Print

[jstange]

I am heating a 2800 sq ft ranch on a basement.  There are 2 furnaces installed both with coils installed in their plenums for the heat.  I also have a plate exchanger for my domestic hot water.

OWB is 65' from the house.  Thermopex is trenched 4' deep to the house and enters through the basement wall, to the hot water heater and on to furnace one then to furnace two before returning.

Total loop is approximately 250' with 130' of that being in the ground.  Only using one outlet on the stove with one pump.

I usually fill the thing 3 times a day during the winter.  Morning before work, Evening as soon as I return from work and Bedtime just as a follow up to be sure there is adequate fuel in there as nobody likes the 3am nostril icicles.

I have read here and other places that people have their top temp set lower than mine.  After reading around, I just questioned if the 180 and 20 degree swing was too much.  Since I intend to burn primarily bituminous coal this season, I know there are a few changes that I need to make, just trying to figure them out in advance.

The whole draft fan setting in the rear is what I think confuses me most.  When I am burning coal, wouldn't I want that wide open so as to stoke the coal with more air flow?  And from what I have seen wouldn't I also absolutely want to change the swing from 20 degrees to far less like closer to 8 degrees so the coal has less of a chance of going out?

I appreciate the help and tips.

-Jeff

[Scott7m]

Burning coal can require a tighter swing of likenyou mentioned, 8-10 degrees

I still can't fathom how your going through so much wood, has it always been that way?

[yoderheating]

 Running the furnace at a higher temperature will use more wood but not a significant amount so long as the furnace and pipe is well insulated. I have been back to do a service call on a furnace I installed and would hear complaints about the furnace burning to much wood. Then I would open the back of the furnace and they had removed some of the insulation. People continue to amaze me.

[jstange]

Scott,

Yes it's always been that way.  Unit is bone stock as it was installed.  Haven't removed any insulation or anything. 

I get the wood trucked in 20 pulp cord at a time, (semi load) and it lasts about a season and a half at best.  Coal is much cheaper, but it's harder to get up here and I don't have the means to haul large quantities.  Can only haul about 1 ton at a time.  Don't have room to get a 24 ton load delivered, but I sure would love it!

I also haven't cleaned the stove other than the inside at the end of the season and obviously the ash pan.  I figured something could be tweaked with the water temps a little and maybe that would help, which is why I posted in here.  Almost everybody I have spoken with thinks that 180 with a 20 degree swing is excessive.  I may drop down to 170 this season and give that a shot.  I probably have about 7-9 cord on the ground and I am hoping to supplement with coal to make it last this winter.

[RSI]

Are you sure you are really getting 20 cords? Unless it is super dry there is no way they can haul that much just because of the weight. Around here 10 is the limit unless they have a light weight trailer they can do 12.
A cord of logs usually weighs 6000+ Lbs when green.

[jstange]

Twenty pulp cord, tandem trailer semi load.  I know it's not a full 20 cord,  but it's common here in Michigan.  8' logs mostly red oak.  They can haul up to 80,000lbs here in Michigan.....

I don't buy fresh cut, I buy 1 year seasoned, although they are still pretty green not being cut or split until I get them.

[Scott7m]

What is the insulation quality of the home? Never heard of anyone using that much with a heatmaster.

180-170, won't make much difference at all, likely won't be able to tell a difference

Are both of those furnaces on the same loop? 

[jstange]

Insulation is fair.  It's a 1970's home, remodeled a couple of times.  I don't have any drafts that I have found in all the years I have been here.

Both furnaces are on the same loop.  It heats the house very well, no complaints there.  Just really surprised how much wood I pump through it.  Unfortunately, I am a considerable amount North from you so it's like comparing apples to oranges.  Or temps are regularly 20 degree's or lower here in the winter.  The burner essentially has zero protection from the elements.  I only have the stubby chimney no added pipe. 

[Scott7m]

Im not comparing my personal stove, just from other customers/folks in your region and further north.

Well, my point about 2 stoves on the same loop was more in concern for your boiler, not heating the home.

If your return water is coming back under 140 your going to greatly shorten the life of the boiler, I would def not run it any lower than 180 in your case

[jstange]

That makes sense.  I will check it when I fire it up in a couple of weeks.  I don't think there is that much heat loss in the return line, however, I honestly have never checked it. 

[HandyMark]

It seems to me it would be worth installing an inline thermometer on the return line at least for your piece of mind. It may help you decide if you can safely drop your operating temperature.

[jstange]

Another great tip!  That's something I will get on immediately.  Until I started reading this forum again a few days ago, I didn't even realize the importance of the return temp.  Will work on getting that installed this weekend and since I have had the parts for 2 years, maybe I will cut in the hot tub at that same time.

[Scott7m]

Your delta T is what your checking.  If the water enters ur first exchanger at 180 and it pulls off 20 degrees, then your delta T is 20.   

So if your next furnace is also on, and it takes 20, your already down to 140.  We dong know if anyone is taking a bath right now either lol

So it's likely your already crossing that danger zone at certain times, it's not good to do that, let's hope your not keeping it below 140 much