New Mt.Vernon AE pellet stove owner - not as toasty as I thought!

"1.8 lbs/hr. this is a 40 lb. bag in 24 hours. this is what is usually consumed by an average pellet stove running at its lowest or nearly its lowest setting."

I'm going through this exercise yet again, trying to figure out how much of our situation is house-related vs. how much of it is stove related.

We are at the very end of a 55 lbs. hopper full of pellets that's been running since about 10:50pm last night. We've been running at feed setting 4 as recommended in the owners manual. The owner's manual specifically says not to run the stove on high or low on a regular basis, but to run the stove on a feed setting of 4. We probably have another hour's worth of pellets in the hopper, maybe two hours worth.

EDITED: Full hopper of 55 lbs. pellets took almost exactly 27 hours to burn at feed setting 4, which corresponds to almost exactly 2 lbs./hr.

I'm estimating that gives us a feed of about 2 lbs. per hour. Mike, I believe that's what we calculated when we did this last year about this time. That gives us a BTU production of 17k/hour, or 40,800 BTUs in a 24 hour period. This BTU production agrees with the stated specs for the stove:
8500 to 42,500 BTUs. Napoleon states that this stove is rated to heat 800 to 2000 sq ft. Our house is 1410 sq ft.

I read on a Dept. of Energy web site that a stove rated at 60,000 BTUs can heat a 2000 sq ft house, while a stove rated at 42,000 BTUs can heat a 1300 sq ft home. So, yes, our stove is slightly undersized for our space.

http://energy.gov/energysaver/articles/wood-and-pellet-heating

Rather than lose money on swapping out stoves, we've been trying to insulate and seal this house, and that has helped.

I am considering selling this Napoleon and buying a bigger Englander off of AM FM Energy's web site, but for the moment I am fighting that off. After all, a bigger stove burns more pellets, so a bigger stove will cost us more money to run, in addition to the money we'd lose on swapping out stoves. So if we can get away with hanging on to the BTUs we already make we'll come out money ahead, no matter how much of what fuel we burn.

It is frustrating to deal with the inconsistencies in stove ratings vs. area heated.

Mike, if we were to swap out for a larger Englander, what stove and what size would you recommend?

becasunshine said:

I'm estimating that gives us a feed of about 2 lbs. per hour. Mike, I believe that's what we calculated when we did this last year about this time. That gives us a BTU production of 17k/hour, or 40,800 BTUs in a 24 hour period. This BTU production agrees with the stated specs for the stove: 8500 to 42,500 BTUs. Napoleon states that this stove is rated to heat 800 to 2000 sq ft. Our house is 1410 sq ft.

Click to expand...

Your stove is rated at 42,500 BTUs/hour, or 5 pounds per hour. At that rate, it should be able to burn a bag in only 8 hours. My 30,000 BTU/hr stove can go through a bag in about 10 hours, so I would think you should be able to get more heat out of yours.

The sq ft ratings are very crude estimates for a well-insulated house in a "typical" climate.

17k/hour, or 40,800 BTUs in a 24 hour period.

Click to expand...

I think you slipped a decimal point. 17,000 * 24 = 408,000

Your stove's capacity is:
(42,500 BTU/hr) / (8500 BTU/lb) = 5 lb/hr
5lb/hr * 24 hr/day = 120 lbs/day = 3 bags/day

If the 42,500 BTU is output capacity, divide by efficiency (approximately 75%) to get input of four bags per day.

Open the throttle and let her burn!

Welcome to the Mount Vernon world......I think we all have struggled at one time or another to get enough heat out. For a long time I ran my stove at 0 or - flame height until last year when we had a discussion here and it was point out as others have already that lower flame height =less pellets=less heat. When it gets cold like it is now I run it wide open +5.
The other thing is I run it on the softwood pellet setting even though I am using a hardwood pellet, because softwood gives you the longest time in between auto cleaning. Some on here run on the sunflower setting, which does put out the heat but also uses a lot of pellets. Again more pellets more heat.
The out cleaning is ok, but personally I wish I could turn it off. Reason being is the stove shuts down more when it is burning on high than on medium and ever time it shuts down it is not heating the house as well as when its running. I am sure others can tell you the exact run time between cleanings based on the different fuel types. So, with this stove its a balance of getting heat by running it on high vs how often it auto cleans. This is one balance I have not been able to find when it gets real cold out.

Another thing to consider. You will get more heat out of the stove on manual setting rather than automatic setting. Or, perhaps more accurately, the stove will maintain a higher temperature for the same thermostat setting. Automatic approaches the temperature setpoint while manual will overshoot the setpoint. In really cold weather I prefer the stove to be more aggressive in pursuing it's setpoint.

