Internal firebox temps?

[pell it]

Anyone else have an oven thermometer in their firebox? I'm curious as to
What temps others are seeing for various pellets.

J.T. I thought I remember seeing one in your pictures from the pellet reviews.
Do you have the readings recorded?

I am basically looking at how my "El cheapo" stove burns compared to you heavy
Hitters out there. I feel that the air temp exiting the exchanger tubes is more a measure
Of stove design efficiency than a measure of pellet burn qualities. I know I am outgunned
In the heat exchanger efficiency category, but I would like to know if I am even in the ballpark
On how well the stove is firing.

Feel free to plant a boot in my keister if I'm all wet on this train of thought!!

 

[jtakeman]

No I don't monitor the fire box temps. quazi95(Rob) from woodpelletreviews has it in his lopi stove. I haven't heard him mention any temps though.

I'm more concerned with what comes off the convection as that is what heats the house. I could measure firebox and exhaust temps. But not sure how they would compare. I assume(not good to do-gets me in trouble all the time) that the firebox temp should be lineer to the convection temps. As the firebox temp rises so should the convection temps.

I think comparing stove to stove is gonna be a toughie! Lots of variables I suppose(as bad as assuming) that if you measured firebox-convection and exhaust temps. But I believe your still gonna get stumped. The variable that stands out is the feed rate or volume of fuel feed. Should be tough one to tackle!

I agree the most important thing is heat exchanger efficiency! Its where the stoves makes it or doesn't. They all make fire, But the one that sends as much as possible(there is a fine line here too) to warm the house should be the clear winner. But the line I mentioned is it can't cool the exhaust too much or other things could start happening.

We have a few stove manufacturer's that hang out here. But they never seem to jump in to these topics! I think they like keeping all this stuff a secret or just start laughing at us pair heads chatting about what we guess at! Be nice if they would at least give us a few bread crumb's to follow. I keep getting lost in the forest!

 

[SmokeyTheBear]

What's that you say there be pigs in the forest that are lost ????

You've got to watch those interacting thermodynamic equations, some of them cause massive headaches.

 

[jtakeman]

I suppose I can get some readings from my stove if you want to start stove comparing? I'm game. Already know I got a good one here!

One last thing I didn't mention. Were gonna need a standard pellet to make things fair! What brands you got available!

I think bear said were gonna get headaches over this opening up large cans of worms! ;-)

 

[BrotherBart]

I have a mag thermo on the side of the firebox on the PDVC in the basement but it is for seeing how much gain in temp I get at different feed rates at the moment. Hey, I am a wood stove guy. Gotta have my thermometer.

Won't be comparing pellets. I am up to my keister in Stove Chow. But I will be able to say for a long time that they are the best pellet I have ever burned. They are the only pellet I have ever burned. :lol:

Ignorance is bliss as they say.

 

[pell it]

I'm not really looking to compare stove vs stove (it would be like Kia vs Viper) I'm more interested in firebox temp for a given feed rate for various pellets as a baseline for further assumptions.

I have been seeing a 25-40 degree variance with the same pellet mix at the same feed rates.

 

[jtakeman]

I'm not really looking to compare stove vs stove (it would be like Kia vs Viper) I'm more interested in firebox temp for a given feed rate for various pellets as a baseline for further assumptions.

I have been seeing a 25-40 degree variance with the same pellet mix at the same feed rates.

Do you measure the convection temps too? Betting as you see the increase in the firebox temp the convection temp also rises. Not sure if it will be linear though?

 

[SmokeyTheBear]

I have a mag thermo on the side of the firebox on the PDVC in the basement but it is for seeing how much gain in temp I get at different feed rates at the moment. Hey, I am a wood stove guy. Gotta have my thermometer.

Won't be comparing pellets. I am up to my keister in Stove Chow. But I will be able to say for a long time that they are the best pellet I have ever burned. They are the only pellet I have ever burned. :lol:

Ignorance is bliss as they say.

Only up to a certain amount of ash and then you look for alternatives.

