VC Encore Learning Curve

[bazzolic]

Hey Everyone-

First, thanks for providing this lurker with a lot of great information. We burned non-cat stoves when I was younger, just installed a VC Encore into my first house that I renovated. Getting up to speed with catalyst burning over the last two weeks, but had a burn last night that had me real nervous...

I've been running hot on smaller-sized loads, trying to work to control it...

Fuel is sugar maple and some poplar - took down overhanging trees in May 2016 before I spent 20k on a new roof; has been covered with good air movement through a Northern Ohio summer. Seems plenty seasoned with cracks, but can't believe it'd be overly dry? Chimney is ~25ft with one slight 4ft bend section in the attic to get around a roof beam before exiting the roof.

Been getting the stove hot with small pieces and then down to light bed of coals before adding 3-4 splits east-west; let it catch then engage damper (cat chamber will fire) and close air control nearly (or completely) all the way. Even just these lighter loads, it will rise to 600 griddle plate with catalyst temp probe right in the middle.

Last night, we had wicked 20-30 mph winds as temps dropped to around 30; had been burning in the evening hot; finally died back to coals, but perhaps had too large a coal bed? Temp was down to 450 so I put 4 more splits in and since was already running hot (figured because of great draft) I damped and closed the air control all the way down from the get-go.

Well, crap. Stove top isn't too bad (600-650); but catalyst temp is near the top of "safe" range so I try to open the damper to allow some heat up the pipe.

Well, double crap - start getting a bit of smoke backfill from pipe section seams and a roaring fire! Close the damper back down, open the windows, turn on all the fans, and have my phone ready... Basically just watching this thing over-fire for two hours fully clamped down was scary - 750 stove top and cat probe just a micro-smidge above the upper limit...

I think by opening the damper to let heat up the pipe with the air control choked I had a hungry fire sucking air back down, essentially a hot-stove back-puff?

I've since learned about the ash trick as well as keeping a sopping-wet log around... Two questions remain, though:

First- damage? Nothing on the external stove or piping was glowing, so hopefully I'm okay. However, the fire brick on the inside was a-glow, though... Can the catalyst also handle being at max or a tiny bit above (I guess how accurate is the standard probe) for 1-2 hours? Hopefully not a $200 catalyst mistake, really hope nothing warped...

Second- what the heck? How can I keep this stove from firing so hot? I'm going to start over with very small loads, let coals burn down more. Definitely don't have ash tray open; I'll try the dollar-bill trick once I get home but it's only two weeks old! I can't fathom the wood is that dry, but it is smaller-size splits - still... Do I need to have installers back out to have a look? Air leak somewhere? Also noting the intake holes to completely choke off if it should happen again, but I want to prevent here....

Thanks for the help!

 

[Excavator]

I have a older Encore that I rebuilt and have tall chimney as well as a liner. If I reload at 450 or higher I will always get a over fire like that with my seasoned wood. I have to let temps get lower before reloading. I also have to engage cat a lot sooner since I installed my insulated liner few years ago.
One thing I do in over fire is I open the windows in that room and let some cold air in room plus I put large pot of water on top of stove to help draw off some heat. Wet log also just in case. Try some larger splits as well.

 

[bholler]

In the event of an over fire open the door the large amount of air rushing in the door will really drop the temps in the stove and chimney. The only time this is a bad idea is if you have a chimney fire.

 

[RandyBoBandy]

Is this a new model? I am not 100% on this but I believe the everburns or flexburns had a tendency to go nuclear on people. Stick around on this forum, there are plenty of people here with much more knowledge than myself. And welcome to the forum. Good luck.

 

[Herdvet]

Is yours a new Encore (2014)? I bought mine a year ago and it began overfiring almost immediately - still is. Only way I've found to prevent it is to shut it down well before it gets into the high range. Even then it usually will eventually get too hot. Only thing I can imagine is that there's some sort of other source of air that I can't find. Chimney cleaners came yesterday and confirmed what I feared - lots of creosote.

Have you installed the thermometer that came with it? I did, and tried using the converter, but it burned out, too. VC replaced it but I'm nervous about reinstalling it. Wondering whether the tiny hole the thermometer made in the back could be the unwelcome source of air. Ideas, anybody?

 

[RandyBoBandy]

Is yours a new Encore (2014)? I bought mine a year ago and it began overfiring almost immediately - still is. Only way I've found to prevent it is to shut it down well before it gets into the high range. Even then it usually will eventually get too hot. Only thing I can imagine is that there's some sort of other source of air that I can't find. Chimney cleaners came yesterday and confirmed what I feared - lots of creosote.

Have you installed the thermometer that came with it? I did, and tried using the converter, but it burned out, too. VC replaced it but I'm nervous about reinstalling it. Wondering whether the tiny hole the thermometer made in the back could be the unwelcome source of air. Ideas, anybody?

You should jump over to the 2016/2017 VC owners thread. Pleanty of knowledgeable members over there. If you are overfiring how do you have so much creo? What is your exhaust setup?

 

[Herdvet]

You should jump over to the 2016/2017 VC owners thread. Pleanty of knowledgeable members over there. If you are overfiring how do you have so much creo? What is your exhaust setup?

Thanks, I'll do that. Meanwhile, to answer your?s, while the stove is indeed overfiring, in trying to control it, I'm choking it much of the time, thus the creosote. Exhaust is into a steel liner installed the same time as the stove, just a year ago.

