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

[slls]

I do not have that plate at the intersection of the hopper and the auger. Here's a picture of the auger in the empty hopper. View attachment 120443

Also, I did a "one Mississippi, two Mississippi" count on feed rate 4 while I had the auger turning, so I could vacuum out all fines and the remainder of the pellets, and start fresh with new pellets. (I cannot believe this, but I do not appear to have any sort of digital stop watch thingy around here. Don't even ask about my coal-fired cell phone. It can call a tow truck if I'm stuck and that's about it, but that's about all I want in a cell phone anyway.)

Based on my count, feed rate four is as follows:

Auger turns every EIGHT seconds
When the auger begins turning, it turns for TWO seconds. After the auger finishes turning, there is a SIX second interval before it begins to turn again.

Is that a solid auger, not the spring type like other Quads?

 

[becasunshine]

Is that a solid auger, not the spring type like other Quads?

slls, I must confess, I stole this thread. We have a Napoleon NPS40 free standing pellet stove, and we have questions about the feed rate. But yes, as far as I can see, it's a solid auger.

 

[RockyMtnHigh]

Keeping on the Quad part of things, the AE is a spring auger like the older quads.

 

[becasunshine]

From the NPS40 users manual:

SYMPTOM
Feed rate dial has
no effect on the fire
(timer control only)

- Secure all connections to the power control module.
- Perform a resistance test to the potentiometer by placing the two test leads from a multi meter into the
leads of the potentiometer. The potentiometer should have a range of 850 KΩ (± 10%).
Potentiometer readings:
Full counter-clockwise (switched off) = open circuit, overload or infinite resistance
Low fire .......... 900 KΩ to 1,050 KΩ
High fire ......... 56 KΩ to 62 KΩ
If the range is not close or does not vary then replace the potentiometer

I saw this in the trouble shooting section in the manual. I admit, I blew past it because my thinking was that turning the feed rate dial *does* have an effect on the pellet feed- it always has- but that the dial settings and the pellet feed don't match up. A feed rate of 4 doesn't really equal 4 lbs./hour feed rate. We've proven that by now.

It never occurred to me that a failing or failed or bad potentiometer could simple skew the feed rate- the feed rate will still be variable, but not true to the dial settings.

Good call, Harvey!

We threw a fresh 40 lbs. bag of pellets into the empty hopper at noon, turned the feed rate to 4.5, then left the house to attend a family function. When we got back we didn't pay attention to the stove immediately.

When we did look at the stove's hopper at 10pm, it appeared that about half of the 40 lbs. was gone. The Hubs put about 3/4 of a new bag of pellets into the hopper to fill it- so that makes sense. About half of the previous bag, or 20 lbs., burned in 10 hours. That's 2 lbs./hour at a feed rate setting of 4.5. About 3/4 of a new bag fills the hopper, or about 30 lbs. added. It's a 55 lbs. hopper and it is full. So, give or take 5 lbs., it appears that the estimate of 20 lbs. burned with 20 lbs. remaining in the hopper, add about 3/4 of a new 40 lbs. bag or 30 lbs. to fill the hopper and a 55 lbs. hopper is full.

^^ The point is that on the previous timed burn at feed setting 4, we burned 40 lbs. in 22 hours, or 1.8 lbs./hour. In the 4.5 feed setting burn it appears that we burned about 2 lbs./hour, which is a slight increase.

We are now burning from a completely full hopper at feed setting 4.5, and we'll time this one as well, or at least we'll start timing it.

Hubs does own a multimeter, so we'll suspend the timed test briefly tomorrow and check the potentiometer. That should be fairly quick and easy. Maybe that's where the problem lies!

 

[becasunshine]

Sorry it took us a bit to get back to this thread (that I stole. Sorry OP!) We've had a family weekend here. Timed burn on feed setting 4.5 was interrupted a couple of times. Will get back to that now that weekend is finishing up.

