Found a Used Harman Super Magnum & Have a Few Questions

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guysnydr
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Posts: 51
Joined: Sat. Jan. 09, 2016 2:39 pm
Location: Williamsport PA
Hot Air Coal Stoker Stove: Harman Super Magnum
Hand Fed Coal Stove: Previous stove - Harman Mark III
Coal Size/Type: Rice
Other Heating: Oil Fired Forced Hot Air

Post by guysnydr » Thu. Jan. 12, 2017 5:41 pm

Last week I was fortunate enough to discover a lightly used a Harman Super Mag for sale. It was purchased new in 2012 and used 3 seasons. I wasn't necessarily ready to pull the trigger on a stoker yet but the folks had sold their house and just wanted it gone. I offered $1500 cash and to my pleasant surprise, they accepted the offer. I wasted no time picking it up and it's in exceptional shape. The local Harman dealer sells the same stove for $3,789, plus tax so I think I got a great buy. The stove will replace my trusty handfired Harman Mark III.

Anyway, I have a few questions for you experts out there.
#1 The main reason why I have not made the switch to a stoker prior to this is because I LOVE that I can still heat with the Mark III when I lose power. It doesn't happen a lot, but it can/does happen from time to time and it is a concern. I understand there are battery backup systems out there, I am sure this subject has come up a lot so I apologize in advance for the redundancy, but should I just buy the inverter/charger kit that Harman sells and be done with it or? It appears to me that it is actually just a SureFire Stove Sentry 512 inverter/charger with the Harman logo on it? They run in the $500 range from what I can see. I would like to use a deep cycle battery, maybe two with whatever I do since I already have these batteries for my boat and it would give me something to do with them in the winter. Is there another brand and model of auto switching inverter / charger that any of you are using that is sufficient to run a stoker like this and that is less expensive than this one??

#2 Roughly how long could I expect 1 deep cycle battery to run this stove?

#3 Is there much value in unplugging the blower fan when it is running on battery to conserve battery power?

#4 On another topic - I see it has a removable cover on the top. I have a forced hot air furnace and my main trunk line/duct happens to be within a couple of feet of where my stove sits. Can I pipe right into that existing heat duct with it, or is that a no-no? I have read that you shouldn't, just wondering why? I don't use the oil furnace much if at all while the coal stove is running and it would almost never run at the same time as the Super Magnum since it has a thermostat on it and would maintain temperatures better than the Mark III. Is there a fear of heat running back into the oil furnace or something that I should be concerned about?

I am certain that I will have a few more questions about this stove but this is all I can think of for now. I am excited to hook it up but will likely finish out this season with the Mark III. Just doing some thinking and planning right now before I do the actual switch. The Mark III has been one heck of a stove, I hope I'm doing the right thing here!

Thanks to you all in advance!

- Guy

 
titleist1
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Post by titleist1 » Thu. Jan. 12, 2017 8:06 pm

Congrats on the mag stoker you must have been wearing a mask when you picked it up cause that was a steal!

I made the same migration as you from a Mark III to a mag stoker, mine is the older version not the super mag so I can't help with the questions. I kept the Mark III and a stash of nut coal in case we lose power for a long time since I am not interested in running the generator over night.

Others have piped into their main duct work successfully, both the supply and return sides. How well does the heat circulate now with the Mark III - I am assuming it is not connected to the duct work?

 
guysnydr
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Posts: 51
Joined: Sat. Jan. 09, 2016 2:39 pm
Location: Williamsport PA
Hot Air Coal Stoker Stove: Harman Super Magnum
Hand Fed Coal Stove: Previous stove - Harman Mark III
Coal Size/Type: Rice
Other Heating: Oil Fired Forced Hot Air

Post by guysnydr » Thu. Jan. 12, 2017 8:57 pm

LOL, I didn't wear a mask but I did go get it within a few hours of agreeing on the price! Wasn't taking any chances... ;)

The Mark III is not hooked into ductwork, it just convection heats to the upstairs. I assume the Super Mag will do just as nice a job if set up the same way as the Mark III, but I can see where heat would be even better distributed if it was tied right into the ductwork.

Basically my setup is a ranch house with stove in far gable end of basement, stairway is open and basically in the middle of the house but slightly off-center. Heat goes up the stairway and it also acts as my cold air return. This setup works fine, but I do have two bedrooms on the far end of the house that don't heat quite as well as the rest of the house. This is why I thought maybe tying the Super Mag into the existing ductwork might be good. My oil furnace and stove are almost back to back so to speak. The oil furnace is in the back corner enclosed in a block wall room, and the stove is on the other side of it. Therefore the ductwork is just within a few feet of the stove and would be easy to tie in to.

 
titleist1
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Post by titleist1 » Thu. Jan. 12, 2017 9:54 pm

You are describing my set up exactly....right down to the cooler far end bedrooms....

what I did to even the temp out a little better back there was to hang some flex duct from a floor vent down to the basement floor. the cooler air drops from the bedroom to the basement and the warmer air is pulled into the bedroom.

