Englander 32 Modification

[weee123]

So this year I did an experiment with my 32’s secondary air after I saw an old post by BrotherBart about how he modified his 30’s secondary air intake.

Essentially he did some math based off this website http://www.gulland.ca/florida_bungalow_syndrome.htm

Which explained the florida bungalow system and how different chimney heights would affect how a stove would run. Based off his chimney height which was similar to mine he covered up half of his stoves secondary air intake which is an 1.5”x1” rectangular hole in the back of the stove.

Now on the 32, this hole is increased to 1.75”x1” to feed more secondary air to help meet emissions. Now we’ve all seen the posts of some new 2020 EPA stoves becoming uncontrollable and needing key dampers (sometimes 2!) to try to gain some control. My stove was no exception.

With a manometer hooked up to my flue and the key damper I was able to have some control over the stove, but on a full load on a cold night it still wanted to run away. So I initially covered approximately 40% of the intake to start this year which did help some and gained some more control back over the stove. Then I came across BrotherBart’s post and link, did some napkin math, measured my intake size and compared it to the 30’s size, and decided to cover it up to 60%.

Now with it being covered at 60%, I feel like I have absolute control over the stove and haven’t needed to use my key damper even on a full load. The manometer needle is no longer bouncing off .15 plus and hangs around .09-.1. I did my first full load with it covered at 60% without using the damper and got over a 9 hour burn and woke up to this left in the stove

Usually, I’m left with nothing. Even on a full load with the damper closed and the intake covered by 40%. Needless to say I am beyond happy and hope this post can help others.

 

[Gearhead660]

Good to hear you got the stove under control. I was having issues controlling my stove with a full load last year. I tried restricting the secondary air, but it required continuous adjusting. Added a key damper. Totally different stove. only need to make one adjustment and its good. No issues controlling flue temp.

 

[weee123]

Adjusted it down to 70-75% as it would still run on a stuffed full load after an hour with the cold temps out.

Similar cold temps out today, full load, and didn’t even have to use the key damper. Was able to adjust primary air freely without it taking off. Open up the primary some and it increases burn as expected. Close it off and it slowly drops down like it should. Usually it wouldn’t and might actually increase. Still burning cleanly, no smoke out of the chimney, and active secondaries.

Even when it warmed up into the upper 40s almost 50 on Saturday it was still functioning properly and cleanly. Overall, exceptionally pleased with how the stove runs now.

 

[Highbeam]

Upsizing that secondary inlet to 1.75” is to accommodate the extra air tube in the 32. The 30 only has 4. But yes, they added more secondary air. Full throttle all the time!

 

[weee123]

I understand that. Full throttle all the time with no semblance of control is not what I’m going for especially in my home. I’ve seen enough posts on here and elsewhere where these new EPA 2020 tube stoves installed on taller chimneys runaway and turn into night lights.

It’s not like it’s an immediate runaway either. It happens after an hour or so of running the stove after it’s been shutdown even with proper operation and shutting down soon enough. There’s just too much unregulated air into these stoves in an effort to burn as clean as possible and without modification on some installs it’s made them unsafe.

 

[NickW]

Interesting read including the link!

I have an NC30 with 24' of vertical flue and a 4' horizontal run. Originally (without a damper) I fought overdraft early in a burn air fully closed, but if I left it fully closed I had charcoal instead of coals and smoked glass. Installed a key damper and it helped immensely. I can still get the take off 1-1 1/2 hours in, but it is absolutely controllable. It's just annoying to have to make adjustments that far into a burn.

Does the partial blocking of the secondary air inlet then cause a more dirty burn because there isn't enough secondary air to combust all the volatiles/smoke?

 

[weee123]

Interesting read including the link!

I have an NC30 with 24' of vertical flue and a 4' horizontal run. Originally (without a damper) I fought overdraft early in a burn air fully closed, but if I left it fully closed I had charcoal instead of coals and smoked glass. Installed a key damper and it helped immensely. I can still get the take off 1-1 1/2 hours in, but it is absolutely controllable. It's just annoying to have to make adjustments that far into a burn.

Does the partial blocking of the secondary air inlet then cause a more dirty burn because there isn't enough secondary air to combust all the volatiles/smoke?

So with my adjustments, I was doing them in increments as you can see. That way I can assess and revaluate after seeing how it burned, quality and cleanliness of burn, and if it left any unburnt wood. After this last adjustment I’m hopeful this should be the last. I’m still getting active secondaries, but no more blow torch or running away as of right now.

I was getting extremely irritated at having to make further adjustments an hour or more into a burn to keep it from running away, essentially forcing me to sit by the stove when I completely fill it for 1.5-2 hours. Obviously this prevents me from loading the stove before work and I have to time it right before going to bed.

