Creosote buildup in Harman P68

[deadhang]

Hello all,
New to the forum, but I've read through a lot of threads here. Great info!

We bought a new Harman P68 last fall and used it as our primary heat source in our 176 year old 1750 sq ft farm house in SW Maine. It was our second winter in this house. The first was very expensive using an undersized propane fueled furnace with very drafty windows. I rehabbed all the windows and got rid of all the drafts, and we went with the pellet stove. It was professionally installed by the stove shop we purchased it from, in the middle of the house where the chimney is located. No OAK installed after considerable debate. The final decision came after the seller said it was unnnecessary. I figured I would go the first year without and reevaluate. After trying a handful of different brands, we burned almost 3.5 tons of JW Crabbe pellets. Finally getting around to the annual cleaning to get it ready for next season. Was finding a lot of creosote buildup all over the inside of the stove as well as in the exhaust pipe. Searched around and found videos of cleaning pellet stoves, and after watching people use paint brushes and vacuums to clean their stoves I got really jealous! Mine is certainly not that easy to clean with all of the creosote. After our first baby was born in December, I got a little more relaxed with the daily cleaning of the stove, but kept up with the monthly cleanings.

I know this is getting long winded but I wanted to provide as much info in the initial post that I see is usually requested by responders.

Anyway, my main question is how do I prevent the buildup of creosote in my stove? Is OAK the answer? If so, I read that the OAK piping should be less than 17 feet in total length. With the stove located in the center of the house, how would I do that? It is roughly 16 feet to the closest exterior wall, but it would be a bit of a trip hazard if I don't run it through the basement, so down a foot or 2, across basement to exterior, and then up 2-3 feet to keep from getting buried in snow, would be a total of 20 - 25 feet or so.

OAK? Better pellets? Any thoughts would be greatly appreciated.

Kevin

 

[johneh]

creosote is caused by the incomplete combustion of wood .
So run your stove hotter or run it full tilt at least once a day
to burn off the creosote
In 15 years of using pellets (always the best I could get) I
have never had a creosote problem

 

[Tonyray]

what the above poster said about incomplete combustion is correct.
I have a P61A which is the same stove other than size....
you had not mentioned your feed rate and temps you we're set at during burning.
The couple times I had what you call creosote was I burned stove chows from HD which many of the bags had damp pellets and other time I was NOT burning hot enough as I was trying to save pellets by using too low of a feed rates and set at low temperature.
Running Room/Auto during shoulder seasons of spring/fall always for me produces a bit dirtier burn with the Constant ON/OFF as it's just not staying real hot long enough before it shuts down.
btw: running your harman at full throttle as poster said for a little while will turn that sticky black residue into a light powder that you can just brush or vacuum of the inner walls.
I noticed the past 2 yrs that with using a good grade of pellets[I try to burn all Softwoods] my exhaust tunnel behind the combustion fan barely has any ash to remove and same with the outside Pipe..been using a feed rate of 3.5 to 4 all the time....
Good long burns in room/manual or stove mode helps keep the stove walls cleaner..
As far as an OAK, lot of info here from pellet burners on the subject....I would say most are positive about having one But others will chime in who Don't use one.
we would sit on the living room floor and feel drafts running along the floor which was needed air going back to the stove..[Has to come from somewhere for needed combustion]... either outside free air via OAK or inside air which I must point out you just heated with pellets..Installing an OAK eliminated the drafts.
As far as your brand they are 100% softwoods so should be good there....
It takes a Real crappy pellet brand to cause Creosote just on it's own..most times it's the stove settings of not burning hot enough or a combo of both.
let us know more about your settings and your burnpot status like un-burned pellets, extreme amounts of ash or things like that but it's already July

 

[Lake Girl]

If you cannot run the OAK up the chimney, the longer install through the basement may need to be upsized just like pellet venting must be upsized based on EVL.

Part of your creosote problem may be due to a slightly negative pressure situation in the house due to elimination of drafts from the windows...

 

[rona]

It has been spoken of many times but if you plugged all the air leaks because of cold drafts in the house you will be preventing the stove from getting enough air to burn properly. I think you know that or you wouldn't be looking at bringing in outside air for your stove. I would run a pipe into the basement from the outside then bring it up right in back of the stove so you can hook it up to the stove. Depending on the situation you can do it a couple ways . A old plumber gave me this advice . bring a pipe through the wall into the basement and let it hang into a pail a inch or so from the bottom of the pail. Cold air won't rise by itself so it will stay in the pail until it is sucked out by a vacuum created by the pellet stove or in my case by the furnace running. Both heating sources will creat a vacuum by the combustion of a burning stove. You can attach a pipe to your stove and drop it through a hole in the floor in back of the stove and just let it hang in the ceiling of your basement. It will suck the air from the basement and in turn from the pail that is being used to bring in the outside air.
The creosote can also be caused by running the stove at a low temp but if you run the stove on high for a hour or so each day it should clean itself up. Running on low temps will slow the exh fan and eventually plug the pipes as it can't blow all the soot out.

