What is your temperature of room air coming out of your pellet stove

Based on the laser it's reading the front of the stove near the top of the firebox.

So to answer the O/P, the air exiting the vents (stove on high, 260 CFM blower on high) is 210F. Now if I stick the thermocouple between the gasket and metal at top of door (best I can before I burn my flesh off), it read 430F.

Doug Doty said:

now how to measure the air..

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The best way to measure air temperature is with a wire thermocouple. A thermocouple can measure the air temperature with no influence by surface temperature as long as it is not touching the surface.
Even a cheap ebay thermocouple meter will be accurate to just a few degrees worst case.

woodmakesheat said:

Based on the laser it's reading the front of the stove near the top of the firebox.

So to answer the O/P, the air exiting the vents (stove on high, 260 CFM blower on high) is 210F. Now if I stick the thermocouple between the gasket and metal at top of door (best I can before I burn my flesh off), it read 430F.

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I imagine (never tested it) that the top of the outside of my firebox, right above the door is getting above 600 degrees in as much as every year I have to repaint the front with header paint because it gets burned off and I've had to reinforce the firebox inside with a 1x1 angle because the metal was warling inward... I know it's toasty there.

I have a Fluke (not an HF) so I would imagine it's pretty accurate. I mostly use it to ascertain the floor temperatures in my shop which has PEX heat.

checkthisout said:

That's 325 degrees on the metal tubes, yes? Your actual air temp after passing over passing over those 325 degree tubes is probably much lower than the surface temperature of the tubes.
You'll need an actual thermometer/thermistor to measure the true temperature of the air exiting the stove.

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I checked mine this morning using thermocouple in the middle of the air stream and it readx231 degrees. For the MVAE owners I was running in manual mode, convection blower on normal, heat output on high and flame height on 4.

I too checked this morning - I'm at 133 with the feed rate on low and the convection fan on right smack in the middle. When I have the feed up in the middle I cant get my hand too close to the air outlet without getting air fried.

Mysticenchantment said:

I too checked this morning - I'm at 133 with the feed rate on low and the convection fan on right smack in the middle. When I have the feed up in the middle I cant get my hand too close to the air outlet without getting air fried.

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Hmmm. My Harman Accentra insert has never run that warm that I remember . . . . .

120 degrees not touching the metal tube with a darkroom thermometer. That's on low.

It is possible to increase the thermal transfer efficiency of any stove, though it entails dismantling the cabinet and in some cases that would deteriorate the cosmetic appearance of the unit because the cabinets are weldments (with the exception of the access panels that are screwed on).

You can increase the thermal efficiency by adding radiation surface to the HX. Manufacturers tend to make their HX's from smooth metal weldments and the addition of metal, thermally bonded to the HX can increase thermal transfer, in other words, adding metal in the air stream causes the additional metal to conduct more heat and transfer that to the air flow..

If you aren't concerned with cosmetic appearance and have some mechanical aptitude, you can add surface area via extruded aluminum heat sinks to the HX but they must be thermally bonded to the HX itself. Been done before and it works but it can be an ugly process, simply put, dismantling the unit and putting it back together again and adding radiation surface to the HX.

When you see a rated BTU output on a stove specification, thats Gross BTU output, the actual realized BTU output is less, most times at least 15% less than the rated BTU specified.

Compare it to the radiator in you car. The reason your radiator works (and your car don't overheat) is, the radiator has much more radiating surface (for thermal transfer) than it's actual physical size because it's comptised of finned heat sinks, thermally bonded to tubes that carry fluid and transfers the heat of the coolant to the air. If you radiator was a solid block with no heat transfer capabilities, your engine would overheat because it can't rid itself of residual heat. A car engine in reality is a very inefficient machine, most of the energy produced is wasted in heat and that heat has to go somewhere.... your radiator.

The physics lesson for today.....

SidecarFlip said:

You can increase the thermal efficiency by adding radiation surface to the HX.

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It's really convective surfaces or air turbulators that you are adding. Pellet stoves work mostly by convection heat transfer, their surfaces aren't hot enough to move much heat by radiation.
A small increase in the turbulence of the air in a heat exchanger can significantly improve it's efficiency. A large increase is counter productive because it reduces the volume of air moving through. Increasing the area that the air is flowing over (convective surface) provides more opportunity for heat to transfer to or from the air (increased exchange).

Sounds good to me, I know it works but can really make a good looking stove fugly.

Just got an oven thermometer yesterday. Haven't measured the Harmon, but the Hastings runs 225F on level 3 and just at 150F on #1. Those numbers may be misleading as I set it on the door ornamentation (opened from the rest of the stove) so it is 2-3" away from the vents. Also, I just changed pellets and haven't adjusted the damper for best burning (flames aren't as sharp as they were before).

Englander on heat level 1, convection blower on level 9

Surface temp at the exit louvers -295
Air temp @ 1" in front of louvers -155

funflyer said:

Englander on heat level 1, convection blower on level 9

Surface temp at the exit louvers -295
Air temp @ 1" in front of louvers -155

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-295?

I've never seen a liquid nitrogen fueled stove before.

