New to Me Harman Magnum. Questions

A Coal stoker furnace or stove controls most operations including automatically feeding the coal. They are quite similar to any conventional oil and gas units and easily operated for extended periods of time. They commonly use rice coal but may use larger sizes like buckwheat. They can be used as primary heat, supplementary heat or have a dual set up with your existing oil/gas furnace.
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2001Sierra
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Posts: 1845
Joined: Wed. May. 20, 2009 8:09 am
Hot Air Coal Stoker Stove: Keystoker 90 Chimney vent
Coal Size/Type: Rice
Other Heating: Buderus Oil Boiler 3115-34
Stove/Furnace Model: Keystoker 90 Chimney Vent
Location: Wynantskill NY, 10 miles from Albany

Post Tue. Nov. 06, 2012 9:29 pm

I am turning my Keystoker 90 into a mini furnace. I did not get the duct ring in the top from the factory but will now weld one in. I ran a Buderus hand fed for years in the basement family room, and supplemented the heat with a few hundred gallons of fuel oil. Well, in comes the Keystoker 90, and knocks the socks of my previous arrangement. Last 2 years thermostats where turned off for the oil fired Buderus. I did a redneck hookup to the Keystoker gathering the air off the front and feeding my air distribution blower of many years and all of a sudden the house was equally warm. Cold weather was forcasted last nite so out came the redneck setup. This morning my bride of 32 years said " I was wondered why the house has not been that warm? Now you hooked up that tube and everything is better :oops: Tis weeekend it will be warmer and I will sell the new duct ring into the top, showing the cleaner and more efficient connection of the convection blower to the distribution blower. The Keystoker Koker should kick your install up a notch or two if installed into your existing furnace. I only wish this site and my knowledge I have now was here 30 plus years ago :x All in all I never went off half cocked and did anything stupid with my install. Everything is still pleasing to the eye, and very functional as well.


LiftedAWDAstro
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Posts: 171
Joined: Mon. Feb. 09, 2009 5:02 pm
Hot Air Coal Stoker Furnace: Keystoker Koker 160
Coal Size/Type: Rice
Stove/Furnace Make: Keystoker
Stove/Furnace Model: Koker
Location: New Haven, NY

Post Thu. Nov. 08, 2012 8:08 am

The Koker will definitely do what you want. I have mine connected in series with my oil furnace and only use the oil furnaces' blower to push all the heat throughout the house. A hand-fired stove won't work any better than the stoker you have now, in fact the hand-fired will require more work as you'll need to tend to it more often.

kirtdog
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Posts: 12
Joined: Tue. Oct. 16, 2012 1:41 pm
Hot Air Coal Stoker Stove: Harmam magmum
Coal Size/Type: rice
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum
Location: State College PA

Post Wed. Nov. 14, 2012 12:24 am

I finally got around to cutting a return vent in the floor and it has helped some. I am thinking I am going to have to use the duct on top of the stove in order to get the amount of heat that I want upstairs. I really don't want to cut another hole in the floor so I think I am going to just use one of the existing supply vents. It is much easier to disconnect one of them from the main system than to cut another hole. Any thoughts??? Also, If I use the duct on top of the stove, will the radiant heat be enough to keep my basement somewhat warm?

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titleist1
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Posts: 4404
Joined: Wed. Nov. 14, 2007 4:06 pm
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite
Location: Cecil County, MD

Post Wed. Nov. 14, 2012 12:58 pm

I have a mag stoker in my garage workshop with the vent coming off the top ducted to the upstairs. The workshop is only 20x24 and has insulated floor, walls & ceiling, however, there is a 5' opening to the 24x24 garage that is closed off with only hanging plastic. The workshop will get to 80* just off the radiant heat from the stove as well as the duct that runs across the ceiling to get to the upstairs vent. I am sure your basement is larger and may not be insulated as well so your heat loss would be greater. But I still think you would get plenty of heat off the stove to keep it comfortable.

Make sure you don't place your duct off the stove too tight to anything combustible! The duct going across my ceiling gets hotter than the flue pipe. I have a 1" air gap from the ceiling and I'd be worried if I didn't!
I drive a VW TDI, heat my home & workshop with two coal stokers and have two vintage JD diesel tractors....
The EPA just loves me!!

