Use of draft dampener

I have a MBW coal/wood fired boiler. I have done several searches for Menomonee Boiler Works and can't find anything about my boiler. It appears to be a suplimental heat source meant to be used alongside of an oil or gas fired boiler.

This boiler is well made and has a fire brick lined chamber with a grate and ash pan. It has a combustion blower and electronic controls for high and low limits.

Is anyone familiar with this boiler??

My main question is about the use of a dampener in the chimney. I have had numerous wood stoves in the past an have always had a fully open chimney with no draft dampener, and controled the heat and burn rate with incoming air or inlet draft.

I have read several posts on this forum stating to turn the draft way down in the chimney once the coal fire is burning well. Is this correct?? can I install a draft dampener and mostly close it off ? If so will this slow down the burn rate of the coal?? And increase the amount of heat the water jacket can pick up from the burning coal or wood??

I'm having trouble getting the circulating water to get above 140* even with a roaring fire using wood, coal or a combination. The temperature of the chimney pipe is around 450*.

I'm getting only about 3-4 hours burn time from a five gallon bucket of coal, maybe about 7 gallons sometimes. The coal I'm using is hard coal and is a mixture of rice up to nut. I can get the whole bed of coals burning, about 5" deep, 18" wide and 24" long. Even with this very hot fire I can't get the water up to 180* like I would like.

Will a dampener in the chimney 'keep the heat in' and allow more heat to transfer to the water jacket and raise the water temperature??

If I close a dampener in the chimney and the combustion blower is forcing air through the bed of coal, will there be enough venting of gases? The boiler is outside the house, in a stand-alone shed with a Masonry chimney that is 18' tall and draws well.

I just seems wrong to restrict the outging gases from the fire chamber, but this may be just left-over ideas from airtight wood stoves.

Any help and suggestions would be appreciated.

Thanks, Greg

Since I recieved no replies or help on the subject of using a flue damper, I decided to just go ahead and install one and try it.

The results are that the heat in the fire box is not as high with the reduced draft from the mostly damped flue. But the fuel burns longer.

It is very hard to be specific, or quantatative because the boiler is constantly sheding heat into the house hot water heat system, and the amount of heat shed varies with the weather and demand from the house domestic hot water system.

In general, with the damper mostly closed, the water temperature is about 5-10* cooler, but a firebox full of wood and or coal burns about 20-30% longer. In my boiler this is about an additional hour or so before more fuel is needed.

Hope this helps anyone else with similar questions.

LsFarm

LFarm wrote:Since I recieved no replies or help on the subject of using a flue damper, I decided to just go ahead and install one and try it.

The results are that the heat in the fire box is not as high with the reduced draft from the mostly damped flue. But the fuel burns longer.

It is very hard to be specific, or quantatative because the boiler is constantly sheding heat into the house hot water heat system, and the amount of heat shed varies with the weather and demand from the house domestic hot water system.

In general, with the damper mostly closed, the water temperature is about 5-10* cooler, but a firebox full of wood and or coal burns about 20-30% longer. In my boiler this is about an additional hour or so before more fuel is needed.

Hope this helps anyone else with similar questions.

LsFarm

Hello,

My father has a Menomonee boiler. What model do you have? I know they made different models. What color is it, my father's is green and shaped like a vertically standing chunk of cross country gas line pipe. I also saw one that is not shaped like it was made from a chunk of pipe. Are you in Michigan? I think Menomonees were built in the upper peninsula of Michigan, but as you know have been out of business for many years. My father has burned wood exclusively except for when he had about three or four pails of coal from the basement of an old apartment house that he bought. He just wanted to use up the coal. Dad has always had a damper between the top of his boiler and the brick chimney going up through the middle of his house. Builds a fire then shuts it down most of the way.

MarcC

i know i my coal stove if i close the dampner i get less heat from the stove but it burns much longer.If i leave the dampner fully open the the stove will put out around 650 to 700 degrees of surface heat but shorter burn times.The more draft u have the hotter the stove gets i found this out thru trial and error.Also with the dampner closed i average around 220 flue temp at the base of my 40 foot ss liner and the stove temp is around 450. If i leave the dampner fully open my flue temp is around 300 which i can live with cause of the extra heat output of the stove.

Hello MarcC. Thanks for the reply. My MBW boiler is an upright oval shape with a flat bottomed V at the bottom The Flat bottom is the grate with the sides of the V the firebrick sides of the firebox.

The unit has sheet metal sides and top that are painted green. It is about 30" wide, 50" tall and around 50" deep. The firebox door is 12" wide, 14" tall with a hinged flap over the top 4" of the opening.

