BTU rating

Hi tow- Normally Max BTU input is what is listed. The burn rate per hour is gonna be around 6.0-6.5 lbs which will give you around 50000 btus x the efficiency of the stove for output heat per hour. If they are saying 32000 btu is normal output, check to see what their burn rate per hour is. 32000 is about 3.5-4.0 lbs of pellet per hour input btu rating. Hope this doesn't confuse the matter. I have never heard a MFR say "under normal conditions" you set the burn rate somewhere within the stove's ultimate capability and low..... Good luck,

The 50k rating is input.The stove is 80% eff.You go from there.Also they make a 35k stove,you did not get the wrong one?

They did not make a 50k "output",just "Input".Page 3. http://www.globalindustrial.com/sit...PH50CABPSENGHPPelletManual_2012CabinetGHP.pdf

towkee said:

... I emailed the company and there response was the 50,000 BTU's is under "optimal laboratory conditions" and 32,000 is under "normal conditions". They assure me that it will heat 2200 square feet.

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It is always good to list the exact model in question.

The company gave you good info, but did a bad job of answering you. I'll just re-state what the above experts said: You bought a 50,000 BTU input stove, which puts out about 32,000 BTU of heat into the room, and sends the rest up the flue with the exhaust gases. That's stated on page 3 of the PDF which Bob_Bare attached.

The Gov't then suggests that the 35,000 BTU will heat the avg 2200 sq ft home, so that's what the companies put on their advertising. Of course all our homes are different, some tight as a drum, or mine where the candles flicker when the wind blows.

Like Stovelark mentioned, each pound of pellets contains about 8000 BTU, so the speed adjustment of the feed auger (4, 5, or 6 lbs/hour) will control the heat into the stove. Your stove room fan speed, and how clean you keep the stove, will determine how much heat you get out. The factory was able to get 78% of the heat input into heat output, your mileage may vary.

And to you question: yes, all companies put the "input BTU" in the ads because WE are all suckers for the biggest numbers.

Stoves are more efficient the hotter they are. Because of this, it would be better to get a smaller stove and run it on high than a larger stove and run it on low.

towkee said:

Hi, I am looking for some advise on BTU ratings. I recently purchased a pleasant hearth cabinet stove which I found on line and all the literature and manual said it was rated as 50,000 BTU's. I get it home and open the packaging and the sticker on the front says it is rated at 32,000 BTU's. I emailed the company and there response was the 50,000 BTU's is under "optimal laboratory conditions" and 32,000 is under "normal conditions". They assure me that it will heat 2200 square feet. I am less than impressed. Has anyone else run into this problem? Are all BTU's listed on the units under "optimal laboratory conditions"? Thank you for any thoughts!

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50k is theoretical input, which is the number stove mfrs will advertise. 32k is the measured output on the white EPA card that they include inside the firebox of the stove. If you look carefully at the card, I think you'll see it say "output".

TimfromMA said:

Stoves are more efficient the hotter they are. Because of this, it would be better to get a smaller stove and run it on high than a larger stove and run it on low.

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In general I suppose that's most likely true, but every stove is different. My stove has an efficiency rating at both max and min output. The difference is less than 1%. Really, inconsequential. Far more important is for the owner to adjust the stove for optimal efficiency. As we've all learned, they're not plug-n-play, they need fine-tuning, because everyone's setup is different. Different vent setups, different air pressure conditions, etc.

I have a harmon accentra insert, and that is rated at 45,000 BTU, and the maximum feed rate of 5 lbs an hour, but I've never gotten it to feed more than 3.5 lbs/hour - I think my chimney is too tall

smirnov3 said:

I have a harmon accentra insert, and that is rated at 45,000 BTU, and the maximum feed rate of 5 lbs an hour, but I've never gotten it to feed more than 3.5 lbs/hour - I think my chimney is too tall

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??? How could your chimney height influence how many pounds per hour your auger delivers pellets? It would have more to do with pellet length and density, wouldn't it?

tjnamtiw said:

??? How could your chimney height influence how many pounds per hour your auger delivers pellets? It would have more to do with pellet length and density, wouldn't it?