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Horace
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Posts: 496
Joined: Thu. Sep. 18, 2008 12:15 pm
Hot Air Coal Stoker Stove: Harman ST8-VF8 / Frankenstove
Location: Central PA

Post Wed. Nov. 14, 2012 2:18 pm

kirtdog wrote:Also, If I use the duct on top of the stove, will the radiant heat be enough to keep my basement somewhat warm?
Depends on how big the basement is, how well insulated, etc. What I found with my stove was after I ducted it to the upstairs the basement became comfortable. Very comfortable. Before ducting, my basement was near 80* and upstairs was in the high 60s. Once I ducted it the basement dropped to the low 70s and the upstairs came up to the low 70s. No more roasting in one place and freezing in another. Everyone's house and set-up is different, of course, but it worked really well for me.
The best weapon and tool one can ever possess is patience.

kirtdog
New Member
Posts: 12
Joined: Tue. Oct. 16, 2012 1:41 pm
Hot Air Coal Stoker Stove: Harmam magmum
Coal Size/Type: rice
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum
Location: State College PA

Post Mon. Nov. 19, 2012 8:48 am

I haven't given up on the magnum yet. This may be a dumb question but how big (high) should the flames be? I don't want to overfire the stove and mess something up. I am still trying to avoid using the takeoff on the top of the stove so I want to make sure that I am burning the stove to its full potential without doing damage. Any help is appreciated.

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titleist1
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Posts: 4404
Joined: Wed. Nov. 14, 2007 4:06 pm
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite
Location: Cecil County, MD

Post Mon. Nov. 19, 2012 9:57 am

When mine is firing the flames will be touching the top of the triangular baffle. I think that flame height would be a result of quite a few variables like the combustion air volume, coal quality, grate holes clean or not, fly ash under grate, etc. I watch a couple things are more closely than flame height, though.

The first is that you aren't pushing more air into the firebox via the combustion fan than you can exhaust out the flue. If you are then the exhaust will look for other ways out of the stove and into your living space via the hopper or around the glass. My combustion fan plate is only open 3/4" from the flat part of the plate to the edge of the fan cage arc. You can compare the firebox draft versus the flue pipe draft with a manometer to make sure you are balanced correctly.

The second thing I watch are the temps on the stove body and the exhaust. The flue body gets to about 600* (mag thermometer on top-front corner of left sidewall) when firing for about 1/2 hour and the corresponding flue temp is 250* (probe thermometer about 18" from stove exhaust port). When idling for the day, the side temp settles to about 350* and the flue temp is at 125*. I have a baro on mine that keeps the flue draft at about 0.04.
I drive a VW TDI, heat my home & workshop with two coal stokers and have two vintage JD diesel tractors....
The EPA just loves me!!

kirtdog
New Member
Posts: 12
Joined: Tue. Oct. 16, 2012 1:41 pm
Hot Air Coal Stoker Stove: Harmam magmum
Coal Size/Type: rice
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum
Location: State College PA

Post Wed. Nov. 21, 2012 10:14 am

I am about to give up. I can't get the heat upstairs. I thought the heat would come up through the basement stairs and circulate through the house. I did cut a return vent at the opposite end of the house thinking that it would pull the heat. It isn't working. I am trying to avoid putting more holes in my floors. I may just have to suck it up and run the duct off of the top to the first floor. :(


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LsFarm
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Posts: 7385
Joined: Sun. Nov. 20, 2005 8:02 pm
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland
Location: Michigan

Post Wed. Nov. 21, 2012 10:34 am

This is a VERY common complaint, trying to make a stove into a furnace..
Go to the venting, chimneys forum and do some reading, there are many threads on this subject..

I'll tell you what WORKS.. You HAVE to remove cold air from upstairs.. just having a vent in the floor will not
assure that cool air from that floor will fall into the basement.. You MUST use a duct, like a dryer hose from that
vent in the floor over to the inlet of your circulation fan.. this way you are PULLING cool air from the upstairs, and
then the flow of air up your stairs will increase noticably.

Think about a furnace, it has cold air return ducts, and hot air out ducts, they open into each room upstairs.. so you
can't expect to heat the house well or evenly with just the staircase as your 'ductwork'.. Many staircases end up having
cool air flowing down, and hot air along the ceiling of the stairway flowing up... but they get mixed, the flow is not separated
by rooms or walls or ducts, so it doesn't work well..

We've had several forum members who installed the clothes-dryer vent from a floor vent to the inlet of the stove's fan, and had great success getting a much better air circulation in the house..

It can be done, you just have to figure out the airflows in your house, or create the ones you want.

Hope this helps..
Greg L
Burning Pea/Buckwheat through an antique stoker [semi retired SSboiler],
Running an Axeman-Anderson 260M boiler burning Pea, About 150-250#per day
Farming, Fixing, Fabricating and Flying: 'spare time' what's that?

User avatar
titleist1
Member
Posts: 4404
Joined: Wed. Nov. 14, 2007 4:06 pm
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite
Location: Cecil County, MD

Post Wed. Nov. 21, 2012 11:47 am

As Greg said the air circulation issue is the most common problem heating with stoves. Some folks have found that just cutting a hole in the floor for a vent only allows more heated air at the basement ceiling to go up through this vent rather than allowing the cold air to drop. The fix is to have a duct from this vent to the basement floor.