Mr. Sunshine is in the stove innards with his multimeter. Here are the readings per feed setting:

Potentiometer (rheostat) turned completely off, feed setting OFF: No reading/off the scale

Potentiometer (rheostat) turned on, feed on, but just barely: 1096 kilo ohms

Potentiometer (rheostat) on Feed Setting 1: 1071 kilo ohms

Potentiometer (rheostat) on Feed Setting 2: 784 kilo ohms

Potentiometer (rheostat) on Feed Setting 3: 606 kilo ohms

Potentiometer (rheostat) on Feed Setting 4: 410 kilo ohms

Potentiometer (rheostat) on Feed Setting 5: 138 kilo ohms

Potentiometer (rheostat) on Feed Setting No Number, dial turn up as high as possible: 56 kilo ohms

So the potentiometer/rheostat appears to be working correctly.

What next??

 

[Harvey Schneider]

Sorry it took us a bit to get back to this thread (that I stole. Sorry OP!) We've had a family weekend here. Timed burn on feed setting 4.5 was interrupted a couple of times. Will get back to that now that weekend is finishing up.

Mr. Sunshine is in the stove innards with his multimeter. Here are the readings per feed setting:

Potentiometer (rheostat) turned completely off, feed setting OFF: No reading/off the scale

Potentiometer (rheostat) turned on, feed on, but just barely: 1096 kilo ohms

Potentiometer (rheostat) on Feed Setting 1: 1071 kilo ohms

Potentiometer (rheostat) on Feed Setting 2: 784 kilo ohms

Potentiometer (rheostat) on Feed Setting 3: 606 kilo ohms

Potentiometer (rheostat) on Feed Setting 4: 410 kilo ohms

Potentiometer (rheostat) on Feed Setting 5: 138 kilo ohms

Potentiometer (rheostat) on Feed Setting No Number, dial turn up as high as possible: 56 kilo ohms

So the potentiometer/rheostat appears to be working correctly.

What next??

The next question is "Does the on/off ration of the auger change with feed setting?"

 

[stoveguy13]

count the timing of the auger on all the settings

 

[becasunshine]

Feed setting zero, feed on but just barely: 16 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-16

Feed setting 1: same as zero, 16 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-16

Feed setting 2: 13 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-13

Feed setting 3: 11 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-11

Feed setting 3.5 according to the brackets painted above the dial number, this is the beginning of the optimal/acceptable feed range: same as feed setting 3, 11 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-11

Feed setting 4, recommended feed setting according to the manual: 9 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-9

Feed setting 4.5 according to the brackets painted above the dial number, this is the top limit of the optimal/acceptable feed range: 8 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-8

Feed setting 5: 6 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-6

Feed setting maximum, dial turned all the way up to stop: 4 second cycle, auger turns for seconds 1-3, auger is idle for second 4

Beginning a timed burn at feed level 4.5, upper range of optimal/acceptable as indicated by bracket above feed dial, at 6pm on 12/15/13.

 

[Harvey Schneider]

Feed setting zero, feed on but just barely: 16 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-16

Feed setting 1: same as zero, 16 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-16

Feed setting 2: 13 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-13

Feed setting 3: 11 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-11

Feed setting 3.5 according to the brackets painted above the dial number, this is the beginning of the optimal/acceptable feed range: same as feed setting 3, 11 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-11

Feed setting 4, recommended feed setting according to the manual: 9 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-9

Feed setting 4.5 according to the brackets painted above the dial number, this is the top limit of the optimal/acceptable feed range: 8 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-8

Feed setting 5: 6 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-6

Feed setting maximum, dial turned all the way up to stop: 4 second cycle, auger turns for seconds 1-3, auger is idle for second 4

Beginning a timed burn at feed level 4.5, upper range of optimal/acceptable as indicated by bracket above feed dial, at 6pm on 12/15/13.

So, now we know that the duty cycle of the auger ranges from about 19% to 75% That sounds like a reasonable range. That begs another question; "Is the auger turning at the correct rotational speed?"

 

[becasunshine]

I received an auto reply to my initial email to Napoleon customer service, along with a case number. The auto reply said that I could reply to that email and include/attach any further information and documentation.

I've been responding to that email at intervals over the weekend, sending along all of the information from the timed burns, the potentiometer results, the auger intervals, etc. as we collect that information.