 

[RandyBoBandy]

Thanks, I'll do that. Meanwhile, to answer your?s, while the stove is indeed overfiring, in trying to control it, I'm choking it much of the time, thus the creosote. Exhaust is into a steel liner installed the same time as the stove, just a year ago.

Insulated liner? Into existing clay or masonry chimney? How long is your chimney? What most of us VC burners have been doing is modifying the secondary air inlet to restrict the air better. Once you start reading the owners thread you will get a few different methods we are all doing. I would also suggest investing in the Auber instruments AT 100 digital probe thermometer for your cat.

 

[jharkin]

Welcome Bazz..

Definitely come join us in the 2016/17 thread (in my sig). A few thoughts...


#1 - One summer seasoned hardwood should not be too dry at all. Around here I would let that stuff season at least 2 years to get it down under 20% moisture. I've burn wood seasoned 3+ years and under 15%. That alone wont make the stove go nuclear.

#2 - How tall is your chimney? some of your symptoms might be because of extremely strong draft. Reckless has a situation like that and has posted some ideas in the main thread

#3 I run into overfire problems when I am running very large load and the draft is exceptionally strong due to very cold outside temps (10 or under) and/or high wind. When my cat goes nuclear, usually opening the bypass for 5 minutes brings it back down to a reasonable (under 1200) temp and then I can reengage. This doesn't usually make the stove top temp go crazy for me, which is why I suspect you might have exceptional draft or a leak.

#4 Speaking of leak - do the dollar bill test on all doors, ashpan, etc


I wrote a little how-to on operation while back, but now I close the bypass even earlier- before 450F griddle temp.
http://www.hearth.com/talk/threads/used-vc-encore-can-not-get-extended-burn-time.120576/#post-1615531

 

[bazzolic]

Thanks for the replies everyone.

It has been fairly warm the last few weeks (not burning often) and been running several iterations of test-theories.

I'm still testing a few more theories, then I'll report back fully... Luckily my vendor has been pretty helpful and through them VC.

Out of curiosity, when burning non-cat do you get ignition of flames in the secondary chamber once the damper is closed? If so, at what temp? Trying to figure out if I burned out my catalyst (one of the theories, new condar catalyst on the way to test more-fully).

Also, for consistency of reporting temps - where do you all keep your stove top thermometers? VC told me to place between griddle plate and chimney (not what is in manual - says griddle plate). Makes sense (better whole-stove temp), but figured I'd get your opinions.

Will look for that AT-100 thermometer, @RandyBoBandy - thanks

And @jharkin -

#2 Chimney is ~25ft with one slight 4ft bend section in the attic to get around a roof beam before exiting the roof

#3 I agree - I'm in Cleveland, about half a mile from the Lake so we get some whipping wind. Also, could the catalyst chamber temp probe entry site be an area of significan leak? Vendor installed it, looked around and didn't see any cement seal or anything... (photos)

#4 I'm also skeptical of the seal on the ash door. I mean everything is brand new, but the dollar bill pulls out pretty easily... I'll try to take a video and upload tomorrow when I get back home.

Thanks again, everyone!

 

[Dobish]

there shouldn't be any cement on the cat probe.

is there any resistance on the ash pan handle? i know that when I first got mine, it was ok, then i used the stove for a while and had to adjust the handle so it fit a lot tighter. it wasn't a seal thing, the handle was just too loose. I ended up having to add another small spacer to make it fit correctly and snug...

 

[RandyBoBandy]

Thanks for the replies everyone.

It has been fairly warm the last few weeks (not burning often) and been running several iterations of test-theories.

I'm still testing a few more theories, then I'll report back fully... Luckily my vendor has been pretty helpful and through them VC.

Out of curiosity, when burning non-cat do you get ignition of flames in the secondary chamber once the damper is closed? If so, at what temp? Trying to figure out if I burned out my catalyst (one of the theories, new condar catalyst on the way to test more-fully).

Also, for consistency of reporting temps - where do you all keep your stove top thermometers? VC told me to place between griddle plate and chimney (not what is in manual - says griddle plate). Makes sense (better whole-stove temp), but figured I'd get your opinions.

Will look for that AT-100 thermometer, @RandyBoBandy - thanks

And @jharkin -

#2 Chimney is ~25ft with one slight 4ft bend section in the attic to get around a roof beam before exiting the roof

#3 I agree - I'm in Cleveland, about half a mile from the Lake so we get some whipping wind. Also, could the catalyst chamber temp probe entry site be an area of significan leak? Vendor installed it, looked around and didn't see any cement seal or anything... (photos)

#4 I'm also skeptical of the seal on the ash door. I mean everything is brand new, but the dollar bill pulls out pretty easily... I'll try to take a video and upload tomorrow when I get back home.

Thanks again, everyone!

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From your picture your cat looks fine. In bypass mode everything should be going up the stove pipe. I close my damper between 350-500 on the GT (griddle top). I have my thermometer on the GT towards the back in the middle. If you have an IR thermometer you find temps can range about 100 degrees different in each corner of the stove. Just depends on the hotspots of your fire. I put a little cement around my cat probe on the outside of the stove just to help seal things up. If the dollar bill pulls out easily on the ash door just tighten the latch some. New gaskets will compress quickly. With your chimney being 25' you might want to try closing your damper closer to 350 GT.

 

[RandyBoBandy]

Your cap is also looking pretty black which makes me think you either trying to run to low or your wood is not seasoned enough.