England PDVC-25 Pellet fluctuations

pitt800 said:

I'm working on a englander 25 pdvc pellet stove. I was called because the customer said they needed a new combustion motor, which I tested and was fine, the determination was made that the control board was bad. I had a used control board that I installed, after a day the customer called and stated that the flame goes down and almost dies out and then the flame gets higher and continues low then high. They like running it on 3 so I watched the lower auger deliver the Pellets and it will push alot of Pellets out on a turn then the next turn it may push 3 or 4 out, the next turn alot more Pellets and then another turn a large group. Due to the pellet delivery being like that, the flame goes up and then almost dies out. And it continues like that..any help would greatly be appreciated. ..

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For discussion purposes:
Assuming the new...used control board was OK? The stove PDF file shows it wants dry Premium hardwood pellets. Are they dropping normally? Is the read end of the auger in good working order, like missing a piece of it? I would think the pellet feed rate would be dependent on Control board and augers functioning correctly, and then the quality of the pellets: size, moisture.

Sounds more like an issue with the pellets and the variability of the size feeding different amounts. Very common issue and the ? pops up almost monthly. More prevalent with top feed pots.

How do the pellets look? Are they fairly the same size? Lots of small shorts mixed with long ones? Maybe long ones are getting hung up in the hopper or on the restriction plate?
My old stove doesnt have the adjustable plate in the hopper but i believe it is adjustable for the reasoning of pellet size/length compinsation.. my stove fluctuates as well at times and i have figured it to be the pellets as it doesnt do it with every brand i have run.
Just a thought but worth trying a diff brand of pellet especially if they changed brands recently.

First, do you get the same number of auger rotations each time?

F4jock said:

First, do you get the same number of auger rotations each time?

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Gotta start right here for sure.

That said I've had a two batches of Themaglo pellets now. The first burned hot and with a lower flame.The second batch has more random sized pellets and a glazed look on the surface, some even look like they got scorched or over burnished in process. The second batch smells different and burns with much higher flame and don't last as long on the exact same setting in my P61. The random length is causing the Harman bang as the long ones get crunched or broken.

alternativeheat said:

Gotta start right here for sure.

That said I've had a two batches of Themaglo pellets now. The first burned hot and with a lower flame.The second batch has more random sized pellets and a glazed look on the surface, some even look like they got scorched or over burnished in process. The second batch smells different and burns with much higher flame and don't last as long on the exact same setting in my P61. The random length is causing the Harman bang as the long ones get crunched or broken.

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Interesting to hear your experience. I had six bags of Empires last year that were also hard and glazed over, the auger was lifting and bang each feed cycle. I promised to pick up some more ( a local product ) and give them a run again. I assumed that the pellets were rushed out because they were sold out at all of their locations last March.

My auger will feed with a very regular ON-OFF cycle, but the actual amount of pellets dispensed vary with each cycle. Sometime none will drop for 2-3 cycles, then several will drop at once. I think it's mostly normal and expected.

WOW! My Harman is very consistent feed-wise.

Harman has a straight horizontal auger with the shuttle helping settle the pellets. But with the firepot being right at the mouth of the auger it could vary a bit and one can't really tell. Bixby has a feed disc dropping into pot and Whits have a steep auger incline before dropping pellets, Countryside drops pellets from a horizontal auger but only a couple inches into the pot.

You can kind of tell how the feed is going by the movement of the solids in the firepot. If I was getting just a few I'd know.

pitt800 said:

I'm working on a englander 25 pdvc pellet stove. I was called because the customer said they needed a new combustion motor, which I tested and was fine, the determination was made that the control board was bad. I had a used control board that I installed, after a day the customer called and stated that the flame goes down and almost dies out and then the flame gets higher and continues low then high. They like running it on 3 so I watched the lower auger deliver the Pellets and it will push alot of Pellets out on a turn then the next turn it may push 3 or 4 out, the next turn alot more Pellets and then another turn a large group. Due to the pellet delivery being like that, the flame goes up and then almost dies out. And it continues like that..any help would greatly be appreciated. ..

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As long as it seems like nothing is wrong with the auger motor it sounds like this is expected behavior for this stove. At the lower heat settings the height of the flame will be noticeably varied. On setting 3, if the flame is going on completely, then there could be something wrong or perhaps the pellets are extra long. There is a plate in the hopper that can be adjusted if you think the pellets are long and are not feeding in the correct portions. However, the behavior you describe where a large group of pellets come at one time and then you see several rotations without -- that seems to match how my stove typically runs on the lower settings.

EDIT: I have been informed that the following is incorrect for the two auger stoves and that it is only true for single auger stoves in the ESW line.
If the stove is a 2009 or newer you could try playing with the Low Fuel Feed button (increasing it one at a time and watching the burn to make sure the burn still looks ok (you have to wait a fair amount between each change ~15-20 minutes to see a change.) However, if it is not at least a 2009, the Low Fuel Feed and Low Burn Air buttons will only impact heat settings 1 and 2 as opposed to the whole range.

