magnum 7500 new stove need help.

[spray]

you guys really seem to like these clinker pots i hope i have the same luck mine should be here in a couple of days hope it is finally the fix.
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magnum 7500 since 04

[RobC]

I hope so too. Make sure you let us know how it works out.

[spray]

robc do you use your draft exhaust plate if so where do you run yours at?? mine is full closed for corn \pellet mix.
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magnum 7500 since 04

[rdaly]

I'd like to point out that the manual states no more than 1/2 inch of fuel in the firepot after startup, not coals. I burn a corn pellet mix, and the corn after initial burn is loose and fluffy and usually is about halfway up the stirrer with the new fuel being sprinkled on top. I didn't come up with the pot being 1/2 to 3/4 full. I think Charlie did who is an AES dealer and has contributed a lot to this forum.

I bought 2 pots and 2 stirrers with my furnace 3 or 4 years ago and their both still in good shape. I don't burn on setting 3 a lot either because the furnace couldn't heat my whole house and I had a baby upstairs to suppliment the rest of the house; I do a lot of burning on 1 & 2 except for low teens and colder.

I'm not that fond of the furnace either. If you're using the furnace in a basement, the poor output of the blower doesn't get the heat upstairs good, and in my case the uninsulated ductwork in the basement provided for heat loss through the ductwork. Had do do over, I would have got a 3500 instead of the furnace and the baby.

[RobC]

Spray, no I don't use the draft plate.

Rdaly, I guess we'll need clarification from Cornman on the fuel level. I think the owners manual needs to be rewritten and less vague since it seems people get two different meanings from certain things in it. From what I understand the higher levels of fuel in the fuel pot that submerge the stirrers will make them go faster. This is what my dealer told me too. When the fuel level is up that high on my 7500 it smothers the air flow and will soon overflow the pot and make a huge mess. My level runs real low. Just a layer or two of corn and or pellets on the bottom. I have found this is the easiest on the stirrers even though it still eats them.

[spray]

rdaly, i can see burning your furnace on 1 and 2 settings that the fuel stirrer would last a long time on 3 is where my furnace burns alot better i use a little more corn than 2 but it creates alot more heat. that is why i burn out stirres and you dont i guess. for the fire pot level i agree that when they run 1\2 full they are easier on stirres from burning them but then i seem to get alot more clinker balls then as well which grinds them down as well. there is a design flaw in this unit that we never were given a fix on. just discontinued.hope my new clinker pot works as good as i am reading. also i agree that the blower on the 7500 is very weak but if you think about it anymore blower cfm the plenum temp would be lower that they already are which are not very high to start with my biggest hang up with this thing i have to restrict the 12 inch round out to plenum and the cold air return the same that you lose so much air volume. i know when you restrict the blower and put it under a load it works harder and usually will move more air.also overall efficiency of this unit is not good think for a moment on the heat output of the stove and how warm the unit gets on the front side not alot right? now feel the exhaust pipe.not too far from being the same temps i realize the blower is wiping the exchanger tubes of their heat the flu needs to be warm to not have other problems but it in my opinion does not capture near the heat in the stove that it should. thanks for your response and info.
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magnum 7500 since 04

[spray]

i would also like to say that this 7500 would have made alot better water boiler than a hot air furnace with its larger capacity that the 3500 and its inability to move much air. it would be a pretty good boiler platform. i might add that i have been fortunate to be running the original auger motor, auger, draft blower and etc.. never have had to replace any of these items yet on this unit. but have went through the stirres.
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magnum 7500 since 04

[cornbore]

I believe the fuel should be no higher than the main shaft on the stirrer. If the stirrer is submerged in the fire bed it will act like a forge and the life of the stirrer will be limited. I am on my 5Th year with my 7500. I have in the past replaced the draft fan blade with the more aggressive one and the fire pot was replaced after four seasons, have used about a stirrer a season. I bought one of 2024s pots this fall but the 7500 has worked so well with the stirring system this year that I have not tried it yet. When I put the new stir pot in last spring the furnace seemed to change in performance. I am real careful to scrape the pot with the tool daily as the stirrer turns to keep the holes clean I also sealed the exhaust pipe with aluminum tape this year. My door glass stays clean. 13.5% corn from my drying bin.
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Goodbye woodsplitter. Trap Shooter-dust to dust. 2008 Harley Davidson Fat Bob, 7500 furnace

[Sweet Corn]

The first two seasons I was frustrated like you. But then as time rolled on and I experimented with more and more things until I found the sweet spot settings. I only burn corn and each load is different. My first load this year came from the bottom of a drying bin. I wish I could have stored enough of that stuff for the entire year. It burned great with little ash. Now I have current year corn and its higher moisture. Burns okay but more ash. Clinkers change from wagon load to wagon load. Sometimes there are no ball-like clinkers but instead build-up on the stirrer.