I was about at the point where I was tempted to completely cut off the secondaries if the 75% didn’t work. Realistically, my next move was not cutting the secondaries off but making it so I can completely cut off the primary air and then evaluate how that worked.

 

[NickW]

I am going to do some experiments with this I think... Will play with it during the day with shoulder season loads, but that won't really tell me much. The big test will be a full overnight load.

Does anyone have any theories on if there is any significant difference in heat transfer to the stove versus going up the flue by not using the damper much or at all?

 

[Highbeam]

I am going to do some experiments with this I think... Will play with it during the day with shoulder season loads, but that won't really tell me much. The big test will be a full overnight load.

Does anyone have any theories on if there is any significant difference in heat transfer to the stove versus going up the flue by not using the damper much or at all?

The wood furnace guys have taught us that you want to limit the flow through the stove to slow down the gasses and allow heat to exchange to the skin. This is done by regulating the draft to within spec. Overdraft can also damage the stove by creating a blast furnace! Without regulating draft, and with the way modern noncats are designed, adjusting the air control simply switches where the air comes from. Be it the primary or secondary system. One of those will satisfy the draft.

We all should be using manometers to measure the draft strength, especially when using key dampers.

 

[NickW]

The wood furnace guys have taught us that you want to limit the flow through the stove to slow down the gasses and allow heat to exchange to the skin. This is done by regulating the draft to within spec. Overdraft can also damage the stove by creating a blast furnace! Without regulating draft, and with the way modern noncats are designed, adjusting the air control simply switches where the air comes from. Be it the primary or secondary system. One of those will satisfy the draft.

We all should be using manometers to measure the draft strength, especially when using key dampers.

Right. I am able to control it well now with the damper I added, but I want to try to reduce the babysitting time on my overnight loads so I can start later and get to bed at a reasonable time. Currently I am spending 1 1/2-2 hours damped down farther than I can leave it at overnight.

I just wrote a book in the "What's in your stove now" thread. Want to try to get to the overnight setting sooner without having to damp it down so far then open back up by limiting secondary air a bit but still cleanly get good burn times.

 

[Highbeam]

Right. I am able to control it well now with the damper I added, but I want to try to reduce the babysitting time on my overnight loads so I can start later and get to bed at a reasonable time. Currently I am spending 1 1/2-2 hours damped down farther than I can leave it at overnight.

I just wrote a book in the "What's in your stove now" thread. Want to try to get to the overnight setting sooner without having to damp it down so far then open back up by limiting secondary air a bit but still cleanly get good burn times.

Your problem is real. It's one of the reasons I switched my house stove to a cat stove with a thermostat to automatically adjust the air settings to keep a long, clean, burn of the desired heat output.

The NC30 rages through full loads in a few hours, no hope of long controlled burns in my experience. Perfect for a shop stove!

 

[NickW]

Your problem is real. It's one of the reasons I switched my house stove to a cat stove with a thermostat to automatically adjust the air settings to keep a long, clean, burn of the desired heat output.

The NC30 rages through full loads in a few hours, no hope of long controlled burns in my experience. Perfect for a shop stove!

I do OK with longer(ish) burns, just trying to get dialed in a little more. Normal weather I am able to keep 2500sf heated well enough to 100% keep the baseboards from kicking in. This arctic cold with wind I'm not being as successful.

Do you monitor flue and stt on your NC30 in the shop? I just made a post in the other thread because some of the other folks think I should be able to run a higher stt than flue. I typically am running 150 degrees higher in the flue than stt (with the blower running on high).

 

[weee123]

My flue temp is always lower than my STT even without using the flue damper. I have an auber flue probe so I can see exactly how hot my flue gases are immediately.

When adjusting my flue damper I look at my manometer and adjust it down to around .08 iwc. I really only try to adjust the damper when it starts getting above .11. I will let it go at .10 unless it looks like the stove is about to run, which appears to no longer be an issue (fingers crossed).

How tall is your chimney?

 

[NickW]

24' of vertical flue with 4' horizontal 42" above the stove. So when it's HOT it drafts hard because of the height, when it cools off it loses draft badly because of the horizontal run.

 

[weee123]

Are you able to change the horizontal run to a 45*? This is how I have mine set so it has as little horizontal as possible. It will draft harder but won’t lose draft so easily as with a long horizontal run

 

[NickW]

I thought about it but decided against that because it would be a very small difference in order to maintain clearances and I don't think it would make enough difference to bother, especially with us moving to the Northwoods soon (hopefully...🙄).

 

[Highbeam]

I do OK with longer(ish) burns, just trying to get dialed in a little more. Normal weather I am able to keep 2500sf heated well enough to 100% keep the baseboards from kicking in. This arctic cold with wind I'm not being as successful.