 

[SmokeyTheBear]

I'm not really looking to compare stove vs stove (it would be like Kia vs Viper) I'm more interested in firebox temp for a given feed rate for various pellets as a baseline for further assumptions.

I have been seeing a 25-40 degree variance with the same pellet mix at the same feed rates.

Do you measure the convection temps too? Betting as you see the increase in the firebox temp the convection temp also rises. Not sure if it will be linear though?

Linear, not exactly. Usually close enough for small ranges of variation.

 

[pell it]

I'm not really looking to compare stove vs stove (it would be like Kia vs Viper) I'm more interested in firebox temp for a given feed rate for various pellets as a baseline for further assumptions.

I have been seeing a 25-40 degree variance with the same pellet mix at the same feed rates.

Do you measure the convection temps too? Betting as you see the increase in the firebox temp the convection temp also rises. Not sure if it will be linear though?

So far my convection temp readings are done with a meat thermo that tops out at 220. I am looking around at a thermocouple set-up for my "work" Fluke.

I suspect the fluctuations may be fuel metering related especially in the lower heat settings.

 

[SmokeyTheBear]

I'm not really looking to compare stove vs stove (it would be like Kia vs Viper) I'm more interested in firebox temp for a given feed rate for various pellets as a baseline for further assumptions.

I have been seeing a 25-40 degree variance with the same pellet mix at the same feed rates.

Do you measure the convection temps too? Betting as you see the increase in the firebox temp the convection temp also rises. Not sure if it will be linear though?

So far my convection temp readings are done with a meat thermo that tops out at 220. I am looking around at a thermocouple set-up for my "work" Fluke.

I suspect the fluctuations may be fuel metering related especially in the lower heat settings.

Yep sure does make a difference, also the ash deposition rate on the heat exchanger will cause a fairly steady decrease in heat being transfered.

 

[jtakeman]

I'm not really looking to compare stove vs stove (it would be like Kia vs Viper) I'm more interested in firebox temp for a given feed rate for various pellets as a baseline for further assumptions.

I have been seeing a 25-40 degree variance with the same pellet mix at the same feed rates.

Do you measure the convection temps too? Betting as you see the increase in the firebox temp the convection temp also rises. Not sure if it will be linear though?

So far my convection temp readings are done with a meat thermo that tops out at 220. I am looking around at a thermocouple set-up for my "work" Fluke.

I suspect the fluctuations may be fuel metering related especially in the lower heat settings.

Yep sure does make a difference, also the ash deposition rate on the heat exchanger will cause a fairly steady decrease in heat being transfered.

One of the reasons my tests were all taken with a clean stove. I tried my best to get the temps logged within the first 2 hours. By the end of the 2 bag run some of the higher ash brands dumped some 5 degrees. Ash is a pretty good insulator. ;-)

 

[pell it]

What I am observing is that the auger will run thru 2-3 cycles without dropping any pellets (maybe one or two) and then it will drop a large qty. By the time it drops the pellets, the flames have all but died out and it then takes a second for the new pellets to catch. (this is most prominent on the two lowest heat settings) I have watched the motor/auger coupling and the auger moves, just does not feed.

I thought it was due to the amount of fines in the batch of Stove Chow I have and have since begun to sift every bag. I figured the fines were accumulating in the lower auger section robbing space that actual pellets should be filling. I ran the stove out of pellets and gave a thorough vacuuming to the hopper and auger. This did help some, however, the issue still exists.

I have emailed US Stove a few times and am getting the silent treatment. They must not want to support new stove offerings. Guess I got what I paid for!

I am now "adjusting" the draft airflow to try and get the most consistent burn I can from the stove. I will make an adjustment and let it run a couple days to see how she responds. Now that it is cold enough here to run 24/7, I have more opportunity to dial it in for the best results possible. Unfortunately, I bought two tons of "not the greatest" pellets, and had I found this site earlier, would not have made that mistake. I do not have the physical room to fit another full ton of a good pellet for the real cold season, so I am trying to make the best with what I have.

