RandyBoBandy
Minister of Fire
I get great secondaries on my Defiant up at the cabin. The house stove is not as exciting . My guess is a shorter stack at home. I also fill the stove at home up to the griddle.
2021/22 VC Owner thread
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Woodsplitter67
Minister of Fire
I am a short stack also.. but I went with an 8 inch stove pipe over the 6in.. i wanted to make sure I had plenty of draft..
Last nights burn. Loaded 5 large splits. Looks pretty good to me.... Interesting undulations in the secondary temps. I set the air to 60% and went to bed, never touched it till morning.
During the start I left the air at 100% up to 1287F and then set it to 60%.
During the start I left the air at 100% up to 1287F and then set it to 60%.
Logger has provided interesting data.... although I suspect once I re-learn the stove it will get ignored..... Nice thing is I can just set it to record and it will log 16k data points per channel (11 days @ 1 per minute) and if I want to look at it I can dump it to a PC. I was able to wire TC's in parallel so it does not interfere with my Watlow TC displays.
It has performed very well so far, no complaints. Only thing I don't like so far is you can only set an alarm on TC-1. No bigee as I have my Watlow's set to alarm.
I got mine on Amazon, $170: PerfectPrime TC0520, 4-Channels They also make a Bluetooth version. More expensive of course.
You could be right about the bimetal regulating, maybe that is it.... Don't know how to tell for sure.
Yes sir! happy days are here again!
RandyBoBandy
Minister of Fire
I replaced an old scary 8” with a 6” in anticipation of replacing the encore with something newer down the road. Even at 15’ of 6” my encore is not happy about the change.
RandyBoBandy
Minister of Fire
So after 3 years of reading about how you all can see the glow from the cat I finally saw it this evening. Can see a nice glow through the crack where the flame shield is hanging.
On another note...does your stoves creak and crack a lot when it’s up to temp? The last two evenings I’ve had this one up to 1500 or so on the cat and held it there for an hour and it has popped more this evening than it has the entire time I’ve been running it. Griddle temp about 450, flue temp about 350 on outside of pipe (normal for that gauge, It reads a touch low).
Seems to have settle down now but was really making some noise there for a while.
On another note...does your stoves creak and crack a lot when it’s up to temp? The last two evenings I’ve had this one up to 1500 or so on the cat and held it there for an hour and it has popped more this evening than it has the entire time I’ve been running it. Griddle temp about 450, flue temp about 350 on outside of pipe (normal for that gauge, It reads a touch low).
Seems to have settle down now but was really making some noise there for a while.
RandyBoBandy
Minister of Fire
Yeah these stoves will make all kinds of noises during heating up and cooling down. Both of my VC stoves do this.
Cat glow: Your site line has to be just right.....
Creaking and cracking: My stove definitely ticks and pops when heating up. Once it heat soaks it quiets down, guessing 30 minutes or so. I suspect joints are just finding a new home after thermal expansion.
After I put in my new glass screws (star drive instead of Philips) I heard the glass ticking a lot For a couple days. I backed off the screws just a touch and it went away.....
I was seeing higher cat temps too.... (1400+ is high for my new configuration.... hahaha) Been single digits overnight here as well. This morning it was heading to 1400 again, griddle was cold (300), seemed like the flames was ripping right up the secondary, I tried to hold it off by closing down the air with minimal effect. Then I closed my exhaust pipe damper and it came right back down, opened up primary air and things seem more normal. Clearly seems to be a case of overdraft.....
Nice having a stove that responds to changes in settings!
I don't know, 1400 secondary temp seems perfectly normal to me especially with the primary air closed down, not a sign of a problem.
Yes I also get lots of creaking especially as the cat heats up.
On my flexburn Encore I can see the glow of the cat through the glass if the wood is burned down far enough, through the crack above the fireback.
On my Intrepid II I can see the cat glowing through the gap next to the primary air control. Something else that has mystified me - even with the damper closed I can sometimes see flames through that hole as well. That spot should be behind the damper and "after" the catalyst. I usually see it when the stove is at peak burn and wanting to go nuclear. it can't because of restricted secondary air, but maybe the air leaking in through that gap is allowing for some "tertiary combustion" in the flue collar? idk
Yes I also get lots of creaking especially as the cat heats up.
On my flexburn Encore I can see the glow of the cat through the glass if the wood is burned down far enough, through the crack above the fireback.
On my Intrepid II I can see the cat glowing through the gap next to the primary air control. Something else that has mystified me - even with the damper closed I can sometimes see flames through that hole as well. That spot should be behind the damper and "after" the catalyst. I usually see it when the stove is at peak burn and wanting to go nuclear. it can't because of restricted secondary air, but maybe the air leaking in through that gap is allowing for some "tertiary combustion" in the flue collar? idk
Agreed, I did not mean to imply 1400 was a problem, just hotter than my stove has been running with everything set in the "cruise" position. When I cut back on the draft (by closing the pipe damper) it came back inline with previous cat temps.
Sure would be nice to hear from VT castings what "normal" is.....
Based on my own experience I think:
- 1700 - 1800+ is too hot (crumbling cat, distressed refractory)
- 1000 - 1100 seems to be too low (incomplete combustion, I see / smell indications of some smoke in the exhaust)
- 1200 - 1400 seems to be working for me at the moment.
The numbers I always hear which I think is in the manual (I don't have it in front of me) is that the operating range for all ceramic catalytic elements is 500-1650 F. Brief trips above 1650 are ok but will eventually break down the ceramic matrix and cause damage.