I've not yet received a technical service response from Napoleon- not surprising, it is the weekend- but perhaps we'll hear something next week.

I don't know how to measure the rotational speed of the auger. The hopper is full right now, but I can wait to measure the rotational speed or I can unload the hopper. I have seen the auger turning and it appears to turn without binding or distress. The auger motor sounds completely normal with the hopper full of pellets and will the hopper empty. It is carrying pellets to the burn pot- at least enough pellets to keep the stove running and producing heat. But is it turning fast enough during those intervals? I don't know.

Thank you again, Harvey and everybody, for your help!

 

[chken]

So, when the augur is running for its 3 secs every cycle, do you see very many pellets falling? Does a different brand of pellet, give you a different result?

 

[becasunshine]

So, when the augur is running for its 3 secs every cycle, do you see very many pellets falling? Does a different brand of pellet, give you a different result?

Chken, the short answer is "Yes." There are plenty of pellets falling during the turn portion of auger cycle. When we turn the feed rate up to maximum during the ignition cycle, it will fill the pot almost to full while the igniter heats up to ignite the pellets in the pot.

The owner's manual stipulates that small pellets will affect feed rates and burn times by a factor of plus or minus 20% depending on fuel quality. The feed rate at feed setting 4 is supposed to be 4 lbs./hour. We are getting results that vary from 1.8 lbs./hour to 2 lbs./hour at feed setting 4. This is a 45% - 50% variance from the expected feed rate of 4 lbs./hour- far greater than a 20% variance as allowed by Napoleon's stated parameters.

 

[stoveguy2esw]

So, now we know that the duty cycle of the auger ranges from about 19% to 75% That sounds like a reasonable range. That begs another question; "Is the auger turning at the correct rotational speed?"

agreed, it looks mechanically like the cycles are acceptable and it ohmed out spot on on the range pot. question at hand now is what is the "RPM" of the motor and is it correct for this model stove?

sorry for taking so long to get back in this becca, the weekend has been rather trying. my kindle would not allow me to respond while I was up there I was able to read but not post and it wouldn't download tapatalk (gotta ask webbie about that) wife is doing well, hoping for her to come home Tuesday.

 

[Harvey Schneider]

agreed, it looks mechanically like the cycles are acceptable and it ohmed out spot on on the range pot. question at hand now is what is the "RPM" of the motor and is it correct for this model stove?

sorry for taking so long to get back in this becca, the weekend has been rather trying. my kindle would not allow me to respond while I was up there I was able to read but not post and it wouldn't download tapatalk (gotta ask webbie about that) wife is doing well, hoping for her to come home Tuesday.

I did a quick look at auger motors that claim to be compatible with your stove. The one motor that I can see the ratings on is rated for one rpm.
Other things to consider:

• slipping couplings
• blockage
• auger alignment

If this conversation was under a thread title that referred to the correct stove type you might get input from people with more knowledge of your stove.

 

[becasunshine]

agreed, it looks mechanically like the cycles are acceptable and it ohmed out spot on on the range pot. question at hand now is what is the "RPM" of the motor and is it correct for this model stove?

sorry for taking so long to get back in this becca, the weekend has been rather trying. my kindle would not allow me to respond while I was up there I was able to read but not post and it wouldn't download tapatalk (gotta ask webbie about that) wife is doing well, hoping for her to come home Tuesday.

That was my FIRST question, Mike- how's your WIFE? We are so glad to hear that she is doing well and that she will be back home soon. There is no place like home!

With a little help from our friends we can tear the stove down, get to the auger motor and see if there is a serial number on it. It won't happen tonight, unfortunately, stove is up, running and hot, and The Hubs is on a conference call sorting out a work problem with a group of coworkers. He's head's down right now and it seems that they are all in the thick of it, i.e. it won't be over in a minute.

But yeah, so we need to know what motor we have on this auger, and if it's the appropriate motor for this stove, right?

