Harmon Magnum Stoker Overfire

Ok I have read the manual for my stove and theres not much for overfire except a drawn picture. How do I know if I am pushing too much coal thur my stove. Now I have it set for about 2 dots and I am getting a nice 2" thick band of hot coal across the whole grate. About 80% of the grate is spent coal, from just past the peak of the arc to were the ash falls is not lit. Should the whole grate be hot coals, or can it even go that much? I relize I don't want hot coals dropping into the ash pan. How do I find that happy medium between max BTU and wasting coal.

Hey Jeep Imnot familiar with Harman stoves at all butI would think that if the coal is allready burnt that far up the grate that would be room for you to bump up the feed. When my Channing 3 is cooking hot the coal is still burning right up to where the air feed stops then it dies off for about an inch before falling into the ash pan. Im sure someelse in here will be able to help you more specifically than me. Oh is that jeep junky as in "jeep off road junky"? Jim

Hello JeepJunky, you are 'overfiring' your stoker when you have hot, still burning coal dropping into the ash pan. Right now you probably can increase your feed untill you have increased the burning coal and narrowed the band of ashes at the end of the grate.

Do you have your stoker combustion blower set to run continously? If not you need to set it up this way, it makes the burn of the coal more complete.

Matthaus has run a couple of these stoves, I'm sure he will fill in the details soon.

Can you take a no-flash photo of the burning fire and grate, and post it Here?

Greg L

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Thanks for the quick repleys. It's sounding like I can crank it up a little more. This will be the first good weekend I can keep an eye on it and get it dialed in. I'll take some before and after pics once I get it cranked up.

Greg the way the fan is set up now the combustion fan is on when ever the thermostat is calling for heat. But when the stove goes to maintance mode the combustion does not come on at all. So are you saying the combustion fan should be modified to come on even during maintance?

Jim yea I do take my CJ-7 offroad, I mostly like to play on the rocks. Went to Paragon when it was open and Bradford for the Jeep Jam. Planning on going to Raush Creek this spring. Do you have a toy too?

Dennis

Yes, I'm pretty sure that Matthaus has his Mag Stoker set so the combustion fan runs 24/7, the thermostat runs the stoker motor. With the added combustion air, the coal burns at it's hottest, and you get less unburnt or partially burnt coal in the ashpan.

The older bed-type stokers didn't have the constant combustion air, I think all the current stokers use it though.

Greg L

as being a proud owner of a Harman mag stoker I can tell u that your not overfiring that stove. It is also a good idea to run the combustion fan all the time. Just run the plug into a power strip or wall outlet. If u run the fan 24/7 u will also have to increase the feed rate to compensate for the burning coal. I have both my fans setup to run non stop and I use the thermstat to control the feed motor. I've found I get a complete burn with max heat output of the coal at any given time. And as lsfarm has said. As long as your not pushing hot coal off the grate your not over firing it. Each stove and setup is different so u will have to play with it till u find the sweet spot. I know on mine if I have 1 inch of ash at the end of the grate the stove body is almost around 700 deg. Which is real nice when it's 20 below outside..

Hey Jeep This is a picture of my old rot box,beleive it or not it was painted about 5 years ago, its still out back ready for me to find a rust free southern truck for swap out...I put 1 ton axles and driveshafts on it, and changed out the stock steering for an ORD crossover steering kit(so it can turn on jeep trails) and I have a locker for the rear end as well as a disc brake conversion kit that I never put on before I parked it. Im actually on again off again trying to sell it. Jim

I put a Powertraxx locker in my K1500 Chevy pickup and I wish I had never done it. It worked great for a while, like 2 years, then something twisted inside the locker and it wouldn't unlock. I lived with it until my $550 tires wore out in 2 months so I had to fix it. Long story short I couldn't get the locker to come back out no matter what. I should have just put an air locker in in the first place because it cost me $900 for a replacement rear end because I had something to deliver and didn't have the option of shopping around.

hi jeepjunky,

i also have the combustion blower on my magnum on continuously, along with the distribution blower always on---set the distribution extend timer setting to 15 and it will always be on, blowing hot air off the stove.