If I had some firebox temp readings from other stoves at a given feed rate, I would have something to shoot for with my tinkering.

 

[jtakeman]

Ah, I'm catching on now.

But first, Is there an adjustment to tweak the feed rate on the US Stove controller? Should be something in the manual on adjustments. Though I saw something on an older US Stove. Maybe snap some pictures of both the front and back side of the controller. Not sure what they are sending to market after the Breckwell purchase. Controller could be different???

Also to be consistent where are you measuring the temps? I can check some with a laser on my stove for you at medium feed rate.

 

[fmsm]

Long time lurker of this great site. Funny this thread appeared as on Sunday I bought an infra red temperature probe at hd for thirty bucks. The sole purpose was to record temps inside my new Harman P35i.

I hit 424.8 at the top of the flame and 229 air temp coming out of the heat exchanger

 

[GrahamInVa]

Long time lurker of this great site. Funny this thread appeared as on Sunday I bought an infra red temperature probe at hd for thirty bucks. The sole purpose was to record temps inside my new Harman P35i.

I hit 424.8 at the top of the flame and 229 air temp coming out of the heat exchanger

Welcome!

FYI.. Infrared guns can't measure air temps. They only measure the temp of something solid. They are a handy tool to have though..

A meat thermometer or a thermocouple is the best way to measure air temps. Which by the way is the best way to evaluate your pellets.

 

[pell it]

Ah, I'm catching on now.

But first, Is there an adjustment to tweak the feed rate on the US Stove controller? Should be something in the manual on adjustments. Though I saw something on an older US Stove. Maybe snap some pictures of both the front and back side of the controller. Not sure what they are sending to market after the Breckwell purchase. Controller could be different???

Also to be consistent where are you measuring the temps? I can check some with a laser on my stove for you at medium feed rate.

The controller is very basic. (I can snap some pics later) On/off, auger button (to prime it from empty), fan (sets conv. fan to high), mode (manual or tstat), heat level (scrolls 1 thru 5), and an auger trim button. According to the manual, the auger trim is only active for heat setting 1. It allows you to "slightly increase or decrease the feed rate". There is one increased rate and one decreased rate. I have timed the increased rate vs the std heat 1 setting: STD "1" auger on 2 seconds and off 5 seconds "increased" rate auger on 2.7 seconds and off for 5 seconds.

The control board is basically a PIC/CPU chip with some triacs to control the motors. There are no adjustment pots or anything. I am actively researching scrapping the factory controls and building one of Snowy's bullet proof industrial ones so that I can have some control over things. (the wife would not be happy though, she likes the hit "ON" and walk away auto ignite feature)

With the 6039 multi fuel I had before, you could get into the settings further and dial it in. (adjust draft fan, auger rate, etc) this one seems to be devoid of that functionality. This stove does not even provide a means to control the draft airflow. I had to install a 2" ball valve in my homemade OAK, otherwise it was blowtorch city!


My oven thermometer is to the left of the burnpot, slightly infront, and @ 4-5 inches away. (this was the only spot it will sit on)

Interesting you mention US Stove purchasing Breckwell. Maybe this is a Breckwell basic design that was put on the chopping block for cost effectiveness and sent overseas for manufacturing. It does have a slight resemblance to the Mojave line and the 50 lb hopper and 45K BTU are close to the 5660 specs.

 

[jtakeman]

Certainly sounds like the standard Breckwell controller. One thing I hated with them is not having a variable speed combustion blower. Runs full out and you adjust with the damper. I much perfer a variable speed blower where the damper is set and stays there through out the stoves heat ranges. But thats another story!

How is the length of the pellets your using? If they are on the long side try another brand that is shorter in length. You'll get more fuel to the burnpot. Might be something that helps get around this. Worked for my similarly controlled Breckwell bigE. Just a thought!

 

[pell it]

Certainly sounds like the standard Breckwell controller. One thing I hated with them is not having a variable speed combustion blower. Runs full out and you adjust with the damper. I much perfer a variable speed blower where the damper is set and stays there through out the stoves heat ranges. But thats another story!