I have owned the freestanding version of your stove for 4 years now. Here's what I've learned:

1) "It will run you out of there" indicates to me a dealer who does a lot of wood stoves and some pellet stoves. It has come to mean, to me, a person who focuses on lots of heat production but less on HOW that heat is produced and distributed and on saving energy. A modern pellet stove is designed to use outdoor air for combustion and to use that combustion to heat indoor air that is pulled from inside the house. The two loops are separate, which contributes greatly to efficiency and comfort.

2) The very first thing to find out is your OAK status. You MUST have one! Running an MVAE without an OAK is like trying to do 70 on the highway with the parking brake on. Can you do it? Possibly. But you will waste stunning amounts of energy doing so, and likely never get to your goal. Dealers - especially wood stove dealers - very often claim you don't need one. You have heard an idiot speak when that happens, or perhaps more generously a person who has a poor knowledge of building science. There is no debate here - a stove without an OAK is using already conditioned (heated) air for combustion, and sending it outside at the end of that process. Air does not magically appear - it must come from somewhere. No OAK means it comes from inside the house and is immediately replaced with cold outside air through very tiny leaks all over your house. And I can also tell you that I was stupid enough to allow an install of an older stove without an OAK, a decision I am now trying to fix (I was an idiot when I allowed it).

3) As a very knowledgeable member pointed out, this is really just physics. I think you'll come to enjoy your MVAE, but only after the dealer has done more on their part. The room size and layout (over 3 dimensions, not just two, b/c of the cathedral ceiling) is a challenge but I suspect you're not at the max yet for this stove. Please tell us the OAK status and outside temps. Once we know that, this is a fantastic forum for help. Great people here!

Check this out for auto clean cycle times, among other details of your MVAE.

https://www.hearth.com/talk/threads/mt-vernon-ae-downloadable-trouble-shoot-manual.105258/

I just did a quick heat check between with a hand held temp. gun and on Sunflower- it read 430f. On Softwood it read 230 so about double the heat but also from what I recall last time I ran it on sunflower for an extended period it was double the pellets. Which goes to the theory more pellets more heat.

LMPS said:

I just did a quick heat check between with a hand held temp. gun and on Sunflower- it read 430f. On Softwood it read 230 so about double the heat but also from what I recall last time I ran it on sunflower for an extended period it was double the pellets. Which goes to the theory more pellets more heat.

Click to expand...

On softwood running on medium with a feed rating of +2 I'm seeing 320 at the center of the stove discharge. (Barefoot)

But I never tired sunflower. Thanks for the tip.

Harvey Schneider said:

I think you slipped a decimal point. 17,000 * 24 = 408,000

Your stove's capacity is:
(42,500 BTU/hr) / (8500 BTU/lb) = 5 lb/hr
5lb/hr * 24 hr/day = 120 lbs/day = 3 bags/day

If the 42,500 BTU is output capacity, divide by efficiency (approximately 75%) to get input of four bags per day.

Open the throttle and let her burn!

Click to expand...

Do you know the max lb/hour on the MVAE?

With H&H revising the output on this stove from 60k to 52k, I'm wondering what if anything has changed. My dealer told me that nothing had changed, aside from a revision in the paperwork.

At 52k assuming 8500 BTUs/lb I'm calculating 6.1 lbs/hr max. Which equates to about 3.5 bags in 24 hours.

gregt23 said:

The thermostat is beside the stove around a corner where the fireplace protrudes slightly. It is beside and slightly behind the direction of where the heat blows.

Click to expand...

You should move the t-stat it is not in a good location at all this will not allow the stove to run properly

john193 said:

Do you know the max lb/hour on the MVAE?

With H&H revising the output on this stove from 60k to 52k, I'm wondering what if anything has changed. My dealer told me that nothing had changed, aside from a revision in the paperwork.

At 52k assuming 8500 BTUs/lb I'm calculating 6.1 lbs/hr max. Which equates to about 3.5 bags in 24 hours.

Click to expand...

The meaning of the spec is somewhat obscure. The spec is for input energy, not output, and the type of fuel is not specified. I'm wondering if they were claiming the 60K based on a really hot pellet (9300 BTU/lb ?) vs the average 8500 BTU/lb. I don't believe that they spec the lbs/hr anywhere.
For comparison I checked the boiler that was sized for the whole house plus domestic hot water and it is 111,000 BTU/hr. So the 52,000 BTU/hr seems appropriate for the first floor of my house. It carries the load even in this cold weather (in the teens every night).

john193 said:

Do you know the max lb/hour on the MVAE?