this time of year in the poconos (low 40's now), I usually just run 1 dot with the thermostat set at 73 upstairs, and everyone's comfortable. everyone's home is different & this is subjective at best.

do you have a barometric damper installed on the flue?..if not, you are certainly helping to heat dillsburg instead of keeping the heat in your home and saving fuel.

where is your stove located? are you taking advantage of the 6" duct option on the magnum if it is located in the basement or a lower floor?

don't use wet coal with this harman, keep some (55 gal. drum perhaps) inside to dry. I used a bit of wet coal last season & though it did not affect the heat output, it did provide some unnecessary rust on the inside & stoker assy. for me to remove this past summer. if you see black water spots from the rear of the stove on the floor...it's too wet.

i have a jeep liberty & getting home from work at 1 am on this mountain in the winter snowstorms is no longer a problem...and fun (sometimes?).

stick around this forum & you'll learn quite a bit that Harman failed to print with their manual.

regards,
tom

OK let me first start by saying thank you for the WARM welcome. Now as for my set up yes the stove is in the basement and it is hooked to a 6 inch duct "T"ed to two vents. Even though Harman says not to run two. I figured why not try it.
Also yes I have a barometric in the flue but it is on the horizonal not the vertical the way it is show in the manual. Is that a problem?

Ok I ran it for the first full day thursday and I screwed something up. When my wife left for work the house was 75 as I had it set to. She turned it down to 70 and left. When she got home the house was 78 and rising. The stove was not dropping into maintiance mode. ie. both fans and the feed motor are running all the time. So I replaced the thermostat(no change, still no maintiance mode) and started tracing the wire and checking connections. Finally got to the control box and the lower blade connector the is in the control box that the wires from the thermostat hook to came off in my hand now what????
I'm not much of a solder'er and I'm sure the piece that come off was in a PC board of some type. My first thought is to open the control box up and put the little blade back in its holes and try to crazy glue it to the board. I'll just have to ginger with it when I plug the thermostat back in.
Any ideas would be great. This sucks I was so excited about keep this stove running and now I'm down again.
As for you offroad guys I'll try to get some pics of my rig up. Next spring I'm planning on going to Raush Creek wheel it would be great to meet you guys.
Dennis

Sounds like you are dealing with a Harman control box that is not functioning properly. If the terminal was broken that would make an open, meaning idle mode only. So sounds like something is funky inside the control, or possibly you have the stoker control timer or the distribution blower timer set to zero, which means it will run all the time. Try turning each timer two detents clockwise and see if the stoker/blower will shut off.

I have run my Harman without the Tstat and had good results, so in the mean time you should be able to manually control the stove if you can get it to function properly with the timer. I set mine up to push at maximum stroke (max dots) then use the timers to regulate the heat. This will not work if you have a Tstat hooked up! So don't try it once you get the terminal soldered back on, will run the fire right off the grate! nfire:

I happen to have two Harman controls that I removed to install Coal-trols. PM me if you can't get the problem solved and maybe I can offer you one at a price that will be agreeable.

When you guys get photos of your off-road jeeps, trucks etc. Please post them under another title in the 'off topics' forum. I'll add a few my self

I'd like to keep this thread about possible overfiring of a Harman Stoker

Thanks, Greg

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I made the same mistake with the timers at first- you would think a "0" setting is "off" but it's really "full time on". Then I read the manual to see what I was doing wrong . Then I set the timers the right way 8) .

When all else fails, read the directions !

I'm planning on going to Raush Creek wheel it would be great to meet you guys.
Hey Jeep when you come up bring a trailer I can take you right down the road to the coal breakers you can fill up they are deep mine coal breakers let me know sorry Greg I could not Help myself

Thanks for the help everyone, I'm up and running again. I soldered the blade connector back to the board and now it's going in and out of maintiance mode like it is suppose to. As for the overfire question I turned up the feed about two turns and wow what a difference. I can't believe the amount of heat I'm getting out the unit with such a low chimmey temp (Between 250-300). I still have lots of questions but I'll start new topics for them, and for the off road guys look for something in the general topic area soon.