2016/2017 VC owners thread

[RandyBoBandy]

At what CAT temps does everyone start to get worried? I currently have my temp alarm go off at 1650, but semi regularly seem to hit that temperature on my Defiant 2n1. I have been thinking about closing off part of the secondary air on the underside/back of the stove. I remember reading a VC owners thread a few years back where someone put screws in the holes under the CAT chamber.

I really don't even like to 1550. It seems to close to the danger zone for me. With the little stopper tab pulled out of the secondary shutter I rarely see cat temps hit 1600.

 

[trispad]

Every flue system is different, but 600 flue is high for a cat stove

Any thoughts on where to start to diagnosing the high flue temp? Checking the griddle and door gaskets?

 

[RandyBoBandy]

Any thoughts on where to start to diagnosing the high flue temp? Checking the griddle and door gaskets?

That's a good start. What does the firebox look like when your flue temp is 600*?

 

[Diabel]

What is the location of your flue thermo? In relation to the stovetop

 

[trispad]

That's a good start. What does the firebox look like when your flue temp is 600*?

Generally uninteresting and black. There will be some activity at the back of the fire box, but definitely no flame show.

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[trispad]

What is the location of your flue thermo? In relation to the stovetop

Flue probe is on the back of the stove pipe, 18" up. Not sure if relevant but it does have an 8" oval to 6" round adapter to 6" pipe. All double wall.

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[Diabel]

Flue probe is on the back of the stove pipe, 18" up. Not sure if relevant but it does have an 8" oval to 6" round adapter to 6" pipe. All double wall.

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These probes are relatively inexpensive. 20.00 more less, get another one and try it out. You never know maybe yours is defective

 

[RandyBoBandy]

Generally uninteresting and black. There will be some activity at the back of the fire box, but definitely no flame show.

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Interesting. With flue temps that high you would think there would be s crazy hot active fire going on. Maybe diabel is on to something try a new probe thermo and see what happens.

 

[trispad]

I am currently using a digital probe. I will getting an analog probe to compare against.

 

[Diabel]

Digital probes are usually pretty accurate in my opinion.

 

[jharkin]

hey guys.


My 2550 got its first workout of this season this past weekend when temps went to 10F Sat night. Burned 24/7 from Thu to Mon and overall no issues. Saturday night with the extra strong draft the cart went to 1650+ and I had to open the bypass for a while to let her cool but then it settled down.


I am interested in all this modification of the secondary. My concern is the same as diabel though - by blocking the secondary it seems like what we are dong is starving the cat for oxygen and thus reducing temp because its not burning all the smoke that's passing through.

I wonder if a better approach is to maybe block off one or both of the EPA holes in the ashpan to reduce the primary smoke production? It seems like that would be a better way to slow it down while retaining high efficiency? Maybe even stretch out the burn time?

 

[Diabel]

With the mod Reckless suggested my stove seems to be working better. It was working fine until the outside temps dipped and my cat started acting up. Crazy temps.
Now with the mod the firebox temps are the same, flue temps are also the same, burn times the same.
But the cat temp it much more responsive to the primary air control. It has been cold here (high pressure) but I have not seen the cat exceed 1550
So, for sure improvement.

I am still a bit concerned about the stuff coming out the pipe. Appears like steam, white and dissipates within 6-8'. Before the mod, it was just waves of heat but the outside temps were above freezing.

 

[RandyBoBandy]

hey guys.


My 2550 got its first workout of this season this past weekend when temps went to 10F Sat night. Burned 24/7 from Thu to Mon and overall no issues. Saturday night with the extra strong draft the cart went to 1650+ and I had to open the bypass for a while to let her cool but then it settled down.


I am interested in all this modification of the secondary. My concern is the same as diabel though - by blocking the secondary it seems like what we are dong is starving the cat for oxygen and thus reducing temp because its not burning all the smoke that's passing through.

I wonder if a better approach is to maybe block off one or both of the EPA holes in the ashpan to reduce the primary smoke production? It seems like that would be a better way to slow it down while retaining high efficiency? Maybe even stretch out the burn time?

Interesting approach but once in cat mode how much of the air is actually being pulled in through the EPA holes in the ashpan? I can see how this may help with slowing the gassing off of the wood, in return giving the cat less smoke to process and equaling lower cat temps. What I did was take the pin out of the shutter and change the timing to 3 oclock on the coil. This way I still get full air on light off and around 1200 degrees, give or take, the shutter is completely closed. I am toying with the idea of turning the coil back to 2:30 to keep the shutter open a little longer before completely closed. If I can time it right the shutter will "just" completely close, so when the cat cools down a little it will ever so slightly open giving it a little more oxygen to keep the burn going strong. This is all in theory though I suppose!