 

[SwineFlue]

Feed setting zero, feed on but just barely: 16 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-16

Feed setting 1: same as zero, 16 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-16

Feed setting 2: 13 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-13

Feed setting 3: 11 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-11

Feed setting 3.5 according to the brackets painted above the dial number, this is the beginning of the optimal/acceptable feed range: same as feed setting 3, 11 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-11

Feed setting 4, recommended feed setting according to the manual: 9 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-9

Feed setting 4.5 according to the brackets painted above the dial number, this is the top limit of the optimal/acceptable feed range: 8 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-8

Feed setting 5: 6 second cycle, auger turns for seconds 1-3, auger is idle for seconds 4-6

Feed setting maximum, dial turned all the way up to stop: 4 second cycle, auger turns for seconds 1-3, auger is idle for second 4

Beginning a timed burn at feed level 4.5, upper range of optimal/acceptable as indicated by bracket above feed dial, at 6pm on 12/15/13.

I think these numbers explain what you're seeing, Becca. The auger duty cycle on feed setting 4.5 is half that of the max setting. In other words, the very top limit of the "optimal" feed range will run the stove at only half of its rated capacity.

 

[becasunshine]

I did a quick look at auger motors that claim to be compatible with your stove. The one motor that I can see the ratings on is rated for one rpm.
Other things to consider:

• slipping couplings
• blockage
• auger alignment

If this conversation was under a thread title that referred to the correct stove type you might get input from people with more knowledge of your stove.

I can't comment on the slipped couplings because I have no idea what that means- I can't envision it in my mind, I don't have enough knowledge to draw myself a mental picture. I can say that the auger sounds and looks like it is running smoothly.

Blockage- no- it's clean as a whistle. I just cleaned the hopper. I ran the auger and made sure that I vacuumed the fines out of all the threads. The auger turned smoothly, without any sounds or visual signs of being jammed or bound.

Alignment- similarly, when the hopper was empty and I could see/hear the visible portion of the auger, it seemed fine to me, no sounds or visual indications of being out of alignment or off-center. When the hopper is full, the auger motor sounds fine and pellets drop regularly.

We had an auger jam once, when I left pellets in the hopper over the summer (direct vent, no chimney) and the pellets that were in the auger tube jammed up. With help over the phone from a stove tech, I unjammed the auger and got it running smoothly again. So, I know what an auger jam sounds like.

About changing the title of the thread, or moving the integral parts of the conversation to an appropriately titled thread, what is the appropriate protocol? Perhaps one of our friendly mods can help me!

 

[becasunshine]

I think these numbers explain what you're seeing, Becca. The auger duty cycle on feed setting 4.5 is half that of the max setting. In other words, the very top limit of the "optimal" feed range will run the stove at only half of its rated capacity.

I guess that the question now is: what did the engineers intend? Did they intend for the stove to meet the feed rate/hour criteria stated in the manual, or did they mean for the stove to do what it is actually doing? Because both realities can't live in the same stove.

We are currently running a timed burn at 4.5 with a full 55 lbs. hopper load, to test the actual feed rate at the top of the recommended feed rate setting.

 

[SwineFlue]

I guess that the question now is: what did the engineers intend? Did they intend for the stove to meet the feed rate/hour criteria stated in the manual, or did they mean for the stove to do what it is actually doing? Because both realities can't live in the same stove.

We are currently running a timed burn at 4.5 with a full 55 lbs. hopper load, to test the actual feed rate at the top of the recommended feed rate setting.

The manual says it will feed 5 pounds per hour (42,500 BTU/hr). That is probably true at the max setting. One would assume that setting the dial to 4.5 would give you 80-90% of the max feed rate. But your timing numbers show that it's only 50%.

I bet you'll get about 2.5 pounds per hour...

 

[becasunshine]

The manual says it will feed 5 pounds per hour (42,500 BTU/hr). That is probably true at the max setting. One would assume that setting the dial to 4.5 would give you 80-90% of the max feed rate. But your timing numbers show that it's only 50%.

I bet you'll get about 2.5 pounds per hour...

I'm betting about the same thing, SwineFlue.