With H&H revising the output on this stove from 60k to 52k, I'm wondering what if anything has changed. My dealer told me that nothing had changed, aside from a revision in the paperwork.

At 52k assuming 8500 BTUs/lb I'm calculating 6.1 lbs/hr max. Which equates to about 3.5 bags in 24 hours.

Click to expand...

i think the main reason the changed it was that they did not want the MT vernon to show higher btus then the xxv same reason they increased the heat output on the new accentra insert

stoveguy13 said:

i think the main reason the changed it was that they did not want the MT vernon to show higher btus then the xxv same reason they increased the heat output on the new accentra insert

Click to expand...

This is basically what my dealer said.

becasunshine said:

EDITED: Full hopper of 55 lbs. pellets took almost exactly 27 hours to burn at feed setting 4, which corresponds to almost exactly 2 lbs./hr. I'm estimating that gives us a feed of about 2 lbs. per hour. Mike, I believe that's what we calculated when we did this last year about this time. That gives us a BTU production of 17k/hour, or 40,800 BTUs in a 24 hour period. This BTU production agrees with the stated specs for the stove: 8500 to 42,500 BTUs. Napoleon states that this stove is rated to heat 800 to 2000 sq ft. Our house is 1410 sq ft.

Click to expand...

ok, 17K over 27 hours is 408K, not 40.8K an input value based on 8.5Kbtu pellet potential would put 40.8Kbtu/hr at 4.8 lbs/hr means to input that much heat with this fuel the needed feed rate would be 8.33 hours for a 40 lb bag. or 11.45 hours for 55 lbs

so in order to release the 40Kbtu we have to burn that much volume, remember, its not the stove that makes the heat, its the fuel.

now, here's the question of the day, what is heat range 4? is it high low or medium (4 out of what). if this is the high rate and the stove can only feed 2 lbs/hr at that rate it aint a 40Kbtu stove plain and simple.

now if the stove is on a stat then it skews the data quite a bit as there will be time when the unit is not feeding at all (on/off) or feeding on low (high/low) so to get a true reading on potential it would have to be run unaffected by a stat. on other words if the stove feeds 4.8lbs/hr when heat is called for and shuts off when the stat aint calling for heat, the stove would be running 30.7% of the time at that rate or roughly 1/3 of the time. if you are running a stat would this jive with what you are seeing with the stove running?

stoveguy2esw said:

ok, 17K over 27 hours is 408K, not 40.8K an input value based on 8.5Kbtu pellet potential would put 40.8Kbtu/hr at 4.8 lbs/hr means to input that much heat with this fuel the needed feed rate would be 8.33 hours for a 40 lb bag. or 11.45 hours for 55 lbs

so in order to release the 40Kbtu we have to burn that much volume, remember, its not the stove that makes the heat, its the fuel.

now, here's the question of the day, what is heat range 4? is it high low or medium (4 out of what). if this is the high rate and the stove can only feed 2 lbs/hr at that rate it aint a 40Kbtu stove plain and simple.

now if the stove is on a stat then it skews the data quite a bit as there will be time when the unit is not feeding at all (on/off) or feeding on low (high/low) so to get a true reading on potential it would have to be run unaffected by a stat. on other words if the stove feeds 4.8lbs/hr when heat is called for and shuts off when the stat aint calling for heat, the stove would be running 30.7% of the time at that rate or roughly 1/3 of the time. if you are running a stat would this jive with what you are seeing with the stove running?

Click to expand...

Ok, well, that's what *I* get for doing math in the wee hours after a long day of canning!

Here are the numbers:

Per the manual:
The stove is rated to heat 800 sq. ft. to 2000 sq. ft.
The BTU/hour output is 1.0 to 5.0 lbs./hour
The BTU/hour output is 8500 to 42500
Hopper capacity is 55 lbs.
The manual quotes pellet heat content as "approximately 8200 BTU per pound minimum."

The feed control is a continuous dial from 1-5, with 4 being the recommended setting. I assume that's a 4 lbs./hour feed, then.

The stove is not hooked to a thermostat, nor is there the capability to do so, as far as I know.

I had the hopper filled to the rim when I began timing it, but not over-full. The hopper lid could close completely without obstruction. The stove ran continuously for 27 hours, with one of us making sure toward the middle to the end that the remaining pellets were moved down to the bottom of the hopper and within reach of the auger. During this time, we shut the stove down twice to remove clinkers from the burn pot. Each time the stove was shut down for approximately 10 minutes, at the end of which we reached in with gloved hand and dumped the burn pot into the stove's ash drawer. This 20 minutes of shut down was subtracted from the overall run time.

