Piet
New Member
Posts: 23
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Post by Piet on Feb 28, 2021 12:17:29 GMT -8
Hi all. 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) Is there anyone who is great with google sheets or Apple numbers? Of another diagram generator? I have my data a google sheet but I wish the diagram looked more like a Testo's. Here's an editable link to my sheet: docs.google.com/spreadsheets/d/1rSF5hL-CYpth-41ebqQEGF81g5M9e5bM6HRJ9Q86ayw/edit?usp=sharingThanks! Piet
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Post by Vortex on Mar 1, 2021 14:48:50 GMT -8
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.
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Post by Vortex on Mar 4, 2021 1:45:02 GMT -8
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.
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Post by peterberg on Mar 6, 2021 2:32:48 GMT -8
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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Post by anotherluke on Jan 28, 2022 1:01:01 GMT -8
Hi Everyone- I am doing my first test this weekend with my Testo and have some questions. I can't seem to find much good information online. The "sintered filter" on the solid wood adapter is 13 mm. Is this the size hole we need to make in the chimney pipe? It is pretty large- about 1/2". Where do you usually measure from in the chimney pipe Peter? I wish there was a video somewhere online of how to do it but I only saw videos for how to measure a gas furnace. Do you have to calibrate the testo to test for a long burn? How would you recommend adding wood? We are testing an 8" ceramic fiber J core with a mass. Here are pictures of the stove we are planning to test in case you are curious. I saw Peter's responses above and they sound like settings in the "EasyHeat software". What settings do I need to pay attention to for the Testo itself? Thanks in advance!
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Post by Vortex on Jan 28, 2022 2:11:27 GMT -8
Don't use the probe that came with the solid fuel adapter use the normal one, that sintered one blocks up really quick. The normal probe is 8mm so you only need an 8mm hole, but if you have a metal chimney pipe it can create problems with the testo thermocouple signal, as the testo is not earthed, so what I do is drill a 10mm hole and wrap the part of the probe that goes into the chimney in plumbers PTFE tape.
Measure at least 1 meter up the chimney from the stove. The testo should be recalibrated every year, it will automatically zero the CO sensor before starting every reading, and again when you turn it off.
The testo needs to be set to wood as the fuel, which on mine only exists as an option if I set the location to Germany, (you can still have the language as English though). You also need to set the CO Sensor Protection to 5000ppm, so it will automatically dilute the gas if it goes over 5000ppm CO to protect the sensor.
You need to take the probe filter out when the testo is not in use to allow it to dry out, as they get wet with condensate and then the testo cant suck the gas through it very well and will give the error - pump flow rate too low.
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Post by peterberg on Jan 31, 2022 6:54:43 GMT -8
I'll second Trevor in most if not all of this. I would add that the folters of the solid fuel adapter set will get wet as well. I take the first one out after every test run as a routine. Furthermore, when you've taken out the probe filter after the test is done, don't shut down the Testo but let it run until the O² is above 20% and the CO as low as 20 ppm or less. Doing it this way, the CO cell will live quite a bit longer.
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Post by Vortex on Jan 31, 2022 11:22:23 GMT -8
Good point, the older testo I borrowed before didn't auto zero when you turned it off, but the newer one I have now does, the pump keeps running until it zero's the sensor. I found that if I keep the solid fuel adapter hanging vertically (so the inlet filter is at the top), then I dont have to take that filter out between burns as it drains on its own.
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Post by anotherluke on Feb 1, 2022 22:02:22 GMT -8
Thank you Peter and Trevor for the timely responses- very helpful information. I will post our results in a separate thread. Do you have any reading recommendations for interpreting the results? I imagine I can educate myself over time with google searches, though it will take some time. Yesterday I tried to find out what a typical CO ppm reading would be for a modern EPA (US environmental protection agency) approved stove and I didn't find anything initially.
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