The behavior described by the OP could also be caused by a vacuum leak. If the vac switch is marginally satisfied the upper auger could by skipping cycles or partial cycles.
To determine if this is happening, watch the back of the upper auger. It should run for the same amount of time on each cycle (for a given feed setting). If it doesn't, it is probable that there is a vacuum leak (door seal, vac tube to the switch, etc).

Deromax said:

My auger will feed with a very regular ON-OFF cycle, but the actual amount of pellets dispensed vary with each cycle. Sometime none will drop for 2-3 cycles, then several will drop at once. I think it's mostly normal and expected.

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I am with Deromax on this one...my pellets feed exactly like that as well...a bunch, then maybe 10, then a bunch...my flame goes all the way down...then high...I think/thought its normal...

Marina1327 said:

I am with Deromax on this one...my pellets feed exactly like that as well...a bunch, then maybe 10, then a bunch...my flame goes all the way down...then high...I think/thought its normal...

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That is the nature of a screw type conveyor known as an "auger".

Deezl Smoke said:

That is the nature of a screw type conveyor known as an "auger".

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That's what I am thinking....its fills up the little "slots" or doesn't or only puts a few...seems logical to me. I am thinking that is normal behavior for the OP's stove he is working on. At least that's how my serenity works.

Marina1327 said:

That's what I am thinking....its fills up the little "slots" or doesn't or only puts a few...seems logical to me. I am thinking that is normal behavior for the OP's stove he is working on. At least that's how my serenity works.

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That is probably true for low settings on fuel feed. At higher settings, the upper auger runs longer and fills the lower auger more fully. Even then, there will be some variation in flame height.
I haven't noticed that on my 25-PDVC, but that would only happen when the thermostat puts it in fuel feed = 1. The rest of the time it is running at 9/9.
Bottom line is.., If the stove is serving it's purpose, it doesn't need to be fixed.

I've been trying to find a decent video of the screw conveyor characteristics, but all that show an open top screw or otherwise informational, also have what is commonly referred to as foul language or distasteful references. Trying to keep this a family show, I'll refrain from linking those. But I'm still looking.

It really does not matter how full the auger is so much as the diameter and product sizing that the screw is conveying, as well as the pitch length of the screw. So a full auger of long pitch length that rotates slowly with off shape product will still give a pulsed output of product. Even of the motor runs solid, it is the screw inside a tube or trough that creates the pulsing of product. The motor that starts and stops as a pulse, pulses the screw which can amplify the issue of product pulse feeding.

Smaller pellets may mitigate the problem, as they'd be more consistent in their drop rate, while longer pellets would be more variable. Also make sure there aren't a lot of fines in the hopper limiting the amount of pellets being drawn up the augur chute.

The flame in my stove goes up and down all day long. A few cycles with hardly any pellets, then it'll dump a bunch. I thought it was normal. Now I'm going to obsess about it.

Harvey Schneider said:

That is probably true for low settings on fuel feed. At higher settings, the upper auger runs longer and fills the lower auger more fully. Even then, there will be some variation in flame height.
I haven't noticed that on my 25-PDVC, but that would only happen when the thermostat puts it in fuel feed = 1. The rest of the time it is running at 9/9.
Bottom line is.., If the stove is serving it's purpose, it doesn't need to be fixed.

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This makes the most sense to me, if the stove is not burning dirty and is producing the proper amount heat, it is functioning correctly .

It happens the most at the lowest setting, where my stove stands the bulk of its time. The flame will decrease but not to the point of "nearly die"!

F4jock said:

You can kind of tell how the feed is going by the movement of the solids in the firepot. If I was getting just a few I'd know.

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Actually Harman's are all over the place on feed rate according to what the ESP requires to be satisfied unless you are one of the latest advocates of running feed rate 1 at output 5 in Stove Temp mode ( we have a few adopters of that at least in trial stage). That probably makes for even pellet delivery but who knows.. Anyway, if you run normal feed rates of 3-4.5 then it's ever varying from 1 to that setting . And then take into account pellet size. The biggest variation though is pellet grade IMO, that will determine what our Harman's do with them.

alternativeheat said:

Actually Harman's are all over the place on feed rate according to what the ESP requires to be satisfied unless you are one of the latest advocates of running feed rate 1 at output 5 in Stove Temp mode ( we have a few adopters of that at least in trial stage). That probably makes for even pellet delivery but who knows.. Anyway, if you run normal feed rates of 3-4.5 then it's ever varying from 1 to that setting . And then take into account pellet size. The biggest variation though is pellet grade IMO, that will determine what our Harman's do with them.

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Yeah but I've never know it to feed three or four pellets in several rotations.

Changed the title so it would attract Mike's eyes ... searched the troubleshooting pages at England Stove and tried a search through the forum to see if I could find on/off times for auger but no luck. I know I've seen auger times somewhere along the line but can't remember stove brand....