 

[jharkin]

Interesting approach but once in cat mode how much of the air is actually being pulled in through the EPA holes in the ashpan? I can see how this may help with slowing the gassing off of the wood, in return giving the cat less smoke to process and equaling lower cat temps. What I did was take the pin out of the shutter and change the timing to 3 oclock on the coil. This way I still get full air on light off and around 1200 degrees, give or take, the shutter is completely closed. I am toying with the idea of turning the coil back to 2:30 to keep the shutter open a little longer before completely closed. If I can time it right the shutter will "just" completely close, so when the cat cools down a little it will ever so slightly open giving it a little more oxygen to keep the burn going strong. This is all in theory though I suppose!

I know on very cold nights when I have an exceptionally strong craft its pulling a decent amount of air through those EPA holes, as I still get flame in the firebox even with the primary completely closed. This generally happens whenever the outside temp dips below 20.

In other threads it was mentioned that those EPA holes where put in the aspan on purpose to provide a small amount of air flowing up through the grate directly into the coal bed, to help keep the coals alive when the primary is shut.

I don't think that blocking both EPA holes would be a good idea.... maybe just one of them.



Interesting logic on the moving the coil. I remember Reckless found the same thing, that at stock timing the coil would wind all the way past fully closed and start to open up again when cat temps got excessive like 1600+. Stock timing is around 4-5 o'clock I think?


I'm thinking, maybe I'll close off one of the two EPA holes and change my secondary timing the way you did and see what that does.

 

[Excavator]

Been following this thread last few days and just wanted to add my thoughts. I rebuilt my 0028 encore again few years ago when i installed my insulated liner and block off plate. I have come to my own conlusion that now my draft is just much stronger and i simply reload stove and close damper around 350 or 400 griddle temp. Then in about 10 minutes my cat probe hits 750 i will close air half way and never have problem. Now if i experiment and not engage cat till griddle temp hits 500+ then she will slowly creep up to 1700+ and then aftet making me nervous it slowly comes back

 

[Dobish]

i had a really good burn last night... secondaries in full effect, the stove top around 500, and the flue temps at 300. Cat temp around 1200. It was really nice. i woke up this morning, the stove temp was 200, and the cat temp was around 200.... stove still had big coals in it.... i loaded up a fresh load, and as it is heating up, I hear what sounded like rain on a tin roof coming down my chimney. I have heard this on occasion, but it was a bit unnerving. I tapped on the pipe and I could hear more stuff falling down....

 

[Diabel]

i had a really good burn last night... secondaries in full effect, the stove top around 500, and the flue temps at 300. Cat temp around 1200. It was really nice. i woke up this morning, the stove temp was 200, and the cat temp was around 200.... stove still had big coals in it.... i loaded up a fresh load, and as it is heating up, I hear what sounded like rain on a tin roof coming down my chimney. I have heard this on occasion, but it was a bit unnerving. I tapped on the pipe and I could hear more stuff falling down....

When was the last time you cleaned your chimney?

 

[Dobish]

When was the last time you cleaned your chimney?

i cleaned it this past summer... The moisture meter hasn't gone over 18% on anything i have checked this year. Temps do get a little low at night sometimes. I was burning really dry cedar this morning, and I thought that it might have just been particulates when the airflow dropped that I was hearing. I will try and get a video so I can capture the sound next time.

Below are pictures of the chimney before (this was after most of a season of burning less than ideal wood:


and after cleaning:

 

[RandyBoBandy]

i had a really good burn last night... secondaries in full effect, the stove top around 500, and the flue temps at 300. Cat temp around 1200. It was really nice. i woke up this morning, the stove temp was 200, and the cat temp was around 200.... stove still had big coals in it.... i loaded up a fresh load, and as it is heating up, I hear what sounded like rain on a tin roof coming down my chimney. I have heard this on occasion, but it was a bit unnerving. I tapped on the pipe and I could hear more stuff falling down....

That would be the dreaded creosote chunks.

 

[RandyBoBandy]

I know on very cold nights when I have an exceptionally strong craft its pulling a decent amount of air through those EPA holes, as I still get flame in the firebox even with the primary completely closed. This generally happens whenever the outside temp dips below 20.

In other threads it was mentioned that those EPA holes where put in the aspan on purpose to provide a small amount of air flowing up through the grate directly into the coal bed, to help keep the coals alive when the primary is shut.

I don't think that blocking both EPA holes would be a good idea.... maybe just one of them.



Interesting logic on the moving the coil. I remember Reckless found the same thing, that at stock timing the coil would wind all the way past fully closed and start to open up again when cat temps got excessive like 1600+. Stock timing is around 4-5 o'clock I think?


I'm thinking, maybe I'll close off one of the two EPA holes and change my secondary timing the way you did and see what that does.

Post your results. I'm curious to see how plugging one of the EPA holes work.

 

[jharkin]

Post your results. I'm curious to see how plugging one of the EPA holes work.

I'm not exactly sure what Im going to try yet. I might first try the method of changing the timing to 3 o'clock and see what that does. Then maybe try plugging one hole.

If I do it all at once we wont know what made a difference....


I can say that Excavators method seems to work also - but when I do it that way the chimney is belching smoke like an OWB for the 10-20 minutes it takes to the cat to climb up to temp.

