Harman Stoker Coal Usage

My Magnum does hold 100 pounds of coal. I can burn through that in 24 hours if I have it cranked up all the way. Now that is max feed rate without overfiring and, of course, both fans going continuously.

I heat with a Magnum stoker and heat a 1600sqft shop with 14 ft celing and at the coldest days I use about a bag and a half 75lb but most days 25 to 35 degree out side I use a little les than a bag a day (50lb bags)

I did drop the water temp a bit however since I run hot water coils in air handlers for my heat, the warmer temps work better, also I wish there were a way to get higher firing rate (when more than one zone is on) my house has 2 heat zones and 1 zone for DHW (indirect fired tank in a tank arrangement). When more than 1 zone is running the air out of the air handler is rather cool. I could turn up the stroke but am concerned about the pilote mode wasting coal, as it is it seems to have incompelte burning I don't know how to decrease the on time or extend the off time any more than I already have. Does anyone have any ideas about that? Regarding the draft, I never measured it, I do have a barometric damper. I'm trying to borrow a manometer. How do I properly set draft? I know the book says .04 over the fire, is that during Idle or normal firing or both? Your setup with the boiler in the basement is much better as I'm sure I have some heat loss in the 85' run plus all the convection losses from the boiler. I live in Oley PA 19547.

Hello bde

I also run a heat exchange coil as well as two zones of baseboard heat, and you do. I have a valve between the zone valve and the air handler coil and I keep it partially closed to limit the flow, since the capacity of the coil is greater than what the boiler can put out. When fully open, it could pull my boiler water down to 100 deg in a short time. With my boiler, pilot mode will give me about 140 deg water which is enough for DHW, I have the hot water coil in the boiler.

With the standard Harman controls, there is no way to vary the firing rate as it is either pilot mode or full burn. A lot of guys here keep varying the stroke depending on the weather conditions, but it really should be set so that when run continuously, the coal will completely burn before being pushed off the edge of the grates. Once set, you shouldn't have to adjust it again. You can adjust the on time on the control box in one minute increments, making the pilot flame bigger in the cold weather, and cutting it back when it gets warmer.

Its a good idea to get yourself a manometer, they are readily available on Ebay, I have one of the Magnahelic needle type gauges, but the oil filled tube units work well too. The draft is set when the fire is burning well, there is a plug in the door that you can remove to insert a metal tube hooked to your manometer. The air shutter on the pilot blower is used to control the draft over the fire. Your barometric damper is set to limit the draft at the breech which is where the smoke pipe attaches to the stove, it should be .05", with the fire burning well.

Bill A.

Bill
Thanks for your reply. I understand that with the standard Harman controls you can't control firing rate. I've wondered if there is any one out there running some home brew controls that give more flexibility. What is the small unit on extreme right of your DIN rail? Just for a reference point, what is you off and on time set to and about how far closed is the air shutter on the blower? When I look at my ash pan I see a black (or least dark) coal in addition to the ash. There is very little light weight fused together ash. I have the off time to 15 minutes, and on time I've varied from 4 down to 1 minutes and it really doesn't make a lot of difference. The worst is that I've used a lot of coal so far.

When setting the draft do you do this in 2 steps? first thru the door and using the air shutter , then in the chimney pipe by adjusting the baro? or do you need to keep going from one to the other?
Bryan

gambler wrote:Using 40cuft per ton, mathematically a 5 gal bucket will hold 34.43 pounds. But make sure your bucket is 5 gal and not 6 or 7.

or 3 to 4.5 gal buckets also Anthracite coal can be 36 lbs per cubic ft to 59 cubic ft depends on the coal