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first off, let me say that I have NO idea why my stove feeds low, but my best guess is that the exhaust fan isn't powerful enough to drive the combusted gases of 5lbs an hour up the chimney.

Remember, on a Harmon, you have a vacuum switch to make sure that you have sufficient draft to ensure complete combustion, and if you aren't pulling enough air, the switch won't let you feed more.

I HAVE noticed that on days with a strong breeze, my feed rate is in the low 3 pound region, while on calm days it is in the high 3's

tjnamtiw said:

??? How could your chimney height influence how many pounds per hour your auger delivers pellets? It would have more to do with pellet length and density, wouldn't it?

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On the other hand, I have noticed that I have a better draft on the right side of the stove than the left (ie when I scrape out the ash, there is a lot more in the right heat exchanger than the left), so maybe that's the issue instead.

The vacuum switch should be pulled in and stay in as long as the stove is running. It shouldn't open and close to regulate feed rate based on the amount of draft you have in your chimney. I don't have an Accentra so I can't shed light on your feed rate. Perhaps you've never ASKED it to feed that much, meaning you never asked for max heat. That model senses room temperature compared to set temp and adjusts the feed rate accordingly. Maybe your sensor is too close to the stove and it lowers the feed rate too soon.
As for the ash, you have to look at the path of the exhaust and realize that more ash will get trapped in the area that first sees the exhaust. It's not unusual to see more on one side than the other of my stoves.

tjnamtiw said:

The vacuum switch should be pulled in and stay in as long as the stove is running. It shouldn't open and close to regulate feed rate based on the amount of draft you have in your chimney. I don't have an Accentra so I can't shed light on your feed rate. Perhaps you've never ASKED it to feed that much, meaning you never asked for max heat.

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Back when I first got the stove and was trying to figure this issue out, I ran it set to max temp / max feed rate. it still behaved the same.

and of course the vacuum switch SHOULDN'T open and close, but if the fan can't pull enough vacuum (like if the flue is clogged with ash or the door is opened), it will pop open

If you never reached the set temperature, then it must be a factor of pellet length/density. I've had long pellets that made me open my feed gate on my Quads all the way while short pellets, like I had this year, made me close the feed gate as far as it would go to get the proper flame height. I've had low density pellets that produced four buckets of pellets per bag while this year's bags produced less than 3 buckets. Moral of the story is that pellets make a huge difference in stove performance. When I had the long, low density pellets, I never could get the heat out wanted out of the stove.

Of course, after having a stove since 2006, you already have learned this lesson. I'm surprised some of the Harman guys haven't chimed in. I guess they've all gone into hibernation for the summer.

tjnamtiw said:

If you never reached the set temperature, then it must be a factor of pellet length/density.

Of course, after having a stove since 2006, you already have learned this lesson. I'm surprised some of the Harman guys haven't chimed in. I guess they've all gone into hibernation for the summer.

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Pellet quality does make a difference, but what I did was I ran the stove on the usual settings (70 F for temp, and 3.5 on feed rate) and timed how many seconds out of each minute the auger was running (as seen on the 'feed' light)

I then cranked the stove up to 90 F and 9 on the feed rate and measured the feed rate

the feed rate remained the same.

I had already calculated that that at the normal setting, I was feeding 3.5 lbs of pellets an hour, based on consumption.

It's weird, but I have gotten used to it. And it does have it's advantages - if the feed rate went up to 5, then the stove would run out of pellets while I was at work on some days.

Like I said, I'm no expert on Hormoan's but if the feed rate didn't change and the thing is running on the room temp probe, then something isn't working!

tjnamtiw said:

Like I said, I'm no expert on Hormoan's but if the feed rate didn't change and the thing is running on the room temp probe, then something isn't working!

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I believe that might be a falicy? in the esp system,with a restrictive exhaust(tall) the programming wants to keep the stove in a certain range for efficiency,so stove will never be able to reach max potential like an older manual control stove.Have heard of this before.Also may be why a lot of older units could be direct dumped into a flue,not requiring a liner all the way up,as you could bump up the combustion blower.