Pellet stove "sweet spot"

[D33r3 6r33N]

So we are on the forth year using our Harmon 25 pellet stove. And it seems that there are days that it burns hotter than others, usually several days, maybe even a week after cleaning. I just figured it had something to do with the ash buildup on the inside of the stove.
Does any one else feel the same way? Have you figured out a way to keep it burning "hot" all the time?

 

[rgs03833]

So we are on the forth year using our Harmon 25 pellet stove. And it seems that there are days that it burns hotter than others, usually several days, maybe even a week after cleaning. I just figured it had something to do with the ash buildup on the inside of the stove.
Does any one else feel the same way? Have you figured out a way to keep it burning "hot" all the time?

4th year is VERY GOOD!, but if it's hotter when after cleaning, than you just made the diagnostic yourself. Do you clean it often? I don't have the same Stove but most are the same principle. I do mine every Friday night, and a good throrough once every month see below.

1. Clean / Vac any obstructions or debrises where you put in your Pellets / Auger. Good time to do it before refills.

2. There are usually Air Exchange Tubes / Air Chambers / Air control / Air Inlet inside the Stove that the Ashes get into - build-up needed to Cleaned out.

3. Clean / Vac where the Ash Pot / Burner / tray really good.

4. Clean / Vac where the Ash dropped after burning / also the Ash Pan real good.

5. Clean / Vac the Metals inside the Stove / Anywhere you see Ash Build-Up.

6. Blowers, Exhaust... Clean / Vac these really good!

Need a good vacuum, if you don't no point wasting your time cleaning. I have to clean my Vacuum everytime I go cleaning my Stove, LOL. There are few good tools, Old Wirebrushes, Small Brushes, Paint Sticks, Small Sticks, Large Qtips, even Metal Coat Hangers...

Basically Clean / Vac everything and everywhere you see Ash Build-Up if you don't, you are wasting your Pellets and Money because most of the Heat just went out the Exhuast.

The Heat from burning needs to Absorb into the heavy Metals / Air Exchange, then it goes to you. If they are dirty or have build-ups... It goes right into the Exhaust instead

Hope that will help!

 

[tractordog]

So we are on the forth year using our Harmon 25 pellet stove. And it seems that there are days that it burns hotter than others, usually several days, maybe even a week after cleaning. I just figured it had something to do with the ash buildup on the inside of the stove.
Does any one else feel the same way? Have you figured out a way to keep it burning "hot" all the time?

I have notice some kind of variance. I think less than 10%, but it is hard to determine if I am imagineing it or not.
I think i have linked some of it to how dirty the burn pot is. When it is almost to full of klinkers the flame is not the same (waving) and the glass will start to get ash on it.
Most of the time I have the stove on 4, and use it a the primary source of heat.

 

[20 20]

4th year is VERY GOOD!, Rgs03833

, just curious what you ment by this?


D33r3 6r33N; I've never noticed any huge differences in heating only very slight. I have to agree with Rgs03833 keep them clean and they work better, and last longer. I had a pellet stove for more then ten yrs once, worked awesome. I'd probably still be running it if the better half hadn't decided to use it for a plant holder. Seems using them for plant holders and over watering, the plant, can cause issue's when the water gets into the stove I never let mine go for more then 3-4 days with out a cleaning.

 

[Deere Greg]

We have the same stove, a Harmon XXV.

+1 on cleaning - do it once a week here, but sometimes once in two weeks - if we are busy. I do not observe any significant difference in performance based on a one or two week clean, but I am sure the efficiency suffers a little for the reasons already mentioned by RGS.

FWIW... I noticed a big difference between this year's pellets and those I used previously. This year I got all softwood pelets... had to turn the feed-rate adjustment down from 4.5 to 3.8 for the same burn performance, which implies better pellets. This years pellets smell like real wood - previously they smelled like particle board dust and not at all pleasant before being burnt. The stove stays much cleaner this year week to week.

I still clean the stove once a week, for me that is about 9 or 10 bags of fuel at this time of year (heats the whole house).

I am not sure what you mean by 'hotter'. If you can expand on that a little it might help me compare your performance to mine.

We use the room temperature sensor mode, which works very well. I observe the flame regularally, principally to check the distance from burning coals to the edge of the burn-pot when it is running "wide-open"... trying to keep a good half inch of ash, and to ensure the flame begins deep inside the burn pot. If either of those conditions are not met, then a better-than casual cleaning is needed... clear all the holes in the burn-pot bottom, and consider a flue cleanout.

Anyway, since you have the same pellet stove, you may find some of the above of interest. Feel free to expand on your observations so we can compare notes in greater detail.

Greg.

 

[charlz]

I have a Quadrafire 1200 insert and am in my 7th winter with it. The build up of ash on the heat exchanger tubes is the main culprit. I have cleaning rods that run a metal slider up and down the tubes as you work the rods. These do fairly well but not as well as when I clean the stove and take a wire brush to the tubes. My stove has a big 'Do Not Pull Rods While Stove is Running' warning sticker which I believe is to keep idiots from burning themselves. I use an insulated glove and work the rods a few times every time I fill the stove, usually twice a day. I want my stove working at peak efficiency all the time. If they are pretty dirty you can instantly feel a temperatures increase in the air coming from the stove.

I clean it out every one to two weeks depending on use and give it a major cleaning prior to each burning season. Since mine is an insert it is a project to pull it out and take it apart for cleaning.

