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[Loglivin2]

Hello everybody. I know when I was shopping for a boiler I would have loved to seen side by side comparisons of various boilers operating. Unfortunately it's not like buying a car. You have to go with what you learn from your given sources and make the best decision for your circumstances. That being said I have an idea where members could compare their stoves and share what we all learn. If we have several interests in this idea I will put my Heatmaster C-250 up for the test. Here is the idea, let me know what you all think or be thinking of a better way to do a side by side test. In my system I can run hot water only and bypass my 2 water/air heat exchangers. What I propose is set boiler to 170 on 180 off. Measure how much water we can get from a given hot water faucet. Maybe the one that is closest to heat exchanger. Shoot for a water flow rate of 5 gallons per minute. Weigh out 150lbs of good seasoned split hardwood. Be nice if we could measure moisture content before starting test. Let the boilers have just enough coals to start the fresh wood burning. Start with the stove at 175, turn on the hot water to the 5 gallon a minute rate , add the wood and let it burn till you can no longer maintain 170 at the aquastat. I have no idea how long that would be but at the end of the test you could make a claim that your boiler would heat "x" gallons of water on 150 lbs of hardwood. Probably sounds like a lot of trouble but at the end of the day we'd all know which boilers perform at what level. I would wait till the temps get up a little more so I wouldn't need the home heat to do the test. I would also measure cold water in and out temps and give all my setup specs so we could discuss all variables. Like I said this is just an idea I'm throwing out there. This forum has been wonderful for me and I'd like to give back where I can. I'm not a boiler expert but I could do a simple test.  Let me know what your thoughts are and we will go from there. Thanks

[fryedaddy]

I'm not sure this is the test you would want to compare stoves with.

If we were to compare and base it on the amount of hot water produced before the aquastat
kick on someone with a larger water jacket would win (in most cases).

I think you should measure the exact amount of water then figure how much wood it takes to
get from a base temperature to set point.

[Loglivin2]

I didn't mean test til stat kicks on. I meant test til wood is gone and won't get the boiler back to 180.
We'd have to compare apples to apples. I have a 125 gallon water capacity. Wouldn't learn much comparing to somebody that has 500 gallons I wouldn't think. Thanks for the input. I think if we put our heads together we could come up with some type of general comparison test.

[woodman]

I think it is very difficult to get a true comparison simply because there are so many variables to everyone's set up. If you want to compare boilers I think you need to isolate it. My thought would be to bypass all heat exchangers and just loop the water back to the boiler. Let the temp drop to 150 then empty the firebox completely. Weigh 10 pounds of wood at a known moisture content then burn it and see what the water temp raised to.

[Loglivin2]

That would be a good simple test. I guess I thinking more of trying to simulate a 12 hr burn but I like simple! It would definitely be a good starter test. Thanks for the input.

[mlappin]

A few other variables as well, everybody would have to be using a flat plate HX for the DHW, my sidearm won’t keep up after so much water is used.

Another variable, some have town water even though they have a boiler while others are using well water, temperatures of the cold water coming out of the tap is also different.

[woodman]

So I decided to run the test. It was dead calm today and temps were in the mid thirtys. I let the boiler run out of fuel and cleaned out all ashes. I isolated the boiler from the heat exchangers and just looped it back to itself. My underground line is 140 feet of thermopex. My boiler holds 150 gallons and I figured 10 gallons in the line. Water temp was stable at 124 when I started. I weighed out 17 pounds of well seasoned wood. I figure 20% mc. So my temp got up to 150. So 160 gallons weigh 1334# *26 is 34,684 btu,s to the water. I used 5800 btu's per pound * 17 is 98,600 potential btu's. Divide 34,684 by 98,600 is 35%. Disappointing, yes. Surprising, no. That's pretty close to what I had always guessed but I was hoping for at least 40%. So this was simple to do and I think fairly accurate, it was a great idea by loglivin2 and I hope we get some more numbers to compare.

[Loglivin2]

Awesome!!!  I can't say I totally followed the math, might have to get you to break that down a little more. So was all your wood gone or was there still fuel left. One reason I wanted to use the heated domestic water variable is I would like to see the difference in heat capture while idling. I know there are a ton of variables but I can't help but think somebody out there has my setup almost exactly with a different brand of boiler. I did have a chance to think on it a little more and taking input from other members I think starting with 40 lbs of wood and the boiler sitting at 150 would be great. Let it heat to 180 then kick on domestic hot water at 5 gal per minute and see how long the boiler would maintain the 170-180 range before the fuel is gone. I may try something like this and try to get the test to take no longer than 1 hour with the boiler cycling at least 5-6 times. I may make a video when I do and share with the group so everybody can witness my systems variable. As far as comparing models I'd like to compare mine to a P&M BL 28-40 or a BL 3444 simply because that was my second choice at the time I purchased. Thanks again for every members input on this topic. Any and all ideas and comments welcome. Maybe there is an engineer out there that can come up with something better to compare.

[mlappin]

I did something similar earlier this year, I weighed out 300lbs of wood and started my old boiler cold and actually tracked stack temps as well.

300lbs of wood took 700 gallons of water from 58 to 156 before temperatures started to drop back off even though I had coals left it wasn’t enough to add any BTU’s to the water.

Stack temps were well over 700 degrees at times.

I loosely ran the same test later with the G400, didn’t weigh the wood out but guesstimated on the same volume.

Started out at 62 degrees, brought all seven hundred gallons up to 180 and had wood left to still burn in the morning that I never added to the firebox. Stack temps never got over 350.

Running the test again in a gasser would be a little more difficult as even when they are tested for EPA approval they are allowed to start out with 50lbs of coals. From my experience takes awhile to get the coal bed build.

Maybe if I do this again I’ll buy fifty pounds of charcoal and get it going in a wheelbarrow or something and only use 250lbs of wood.