Englander 32 Modification
- Thread starter weee123
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I would consider 500-510 low not high on a probe close to proper location. That's not much over where I would worry about excessive creosote formation up at the cap.
I figure 450 at the probe on mine should stay over 250 at the cap, but probably not by much. I don't even run well until around 600, and aim for over 700. My target flue temperature may change as I continue experimenting with the secondary partially blocked.
So I'm currently burning down coals and going to get a little ash out. Next reload will be a full shoulder season load, smaller on the bottom to get the bigger pieces up in the air for less coaling. Will attempt to run damper fully shut, but doubt it will happen even with the air fully open. Theoretically that should give me the best stt to flue temp relationship, but it might really rip through the wood. That's OK and this is a good time to try it because the house temperature is low.
I figure 450 at the probe on mine should stay over 250 at the cap, but probably not by much. I don't even run well until around 600, and aim for over 700. My target flue temperature may change as I continue experimenting with the secondary partially blocked.
So I'm currently burning down coals and going to get a little ash out. Next reload will be a full shoulder season load, smaller on the bottom to get the bigger pieces up in the air for less coaling. Will attempt to run damper fully shut, but doubt it will happen even with the air fully open. Theoretically that should give me the best stt to flue temp relationship, but it might really rip through the wood. That's OK and this is a good time to try it because the house temperature is low.
brenndatomu
Minister of Fire
300-350*...400 is about the max normally...but potato/potahto...I'm running wood furnace with a big heat exchanger.
-0.04" WC draft normally
brenndatomu
Minister of Fire
It is, but chimney draft has the same effect, too high and you are loosing heat up the chimney/overheating stove, too low and you probably can't heat the house properly (in extreme low temps) just gotta experiment and see what works best for your setup...which y'all are. 👍
Internal flue pipe temp? I do realize you are running a wood furnace. I was always curious how they run. So I’ assuming they function the same as a gas fired furnace with the hot gases going through a heat exchanger? For whatever reason I always thought they took the heat off the firebox like a blower on a woodstove would.
brenndatomu
Minister of Fire
Yes, internal, via thermocouple.
There are different designs out there, but the only 2 models that are left currently (other than some "coal burner" models...skirting EPA emissions limits is what that is) are basically a modern secondary burn firebox, thermostat/computer controlled via internal firebox thermocouple(s) and the hot gasses then leave through a large/long heat exchanger to harvest as much heat as possible, which 300* (occasionally 275*) is about it, even with the Kuuma. (worlds cleanest burning wood furnace) http://www.lamppakuuma.com/
They have a large blower like a standard furnace and are designed to be hooked up to the house HVAC ducts...and yes, heat is pulled from around the firebox, and the heat exchanger both.
Running with no secondary blockage just babysitting the manometer and keeping draft at .05-.06”. More robust secondaries and I don’t want to jinx myself but seems to be running very controlled.
I believe my main problem for feeling like the stove couldn’t be controlled was that I wasn’t keeping the draft down from the get go and only adjusting after the fact which was too late at that point. Hopefully I’m not coming back in an hour to say nevermind she started choochin again
I believe my main problem for feeling like the stove couldn’t be controlled was that I wasn’t keeping the draft down from the get go and only adjusting after the fact which was too late at that point. Hopefully I’m not coming back in an hour to say nevermind she started choochin again
Now I know with a standard woodstove one of those heat exchangers in the flue pipe would cause a ton of creosote. Do you have that same problem with the heat exchanger in the furnace or does the computer keep it burning hot enough for that to not be an issue?
brenndatomu
Minister of Fire
No creosote issues, even with the included barometric damper...heck, I'll check the chimney and have occasionally skipped the annual cleaning.
Yes, computer keeps the firebox hot/clean...in the case of the Kuuma they have an adjustment for heat output desired...that basically just raises the firebox temp that the computer is looking for.
On the other brand the thermostat calling for heat raises the firebox temp that is expected.
STT is 600 and flue temp is 550 going off single wall surface temp. Flue prob seems to be about 100 degrees behind which I am assuming is due to how the gases are flowing around the damper and up the pipe potentially the hottest of the gases skirting above the tip of the probe riding along the top of the angled pipe where the prob comes in at the bottom.
I may honestly extend the vertical portion of my flue up a few inches so I can get the probe in there to get a more accurate temp.
Ideally, we would be running barometric dampers that continuously adjust to maintain the required draft strength. This would accommodate different chimney heights, fuel quality, weather conditions, and most importantly the stage of the burn cycle. It wouldn't be that hard to do internally in the stove with some sort of dilution bypass port into the flue.
I love the term "chooching" BTW.
Even a magic heat device can be used successfully but historically they were run too cold with high emissions stoves so lots of junk accumulated. Modern stove designs don't have too much waste heat but as evidenced by this thread, there is some waste heat especially on noncat stoves.
The bottom of the normal range for internal flue gas temperatures on a condar flugard meter is 400 degrees. Below that and you risk creosote condensation. My NC30 is running smokey at 500 during early stages of the burn. That's just too choked down to support secondary combustion in my install. I don't even close the loading door until the flue temps pass 500.
Hold on now. Have you been giving us "single wall surface temp" all along? 550 on the surface is ripping hot!
My flue temperatures are internal from an Auber digital probe. Probably add at least 200 degrees for the internal flue temperature to single wall surface temperature...? More on startup...?
With the auber digital meter and probe into single wall I do not think you need to add anything. The thermocouple tip is actually measuring temperature in the middle of the stream.
The surface temperature of the single wall should be approximately double the reading from the probe at equilibrium.
Due to the high responsiveness of the digital auber, you can see the delay between changes in internal gas temperature and skin temperature that would be way harder to see if using mechanical meters.
I meant if @wee123 was/is measuring single wall surface. My Auber is in double wall so I don't monitor pipe surface temperature.
No lol. The surface temp is 275 I just did the math and doubled it
So my auber is in the bottom of a 45* offset of pipe so the hottest flue gases are above the tip of the probe which is why I measure both surface temp and probe temp once the stove is going and underway.
When I start bringing the damper into play the surface temp shows much hotter internal than the probe does most likely due to how the hot gases are moving after the damper and up the offset.
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