Bad pellets can also cause the stove to not burn well, your firepot should not be filling up with clinkers. They sell different 'grades' of pellets here based on their BTU rating. 8500 versus 8900 BTU's/lb. Doing the math the price difference is really not in line with how many extra BTU's you would get. They might burn better. I pick my pellets by the color, if they look like good wood, they are good wood. If they have greenish stuff (pine needles?) or have lots of black in them (bark and dirt?) etc they are bad (at lest for softwood). I just pick the best looking cheap pellets.

 

[Car Doc]

I dont have that heater but on mine the air holes in the fire pot get smaller as it runs from carbon and the fire is diminished somewhat but never noticed a sweet spot.

I would imagine what you are experiencing is maybe more a matter of the proper air fuel mix coming together better as a matter of lessened air flow due to ash. Possibly an exhaust air adjustment would do the same thing but thats only speculation?

When I clean the ash out maybe once a week I always stick a BBQ fork thru all those air holes to open them up and that does the trick on mine far as the flame goes. fwtw

 

[rgs03833]

, just curious what you ment by this?

4th year is VERY GOOD!, Rgs03833

Oh, when i first got my stove. I neglect the darn thing. I only did a regular cleaning, so few things broke. So 4th year in service and only this is wrong, that's good I mean... Hope that is the only that is wrong, LOL

 

[D33r3 6r33N]

@Deere Greg

85% of the time we set the thermostat and forget it. I fill it (or put about a bag in) when I leave for work and when I get home. About every 12 hours. Last night when I got home I could hardly put my hand on top of the stove it was so hot, also the air being blown out of the stove is so hot you don't want to stand in front of it for very long. But I know that tomarrow or the next day I will have to clean it because it will not be as "hot". I don't scrape the baffles down every day, I just try to clean it with the stove vacuum once a week.

My feed rate is just under 2 and the fire is about an inch from the edge of the pot. It seems that if I have the feed any higher than that it will kick unburnt pellets out of the pot.

I burn Somerset pellets from Kentucky and I keep them stacked on the garage until I move them on the deck and put them in the deck box.

 

[Tollster]

We have been burning a Harmon P61 for about 6 years now, I notice a subtle change when I scrub the baffles, and the sides using the supplied harmon tool and a 6" spackle spreader. You can clean the baffles with it running as well as the sides. Keep the burning pot free of carbon build up, and keep the ash off the plate that sits above the burn pot, it'll crack.
I burn 5 ton a year, oct-april. I typically shut it down 2-3 times during that period to cleen the convection fan, and under the burn pot...there is a plate there, remove the plate and remove all the hard ashes that drop through the small fan holes that supply forced air to the burn pot. You would be surprised how many accumulate there.
Only use filtered power if you need to use a generator to power it, and I believe Harmon has cleaning instructions and tips on their site.

200-220 a ton here for hardwood premium pellets...was 150 when i started. 40lb of pellets equal one cup of ash.....I like that part the most...empty the pan once every month and have or so..

Oh..I have been using shavings of those fire starter logs to start my stove rather than that expensive alcohol base fluid/gel they sell for about 5 years now, I still have the log pack as I just shave offs a little, then crumble it over the bed of pellets, use a propane torch to get the pellets and shavings started, then the stove takes off after a few minutes..

 

[Deere Greg]

@ D33r3

Hi there... Sure, let's compare notes to see if we can identify an explanation for your observations on your Harmon XXV.

I suspect only two issues that could (temporarally) be resolved by a vacuum-only cleaning of the pellet stove as you have experienced. Specifically, clogged air holes in the burn-pot or combustion-air blower congestion.

While scraping the heat exchanger once a week is likely good practice and apt to keep operating efficiency high, it is not likely that a vacuum cleaning would significantly change the amount of deposits, and is not likely your issue.

It is also not likely that a clogged flue would be resolved by a vacuum cleaning. I brush-out my flue after each ton of pellets, but not likely your issue.

The stove is intellegent enough to vary its heat output based on how much it has to heat a room compared to the thermostat setting. Could be simply that some days it does not need to warm the room as much as other days. But you likely thought of that and are comparing similar flame sizes giving different heat outputs.

A vacuum could open partially clogged burn-pot air holes for a short time.
This seems to be a good possibility to explain your situation. Perhaps combustion does not start deep inside your burn pot, leaving very little room & time to burn fuel completely before it reaches the edge of the pot. Clean the burn pot holes all the way to the bottom of the pot - taking care not to poke at the fragile heating element directly under the holes. As mentioned - remove the cover under the burn pot and clean out ashes in that area. Procedure is described in the manual.

A vacuum could also partly open/clean the combuston air exhaust path and blower. that would be my second place to look and clean. Check the manual for that procedure.

Best of luck. Let us know how it goes!!

Greg.

 

[D33r3 6r33N]

I think I may not have conveyed my thoughts correctly.

When I do my weekly cleanup of the stove, I do the tips and tricks mentioned. What I'm saying is; several days after I clean it, the stove seems to be able to transfer the heat better from the inside of the stove to the room.

I haven't been able to put my finger on it and just wondered if anyone else had the same thoughts.

Thanks

 

[Pete Judd]

Toll, for lighting ours, we fill a gallon jar 3/4 full with pellets, then add about 1 cup of stove alcohol. Turn it over in the jar for around 15 min. Gives us months of alcohol damp pellets for lighting.

 

[schmism]

pay attention to your perceived heat output in relation to outside weather conditions.

Things like relative humidity etc and vastly change how the room "feels".

windy days can affect the draft of the stove which can affect the burn = heat output.

really cold days can pull more heat out of the house makeing the stove feel like its not running as hot (and vise versa)