Big E said:

448 degrees with IR, down through tubes. setting 3 out of 5 (I only use 2-4)

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You are pointing IN the tubes where air goes out? at settings 3 i got 280 ' F pointing in the tubes ..same stove.....and at settings 3 i got 520 'F at best in the combustion chamber.pointing my gun all around IN.

Air temp on temp setting 2 (feed rate of 2 also) of my P61A taken with oven thermometer hanging in front of the distribution blower outlets.

219*F +/- 8*

Temp setting 3 (feed rate 3)

241*F +/- 10*

Haven't tried a higher setting yet...

This is with premium LG softwoods.

I'm getting 200 on medium with cheap shoulder season pellets.

i got up around 250f on high when i measured a couple seasons ago. i hung a stove thermometer in the airstream with it not touching any of the stove surfaces.
i might get a few more degrees on high now since i have a different combustion motor and will be running with the gate fully open. i expect that my medium setting will now be sufficient on colder days than it was before with the gate closed down nearly all the way as it was when i had the weak ass motor in.

it's refreshing to see so many folks posting similar temps and not 450 - 500 degree temps as if that's a true read of the air temp exiting the stove. (there was older thread like this with many more exaggerated claims/readings)
show me that (pics please) with a thermocouple or stove thermometer in the airstream, not touching any stove surface, and i will be duly amazed.
i promise i will.

P61A on medium being almost as hot as my flat plate PS50 on high is completely believable to me.

I have a digital temp meter that was once an industrial controller. I ran a type J thermocouple into one of the tubes being careful to to touch the tube. I use this to gauge the general health of my stove. I mapped the temperature of the air for each heat setting.

1) 135
2) 195
3) 240
4) 290
5) 310

Right now, with the stove off it reads 69

update with feed gate all the way open because new combustion fan makes that possible.
i'm getting on medium now what i got on high before. of course that makes sense since more pellets are being fed. (same thermometer i used last time. so even though it's not the best marked, it makes a true comparison)
low is much more useful now. i should have started with a pic of the low reading.
reasoning follows that i should be able to make it through a hard winter on medium now. i like having the extra capability though.

249ish on medium. i'm going to say 270 on high. i've never been much above 250 on high, so i will definitely take this.

I remembered this thread so I thought I would post. I went my first season with Isabella pellets (I live in west Michigan) and got very low heat output from what I could tell. So I got my candy thermometer and clipped it in the tubes. ( inhave a quadrafire Castile insert). I was getting 170-180 air temperatures with the isabellas. I thought I would try a few more brands that are available around here and test before I buy for next year. So I bought 2 bags of Somersets, 2 bags of kirtlands and 2 bags of Pro Pellets. After testing these are the results:

Pro pellets 225 degrees
Kirtlands 215 degrees
Somersets 210 degrees
Isabellas 180 degrees ( on a good day )

I will probably go with the kirtlands as they had the least ash. But the Pro Pellets weren't to bad and they are the hottest. My stove had trouble keeping up last year, now I know why I think. What's interesting is that the Isabellas are soft wood which is supposed to burn hotter. We are talking a 45 degree difference for the same price per ton.

Jonkman said:

What's interesting is that the Isabellas are soft wood which is supposed to burn hotter. We are talking a 45 degree difference for the same price per ton.

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Thanks for the post back ... interesting results. All pellets are not created equal ... even the softwoods. Any info on what softwoods are used? I know I've read that the LaCretes and Spruce Pointes are a combination of spruce, pine, fir.

Lake Girl said:

Thanks for the post back ... interesting results. All pellets are not created equal ... even the softwoods. Any info on what softwoods are used? I know I've read that the LaCretes and Spruce Pointes are a combination of spruce, pine, fir.

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I did a search and found this from an old newspaper article "Isabella Pellet uses only Michigan red pine sawdust purchased from area sawmills, including Biewer, Gutierrez said." Here is the link to the article. http://www.themorningsun.com/article/MS/20110922/NEWS/309229976

Anyways, I never really posted ash content, I would rate them all very similar for volume, with the exception of Kirtlands, which had very low ash. I would go with the Kirtlands, but they are $235 a ton, and I just found a seller by me that is selling Pro Pellets for $185 a ton.

The famous Somersets unfortunately leave hard black formations inside my burn pot I have to chisel out, and for the cost they are not any better than the other at all. So I would rate Kirtlands as the best (they got decent heat at 215 degrees) and the least ash, but because I can save so much with the Pro Pellets I am going with them this year.

Of note, I heard a rumor that Isabella is coming out with a hardwood pellet this year too I guess. Not sure if I will try them though.....

Hi
My Advance is 434 deg f and still warming up!
Harman's are one of the best!

Don2222 said:

Hi
My Advance is 434 deg f and still warming up!
Harman's are one of the best!

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I don't think you can use an IR sensor to get the air temperature very accurately, that is going to be the temp of the metal or glass or wherever that is bouncing off from. 434 degree hot air would be dangerous in my opinion.

Running on Heat level 4 burning Barefoot or Green Team I see 385-450F depending on how recently I cleaned the stove. That is after about 12 hours continuous burn. Measured with a K-type thermo at the exchange output. Average I would say it hovers around 400F.