The boiler is very well made, but is just too small and the firebox to water surface area too small.

I am building myself a new, much larger boiler using a similar firebox design, but with much larger dimensions, mostly in depth and heigth so I can put in longer logs, as well as a higher stack of logs. I plan to still use coal to augment the long winter nights.

The current produced wood fired boilers use either a 'corrugated' roof to the combustion chamber of a bank of cross-tubes from side to side to increase the surface area for better heat conduction. I'm planning on using cross tubes and hot gas baffles to get more heat out of the fire than I'm getting now. It is frustrating to get up in the morning and see a nice 18"x 24" bed of red glowing coals with blue flames dancing above and only have 100* water in the water jacket.

I've looked at and conversed with the owners of big wood boilers that have the cross tubes and they are seeing 150* water with a bed of coals after an all night burn. The size of the combustion chamber compared to the size of their bed of coals would make me believe that the water should be cooler than it is, so it must be the increased surface area absorbing the heat. This 150*+ is what I need to heat my farmhouse and keep my propane supplier from affording another florida vacation home.

Thanks again for the info on the boiler, Take care, Greg

LFarm wrote:Hello MarcC. Thanks for the reply. My MBW boiler is an upright oval shape with a flat bottomed V at the bottom The Flat bottom is the grate with the sides of the V the firebrick sides of the firebox.

The unit has sheet metal sides and top that are painted green. It is about 30" wide, 50" tall and around 50" deep. The firebox door is 12" wide, 14" tall with a hinged flap over the top 4" of the opening.

The boiler is very well made, but is just too small and the firebox to water surface area too small.

I am building myself a new, much larger boiler using a similar firebox design, but with much larger dimensions, mostly in depth and heigth so I can put in longer logs, as well as a higher stack of logs. I plan to still use coal to augment the long winter nights.

The current produced wood fired boilers use either a 'corrugated' roof to the combustion chamber of a bank of cross-tubes from side to side to increase the surface area for better heat conduction. I'm planning on using cross tubes and hot gas baffles to get more heat out of the fire than I'm getting now. It is frustrating to get up in the morning and see a nice 18"x 24" bed of red glowing coals with blue flames dancing above and only have 100* water in the water jacket.

I've looked at and conversed with the owners of big wood boilers that have the cross tubes and they are seeing 150* water with a bed of coals after an all night burn. The size of the combustion chamber compared to the size of their bed of coals would make me believe that the water should be cooler than it is, so it must be the increased surface area absorbing the heat. This 150*+ is what I need to heat my farmhouse and keep my propane supplier from affording another florida vacation home.

Thanks again for the info on the boiler, Take care, Greg

Hello Greg,

Thanks for the information. You sound like an engineer. I typed "menomonee boiler" into google yesterday because my father's menomonee boiler has been wonderful for him, and I'd like to purchase one. He purchased his boiler in approximately 1980 and has been using it as a primary source of heat since then about 50 miles north of Grand Rapids, Michigan. If I had to describe the overall unit in one word, the word would be "elegant". Dad has been heating his 28X48 ranch style house with no problem since that time. The boiler is in the basement which is also 28X48. The hot water as you know has a natural tendency to rise so it flows naturally through the hot water tubing in the house until the thermostat calls for the pump to turn on. Dad purchased it at the same time that another guy purchased his. The other guy got the next larger size, which took slightly bigger pieces. Maybe sometime I can send you a pic of it. I would like to purchase a used one, if I can find one, the next size larger would probably be perfect.

It seems like he had to replace the motor on the pump one time. Possibly the gasket on the door, and he had to add a bead of weld on the handle it seems a number of years ago where the cam action engages to hold the door closed. Other than that, it has been great. Last night I stopped at his house and looked at it. The temperature was 135 degrees on the gage on top of the boiler. He doesn't worry a bit about what the gage says, just builds a fire as needed. When it goes out, builds another. He has a schedule to go up and shear the creosote down the chimney, because he is deathly afraid of a chimney fire. He was on a volunteer fire department for a number of years and witnessed the effects of those. I'm in graduate school now and can't reply to this for at least two more weeks. Good luck. I'd like to take a pic though and send it. Sorry about the terrible rambling here, but just jotting some thoughts down as they come.

MarcC

Marc C when you can, either PM me or reply here and we'll exchange emails or phone numbers.
I may sell my boiler after the new one is built and proven, not sure yet.
I may use it for another outbuilding.
I am in Michigan, just south of Flint.

Take care, Greg