 

[Reckless]

I have been keeping the cat 1250-1450 and no smoke from the stack. Might not work for everyone YMMV. With that said with cat engaged and at 1300 range the pipe directly above the collar reads 200 with external




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[Herdvet]

I bought my Encore 2014 a year ago and it began overfiring almost immediately - still is. Only way I've found to prevent it is to shut down both the damper and the intake well before the stove top thermometer gets into the high range. Even then it will eventually reach the 700 range and above before running out of fuel. Only thing I can imagine is that there's some other source of air that I can't find. Chimney cleaners came yesterday and confirmed what I feared - lots of creosote, presumably from my choking it much of the time.

Last winter I installed the thermometer that came with it, 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?

I should add that the stove vents into a steel chimney liner professionally installed at the same time as the stove, a year ago. And that, aside from the catalytic addition, I'm an experienced VC stove user, having used both a classic Vigilant and an earlier model Encore for many years, in different locations.

 

[jharkin]

When you say "tried using the converter" do you mean the catalyst?

If so, leaving it out I believe is forcing the stove to work like one of the old Everburn Neverburn non-cats and those where notoriously difficult to get to sustain good secondary combustion.

Put the cat back in, should cut down your creosote tremendously.

Also the usual question - how is your wood supply?

 

[jharkin]

Hey guys, maybe we should bring up the operation process reminder again. Ive made a few more tweaks from your suggestions, based off the original procedure I posted during my rebuild.



Vermont Castings Catalytic Stove Guide

Setup:

• Thermometers are your friend. Griddle thermometer is a must, a cat probe is almost a must and a stack temp gauge is nice to have.
• If you don't have an existing cat probe a great setup is the Auber AT100 using a k-type thermocouple. This setup shows the temp in 1 degree increments and responds faster than the Condar monitor. Also allows you to setup audible alarms.
• (add a link to the setup discussion on the AT100 from last year)

Startup Procedure:

• Start up a fire and let it burn wide open to warm up the stove
• On a new load you close the damper (bypass) when the griddle temp reads 450F (we used to say 500, but that causes overfire for some. you need to learn what works for you)
  • Alternate method - if you have a stack thermometer use this is a guide rather than the griddle. I find that reliable light offs happen when my stack surface temp is 400-500 regardless of griddle temp.
• If the cat lights off properly you should see probe temp pass 500 and start rising rapidly toward 1000+ in 5 min or less, if it climbs slowly and stops around 800 that is a catalyst stall and you need to reopen the damper and heat it up some more then try again. Once the cat temp is climbing rapidly start closing down the primary air in stages. the goal is to get the primary air fully closed before the cat temp reaches 1000F.

Cruising:

• Once you are cruising over 1000 and the temp rise has settled down, you can open up the primary again and adjust for the heat output you need.
  
• Any time you see the cat probe temp over 1600 you should be careful (1700+ is the danger zone) - either close the primary air completely to slow things down, or open up the primary air to get more fire in the box, which reduces the amount of smoke the cat has to burn, but burns the load up faster and throws a lot more heat.
  
• In cruising mode the probe temp will normally be in the 1100-1600 range (griddle might be 400-700 depending on how the primary air is set). During this part of the burn the air control will typically be almost closed but the stove is pumping out massive heat from the back casting due to the cat. Probe temp usually will slowly climb through the burn then peak and drop off fast. This part of the burn might be 1-2 hours for a couple splits or as much as 4-6 hours on a full packed load of Oak.

End phase of the burn:

• Once the probe temp peaks and starts falling s you know the major out gassing phase of the burn is done. You still have hours of usable heat in the coals and at this point you can safely open up the air control to maintain griddle temp without fear of overheating the catalyst.
• Once the cat temp falls below 800 with the air control open the load is pretty much burned out and its time to reload.

How much wood to load?

• If you want long slow burns you can pack it full. When you pack it full use fewer but larger splits.
  
• If you need high heat run a smaller load and keep the air control more open. You have to re-load more frequently but there is less chance of over firing the cat with smaller loads of wood
• Factors that contribute to over firing risk: large loads, using lots of small splits that off gas aggressively, strong draft due to very cold temps or an air leak. You need to learn with experience what combinations of split size, load size and air setting work for different weather.

What to do if you get into an over fire situation?

• 1700F cat probe temp is Condar's recommended limit. 1800 is the point that we have all seen glowing iron. I once hit 2000 for about a half hour. It didn't cause permanent damage or instant cat death but I don't recommend it.
• Ceramic cat's seem to work better for us than the diesel foil steelcats made by Condar.
  
• If the cat goes beyond 1700, first thing to do is open the bypass. Let it drop back to 1200 or so then re-engage
• Doing this once or twice usually bring it back in control. If it doesn't or if the firebox temps get out of control check to make sure you don't have something preventing the primary from closing completely (mine got jammed open once).
• If everything else is good and its still out of control you can try stuffing tin foil into the EPA air holes in the ashpan (behind the front legs)
  
• If even that does work, open up the front door to cool it off with fresh air, or dump a pail of ash on the fire to smother it.

Please suggest additions or modifications to this. Maybe we can sticky it for VC guys.