Do you monitor flue and stt on your NC30 in the shop? I just made a post in the other thread because some of the other folks think I should be able to run a higher stt than flue. I typically am running 150 degrees higher in the flue than stt (with the blower running on high).

I monitor flue temps with an auber. I aim to hold flue temps right around 700-800 and this is always hotter than stove top temperatures. I can’t imagine how you could expect the stove surface to be hotter than the internal flue gas temperature. In a noncat, the stove is heated by those flue gasses so where would the extra heat come from?

Maybe somebody confused surface temps of the flue with internal temperature? Then I can see it. I can keep my external surface flue temps lower than the stt pretty easily.

That said, I aim for high output and not necessarily high efficiency so I don’t spend much time on less hot settings. I also use single wall flue pipe.

 

[weee123]

I monitor flue temps with an auber. I aim to hold flue temps right around 700-800 and this is always hotter than stove top temperatures. I can’t imagine how you could expect the stove surface to be hotter than the internal flue gas temperature. In a noncat, the stove is heated by those flue gasses so where would the extra heat come from?

Maybe somebody confused surface temps of the flue with internal temperature? Then I can see it. I can keep my external surface flue temps lower than the stt pretty easily.

That said, I aim for high output and not necessarily high efficiency so I don’t spend much time on less hot settings. I also use single wall flue pipe.

I use an auber and an IR gun to determine my temps. At 600 STT measured with an IR, my internal flue temps are about 500-510 measured with my auber if my memory serves me. Even at 700 STT my flues at 550-570 round abouts. Only time my flue reaches 600-650 is on a hot reload with a few splits when im letting it rip.

 

[NickW]

I use an auber and an IR gun to determine my temps. At 600 STT measured with an IR, my internal flue temps are about 500-510 measured with my auber if my memory serves me. Even at 700 STT my flues at 550-570 round abouts. Only time my flue reaches 600-650 is on a hot reload with a few splits when im letting it rip.

Wow! In a tube stove! I suppose the internal temperature of the firebox is going to be hotter than the flue, but transferring enough of that heat to the stove top to be higher than the flue is unreal to me...

 

[Highbeam]

I use an auber and an IR gun to determine my temps. At 600 STT measured with an IR, my internal flue temps are about 500-510 measured with my auber if my memory serves me. Even at 700 STT my flues at 550-570 round abouts. Only time my flue reaches 600-650 is on a hot reload with a few splits when im letting it rip.

That's very different from my experience. I easily hit the 1000 degree temperature alarm on my auber probe pretty much anytime I want. Why can't you? Also, inside the house in my blaze king I regularly hit 900 during warm up.

Is your fuel okay? Do you think the 32 model somehow is different than the 30 in this way?

 

[weee123]

Wow! In a tube stove! I suppose the internal temperature of the firebox is going to be hotter than the flue, but transferring enough of that heat to the stove top to be higher than the flue is unreal to me...

Yea when the STT is 700 the internal temp is screaming hot, tubes glowing orange, fly ash on the leading edge of the baffle is glowing orange as the flames wrap around it. With the lights off the whole inside is basically an orange glow. Obviously the stove body isn’t glowing thankfully. Not sure why mine runs this way but I have seen others post their STT’s higher on other branded tube stoves.

 

[weee123]

That's very different from my experience. I easily hit the 1000 degree temperature alarm on my auber probe pretty much anytime I want. Why can't you? Also, inside the house in my blaze king I regularly hit 900 during warm up.

Is your fuel okay? Do you think the 32 model somehow is different than the 30 in this way?

Fuel is 3 year seasoned oak with an internal tested at room temp mc of around 18% or less.

With the 32, they did away with the dog house and added a second layer of baffle board along with widening the secondary opening for the 5th tube. Also removing the blower and leg options. I’m not sure if there were any other changes.

If my flue temps hit 1000 I would have a very scary and dangerous night light in my living room 😬. Not sure why I’m able to get my flue temps lower and STT higher than you guys, just goes to show that every install comes with different running and burning characteristics.

Also I never have any creosote buildup in my chimney besides a thin layer of sooty fly ash and I sweep twice a year.

 

[weee123]

Here’s some pics to show what’s going on. Auber temp is about 40 degrees lower than double surface temp due to it being on the low side of the angle. Also showing primary air position.

 

[NickW]

So pardon me if this is/are stupid question(s)...

Where are the volatiles combusting that would have been firing from the secondary air? If those volatiles are still combusting, how does it make it more controlled?

 

[weee123]

Video of secondaries firing with 2/3 of a full load, primary air shut off, key damper open. Video doesn’t pick up the glow but she’s choochin. 650 STT with 500 flue temp. I did close the key damper by half which halted the temp and activity rise and kept it at the current level which I was happy about.