Assessing Catalyst and Catalytic Burn [VC Encore 2040]

  • Active since 1995, is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.


New Member
Jan 26, 2021
Andover, MA, USA
So, in my quest to achieve a reliable overnight burn, have a couple of questions about burning catalytic. FYI, bought our new place in 11/2020, and the Encore 2040 was installed in 2014.

In progressively working to more serious and longer burns, I took a step back and took out the catalyst. My observation is it was dirty but whole, i.e. no cracking or missing chunks or fractures that I could see. The secondary chamber needed a little cleaning, and there was a bit of ash on top of the catalytic itself.

So, questions:

Is there any way to tell when a catalyst has lost its mojo, aside from the obvious telltale signs of cracking or missing pieces? Keep in mind, I have no observational history with this stove and/or catalyst.

When a catalyst is engaged and in its catalytic burning phase, should I see a discernible jump in temperature output (or any other telltale sign) assuming everything else is static, e.g. air control lever left in same position? NOTE: No catalytic temperature probe so just working off the stove top and stovepipe thermometer readings.

Does the secondary burn at the top of the back, secondary chamber imply the catalyst should also be engaged? NOTE: There is a small gap in the backplate that from just the right angle I can see a sliver of flame rising through the back chamber and/or a red glow, depending on how hot the secondary chamber has gotten.

A back heat shield is installed. Is that normal for Encore owners, and is it keeping secondary chamber heat from releasing into the house (and, instead, simply going up the chimney)?

Big One - When burning in catalytic mode, how much flame should I see in the primary chamber (soft but steady flame wisps, some steady but not aggressive flame, or just burning coal, or something else)? Again, no cat temperature gauge. Also, when burning in catalytic mode, what target temp do other Encore owners have for their stovetop?

My targets are a stovetop in the 400-600 range and stovepipe in the 300-400 range, but as lower as possible on the stovepipe in an effort to keep heat within the stove itself for the house, not going up the chimney. Because we moved in in November and got a late season load of not-so-great wood, burns have been random. Good when I'm lucky to get loaded with dryer wood and obviously struggling when pieces aren't seasoned enough. Trying to get another load of dried wood to take that factor out of the equation.

Any help or perspective helpful!


Minister of Fire
Dec 12, 2015
Long Island, NY
Not familiar with your stove, but I'm familiar with your situation.

You're probably not going to get a good feel for how to run your stove correctly this year because of your wood situation. It sounds like You're buying "dry" wood purchased from someone else- there's no such thing unless it's a woodpile from an estate sale. ;)

Your best bet for dry wood now is to look for standing dead, or deadfall that fell so that it's off the ground. And even then, you have to kiss at some 35% moisture content frogs before you find a 20% MC prince. In my experience, the best find is that rare standing dead oak where it's been gone a few years but the bark is still all there, and there's no spongy punky layer going soft on the outside. It's still a crapshoot, but once in a while you can get some genuinely dry wood out of this kind of find.

You also need a certain bet for next year- that means getting a few cords of pine laid in (it seasons in one year), or some fairly dry hardwood (can also be ready in one year if it started off dead and partly dry). Get it split and topcovered now, and you'll have a better next year.

In general, your cat makes a whole lot of your heat. Do a small load of dimensional lumber scraps and see if you can spot cat activity. If the cat is visible in the stove it'll glow red when the stove is cranking. You may be able to hear it work (it makes a lot of heat locally, so the stove heats up differently and may make different expansion noises when the cat is eating). If you have none of that, you can still get it hot, turn it down, go outside, and look for smoke. A hot cat with fresh smoke hitting it will be burning the smoke and making heat; a dead cat will be passing the smoke through and you'll see it. (Again, use dry wood. Steam looks a lot like smoke.)

Anyway hopefully someone who knows something about your stove will stop by too.


New Member
Jan 26, 2021
Andover, MA, USA
jetsam, thanks for the reply and perspective. Your point about getting ahead on the wood situation for next year is right on -- I'd been focusing so much on solving this year that I'm realizing some effort needs to shift into looking forward. Thanks!

Unfortunately, I can't see the cat and don't have a temperature probe. In this model, there's a backplate where -- once engaged -- burn flow is directed through a channel at the bottom of the backplate, then up behind the backplate, then down another channel further back (and through the cat), and then back up yet another channel to the stove pipe. There's a secondary burn at the top of the first updraft in a small burn chamber -- THAT is what I can sometimes see through a slit where the removable backplate 'joins' near the stovetop. My hunch is if I see burning there (and for sure if there's a reddish glow), then the cat is likely (to definitely) engaged. I just can't see the cat, though your point about looking at what's coming out of the chimney is a good reminder of what that might indicate.

But if I can bend your ear for another round, aside from falling apart and/or fractures, are there any other telltale signs of a cat that's lost its mojo? Pretty sure I'm getting hot enough at times to 'go catalytic', but if the catalyst has gone bad, well, no amount of heat is going to make it do its thing, right?


Minister of Fire
Jan 11, 2008
Ottawa, ON
My targets are a stovetop in the 400-600 range and stovepipe in the 300-400 range,

My VC runs at very similar ranges and I know the cat is working (have the digital probe). As mentioned before, concentrate on your firewood.