50/93 Suggestions for Burning Optimization

I'm new to coal burning (5 weeks in) Everything seems to be going really good hwoever the more I read on this site the more I think maybe I'm not getting everything out of the system. I'm heating 2500-3000 Sf home to 69-71 degrees and basically buring 80-90lbs per day. Seems like people are using alot less (half or more) coal than me. I shake the stove down twice a day prior to filling the Hopper back up an there is some unburnt coal in the ashpan but most seems to be burnt out. Does this seem like to much coal? I have the ash door dampers half to 3/4 open and the back damper just open enough to draft. The baro damper works when the wind is blowing but not much other than that. If I close the dampers more I don't get enough burn/heat to keep the house up to temp. I feel like without a manual damper, like I'm used to with the wood stove, I may be loosing heat up the stack. Don't get me wrong the stove is putting out the heat but maybe I could be getting more and burning less with some changes. Any advice is welcome.

Sounds right to me. I'll use 80 or 90lbs when it is really cold.

Handfired stoves from what I see having used 2 different Harman's have a sweet spot. When you exceed this sweet spot, you will burn more coal & loose more heat up the flue. Heat delivered per lb. efficiency drops. When you settle in at the sweet spot, you can wrap your hands around the flue pipe. Warm but will not burn your skin. But you may need to burn warmer to get the necessary heat into your home. This is okay will not damage anything.
From what I see, an accurate flue temp at or below 225F puts you in the sweet spot I am referring to. Sort like a simmer. I can only burn like this when ambient temps are low 30's toward 40F. Otherwise I need to crank her up to keep warm.

Sounds like normal usage to me. It is cold this year. I normally use less than 50lbs a day, well we have had two weeks of nothing over 30 this past month, plus it has been really windy here. So now I am burning 75-80lbs a day. If your baro is set properly you are getting all the heat you can. A MPD may improve efficency some but I can't really say how much.

Have a great day, Eric

Coalfire wrote:If your baro is set properly you are getting all the heat you can.

The daily usage sounds pretty good if you are providing all the heat for that big a house. So there probably is not anything too wrong with your setup. Ideally you could use a manometer to set your baro accurately, and that might give you more heat per pound. At that high a burn rate, in this cold weather, I would expect to see the baro open more often than just when the wind blows. If the baro has a scale for adjusting, experiment with setting it a bit lower -- of course I don't know what it is set to now. But if you can set a lower draft and the coal still burns well, the draft will be sucking less heat up the chimney.

Sounds about right. That's what I use to go through with my 50-93. USE TOO??? Let me re-frase my answer. I do go through that amount during this cold wheather. I'm going through that same amount with my Kaa-2 boiler, as I did with my 50-93.

33Canuck wrote: Everything seems to be going really good hwoever the more I read on this site the more I think maybe I'm not getting everything out of the system. I'm heating 2500-3000 Sf home to 69-71 degrees and basically buring 80-90lbs per day. Seems like people are using alot less (half or more) coal than me.

Hi 33Canuck, What is the average temp of your 50/93 stove & flue stack?
We are heating a 3,000 sq/ft 200+ year old farm house to the same temp that you are heating (70*F+-).
Over the last three weeks we have burned 500 pounds a week/ or just over 71# a day. The stove temps are in the 425-450*F range just over the loading door. The stack temp before the Baro is 170*F and after the baro it is 130*F. The barometric damper is set @ -.05 WC. with a Dwyer MK II manometer.
Each house and stove will burn a bit different but I will bet your stove temp is over 500*F.

Eddie

PC 12-47E wrote:... stove temps are in the 425-450*F range just over the loading door. The stack temp before the Baro is 170*F ...

Wow! That's a low stack temp for such a high stove temp. This is with your Jotul 507? Gotta get me one of those ....

rberq wrote:

PC 12-47E wrote:... stove temps are in the 425-450*F range just over the loading door. The stack temp before the Baro is 170*F ...

Wow! That's a low stack temp for such a high stove temp. This is with your Jotul 507? Gotta get me one of those ....

Hi Bob, That is with all three burning....It looks like 24# a day for each Jotul 507.
If I find another 507 I will let you know...I think the cast iron may help a bit over steel.

