Harman Magnum Stoker - Hot Water Coil to Heat Baseboard?

Hi everyone,

I am putting a hot water coil in my Magnum Stoker this year and I wanted to know if the hot water should be enough to heat my house using the existing baseboard heating?

My house is 1100 sq ft. The Stoker is in the basement.

I was going to use a 30-50 plate heat exchanger and run a closed loop between the stoker and the exchanger and run the return line from the boiler through the exchanger in parallel.

Any thoughts on this?

Thanks!
beatle78

Hello Beattle78, welcome to the forum. Look at the size of the water pipe/heat collector that goes into the magnum stoker. Then take a look at an actual hot water boiler meant to heat a house. You can see that there is a huge difference in the surface area that is available to transfer heat to the water.

You can get some heat, but not enough to heat a 1100 sqft house. A few forum members are heating a 100 sqft room or two using a loop in a stove.

Most people use the water loops to heat domestic hot water, where there is a storage tank that sits all night and stove is making heat all night, so the tank can recirculate the water over and over, while the stove is making a lot of heat. This small amount of heat over a long period of time with a storage tank works pretty good.

Baseboard needs to have a lot of hot water to work at all, so I don't believe you will be happy with what you described. There is just not enough heat collector area on the stove loop or coil.

Greg L.

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Thanks, this board seems awesome!

Wow, I'm pretty bummed right now. Thanks for the input.

What about a custom coil with more windings in it? Since coal burns pretty hot, do you think that would create enough heat?

I guess my real problem is that I'm having a hard time keeping the upstairs warm.

Get a coal boiler, problem solved.

coaledsweat wrote:Get a coal boiler, problem solved.

I'd love to, but I just bought the stoker 2 years ago and I'm pretty broke.

Hey Beatle, welcome to the forum!

Since it is in the basement is there any way to transfer the heat and provide a path for the cold air to return to the basement? If so you can easily heat your house with that magnum!

On another note I have an Anthraheat Ministoker 80 (80K BTU boiler) that would be perfect. If you look around you might be able to find one. I am going to use mine to heat my domestic hot water in the summer and will use it this winter to run part of my heating requirements for 2,200 sq. ft of living space.

Last year I heated the entire 2,200 ft with an old school Alaska Kast Console II (a 9 year old stoker stove). The house was 75* F downstairs and 73 to 74* F upstairs all of the NE PA winter! Of course I used a Coal-trol controller from the fine folks at Automation Correct to make sure it was a set and forget operation. The only reason I started looking at boiler acquisition was due to the slight amount of coal dust that my wife did not like to see. Of course she was very happy with the toasty house.

Hi again Beatle, What is your home's configuration? Stove is in the basement, but is the basement ceiling insulated or bare joists? Is there a central stairway for heat to migrate up to the main level or what method are you using to try to get the heat upstairs??

There are many, maybe over a dozen threads on this site about getting the heat from a stove to spread evenly through a house.

I'll give you the 'readers digest' version: Put a cold air return duct from the most distant floor in the upstairs, add a piece of either ductwork or even just 4" clothes dryer vent tubing from the floor vent to the INLET of the distribution fan in the Magnum stoker. This will result in a HUGE increase in heat upstairs.

A ducted furnace in a house has a cold air return duct that returns the cool air from the heated portion of the house, reheats the luke-warm air and sends it back out the hot air ducts. The recirculation is what makes the furnaces somewhat effecient.

With your Magnum pulling cold [~50*f] air off the basement floor and trying to heat it effectively to warm the upstairs is a very ineffecient way to try to heat your house. Provide a closed loop and you won't believe the difference.

I'll try to find some of the threads about this subject from last heating season and post links to them.

Hope this helps. Greg L

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Thanks Greg.

Here's what I've done so far.

There is no insulation in the floor joists. It's a raised ranch and I do have a 1 car garage below the living area(the living area is the coldest part of the house).

