Using Smaller Stove Pipe

Does anyone think it would adversely affect the operation of a Harmon Magnum's operation to use an 8-6 in adapter and plum the chimney using 6 in pipe, our old Franco Belge never had a problem with draft the chimney it ties into is 3 and a half stories tall and runs inside the house it will almost suck the flame off a bic lighter when held near the opening . I hate the idea of having to enlarge the hole in the masonry chimney to accommodate the 8 in pipe. Not to mention the 6 in is not as obtrusive looking in the setting the stoves burns .

As long as it produces a good draft it should be fine. I would try to find an offset adater or use it in the vertical plane to avoid ash buildup at its neck. It may reduce the amount settled ash as the gas speed will be higher through the stovepipe.

Hope you are using a barometric damper.

I'm prety sure Matthaus is using 6" for his Magnum in his shop.

Greg L

Hi coalstoves, do you have an old style Harman Magnum Stoker with the flat roof above the fire or one of the new Pent Roof designs? I have seen both styles but both were 6" outlets to the stove pipe, so I'm not sure what you have. As greg stated I am currently using 6" with no issues.

Please post a pic if you can with a tape measure as reference. That way I will be able to see how it relates to my set up with 6" pipe. I'm pretty sure you will have no issue, especially if you start right out with an adapter.

As is always the case draft is the most important, and if you don't have a way to measure it then you will need to check the hopper for moisture. If there is condensation inside the lid you probably do not have enough draft.

Hope this helps.

My chimney opening was only 5" into the side and the stove was 6" outlet, I reduced it down to 5" and it worked fine with our keystoker, had excellent draft being a 3 story brick inside chimney.

Thanks for all the replies, I have never really checked with a tape I always called the big everyday standard stuff 8 in and the smaller one on the Franco Belge 6 maybe I'm actually talkin 6 and 5 , but the general idea carries thru.

I do plan to run a barometric damper got to find a meter to set it up right. This will be my 1st stoker installation and I have been reading past posts here, seems like I will have to be careful of too much draft and its relation to the potential of a hopper fire although from what I see this model Harmon is less prone to that than most other feed designs .

I'll be updating my progress over the next few weeks I tend to do things like this at a leisurely pace . The most fun part will be getting a Coal-Trol and setting it up, I can't wait to see that thing work .

Hi coalstoves Check out e-bay for Draft Rite draft meter as well as Dryer manometer Mark II They are a few on there now pretty good prices the mark II comes in 0 to 3 or 0 - 6 either one will work I think there was 2 Draft Rite meters on two good luck

Well we are all piped in it was a 6-5 adaptation I was talking about.

I put a hand damper (old fashioned type) in the stove pipe, the stove is located in the den on the 1st floor of the home. The main masonry chimney it ties into has a barometric damper at the base in the basement I thought it redundant to install 2 barometric dampers on one stack not to mention syncing them . The one in the basement is calibrated to approx.05 and I plan to monitor the stack temp to get the hand damper dialed in right I'm an old hand at running the Franco Belge types I'm assuming the stoker shouldn't be too difficult of a learning curve .

I’m going to run the Harman control initially, I love the concept of the Coal Trol but cant buy into running the combustion blower continuously well see how it works . I'd appreciate any input on my chimney thoughts and also from some folks who may be happy with the original Harman control along with their favorite settings for the timers.

Probably gonna throw the match to it by mid week, Got to replace a receptacle and add a few screws to the stack fer safety and run the thermostat wire

The correct place for a barometric damper is between the appliance and the chimney. The function of the baro is to control draft or suction in the appliance, not in the chimney. Your location will not provide the draft control needed in your stove's combustion chamber.

I would highly recommend NOT using the hand damper [chimney-choke] with a stoker stove. The combustion blower is forcing air into the stove and through the fire. This sort of 'pressurizes' the stove. If you have any restrictions in the chimney, the combustion gasses [carbon monoxide, sulphur-stink] will be forced out the door seals, and chimney pipe connections.

The CO can kill you or make you very sick!!!