How is the length of the pellets your using? If they are on the long side try another brand that is shorter in length. You'll get more fuel to the burnpot. Might be something that helps get around this. Worked for my similarly controlled Breckwell bigE. Just a thought!

I will look at the pellet lengths when I get home. If memory serves me they are 1/4" to 1" for the most part. I really want to get my hands on some 100% Hardwood pellets to try, thinking the slower burn rate will help. The local guy that had Cubex is out, the box stores are a waste, I will be calling a place in Ma today about Turmans. I tried one bag of the hardwood heat so far but did not notice a big difference, I'll give another shot if it is all I can get.

 

[jtakeman]

Certainly sounds like the standard Breckwell controller. One thing I hated with them is not having a variable speed combustion blower. Runs full out and you adjust with the damper. I much perfer a variable speed blower where the damper is set and stays there through out the stoves heat ranges. But thats another story!

How is the length of the pellets your using? If they are on the long side try another brand that is shorter in length. You'll get more fuel to the burnpot. Might be something that helps get around this. Worked for my similarly controlled Breckwell bigE. Just a thought!

I will look at the pellet lengths when I get home. If memory serves me they are 1/4" to 1" for the most part. I really want to get my hands on some 100% Hardwood pellets to try, thinking the slower burn rate will help. The local guy that had Cubex is out, the box stores are a waste, I will be calling a place in Ma today about Turmans. I tried one bag of the hardwood heat so far but did not notice a big difference, I'll give another shot if it is all I can get.

Because you can't adjust feed rates, You'll have to play around with pellets to get some that provide a consitent feed. Only problem is many brands very from batch to batch. So it could be a crap shoot.

Turmans were one of the best in my bigE. Also seemed to be very consistent from batch to batch year to year. Also some of the softwoods worked very well in the bigE. Spruce Pointe's did well. Okanagan are comprable to the SP's, But They were not on the market when I had the bigE.

Something to consider when comparing stoves is its adjustability. Having both feed trim and draft trim is a plus in all heat ranges. Check out the Enviro's as most of the upper level units have them and they allow tweaking in all heat ranges. A bit more than the entry level stoves but definetly have all the options.

Maybe you could swap out the controller with one from a similar stove with more adjustment? Forget I said that, It might be frowned apon. Could be unsafe and cause many other issues. But if one did there homework and choose one with similar feedrates??? Could be feasable. After all all the safe features will still be their and in service. Cheaper than buying a new stove and many of the controls are made by the same company. Also use the same molex connector and wiring/pinout! Do they have some info on feed rated in the manual?

 

[tjnamtiw]

Long time lurker of this great site. Funny this thread appeared as on Sunday I bought an infra red temperature probe at hd for thirty bucks. The sole purpose was to record temps inside my new Harman P35i.

I hit 424.8 at the top of the flame and 229 air temp coming out of the heat exchanger

Having used IR thermometers at work, I can attest to the fact that they are highly subjective and not very accurate when measuring various surfaces with different reflective characteristics. The better ones TRY to compensate for this with a switch for dark or reflective surfaces but even then, they aren't very good. If you are shooting through glass to get to the internal parts of the stove, you really don't know what you are measuring.
You're better off getting a thermocouple that you can hook to a good multimeter if you want to go there.

 

[fmsm]

Long time lurker of this great site. Funny this thread appeared as on Sunday I bought an infra red temperature probe at hd for thirty bucks. The sole purpose was to record temps inside my new Harman P35i.

I hit 424.8 at the top of the flame and 229 air temp coming out of the heat exchanger

Welcome!

FYI.. Infrared guns can't measure air temps. They only measure the temp of something solid. They are a handy tool to have though..

A meat thermometer or a thermocouple is the best way to measure air temps. Which by the way is the best way to evaluate your pellets.

Thanks! Now I know.......still a pretty cool toy

 

[pell it]

Certainly sounds like the standard Breckwell controller. One thing I hated with them is not having a variable speed combustion blower. Runs full out and you adjust with the damper. I much perfer a variable speed blower where the damper is set and stays there through out the stoves heat ranges. But thats another story!