 

[Tonyray]

It has been spoken of many times but if you plugged all the air leaks because of cold drafts in the house you will be preventing the stove from getting enough air to burn properly. I think you know that or you wouldn't be looking at bringing in outside air for your stove. I would run a pipe into the basement from the outside then bring it up right in back of the stove so you can hook it up to the stove. Depending on the situation you can do it a couple ways . A old plumber gave me this advice . bring a pipe through the wall into the basement and let it hang into a pail a inch or so from the bottom of the pail. Cold air won't rise by itself so it will stay in the pail until it is sucked out by a vacuum created by the pellet stove or in my case by the furnace running. Both heating sources will creat a vacuum by the combustion of a burning stove. You can attach a pipe to your stove and drop it through a hole in the floor in back of the stove and just let it hang in the ceiling of your basement. It will suck the air from the basement and in turn from the pail that is being used to bring in the outside air.
The creosote can also be caused by running the stove at a low temp but if you run the stove on high for a hour or so each day it should clean itself up. Running on low temps will slow the exh fan and eventually plug the pipes as it can't blow all the soot out.

Good advice..
should also be mentioned that many new houses built in the last 30 yrs are so tight with Insulation[a good thang] but air has to be pulled from somewhere as u stated.
could be pulled from the bathroom exhaust fan in the ceiling or a dryer vent..this type of TIGHT house really needs and OAK for better combustion so as Not to pull the air you already paid to Heat.

 

[bags]

All comments above are good advice. I personally think having an OAK is a must. Can you do without? Sure, but.... <<< There are many, many to OAK or not to OAK threads and discussions here so get ready for a bunch of reading. Just plug it into the search bar and kick back for awhile. You can also do some research about air exchange rates. Basically for every cubic inch or foot of air that leaves your house that same amount also gets replaced with air. And that air is the cold outside air getting sucked in thru all the little cracks etc; in your homes exterior envelope. Enough on the OAK but do yourself a favor and definitely read up on it to see what makes sense to you and go from there.

Now onto the creosote. Above comments are also dead on. It could just be a poor quality pellet causing your issue. I have ran my stove as slow and low as it can go for weeks on end and never had any creosote issues. I have been fortunate enough to burn good pellets. I also run a P68 and it is a kick butt stove. Love it!

I know you tightened your homes windows and envelope up but you are getting outside air in somewhere in that old of a home. New homes are tight and they still leak. Many times in places you'd never fathom. I'm a builder construction type and I know nothing is perfect. There is leaky stuff going on even in the tightest places. I still find it happening in my own home I built and went the extra 10 miles on. Still leaks here and there. Every door, window, on and on..... Just the way it is.

I would suggest trying some different pellets for starters. Also it is well know that many dealers do not want to mess with OAKs or talk people out of them. Why? Sometimes they are a hassle to get installed for one reason. Another is they are clueless really. When I was shopping for my P68 and / or other stoves I ran into several nit wit dealers. Hell, with the resources and extensive reading I did here I knew more about pellet stoves than these dealers did and I didn't have any experience with them nor really know squat. Not accusing your dealer of anything but just read up and do your homework. It is your house, your money, and your comfort level along with dealing with any and all hassles of owning your P68.

Good Luck and read up. the info is here along with others help. Some posters above have been in this alternative fuels heating game for many years. Decades even.

 

[bags]

I will add that when burning very low and slow I do get more ash piling or damming up on the front of my burn pot and the glass gets dirty with ash but it is not creosote here. Tony can back me on that as we run Renegade mode often in the shoulder seasons. Easy fix is to just pull that little mess into the pan when you do a quick pot scrape.

Also, as Rona mentioned the vent will tend to collect more ash since the exhaust speed is slowed. Regardless of not having an OAK and burning lower settings you still should not have any creosote IMO. It could be residue from some binding agent or such within the brand of pellet you are using. Research your brand used and see what others are saying about them too. Might find out something that way. I have never seen the name JW Crabbe pellets anywhere nor heard anything about them. In fact I just Googled them and nothing but this one mention right here in this thread.

