Harman p43 and corn....

[TreatyLineFarms]

I recently bought a brand new Harman P43 stove from a local shop. I had originally wanted to burn wood, but I let them talk me into this. I grew up with wood and completely understand it is far from " free heat". Anyway, being a farmer with an abundance of corn, I bought this because they swore up and down it'd burn 50% of dry (15%) shelled corn.

It'll burn straight pellets like its no ones business, but if I try to add some corn to stretch the pellets( I'm sitting on 25,000 bushel of unpriced corn) it will overfeed and shove the fire right off into the ash pan. Sometimes, it'll push raw fuel over the hump in the center and the edges will be on fire. I clean the stove once a week like I am supposed to... I have tried faster and slower feed rates in .5 increments with no difference. Now.... It doesn't do this all the time. It might run 3 days or 3 hours before it does this. All corn is dry, I promise. I have a hard time believing it's a corn issue...been using the same corn out of the same bin and like I said, it does it with no rhyme or reason.

I had the dealer out once and of course, it ran fine for them on corn/pellets.

I wish I had bought a wood stove and my wife is really tired of me cussing at this thing...so any advice will be considered and appreciated.

 

[TreatyLineFarms]

And since making this post and walking back in the family room, it has managed to push the entire fire out of the pot all at once and into the ash pan, setting the ash pan on fire.

I might be mixing 10-12 lbs of corn with a bag of pellets. Maybe.

 

[Bioburner]

You may be surprised by how much the corn can vary in moisture content. I picked up some corn that had missed the truck and proceeded to cook out the water on the wood stove till very low. Made a big difference in burning. 15 percent is the most a stove can try and digest. Sometimes the pellets aren't helping much too. Had some old pellets and that messed up the mix. Been burning straight corn since 02 in one stove or another. PM me and I'll try and give a bit more knowledge of corn and it's other burn factors.

 

[rickwai]

that stove was designed to burn pellets. They dont burn corn worth a crap. You are doing nothing wrong. I would not go over 10% corn. Corn does not do good being bottom fed. It takes alot of heat to get the kernels to light. Even the pc45 harman corn stove is only marginal in my opinion. They burn w/ alot of black soot ash which equals incomplete combustion. Corn will burn w/ a tan to grey ash in the correct stove which is a much better burn

 

[SidecarFlip]

According to Harman's website, all their models are designed to burn a corn/pellet mixture at a 50-50 ratio. Not owning one I cannot comment on that. However, being a farmer too (north of you) and also burning corn (in a different manufacturer's appliance) and having run corn in various ratio's from 50-50 to straight field corn, I can elaborate on some issues that show up.

You say 'unpriced' corn. I say unless you have on farm dryers do you actually know where the RM is? I know what corn came off at this year here and it wasn't anywhere close to 15%RM and in all reality to combust it, it needs to be BELOW 15%RM, more like 12%RM.

I took off corn anywhere from 21-28RM and the test weight was low as well. I suspect you did too. That means it must be artificially dried to below 15RM either in your on farm dryer or at the co-op, in my case, at the co-op.The low test weight equates to less combustiblability in each kernel, not a big deal, but a deal nonetheless.

I also understand the corn reset, I'd never consider burning $7.00/bu corn but anywhere south of $3.75 / BU, it's economically positive to burn it.

In farmerspeak, you are 'taking a bath' on corn this year, guess what, so am I. plan on corn never reaching above 3.75/bu again I suspect, despite the input cost, it will hover around $3.50/bu with e-corn appreciably less, fact of world economics. The party is over, time to pay the fat lady.......

Time to consider alternative crops. the corn waltz is over....

Back to your issues:

Like I stated above, all Harman appliances are rated/designed to combust corn at or below 15%RM, 15% being the absolute high end on moisture content. However, Corn must have adequate combustion air, more than processed wood pellets so the combustion air must be increased according to the percentage of pellets versus corn and again the corn must be below 15RM, more like 12%RM.

In as much as I do not run a Harman I can't tell you how to increase the combustion air ratio but I'm willing to bet the stove comes set up to burn pellets only so it needs to be adjusted for additional combustion air. otherwise the corn will not burn and/or will wind up in the ash pan, smoldering.

There are other appliances on the market that are mich more corn friendly like the US Stove American Harvest Series as an example that are easily adjustable/adaptable for additional combustion air that corn requires to combust, thats what I run, an American Harvest 6039. It's quite happy with any ratio of corn and pellets or straight corn, so long as the a/f ratio is adjusted accordingly and it must be adjusted, no exceptions or the burn will be unsatisfactory to not at all...