How is the length of the pellets your using? If they are on the long side try another brand that is shorter in length. You'll get more fuel to the burnpot. Might be something that helps get around this. Worked for my similarly controlled Breckwell bigE. Just a thought!

I will look at the pellet lengths when I get home. If memory serves me they are 1/4" to 1" for the most part. I really want to get my hands on some 100% Hardwood pellets to try, thinking the slower burn rate will help. The local guy that had Cubex is out, the box stores are a waste, I will be calling a place in Ma today about Turmans. I tried one bag of the hardwood heat so far but did not notice a big difference, I'll give another shot if it is all I can get.

Because you can't adjust feed rates, You'll have to play around with pellets to get some that provide a consitent feed. Only problem is many brands very from batch to batch. So it could be a crap shoot.

Turmans were one of the best in my bigE. Also seemed to be very consistent from batch to batch year to year. Also some of the softwoods worked very well in the bigE. Spruce Pointe's did well. Okanagan are comprable to the SP's, But They were not on the market when I had the bigE.

Something to consider when comparing stoves is its adjustability. Having both feed trim and draft trim is a plus in all heat ranges. Check out the Enviro's as most of the upper level units have them and they allow tweaking in all heat ranges. A bit more than the entry level stoves but definetly have all the options.

Maybe you could swap out the controller with one from a similar stove with more adjustment? Forget I said that, It might be frowned apon. Could be unsafe and cause many other issues. But if one did there homework and choose one with similar feedrates??? Could be feasable. After all all the safe features will still be their and in service. Cheaper than buying a new stove and many of the controls are made by the same company. Also use the same molex connector and wiring/pinout! Do they have some info on feed rated in the manual?

The controller swap is something I can look into and start doing my homework on. (on my own accord of course) This year I am stuck with the pellets I have, but I would like to find next years pellets in the process.

As for feed rates in the manual, the only mention is in the "Heating Specifications" it states "Burn rate: *43,900 btu's per hour or 5.1 lbs of fuel per hour" the asterick denotes based on quality of fuel. (would have to be 8600 btu/pound fuel and 100% efficiency) Other than that, it does list the auger timing for the 5 heat settings with on and off times. From these two tidbits I calculated the other four feed rates assuming the 5.1 lb/hour is the #5 setting.

I will definitely be much better informed for my next stove purchase!

 

[flynfrfun]

What I am observing is that the auger will run thru 2-3 cycles without dropping any pellets (maybe one or two) and then it will drop a large qty. By the time it drops the pellets, the flames have all but died out and it then takes a second for the new pellets to catch. (this is most prominent on the two lowest heat settings) I have watched the motor/auger coupling and the auger moves, just does not feed.

I thought it was due to the amount of fines in the batch of Stove Chow I have and have since begun to sift every bag. I figured the fines were accumulating in the lower auger section robbing space that actual pellets should be filling. I ran the stove out of pellets and gave a thorough vacuuming to the hopper and auger. This did help some, however, the issue still exists.

I notice this on my stove too. Not as bad as yours, but it's there. I think most stoves are like this to varying degrees. I chalked mine up to the space between the auger and the tube it sits in. On mine, the auger is a round screw type. But the tube it sits in is not perfectly round and it is a lot bigger than the auger screw. I think this allows pellets to fall off the auger randomly, so sometimes the auger fins are full of pellets, sometimes not. Anybody know why they wouldn't make the tube the auger sits in a lot closer to the size of the auger itself?

 

[jtakeman]

Many of these controllers are made by the same exact company(name slips me know. I'll post it and a link to their site when I get home!). Most have the DHC-3000 and some of the fancier units have the DHC-4000. The DHC-3000 and 4000 both have the same molex connector and wire pinout AFAIK.

I know the Enviros us them and have variable combustion blower. Also have trim adjustments. Look at them for one that has a 48 to 50K BTU rating. There are some others as well. I'll dig up some names if I get some time to play!