you hit a new high temp. I no longer get that smell at 650. My Intrepid is much smaller than your Encore, but I try to cruise in the 600's for an hour or so per burn. Because my stove is so small I don't have enough fuel available to stay that hot for much longer. I'd love it if I could cruise at 650 for 2-3 hours at a time.
In my alcove install, I’m having issues getting the heat off the stove - internal flue temps regularly 700+. Planning to install a blower for next season.
I also had problems with griddle temps before installing one of the little temperature driven electric fans. I use the ecoflow airmax but the $40 on Amazon would probably work just as well. Definitely not going to feel the air moving but it moves enough air across the top of my stove to keep griddle temperatures down. Would regularly push 700 without it. Usually stays under 550 with it.
I would have a hard time getting my griddle to 700 with secondary operating, even if I had my air control wide open, unless I was using something like pine or project scraps.
I asked about sooteater in the gear forum and no one said they clean through the stove bottom up. I sweep top down with a brush but it would be nice to go bottom up through the stove. I saw it's a dryer brush and it's pretty small. If he's getting that much creosote using that small brush and doing it often I don't think I want to burn like him.
I've seen a bunch of videos of people going down up through the stove on youtube. I personally have a cleanout behind my stove so I go through that. I agree that is probably a 3 inch brush or whatever and he had a lot of large pieces of creosote.
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I bought the sooteater last year and used it during offseason. I go up through the bottom of my stove pipe connection collecting soot in a trash bag tied around pipe being careful not to get it caught in the rod. Soot eater worked great for us. Going through the stove would be too much of a bend for my soot eater rods but it is very easy to clean both areas separately...as long as the stove is cool. If burning wood that creates lots of creosote then cleaning during the burn season would be advisable. Some folks do it monthly and I might too if I used certain types of wood. We are burning hotter this season and that is helping with the glass staying clean. I will see after the season is done how the creosote buildup compares to last year.
150deg STT delta from a heat powered fan sounds crazy, I feel like I always read that they don't really do anything.
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