With the handful of remaining pellets and mostly fines at the very bottom of the hopper, sitting on top of the auger, the stove shut itself down at 27 hours. It could not feed enough fuel to sustain a burn. I'm going to call that a bona fide 27 hour burn time.

55 lbs. of pellets/27 hours = 2 lbs/hour
and that's all we've *ever* gotten out of this stove- which does not correspond to a burn rate of 4 lbs./hour on the best of days.

The auger seems to run just fine, the stove seems to operate just fine, but that's our feed rate at setting 4.

We purchased the stove in 2008, so we are way out of warranty on the electronic circuits and motors by now.

I could call our stove store but I'm not sure how far that will get me. They no longer carry this pellet stove nor that manufacturer's line, and the store has changed management a couple of times since we bought the stove.

I don't think I could force two bags of pellets in a 24 hour period through this stove with a shoe horn at feed setting 4. That has not been my experience, anyway, when we've timed burns. Although, here's a thought- does the auger pick up fewer pellets as the load in the hopper lighten?

Perhaps we are burning more pellets/hour when we keep the hopper topped off- but I swear, I don't know how to time that accurately. I can tell you that I do not perceive that we are anywhere near putting two bags of pellets a day into this stove when it's running continuously on feed setting 4.

If the feed setting is off and always has been, how do we deal with that?

becasunshine said:

Ok, well, that's what *I* get for doing math in the wee hours after a long day of canning!

Here are the numbers:

Per the manual:
The stove is rated to heat 800 sq. ft. to 2000 sq. ft.
The BTU/hour output is 1.0 to 5.0 lbs./hour
The BTU/hour output is 8500 to 42500
Hopper capacity is 55 lbs.
The manual quotes pellet heat content as "approximately 8200 BTU per pound minimum."

The feed control is a continuous dial from 1-5, with 4 being the recommended setting. I assume that's a 4 lbs./hour feed, then.

The stove is not hooked to a thermostat, nor is there the capability to do so, as far as I know.

I had the hopper filled to the rim when I began timing it, but not over-full. The hopper lid could close completely without obstruction. The stove ran continuously for 27 hours, with one of us making sure toward the middle to the end that the remaining pellets were moved down to the bottom of the hopper and within reach of the auger. During this time, we shut the stove down twice to remove clinkers from the burn pot. Each time the stove was shut down for approximately 10 minutes, at the end of which we reached in with gloved hand and dumped the burn pot into the stove's ash drawer. This 20 minutes of shut down was subtracted from the overall run time.

With the handful of remaining pellets and mostly fines at the very bottom of the hopper, sitting on top of the auger, the stove shut itself down at 27 hours. It could not feed enough fuel to sustain a burn. I'm going to call that a bona fide 27 hour burn time.

55 lbs. of pellets/27 hours = 2 lbs/hour
and that's all we've *ever* gotten out of this stove- which does not correspond to a burn rate of 4 lbs./hour on the best of days.

The auger seems to run just fine, the stove seems to operate just fine, but that's our feed rate at setting 4.

We purchased the stove in 2008, so we are way out of warranty on the electronic circuits and motors by now.

I could call our stove store but I'm not sure how far that will get me. They no longer carry this pellet stove nor that manufacturer's line, and the store has changed management a couple of times since we bought the stove.

I don't think I could force two bags of pellets in a 24 hour period through this stove with a shoe horn at feed setting 4. That has not been my experience, anyway, when we've timed burns. Although, here's a thought- does the auger pick up fewer pellets as the load in the hopper lighten?

Perhaps we are burning more pellets/hour when we keep the hopper topped off- but I swear, I don't know how to time that accurately. I can tell you that I do not perceive that we are anywhere near putting two bags of pellets a day into this stove when it's running continuously on feed setting 4.

If the feed setting is off and always has been, how do we deal with that?