Eddie

This will be my first full year with the 50-93 but I'm using about the same as you heating 2400 sq ft from uninsulated basement to 72 / 73*upstairs. Stove temp is 500* with a stack temp of 200* the thing I don't understand is why are you using the ash door slide and not setting the bimetal thermostat on the rear of the stove? keeping the slide just cracked a hair and letting the thermostat open and close the flap on the back, might save you some coal when it is windy due to the fact the wind will suck the flap closed on strong gusts and then it will reopen as the draft eases off. I have a MPD and a Baro in my pipe but on top of this hill I live on I have to cap the baro to keep the heat in the house. I did a test with the MPD closed and the baro open (and set with a manometer to .05) for two weeks, then I did another two weeks with the Mpd closed and the baro capped and my coal usage was exactly the same both weeks. The thing that did stand out was that with the baro open I lost 2* upstairs, both tests the stove was 500*. The Mpd I'm using has the holes in it like most and with the manometer it is only good for 1/2 a point, if I open the Mpd my .05 will go to .05 1/2. So with the Hitzer if you use the flapper on the back the stove it takes care of its own draft the way it likes it to maintain the temp you set it at.

Without knowing what your outside temps have been and how well your house is insulated there is no way anyone can say how well you are doing. My guess is that you might be able to do better.

The purpose of the baro is to provide a constant draft. The wind changes the draft so you see the baro moving around to compensate for the changes as the wind changes. When there's little to no wind it will stay steady and allow just enough air in to reduce the draft to what you have it set for. The stove manufacturer should have provided a spec for what they consider to be the best setting. They usually know what is best for their stove. If you wanted to experiment, going to a higher draft would draw less warm air from the room. A better solution, if you feel the baro is drawing too much warm air from the room, is to run a pipe from the inlet of the baro to outside.

It's best to avoid the manual damper due to the risks of carbon monoxied. Wood stoves don't use baros because they increase the risks of chimney fires. With the baro you don't lose as much heat as you might think because the air flow through the stove is being restricted. As Eddie pointed out, he is seeing a 40 degree drop in temp across the baro. A better way of reducing heat loss, if you have the room, is to use a longer and/or larger diameter pipe. The longer pipe gives the gasses more surface area and time due to the distance traveled to give up it's heat. The larger diameter provides more surface area and slows the flow. The limit here is when you remove so much heat that you can't get enough draft. Here is a link to a pic of my stove in another post.

This Time of Year and Fumes...

I had started with the stove right by the chimney and a short 4" pipe going straight up. The temp at the chimney was about the same as at the outlet of the stove. Going to the longer 4" pipe shown helped quite a bit. The next year I went to a 5" pipe of the same length. With this set-up the temp at the chimney is about half what it is at the stove, which is already fairly low because of the heat exchanger built into the stove. Right now, with the temp outside at about 20* the pipe is 300 at the outlet and 140 at the chimney. When it was in the 40s and 50s last spring I ran for days with the pipe under 100* at the chimney. It doesn't show here but there is a baro on another opening to the same flue. As you reduce the temp it will admit less air to maintain the same draft.

One trick I have found is to close off the air inlet so that the fire drops down below what you need to heat the house, and then open it a little at a time till you get it set right. You end up with a lower air setting that way than if you turn it down a little at a time. When you turn it down you are starting with lots of air flowing through the stove, carrying heat up the stack. When turning it up the stove will reach the same temp before you reach the same air flow rate, so less goes up the stack.

If you can work it into your schedual it might help to shake down three times a day rather than two. The trick here is to not shake it down as much. By not shaking as much you may be able to avoid having any unburnt coal in the pan. When doing this you need to shake more often because you wont get as long a burn time. If you are only getting a little unburnt coal coming down it may not be worth the extra time involved for an additional shake down.

Bruce

Sooo canuck whats up--I love it when fellow coal burners come up with situations & alot of FORUM members try to share thier experience & knowledge & then they disappear Oh well, seems to be something they teach in school or somewhere Hey, thanx for listening, I feel better Oh my God, I've become a grumpy old man

Still here freddy just trying different things to optimize but seems like everything is working pretty good based on he feedback I got. I have been playing with shakedown times and intensities to try to get the coal to burn off 100% and not have some unburnt stuff in the ashpan.

fastcat I need to have the from slide draft open in conjunction with the rear auto thermostat in order to keep a good hot burn across the entire bed of coal and keep the temps up. If I only use the back the fire shut down way to low to keep the temps up on the second floor.

outstanding,then keep the ash door vent cracked I keep saying this--your stove is like a good woman,find out what she likes & stick with it usually if I'm getting to much unburnt little pieces in the ash pan--I'm shaking a little to much--just a solid red line all across the pan & stop----sounds like your doing good canuck PS--I always have a little unburnt in the pan--key words-- VERY LITTLE nature of the coal

Yes with the front slide just open a little. Oliver Powers set me up with that idea when I got started last year also. My oops saying close it , but it also sounded like you were using it to regulate your fire 100% rather that using the rear flapper to do that job and stableizing it with the front slide. Glad to hear you are getting the thing under control. And as everybody says each stove has its own personallity .