I have seen numerous problems caused by various other brands of pellets. Check out what you have for options in pellets where you are and look up reviews on those names to see what others are having luck with and getting good results out of. Might be more of a pellet quality problem than anything.

 

[Tonyray]

I will add that when burning very low and slow I do get more ash piling or damming up on the front of my burn pot and the glass gets dirty with ash but it is not creosote here. Tony can back me on that as we run Renegade mode often in the shoulder seasons. Easy fix is to just pull that little mess into the pan when you do a quick pot scrape.

Also, as Rona mentioned the vent will tend to collect more ash since the exhaust speed is slowed. Regardless of not having an OAK and burning lower settings you still should not have any creosote IMO. It could be residue from some binding agent or such within the brand of pellet you are using. Research your brand used and see what others are saying about them too. Might find out something that way. I have never seen the name JW Crabbe pellets anywhere nor heard anything about them. In fact I just Googled them and nothing but this one mention right here in this thread.

I have seen numerous problems caused by various other brands of pellets. Check out what you have for options in pellets where you are and look up reviews on those names to see what others are having luck with and getting good results out of. Might be more of a pellet quality problem than anything.

Dam skippy bags.
RENEGADE MODE RULES in shoulder season.!

 

[Lake Girl]

Crabbe's are supposed to be decent ... softwood. https://www.hearth.com/talk/threads/new-plant-this-year-for-eastern-canada-crabbes.55519/ However, is it JW Crabbe or HJ Crabbe?

Not sure if they are up to par as the LaCretes, Spruce Pointes which are a mix of softwoods (spruce, fir, pine). Just like all pellets are not created equal... imagine same goes for softwoods. Depends on the quality of the feed stock.

When the Harman was set up, did the dealer do any magnahelic readings? page 13 of the manual (broken link removed to http://downloads.hearthnhome.com/installManuals/Accentra.pdf)

 

[pinetop12]

As others have said .. Run the stove hot ,especially before a cleaning. If you haven;t cleaned the stove yet, crank it for an hour and it'll burn all the junk away.
Burned Crabbes first year I had stove they were decent . Tried LaCretes and felt they burned hotter and cleaned easier. Stove doesn't have to work as hard,nor I .

 

[deadhang]

Thanks for all of the great info, I will start researching the OAK again and try to get it installed this off season. Although I sealed up the windows well, I can definitely still feel drafts when the stove is running. I thought about just running a pipe into the basement, which is usually pretty cool in the winter. But I imagine that will pull warm air from the living space into the basement via the rickety basement door.

The pellets I used were HJ Crabbe, not JW Crabbe, sorry for the confusion. I read some reviews here and other places before purchasing, and didn't see anything bad about them.

I ran the stove in Room Temp mode; Feed Rate at 4, Temp set around 70 or so, and Fan Speed on high. We fiddled with the room temp constantly, based on our comfort level. The stove is in the living room, and many times would heat us out of the room. So I would turn the temp down to conserve fuel. Perhaps I should adjust the fan speed instead and keep the internal temp of the stove high more often.

The dealer did not do any magnahelic readings during the install, and I didn't know to ask until I had read through the manual after they were long gone.

 

[Tonyray]

Thanks for all of the great info, I will start researching the OAK again and try to get it installed this off season. Although I sealed up the windows well, I can definitely still feel drafts when the stove is running. I thought about just running a pipe into the basement, which is usually pretty cool in the winter. But I imagine that will pull warm air from the living space into the basement via the rickety basement door.

The pellets I used were HJ Crabbe, not JW Crabbe, sorry for the confusion. I read some reviews here and other places before purchasing, and didn't see anything bad about them.

I ran the stove in Room Temp mode; Feed Rate at 4, Temp set around 70 or so, and Fan Speed on high. We fiddled with the room temp constantly, based on our comfort level. The stove is in the living room, and many times would heat us out of the room. So I would turn the temp down to conserve fuel. Perhaps I should adjust the fan speed instead and keep the internal temp of the stove high more often.

The dealer did not do any magnahelic readings during the install, and I didn't know to ask until I had read through the manual after they were long gone.

nothing wrong with a feed rate of #4 and a temperature setting of 70..
pretty much where I run my Harman during the colder part of winter [70 -74] but have never had to run the fan on highest speed.
usually we run the fan at about half speed.. If the room is too warm lowering the fan speed would work better than lowering the temp or feed rate.