Woodsplitter67
Minister of Fire
The cat starts to kick off at 600.. I get worried at 1600. Ive been keeping my cat cooler this year At my overnight burn shutting the air down right away and with a medium bed of coals. To light on the cloles the cat will stall some like 800 to 900, to heavy on the coles and the cat gets to hot. my cat is settling in for the night at around 1000 to 1100. still burning clean and not warping the cat and not cooking it until it crumbles. you guys might want to adjust the cole bed some when the box is full.. all the off gassing and large coal bed will put the cat to warp 5....
ALso...remember that the completeness of combustion will not only depend on the cat temperature but the air to fuel mix going into the cat. If it is too rich then you will still get smoke at higher cat temps.
Those ranges seem to agree with my experience.
My manual says nothing about "normal" cat op temps. It says the cat starts to combust when flue gasses are 500 -600F and you should think about closing the bypass damper when griddle = 450F.
The only published guidance on max cat temps I have found comes from Condar website:
- Catalytic reaction maxes out at about 1300° Fahrenheit through any combustor. Exceeding this temperature is destructive to the combustor and to the components of your stove.
- catalysts best operating temperatures are between 600° and 1500°F (316°-816°C)
So I have decided the encore is too big for my house. At 8F outside I have to have a window beside it fully open to keep the house below 80. I can do small loads but then it’s burned out by the time I get the cat engaged, defeats the purpose of a cat stove...
Anyone have any suggestions other than downsizing the stove?
For heat requirement figures a 33k btu blue flame in the basement would over heat the house before I fixed a bunch of the insulation, but it is also 100% duty cycle. No high n low cycle like a wood stove.
Anyone have any suggestions other than downsizing the stove?
For heat requirement figures a 33k btu blue flame in the basement would over heat the house before I fixed a bunch of the insulation, but it is also 100% duty cycle. No high n low cycle like a wood stove.
Woodsplitter67
Minister of Fire
So you can get you cat going with a minimum amount of wood by using this technique. get your fire going as normal.. get the stove to about 450/ 500 move what you have going all the way back to the access cover, add some wood, close the damper. A small amount of wood up against the access cover where the down draft starts will kick off the cat with out having to load up the stove.. once the cat lights off and going you can add wood and turn the air down.. I do this sometimes in shoulder season when i need heat but don't need a lot of heat. The other thing is change the wood your burning. Look at like this. A cord of oak will have 25 million BTUs while the same size cord of poplar will have like 12 million BTUs.. thats a 13 million BTU difference for the same volume of wood. less btu less heat but you can still kick you cat off while burning it. Many people here switch the wood or style of burning to what the conditions are outside. Normally late fall im burning small and medium size wood, the past few weeks Im burning stuff thats 4x5 or 5x5 inches with the box full in the morning all day long. You need to switch up what you doing sometimes.. If your stove is set up correctly.. it will produce a lot less then 33k btus
I’ve spent the last 3 years css big splits 4 n 5 inch stuff, now your telling me I have to split it again
I’m just whining, I appreciate the advice and will give it a try. Probably be the weekend before I have a chance to sort through the pile and get a supply of little stuff.
Regarding wood species...I’m already burning yellow pine, some of it punky. To go any lower I think I’d just had to use rolled up newspaper!
bert670
Member
Nice, well be doing our taxes soon and my Dauntless is due to be delivered this weekend and installed on Monday. Looking forward to getting some wood heat going in the house.
Well.... this was fun, Got my timing mixed up and I needed to load the stove for the night while it still had a thick hot bed of coals going.... the dreaded hot reload I call it. I closed the damper right way (that my have been my mistake), I closed the air down completely as the secondary temp was rising, eventually I called it at 1600F and opened the damper, rinse and repeat..... tried adding more air, less air did not seem to matter. Eventually things got worked out and it burned fine for the night.....
Secondary was completely blocked. Good news is I was able to open the damper and throttle the air down and cool things off. In the past (secondary inlet not blocked) things would continue to heat up, even with air full closed.
First time I closed the damper the secondary was really hot, because I had the griddle open for loading, the secondary was pulling in lots of smoke and air, so it was hot.
Most interesting was on the third attempt I opened the air up and initially the secondary started to rise again but then fell like a rock. The griddle temp during all this was a bit on the cold side ~350F.... My suspicion is that all the combustion was happening in the secondary because the primary was rippin hot and the fresh load had not yet come up to temp. Seems like there was an imbalance between primary and secondary combustion rates.
I think if I had waited initially to close the damper and let the fresh load warm up I could have avoided this.... lesson learned.
Secondary was completely blocked. Good news is I was able to open the damper and throttle the air down and cool things off. In the past (secondary inlet not blocked) things would continue to heat up, even with air full closed.
First time I closed the damper the secondary was really hot, because I had the griddle open for loading, the secondary was pulling in lots of smoke and air, so it was hot.
Most interesting was on the third attempt I opened the air up and initially the secondary started to rise again but then fell like a rock. The griddle temp during all this was a bit on the cold side ~350F.... My suspicion is that all the combustion was happening in the secondary because the primary was rippin hot and the fresh load had not yet come up to temp. Seems like there was an imbalance between primary and secondary combustion rates.
I think if I had waited initially to close the damper and let the fresh load warm up I could have avoided this.... lesson learned.
Yeah, it can be tempting to close the damper early if the load really takes off. I usually set myself a timer for 8 minutes and if the flue temp starts to redline before the timer is up I will close the damper but then re open it once the flue temp drops. I find the extra time with the bypass open helps the load catch and avoid overfiring the cat.
Also.. you mentioned opening the griddle with the bypass closed..? I wouldn't do that
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