I tried tying my mag stoker into the ductwork last year and it worked well for the rooms that were close but the bedrooms furthest down the run of duct weren't getting the airflow. The built in blower on my mag stoker wasn't strong enough. I went back to the 'stairway distribution' method.

 
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captcaper
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Post by captcaper » Fri. Jan. 13, 2017 5:17 am

TI owned a Mk III as well before the Super Mag... because of the "no power" "no moving parts" mentality... wrong.. wish I had bought Super Mag years ago. This thing is well made and much easier to use then the older Mag.. believe me after using it 4 yrs now from October to April 24/7. Long winters here in Northern NH...
You can use any invert-er bought online that can take the total amps for both blowers.. they don't draw much...but I would just pick up a small generator and this will power it fine for days if needed. A battery won't last long.. during outages that go for a day or more.
I also have it in the basement on one end of a 2000 sq ft Cape.. I don't have hot air furnace so I installed flex insulated duct work to a vent in the floor in the main living area... I leave the basement door open (center of house) and cool air goes down and warm air flows up above it to aid heating as well. It get's 40 below 0 F here and this keeps my basement perfect and the main living area as well as the 2nd floor bedrooms.. The vent is at the stair well area in the living room.
The front of the Harman is totally blocked with their kit and all air is sent thru the flex ducting. I also have the Temp probe in the living area.. I added some wire to extend the length which is ok to do as told by Harman to me and it works perfect... keeps the house within a degree...
Be sure to oil the 3 cap oil ports in the back on the feed shafts. And install a barometer and manometer and set the draft to Harman spec's... there are many articles on it on this forum and hand fired forum for the


 
guysnydr
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Posts: 51
Joined: Sat. Jan. 09, 2016 2:39 pm
Location: Williamsport PA
Hot Air Coal Stoker Stove: Harman Super Magnum
Hand Fed Coal Stove: Previous stove - Harman Mark III
Coal Size/Type: Rice
Other Heating: Oil Fired Forced Hot Air

Post by guysnydr » Fri. Jan. 13, 2017 9:41 am

Thanks to you both for the help/info. It is good hear from others who have made the same switch-over as I am about to do!

Regarding the duct work, I wondered the same thing as far as if the heat would even get pushed to the far end of my house before it cools down and isn't really "heat" anymore. My other thought, while it may be completely false, is that if I can get the heat duct idea to work, and place my sensor upstairs in the living area, it might use a little less coal since it isn't trying to heat the basement first, then moving the warm air upstairs? That at all logical to think? Where the stove is located is in an occasionally used family room in the basement. My basement is partitioned off so just more than half of my basement is not being heated by the stove and that air is moving up the stair well to the living area. I don't know, just thought it might make sense that if I were to plum the heat more into the living area of the house it might create less of a demand on the stove?

As for the battery backup, I do have a basic inverter now that I can hook up to it, but the more I think about it, the more I like the idea of a charger/inverter with an automatic switch built in. If I am laying in bed at 2:00 in the morning and the power goes out, I think I would rather just go back to sleep knowing that the thing is already running on battery. Or if I am not home at all when it happens, at least I have the peace of mind knowing that I should still have a fire and some heat when I get home. My understanding is that these stoves will only run without power for maybe 15 minutes or so? Maybe you guys know for sure?

Anyway, I think what I want is an automatic inverter/charger and was hoping someone might know of a good alternative to the $500 version from Harman? I actually saw it online for $429 somewhere, but I didn't check to see what they were charging for shipping.

I do have a small generator that I would use if we lose power for too long, I am just hoping for some peace of mind, especially if I am not home when it goes out.

Thanks again all!

Guy

 
guysnydr
Member
Posts: 51
Joined: Sat. Jan. 09, 2016 2:39 pm
Location: Williamsport PA
Hot Air Coal Stoker Stove: Harman Super Magnum
Hand Fed Coal Stove: Previous stove - Harman Mark III
Coal Size/Type: Rice
Other Heating: Oil Fired Forced Hot Air

Post by guysnydr » Fri. Jan. 13, 2017 9:58 am

Oh, one other question for you guys since you are running a Super Mag. How often do you clean out your chimney pipe? A buddy of mine had a Mark III and switched to an Alaska stoker and he says he notices a lot more accumulation of fly ash in his stove pipe. Says he has to take his apart once a month or so and cleans it because it builds up so fast. Once he said almost half of his pipe was full of ash. This scared him so now he cleans it once a month and says he still gets a fair amount out.

I get some ash in my pipe from the Mark III but nothing like that. I always start with a clean chimney (as one should of course) and then clean out the pipe again in January sometime, then I am good till the end of the season. I might see an inch or so of ash laying in the bottom of the pipe on cleanouts, but nothing too bad. Am I going to see more ash build up from the Super Mag than I did with the Mark III as well?? Just wondered what your experience has been?