I have a 6" flexible duct on the one floor supply vent in the back bedroom that drops to the basement floor. I can feel the cooler air flowing out of this flex duct. You should definitely try this before cutting more holes in the floor.
I drive a VW TDI, heat my home & workshop with two coal stokers and have two vintage JD diesel tractors....
The EPA just loves me!!

User avatar
LsFarm
Member
Posts: 7385
Joined: Sun. Nov. 20, 2005 8:02 pm
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland
Location: Michigan

Post Wed. Nov. 21, 2012 12:12 pm

And if you could end the piece of dryer vent right adjacent to the inlet of the circulation fan of the stove, you would 'almost' have a closed circuit.

Forum member WNY hooked up cold air returns to his Hyfire in his basement, he already had hot air ducts in place.. he was able to raise the upstairs temperature around 10* if I remember correctly.

You can't push hot air into a room, you have to remove cool air, and hot air will replace it.. It just works better this way.

Greg L.
Burning Pea/Buckwheat through an antique stoker [semi retired SSboiler],
Running an Axeman-Anderson 260M boiler burning Pea, About 150-250#per day
Farming, Fixing, Fabricating and Flying: 'spare time' what's that?

kirtdog
New Member
Posts: 12
Joined: Tue. Oct. 16, 2012 1:41 pm
Hot Air Coal Stoker Stove: Harmam magmum
Coal Size/Type: rice
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum
Location: State College PA

Post Wed. Nov. 21, 2012 3:42 pm

i actually did run a duct and it still doesnt seem to be working. The duct isn't the whole way to the floor. It is about 16" or so from the floor. Should I extend it down further?

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User avatar
LsFarm
Member
Posts: 7385
Joined: Sun. Nov. 20, 2005 8:02 pm
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland
Location: Michigan

Post Wed. Nov. 21, 2012 6:07 pm

Take a look at this link, Forum member Qball did it right.

About halfway down page 2 there is a series of photos showing his ductwork.

Cold Air Return?

Greg L
Burning Pea/Buckwheat through an antique stoker [semi retired SSboiler],
Running an Axeman-Anderson 260M boiler burning Pea, About 150-250#per day
Farming, Fixing, Fabricating and Flying: 'spare time' what's that?

WissaMan
Member
Posts: 108
Joined: Thu. Jul. 30, 2009 3:43 pm
Hot Air Coal Stoker Stove: Harman Magnum (MK1) w/ PC control
Coal Size/Type: Rice
Stove/Furnace Make: Harman
Stove/Furnace Model: Magnum
Location: Northeastern PA

Post Sun. Dec. 09, 2012 7:12 am

I had good success running a duct from my Harman in the basement to the two coolest rooms upstairs on the other side of the house. (Actually I built a sleeve around the stove so I have two ducts coming off it). I did have to install two two inline duct fans to help with the flow, however. I also used hard ducting vs. the flexible stuff. I used flexible originally but it gave off a stink when the stove temp got high and the flow wasn't great either. After I upgraded to metal duct the flow was improved. As a bonus I pulled the plastic lining out from the inside of the flexible duct and slid the insulation over top of the metal duct.

The setup works well but you have to keep the room doors cracked and the basement door cracked or else those rooms heat up too much. Also, if you put in duct fans, make sure they are good quality or the heat will kill them. I found that out the hard way after going through three Home Depot pieces of poo. I have Tjernlund duct boosters now and they've been good for a couple years so far. One got a little noisy but has been that was for over a year now and continues to work fine. I suppose you don't have to worry about that aspect if you are using duct fans to pull cold air out of a room.

Lagerlot
New Member
Posts: 1
Joined: Tue. Nov. 27, 2012 4:35 pm
Stove/Furnace Make: Harman Magnum stoker

Post Mon. Dec. 10, 2012 8:40 pm

I have on of these older Magnum Stokers,, I didnt get the deal you did I had to fork over $800 for mine but I know I even got a great deal. I live in a 28 x 52 Ranch style house sitting on a full superior wall basement. When I bought my house it has a wood burner in the basement with a "tent" over the stove that connected to duct work that ran to 4 registers. When I got my magnum I took out the top vent plate and plugged up the front vent. I used a 3ft piece of duct work from the top vent directed up into the tent. In thew top of that tent is a squirel cage fan from an old trailer furnace. I hooked that fan into a 30amp dimmer switch that I placed at the top of the basement steps. I can control how much air comes upstairs. The only change I want to make is I want to put a switch like the switch on a forced air furnace air handler that only turns on when it hits a certain tempature then shuts off on its own, thats just to help with the electric bill. My poor stove has been thru 3 floods with the last one ending with the water at the very top of coal stove. After each flood I dissasembled the fans and wd-40'd the crap out of them. They will get replaced for next year as well as a new hopper ,I had to reinforce that a few days ago. also read somewhere about running the combustion fan all the time for a better burn of the coal which I have done for a short time to see and it does burn better but with everything my poor stove has been thru I don't want to keep that motor running.


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