Click to expand...

yeah, something is amiss, have you ever run it at lower than 4? if so does it really show a difference in feed rate? also, if the company doesn't recommend running at 5 why the <insert expletive> do they have it in the stove?

its possible that the "high range" they are advertising is based on "5" output, but if this is the case there would have to be a massive difference in feed rates between 4 and 5.

doesn't make any sense to me. we'll figure it out, I need something to sink my teeth into today anyway, wife is having her hernia worked on at UVA today i'll have my kindle and cell with me so I should be able to communicate. be nice to have the distraction while im languishing in the waiting room

the easiest way to find out if the stove is feeding the right amount on a setting is to know the auger timing for example on low on for 3 seconds off for 5 on high on for 5 seconds off for 2 seconds i just made the times up but the stove manufacture should be able to give this timing and this will tell you if it is feeding correctly

stoveguy2esw said:

yeah, something is amiss, have you ever run it at lower than 4? if so does it really show a difference in feed rate? also, if the company doesn't recommend running at 5 why the <insert expletive> do they have it in the stove?

its possible that the "high range" they are advertising is based on "5" output, but if this is the case there would have to be a massive difference in feed rates between 4 and 5.

doesn't make any sense to me. we'll figure it out, I need something to sink my teeth into today anyway, wife is having her hernia worked on at UVA today i'll have my kindle and cell with me so I should be able to communicate. be nice to have the distraction while im languishing in the waiting room

Click to expand...

Mike, give our best to your wife! UVA is a great hospital. We have a good friend who is a nurse there.

I'm getting ready to tear the stove down to clean out the exhaust pathway after burning the last of the overly ashy pellets we were trying to clear up.

I'll PM our phone number to you so you can call if you are bored out of your mind in the waiting room, but only call if you want the distraction. Wife first, all the stoves in the world can wait!

stoveguy13 said:

the easiest way to find out if the stove is feeding the right amount on a setting is to know the auger timing for example on low on for 3 seconds off for 5 on high on for 5 seconds off for 2 seconds i just made the times up but the stove manufacture should be able to give this timing and this will tell you if it is feeding correctly

Click to expand...

exactly right. this is the first step Becca. we will want to look at this cycle timing on various settings to see where we are starting from

stoveguy13 said:

the easiest way to find out if the stove is feeding the right amount on a setting is to know the auger timing for example on low on for 3 seconds off for 5 on high on for 5 seconds off for 2 seconds i just made the times up but the stove manufacture should be able to give this timing and this will tell you if it is feeding correctly

Click to expand...

Stoveguy, do you know how to get in touch with the Napoleon manufacturer? I tried to get in touch with them for another question early in the ownership of this stove- couldn't find a phone number, and I believe that I sent an email which never got a response.

becasunshine said:

Mike, give our best to your wife! UVA is a great hospital. We have a good friend who is a nurse there.

I'm getting ready to tear the stove down to clean out the exhaust pathway after burning the last of the overly ashy pellets we were trying to clear up.

I'll PM our phone number to you so you can call if you are bored out of your mind in the waiting room, but only call if you want the distraction. Wife first, all the stoves in the world can wait!

Click to expand...

thanks Becca, im just thinking of the wait nothing really to do so the distraction will help pass the time for me. I can get on the kindle there im sure so will be able to keep up with things in here that way (love that kindle)

becasunshine said:

Stoveguy, do you know how to get in touch with the Napoleon manufacturer? I tried to get in touch with them for another question early in the ownership of this stove- couldn't find a phone number, and I believe that I sent an email which never got a response.

Click to expand...

not off hand, kinda hoping a resident member who works with these stoves will show up, input from a person who is familiar with the way this manufacture's systems work would be invaluable in figuring this out. I know the theory as well as anyone , but not knowing the mechanical/electrical ins and outs of this particular machine isn't helping much. do you know if they have anything of that nature on their website? or a downloadable manual?

stoveguy2esw said:

not off hand, kinda hoping a resident member who works with these stoves will show up, input from a person who is familiar with the way this manufacture's systems work would be invaluable in figuring this out. I know the theory as well as anyone , but not knowing the mechanical/electrical ins and outs of this particular machine isn't helping much. do you know if they have anything of that nature on their website? or a downloadable manual?

Click to expand...

http://www.napoleonfireplaces.com/products/nps45-pellet-stove/

There's a button on the left side of the page that you can click to download the manual.

That's the NPS45, which is the next generation. Our stove is the NPS40. I need to download the 45's manual and compare it to ours to make sure that it's the same. Off the top of my head, the only change of which I'm aware is that the NPS45 has a "purge cycle," in which the combustion fan draws a stronger poof of air through the burn pot to clean it, once at start up and then once an hour during the burn cycle. Oh, and apparently they've put hinges on the access doors (that's a huge improvement over our model) and they are back to some sort of cleaning/filling rake. There was, apparently, a burn pot rake or something like that on earlier versions of our stove as well? but we don't have one. I'm not really sure what that on again/off again gadget does.

Mike, I downloaded the owner's manual for the NPS45. The specs (area heated, feed rates vs. pounds per hour burned, BTU output, etc.) are identical to our NPS40.