Last year I put a 6" to 8" duct coming out of the top of the stoker. I put a booster fan in the 8" register. Then a put a T into 2 6" ducts each with their own booster fan. Each 6" duct is run into our 2 bedrooms. This year, I was thinking of putting in 2 separate line voltage Thermostats for the booster fans to the bedrooms so when the temperature warms up it doesn't get to 90F in the room again (woops)

I leave the door to the basement open and I cut a vent in the hallway floor to allow the colder air to drop back down to the basement.

This worked OK for the bedrooms, but now that my wife is home with a baby, I need to keep the living room/kitchen warm as well.

I like the idea about running a duct from the farthest point down to the intake of the blower fan. I think this might be the missing piece to my problem.

Let me try to put together a floor layout and let you guys debate on the best heating method for my house.

cold wife = oil furnace turned on = BROKE

Hi Beatle, think of each room or heated area as if it were a balloon, you want to fill it with hot air, but you can only fill the balloon so much. Once you provide a vent in the balloon for the air to get out, it lets in more hot air, more out, more hot air in.... and your room gets toasty warm

If your living room is over a garage, is the ceiling in the garage finished [drywall/sheetrock] and insulated?? If not, and the floor joists run the right way, use the area between two joists as the duct, just cover the bottom with sheet metal and insulate it. Or run some insulated vent pipe or hose across the garage ceiling to the far wall/floor of the living room. Hook this vent to the inlet of the distribution fan and you will get lots of heat into the living room.

Greg L

ok, thanks!!

Here is a picture of my house's floor plan. It's a raised ranch and the Stoker is next to the chimney at the bottom of the stairs.

The green vent is where I'm thinking would be best to put in a return vent connected to the Stoker blower motor.

Thought?

THANKS!
beatle78

Hi beatle78, I think that location will work very well.

To give you an idea of how capable the Mag stoker is, Matthaus is using one to heat his shop. This is a concrete floor, 16-18' ceiling, about 25'x45' poorly insulated [at the time] room. At the time I was there [last February during THE storm] the Mag stoker was doing a very good job of keeping up with the weather, even though there were areas of ceiling insulation missing and venting to the outdoors!!

So once you get the air circulation moving the right way, you should be very happy with the heat output from the stoker.

If you hook up your hot water coil to your domestic hot water tank, it will greatly recuce your gas/electric/oil use for hot water, which is usually around $40-60 per month.

Greg L

Hey beatle, a couple additional thought to what Greg said. You may have to block off or partially block off the cold air return shown in blue on the drawing. From what you have shown it appears that the reason the kitchen is cold is because the cold air is taking the path of least resistance and returning to the basement right by the bedroom, setting up a nice little loop that excludes the kitchen and living room.

Also you mentioned a one car garage under the coldest part of the house. If you are still having problems after the cold air return is installed, you could utilize some plastic or a cheap tarp to temporarily isolate the coldest part of the basement. By doing that you would ensure that most of the radiant heat coming off the stove goes up rather into the parking space. One more item that could help, is to insulate the ceiling above the parking space with 1/2" foam board insulation (available in 4X8 sheets), that might help the floor to stay a little warmer. Especially if the floor joists are running the right way as Greg suggested, this would allow the heat from the stove to travel into the insulated space.

Good luck with the science project, there are some of us on the forum that like nothing better than a good science project to hold our interest.

thanks guys.

My garage has an insulated/finished ceiling. I am going to run some insulated duct for the return.

Good point about the current cold air return. If I just shut the vent should that be good enough or should I stick some insulation in it to really make sure no air gets through?

What type of heat exchanger should I use for the hot water tank? I think I'll start another post on this so this thread doesn't get too far out of context

Just closing it should be sufficient, you might even find that partially open is the best. A little trial and error will show what produces the warmest wife and baby!

My house stays toasty on both floors because the upper floor is open on both ends, which sets up a natural convection loop of hot air rising and pushing the cold air back down to the stove on the first floor.

Have fun, now all we need is a little cold weather. We are having 80* days here in Carbondale!

That's awesome that you have 2 open ends!!! Sounds like with a little more work, I'll have a decent loop setup for my house!!

I know I have plenty of heat b/c the basement is probably 90-100+ F in the winter when the stove is running full time