A stoker needs to have a continous slight draw or suction on it in order to keep the fire going, and to pull the gasses up the chimney. With a hand fired stove, there us usually a lot of heat all the time, creating a lot of draft, and this sometimes needs to be 'choked or throttled' with a hand damper.

The idea of a continously running fan is that this provides a better brun for the coal on the grate. Without the constant running fan, the fire is depending on chimney draft to pull enough draft to pull combustion air through the coal bed. When the outside air temps are warm, the chimney draft is reduced so sometimes the fire goes out due to lack of air. The fan running continously prevents the 'out-fire'. Most new stoker styles use a constant running fan.

Make sure you have several CO alarms if you are going to try to use the hand damper, it could be dangerous.

Greg L.

Hi coalstoves, I didn't hear anything in the plans you had for measuring the draft. As Greg stated you need a barometric damper before the chimney, the hand adjustable type that you currently have installed will cause the static pressure in the stove to become positive and should not be used on a stoker stove in my opinion. Not enough draft inside the stove itself means that the hot gases will be pushed through the hopper, thus putting CO in the house.

Based on my experience with the Harman Mag Stokers you will need to install a barometric damper within three feet of the stove and also use a draft gauge to measure the draft in the stove pipe and the stove itself. Per the manual you will need a minimum .04 in the stove and .02 in the stove pipe. The little plate over the intake on the combustion blower is used to adjust the draft in the stove.

On the subject of efficiency, I found that setting the timer up to run the stove more like a hand stoker worked great for keeping the fire at a minimum burn without using the Tstat. I set the stoker stroke for maximum dots and ran the stoker motor for 2 minutes on and 15 minutes off, with the distribution fan off delay set for max so it never shut off. I also plugged the combustion fan into the power outlet near the stove and let it run all the time. Set up like that the stove could run for 4 to 6 days on one hopper of coal and it kept my 800 sq ft poorly insulated garage at 55 to 65* during 30* outside temps. When it got colder outside I would just increase the on time to up to 5 minutes and leave everything else the same. I found that using the Tstat requires some patience to get it set up right, the manual has some good pointers on how to do this.

I am getting ready to try out the Coaltrol on my Harman that I am selling so I will let you know how it works out. I already use one on the Alaska I have in the house and it has performed flawlessly all last year. It keeps the house to within 1* of the set point.

Sorry for the long post, hope this helps.

Coalstoves,

I also have a coal-trol on my Alaska and it too works flawlessly, it saved quite a bit of coal too.

The hand damper on a stoker is like drugs or marriage.."Just Don't Do It!!"

BK

P.S. Is that really a picture of you?

LsFarm wrote:The correct place for a barometric damper is between the appliance and the chimney. The function of the baro is to control draft or suction in the appliance, not in the chimney.

This is true but there is also another consideration; where the the fly ash gets deposited. Fly ash will travel with high velocity flue gases. How much depends on the flue gas velocity. In forced combustion boilers like the A-A or AHS the velocity is considerable. Your chimney should have clean out access at its bottom. If your secondary objective is to get most of your fly ash deposited there you must maintain high flue gas velocity to transport the ash to the chimney. At that point there will be a abrupt change in gas velocity (because of the larger chimney stack size) and the fly ash will fall out and down to the clean out. Placing a barometric damper in the stove pipe will change the flue gas velocity. How it changes where the fly ash travels depends on the specifics of your stove, boiler and flue pipe size. My AHS S130 has a somewhat atypical flue pipe size, 5 inch. This size is more expensive than the common 6 inch. In my first few years of boiler use my convector pipe had a step up size conversion to 6 inch so I could use the cheaper pipe size. At the size adapter the fly ash accumulated due to the reduction in flue gas velocity. In one season the ash would reduce the effective pipe diameter to one half. I now use the more expensive 5 inch all the way to the chimney thimble. Now almost all of the fly ash makes it to the chimney. I do not use a barometric damper for reasons that are unique to my chimney and the AHS boiler. You should think through the specific location of your barometric damper and how it will affect where fly ash gets deposited and how you will clean it out.