In my case I never go above #2 heat setting and #1 on the strirrator. House stays at 70-73 deg. If our weather gets real nasty I’ve found that letting the propane furnace supplement works better than pushing more corn through the 7500. Not so much that the 7500 won’t perform but it’s just more work for me and I’m getting lazy in my old age.

My air intake is always full closed and I think I could block it off even a little more if I wanted to. The only time I open it up is for my weekly run on setting #5 for 15 minutes to blow the junk out.

I keep 5 strirrators on hand at all times and rotate them out as needed. They are made from low carbon (1018) steel and last just as long or longer that any of the AES versions. I added a rib to the middle where they typically get thin. A heat setting of #3 or higher is going to make the strirrator disappear faster. That’s a lot of heat for any material to take. There may be an exotic material (like what they make heat treat furnace components out of) that may stand up to the heat but I’m sure it’s cost prohibitive.

I am close to trying an idea I’ve had for a few years now that will allow me to run a modified version of a clinker pot that has the ability to drop the clinker in the ash pan and keep the fire going without opening the door. The design is in my head and I just need to get it on paper and start building. Finding the time to do it is the biggest problem.

The more I use my 7500 the more I like it. This year has been a very good year so far.

SC

[spray]

thanks for the info i have been burning this 7500 sivce 04 i do understand what you are telling me in difference in corns. i have found the same thing as well.here is my hang up i bought a furnace that was sold to me as a 87% efficiency rating and 76,500 b.t.u.'s i believe this to be listed as how a new car man. list fuel mileage looks good on paper but not so good when i am buying the gasoline and not getting near the mileage they told me it would we all know how this works.any how i sized and bought my 7500 thinking i could get 76,500 btus out of it - the 13% of the so called 87% efficiency rating. i do agree with using propane to supplement your heat rather than to go to #3 setting (alot easier on the back) but this is not why i personally bought a corn furnace. if i want to burn propane i would fire up a 40,000 btu ventless gas log heater that is truely 99.99% efficient.my propane furnace is a 90% efficiency rating and it exhaust through plastic pvc. do you suppose any of these corn furnaces could exhaust through pvc pipe?? correct me if i am wrong but at 87% efficiency which if rated real with say 300 deg. out put heat temps.than the exhaust temp should only be(300x.13%=39 deg.)add room air temp of say 70deg that equals 109 deg flue temps.are any of you guys getting any flue temps this cool?? if i look at propane at $1.59 a gal. at a true 90 % efficiency burning 100,000 btus and exhausting through plastic. then go to corn at nearly $4.00 a bushel from the efficiency standpoint i know what is cheaper and easier this year for sure. i was sold a 87 % 76,500 btu unit that i myself have never been able to get i am willing to keep trying for the rest of this heating season than i am done. like i said i didn't buy a corn furnace so i could burn propane it means supporting my local farmers and not the middle east oil machine to me. thank you.
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magnum 7500 since 04

[tallcorn]

The BTU rating for heaters is the fuel content, not the heat output. The heat output is what is left after you calculate the efficiency. High efficiency gas furnaces use exhaust condensers so the output temperature of the exhaust is cool enough to be able to use PVC for piping. High efficiency gas furnaces remove the heat in the 10% moisture content of the exhaust.
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Countryside 3500P (pedestal version) used 8-9 yrs, 24/7 during days requiring heat. All original motors. Burns moldy corn, and pellets equally well. Burn it if you got it.

[spray]

tall i agree with you i f you look at my post i stated that i figured that i would get 76,500 btus minus the13% efficiency negative.that is the same as calculating the btu input minus the 13% neg. my furnace has never been able to get close to this.i guess the way i calculate overall efficiency is if you have 225 deg air coming out of the stove as heat and you have a flue temp of 225deg. than you have a 50% efficiency rating. being that the 100% would be a electric element or vent less propane at 99.99% since their is no heat loss through a flue. also yes the propane furnace robs all the heat of of it before it hits the power vent plastic flue that is why it has a 90% rating how can a corn appliance only be 3%less efficiency rating and put out in some cases as much heat out of the flue as it does into the room as heat? can anyone answer this for me please?? thank you.
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magnum 7500 since 04

[rdaly]

It seems to me the 87% efficiency is a little bit of an exaggeration. With wood pellets it is necessary to be in the ballpark of 220 degrees out the flue to prevent creosote formation.

[spray]

that is right rdaly you do need warm flue temps or bad things start to happen i was just stating earlier that i was pretty disappointed with my stove from day one on the heat output i have a fairly large home that was only a year old when i bought the magnum advertised btus amount of 7500 was 76,500 and 87% so i figured this should work for what i needed in the terms of btus. but with the impossibility of this unit running that well it was undersized and overrated from day one.
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magnum 7500 since 04

[AlaskaAviator]

I don't think spray is ever going to get it, probably just ought to sell it.
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AES 3500P & 7500 furnace