So, no, it's not going to burn corn with from the factory settings (your Harman), especially new crop over 15%RM corn and you need to increase/adjust the combustion air accordingly but no matter what you do, no appliance will readily combust corn at or over 15%RM efficiently and in most cases, not at all.

There are enough Harman owners on site that I', sure someone will respond and instruct you how to increase the a/f ratio in as much as I cannot, but it must be increased above the pellet only setting and the corn must be below 15RM bu at least a point.

 

[SidecarFlip]

Additionally, any stove will combust corn nut the cirn must be below 15RM and the stove must be able to provide an increased a/f ratio over and above a pellet only level. Some appliances can burn corn only but your Harman cannot.

 

[bogieb]

According to the manual that I got online (which covers both the P43 and P61A), the only thing you may need to adjust for a pellet /corn mixture is the feed rate. It recommends starting at #4 and then adjusting for flame height. Download the manual and check Section 4 (page 12), if you haven't already.

I suspect it is a moisture issue and that the corn is taking too long to burn because it has to dry out before combustion. However, not having burned corn before, I could be wrong.

 

[Bioburner]

Enjoying the burn this AM. Very low RM corn blend 50% on the pellet tray. Wish I could push the camera to get better pic of flame.

 

[SidecarFlip]

Bioburner.....
Enjoying the burn this AM. Very low RM corn blend 50% on the pellet tray. Wish I could push the camera to get better pic of flame

I think I covered the bases with my explaination.

I would also believe the RM is above the 15% maximum threshold. Like I said previously, the RM really need s to be below 15, more like 12-14 for a good combustion ratio. I know what mine came off at and I also know that tanked corn can vary in RM so I like to stay in the 12-14 range to allow for a tolerance.

My stove will run straight corn if necessary but pellets provide an initial burn, corn is tough to ignite and carmelize.

 

[SidecarFlip]

that stove was designed to burn pellets. They dont burn corn worth a crap. You are doing nothing wrong. I would not go over 10% corn. Corn does not do good being bottom fed. It takes alot of heat to get the kernels to light. Even the pc45 harman corn stove is only marginal in my opinion. They burn w/ alot of black soot ash which equals incomplete combustion. Corn will burn w/ a tan to grey ash in the correct stove which is a much better burn

I disagree with that and Bioburner will substiante it. Heat isn't what you need, you need heat and air.

I believe you can run corn in any pellet appliance up to a 50-50 ratio if the appliance is rated for corn or not. It may not be an efficient burn but it will combust (with the proper a/f ratio and dry corn).

Once you exceed a 50-50 ratio, the appliance must be designed for corn and at a 100% corn only fueling, a clinker pot or a modified burn pot (with enlarged combustion air holes and an adequate supply of combustion air must be used..

Corn really doesn't 'burn' in the sense that wood pellets do. It 'carmelizes'. That is, the meat of the kernel liquifies just prior to igniting while the husk (shell) sloughs off. Thats why you get clinkers or coarse ash. It's the husk that winds up in the ashpan or as a clinker bisquit in a clinker pot.

Been doing this for years.

 

[Bioburner]

Ignition temp of corn almost 200 degrees higher than wood and if trying to drive off water it just won't work well.

 

[SidecarFlip]

I was under the impression (maybe incorrectly) that every stove comes with an owners manual that explains operation parameters (at least mine did) and I refer to it regularly, as I forget sometimes......

 

[SidecarFlip]

One other aspect of burning corn thats not widely talked about is the nitric acid that carmelizing corn gives off with the water vapor as it ignites. Nitric is corrosive to venting as well as stove parts made from ferrous alloys.(stainless included). Consequently, manufacturers prefer a no more than 50-50 ratio of corn to pellets as the pellets negate most of the effects of the vaporized nitric acid.

Myself, when running straight corn, I always run a hopper full of straight pellets just prior to shutting down the stove for cleaning and/or end of season to negate the nitric acid impact on venting and internal stove parts. I also fog the inside of the stove with Stabil fogging oil in the spring and completely disassemble the venting, and wash it out inside with soap and water, every year. Been running the same (Duravent) venting for over 12 years now with no visible deterioration to the liner.

 

[Bioburner]

Some manuals are to simple to give the proper knowledge needed for using a stove. Burning wood is simpler and has a broader range of air and temperatures that it can run well in. The triangle of fire taught to all firefighters is, air, fuel, temperature. Corn being denser may need more air but the balance is that feeding it to much air it will cool itself and out it goes. Trying to boil water at 210 degrees can cool the fire an out it goes.