 

[Harvey Schneider]

I think these numbers explain what you're seeing, Becca. The auger duty cycle on feed setting 4.5 is half that of the max setting. In other words, the very top limit of the "optimal" feed range will run the stove at only half of its rated capacity.

Interesting, Is this supposed to be linear:

 

[becasunshine]

All this being said, we have decided NOT to run the stove above the recommended feed range until we get some guidance from Napoleon.

 

[becasunshine]

Interesting, Is this supposed to be linear:
View attachment 120747

Huh. Look at that. (Thank you, Harvey!)

OK, I should say, the counts are me sitting beside the stove, counting "One Mississippi, Two Mississippi..." I did count each cycle a few times to make sure that I was at least counting consistently.

There's always the possibility that I was counting inconsistently, but I would think that I'd count inconsistently, consistently, because we all pretty much do what we do in the manner in which we typically do it. I.E. I'd have to deliberately syncopate my count to be so notably inconsistent that I'd skew a straight line into a curve.

 

[chken]

I noticed that too, about the increments being non-linear, and I wondered why they'd have a "max" setting that they tell you not to use! I mean, it allows them to spec the unit as having a certain btu capability, then they tell you not to use it? Struck me odd, but I'm new to pellets, so I dunno, maybe that's how they do it?

 

[becasunshine]

Also, this is interesting:

When we start up the stove, we typically start it with the feed rate set on 4. This feed rate puts enough pellets in the pot for the igniter to light them, and we can walk away from the stove during the start up cycle and not worry about the burn pot overflowing and/or backing up into the drop tube, or worry about the stove over firing if we get called away. We leave the convection blower OFF until we feel that the air coming out of the heat exchange tubes is very warm. Once the stove warms up, we turn the convection fan to its mid-range setting of about 2.5. Typically the stove runs along at feed rate 4, convection/room blower fan rate 2.5 with no change in cycle, and no issues, unless we inadvertantly let it run out of pellets or we shut it down. If we aren't standing right beside the stove when it gets hot, we will hear the convection blower override switch trip and the convection blower fan come on at its highest setting. This is a factory installed/engineer designed safety feature that helps keep the stove from over firing. If we aren't standing right there during the start up cycle, and we hear the convection fan kick on, we go back to the stove and set the convection fan dial to 2.5. The convection fan will run on high until the stove is cooled enough to allow the over ride safety feature to drop off. When that happens, the convection fan will drop down to the speed that we've manually set. It typically stays right there, with no intervention from a safety feature or over ride, unless we change something.

We've been running the stove on feed rate 4.5, the top of the recommended range, since 6pm, or almost 4.5 hours. The pellet level in the hopper has dropped by 2". At a feed rate of 4.5, which is supposed to correspond to 4.5 lbs./hour, for 4.5 hours, we should have burned 20.25 pounds, or 37% of the 55 lbs. of pellets in this hopper. I would expect more pellets to be gone, i.e. for this hopper to be at least one third empty by now, really, over one third empty, not merely lowered by 2 inches.

BUT- here's the interesting thing- the override switch on the convection/room blower fan has been activated, and the convection fan has been blowing on HIGH even though it is manually set for 2.5, for a couple of hours now.

The stove is putting out heat. The IR thermometer centered on a center heat exchange tube is registering 300'F.

The flame in the burn pot is bright white, sharp and active. Dropping pellets cause lots of popcorn sparks (no pellets jumping out of the burn pot, but lots of sparks fly.) Damper is set on 2 out of five. The flame has a normal, bright burn and a typical life cycle; it will diminish to bright cinders in the pot, and a few smaller flames, until the auger delivers enough pellets to revive the flame and continue the cycle. There is absolutely no build up in the pot. The ash on the door glass is grayish-white. The stove is burning immaculately right now. The only thing that's causing me some concern is that the override switch has had the convection fan on high for quite a while now to keep the stove from overheating.

The over fired override switch has NOT been triggered. The stove has NOT gotten hot enough to shut itself down.

Tonight we are burning a mixture of Turman's and Presto Logs.

Pictures of pellet level at 10:30pm, plus pictures of flame and flame cycle are attached.