Also, this question may sound very trivial but one of the biggest irritations that I have with the Mark III is that every time you shake it down ash also settles "outside" of the pan area and you have to shovel the whole lower part of the stove out every couple of days otherwise the pan won't slide back in. I AM SO NOT GOING to miss that. On the Super Mag, I assume the bulk of the ash drops right into the pan, correct? I assume some fly ash will settle, but I am going to be thrilled if I don't have to shovel that darn thing out very often! It's irritating, especially when I am in a hurry. LOL - I know, trivial, but still irritating! :)

 
titleist1
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Post by titleist1 » Fri. Jan. 13, 2017 10:34 am

I do not notice much difference in fly ash accumulation in the flue pipe going from the Mark III to my old model mag stoker. I could see that being the case though since the Mark III has the firebox baffle and cavity by the back exhaust port to catch a lot of the fly ash before it gets into the flue pipe. The mag stoker is a top exhaust port so what used to accumulate in the back cavity now goes up the flue pipe. Just give yourself easy access to clean out the horizontal section via a capped T instead of a 90.

I have always been able to insert a vac wand without shutting down so clean-out only takes about 30 seconds.

Yes...in complete agreement on how irritating it was to shovel out the ash so the pan would fit back in in the Mark III. Does your super mag have the chain set up to clean the fly ash off the firebox baffle like the older mags? That is the only ash that misses the pan and I shovel that out about once per heating season since it doesn't get in the way of getting the pan back in.

 
guysnydr
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Posts: 51
Joined: Sat. Jan. 09, 2016 2:39 pm
Location: Williamsport PA
Hot Air Coal Stoker Stove: Harman Super Magnum
Hand Fed Coal Stove: Previous stove - Harman Mark III
Coal Size/Type: Rice
Other Heating: Oil Fired Forced Hot Air

Post by guysnydr » Fri. Jan. 13, 2017 11:20 am

Good idea on the T instead of an elbow! I like that idea alot!! May just do that.

Yes, the Super Magnum has the chain slider to clean off the firebox baffle, the knob for it is right at the top of the bin facing the stove.

 
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captcaper
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Post by captcaper » Fri. Jan. 13, 2017 11:43 am

Yes you will get alot more ash in the flue pipe.. install it with a tee so you can access it easily. Well I do anyway as it gets so cold for so long here I go thru a lot of coal..

The ash pan works great... no ash on the sides like the Mk III. The insulated flex duct work works great..to get the heat from one end of the house to another. The front of my stove it totally blocked off so all the hot air goes up the flex work.. the throw off heat from just the stove the stove keeps the basement perfect.. I work there so that was a hope I had and works out better then I thought..


 
guysnydr
Member
Posts: 51
Joined: Sat. Jan. 09, 2016 2:39 pm
Location: Williamsport PA
Hot Air Coal Stoker Stove: Harman Super Magnum
Hand Fed Coal Stove: Previous stove - Harman Mark III
Coal Size/Type: Rice
Other Heating: Oil Fired Forced Hot Air

Post by guysnydr » Fri. Jan. 13, 2017 12:05 pm

I think I will try ducting it. I don't have much to lose. Also, one reason the basement family room doesn't get used much is because it's so dang hot down there! If I block off the vent outlet on the stove as you did, then I would just get some radiant heat down there and I am sure that would keep things comfortable but not as hot as it is now.

I do need to install a cold air return in the back bedrooms. I agree that this would also help draw the heat back there as well. I have thought about this in the past, just have't done it.

Good advice. Now just need to figure out this battery backup issue.

 
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McGiever
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Post by McGiever » Fri. Jan. 13, 2017 1:59 pm

Mo batteries=mo better. ;)
It is all about the AMP Hours

Only deep cycles/golf cart type...never use auto/starting batteries.
Last edited by McGiever on Fri. Jan. 13, 2017 2:03 pm, edited 1 time in total.

 
guysnydr
Member
Posts: 51
Joined: Sat. Jan. 09, 2016 2:39 pm
Location: Williamsport PA
Hot Air Coal Stoker Stove: Harman Super Magnum
Hand Fed Coal Stove: Previous stove - Harman Mark III
Coal Size/Type: Rice
Other Heating: Oil Fired Forced Hot Air

Post by guysnydr » Fri. Jan. 13, 2017 2:02 pm

Yes, I would be using Deep cycles. I work for an RV dealer so they are readily available to me and at good prices.

 
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captcaper
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Post by captcaper » Sat. Jan. 14, 2017 6:35 am

Being a different beast you have to step back and give some time to thought on how you might go. With my basement heated from off heat the bedroom is fine...if I open the door it get's warm in there from flow from living area.. if I close it at night it get's cooler which we love.. but the floors are warm especially the private bath floor with tiles off our bedroom.. stays nice..
Try the simple way first with a plan to be able to add on later.. The Super Mag blows out alot of heat.. 110,000 btu's.... the blower is strong as well. The heat that comes out of the vent at the other end of the house is so hot it will melt anything put on it.. There was a plastic shut lover in the brass frame..that burnt out right off.

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