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[schoppy]

Got another question for you knowledgeable guys. If a boiler (any brand or model) is rated at X max output or X BTU output for 8 hours does that assume the firebox is full to accommodate that BTU output?

I have the G400 now so does it's rated output assume a full firebox to achieve it's rated spec sheet data? I would guess this is also with a good hardwood for the firewood?

Not sure how they arrive at their numbers, anyone know?

[shepherd boy]

The G series was independent Lab tested for white tag label, so those results are what the lab observed under test.I believe the C series was tested on Heatmaster's own lab. A lot of older heatmaster and other brands just pull a number out of the air that makes no sense. One brand says that an indoor furnace in a house should run only half the time so a outdoor furnace rated at 200,000 btu should be able to cary 100,000 btu continous and still be rated at 200,000 btu. There was some thought that epa was going to put a min of 350,000 btu on commercial units and they would be exempt, so they spec'd all their furnaces over that figure. If it's got a white tag lab test believe it. Otherwise it's anybodies guess.

[slimjim]

The lab puts a load on the boiler using plate exchangers, temp gauges and flow meters, the first test they run allows you to ready the unit then a full throttle burn test is run, this then gives you the max BTU for the unit.

[shepherd boy]

Heatmaster C series are tested with coal (they are a coal unit) and were putting more than their max rating. But then quality of coal does vary.

 Yes Slim, the question was: how is it tested? You can get a vary good test with a flow meter, flat plates and temp gauges, that's how it's done. The variable is fuel: moisture, and Quality etc.

[hondaracer2oo4]

Schoppy, here is the G400 test from the lab. http://www.heatmasterss.com/wp-content/uploads/2015/05/101237993MID-002.2-G400-EPA-report.pdf


You can read about how they tested etc. Always a full firebox, just put different BTU loads on the boiler with heat exchanger for the entire duration of the test and see how long the boiler can last putting that output out.

[mlappin]

Also need to assume on the G series that when the tests were done the damper was at 100%.

Thru careful loading of mine, I can get it to run at 60% for 5-6 hours at a time with the water hanging around 176-178, fill the firebox and it will cycle on and off.

[schoppy]

Thanks guys, Honda the report was helpful and answered my main question of how much wood they were talking about for the ratings. 250 lbs. of red oak on average for each test run at about 20 to 23 percent moisture content. Just for grins and giggles I am going to weigh out 250 lbs. of my red oak to see how big of a pile it is.

I think they may have a typo on one of the tests as the numbers on test 4 show a BTU output of 2.47 times that of the other tests.

I can't really tell if the air damper was set at a specific setting or (more likely) the loads were regulated a specific rates. Either way, mlappin you are right that the G400 is a big unit.

[Jared43758]

Wouldn't the outside air temp effect these tests? If it's 50 outside my stove might only run 5 minutes.  If it's zero then I may run 20-30 minutes. The very cold air getting sucked into the firebox to burn the fire cools the box down where the stove has to burn a lot longer.   What's the intake air temp during these tests?    If there was a way to have ducted mild temp atleast air going in the intake of your stove I assume that would make a stove many times more efficient. Now where to get the warm air is a good question.  Stealing from your home is a bad idea for obvious reasons. Running pipe deep into the earth in a U shape for intake air prolly would work but the expense may be great.    Anyone got any great ideas??

[mlappin]

The G series uses preheated combustion air so outside temperatures aren’t as much a concern. It flows up from the bottom, across the back up to the duct along the water jacket, to the front, then thru the damper.

[Jared43758]

That blower sucks that air in pretty fast. If it's 0 or -10 outside that air isn't warm coming in.

[mlappin]

That blower sucks that air in pretty fast. If it's 0 or -10 outside that air isn't warm coming in.

Yeah, but you have the entire back of a G to heat the air with.

[Jared43758]

Can't believe that matter if there was twenty foot. Air doesn't absorb heat like water.  And the speed of the constant air flow is consistently cooling the stove down if 0 degree air is coming in.  And compared to 50 degree air there has to be a major different

[mlappin]

Well maybe we will see this winter, supposed to be another booger like 2012-13.

Maybe I can find a place to place a pyrometer without actually having to open the front cover.

And while air doesn’t absorb heat like water, it’s also easier to heat than water since it can’t absorb as much.

[Jared43758]

Doesn't your stove run a lot longer to get back up to temp when it's 0 compared to 45-50? Even with no load(no furnace running, plate exchanger etc)

[mlappin]

Doesn't your stove run a lot longer to get back up to temp when it's 0 compared to 45-50? Even with no load(no furnace running, plate exchanger etc)

Can’t say I’ve never had it under no load. I have 450 gallons of thermal storage in the shop, even if the house is calling for none, the shop will always pull some heat out of the G400 unless of course all the shop water is also 180 which only happens if I’m running the waste oil boiler as well which is where I get the extra 450 gallons.