I have a Testo 301i. It's not the best for stove testing since it does not have have the functionality for recording multiple measurements over time. It can only measure in real time, in the moment. Anyway, I have figured out my own workaround and I am currently testing Matt's Riserless.
I visited Peter a while ago and he showed me how he does his tests. I remember some but not all tips and tricks.
For my tests to be able to compare against the diagrams of Peter, Matt, Trevor, Yassin and maybe some other folks that use Testo's, what are the ground rules?
- Start testing with a cold system, right after lighting the kindling? - Preheating the system first? - When do you stop recording? Is that right after the last flames are gone? - Any tips on EU certification? - What if the stack temps are kind of high? That lowers the EFF% a lot, right? - Seems that low CO does not guarantee higher EFF%? - My O2 so far does not drop beneath 14%. I see far lower numbers with Peter's and Trevor's latest diagrams. Could that indicate too much leaks or too large air intakes? (think I have got my numbers right, though)
Hi Piet, Peter would be better answering these questions as he's the resident testo expert, but I'll give it a go:
Start testing with a cold system, right after lighting the kindling.
I stop recording during the coaling phase, when the afterburner has gone out, which is usually around 14% O2. Peter usually stops around 17% O2, but I close the air down during the second half of the burn, so would be there all night waiting for it to get up to that.
Yes high stack temps lowers the EFF% a lot. If you have no mass, barrel or contraflow system then you could have excellent clean combustion with very low CO. numbers, but the eff. would be crap as most of the heat would be going straight out the chimney.
The free trial testo software uses a spreadsheet of numbers similar to yours to generate the graphs, so you might be able to play around with it and put your numbers into it to generate the graphs.
I should add to that, filters are important when using a testo on a solid fuel fire. I dont know anything about the Testo 301i, does it use the same probe as the 330, with the small round filter in the back of the probe handle? Those filters have to be taken out after each burn and allowed to air dry, as they get saturated with condensate. You also really need the Solid Fuel Adapter kit: www.testo.com/en-UK/solid-fuel-set-probe-shaft-adapter/p/0600-9765 without it you're going to be slowly but surely coating the insides of your testo tubes and sensors with tar.
I'll second Trevor in this, filters and the Solid Fuel Adapter kit.
The way I test is a little bit different, mainly because I want to know what numbers the heater would generate during a certification test. And for years, I was on my own regarding how to do things and what maximum levels to implement.
So start with levels for the diagram: O² 20%, colour green, efficiency 100%, and red, CO 5000 ppm and purple, temperature 500ºC and blue. This pruduces the easiest readable diagrams so far, also nice to compare with all others one would produce.
I always start cold, right after lighting the kindling, but stop when O² is down to 20% and start over immediately again. The hose from probe to analiser is filled with exhaust gases by then. Some values, like efficiency and CO² for example, are calculated and my Testo 330-2 starts to do that at 20% O². So after reaching that threshold the diagram eyes complete and it creates also a repeatable starting point.
End of test is another matter, the rules say it should end at the point where CO² is down to 1/4 of the highest level reached during that burn OR 4% in case the figure is higher than that. The above means the tail-out is shown on the graph, counting the CO produced during that time, and you have to run your heater very hard in order to reach a highest CO² level of more than 16%. O² and CO² levels showing a balancing act: the higher the first, the lower the other and vice versa.
CO numbers on their own doesn't say it all regarding quality of the burn. Since CO is directly measured it's also diluted by all other exhaust gas components. Therefore, the combination of high oxygen and low carbon monoxide levels is misleading to some extend. So for a certification test the CO level is normalised to 13% O². In order to know what this level is and being able to compare: take the average CO number, multiply it by the average O² number and divide the resulting figure by 13. The resulting figure is the average CO level, normalised at 13% O².
Trevor's combination of core size, firewood size, moisture and species, cooking range and chimney height/quality means his burn times are remarkably long. And as long as a large part of the burn time shows good numbers, his cooking range would do very well in a certification test.
But not all heater cores are created equal, smaller ones tend to be more fiddly due to unfavorable wall area to volume proportions. On the other hand, once a small development core is performing really well an upscaled one will do even better, in my experience.
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deadstarsstillburn: The people over there recommended either a 6" batchbox or an 8" J-tube. I don't know what those are but am going to try to figure that out. What I need is a blueprint that I can scale to fit the need for my house. I have something likne 5000 square feet
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deadstarsstillburn: but I do not need to heat all of it by any means. probably only need to heat half of that, maybe less.
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deadstarsstillburn: moreover, the house has 3 storeys (large attic) so I assume if I get very efficient heating on the ground floor, that will go a long way toward heating the upstairs as well, no?
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