Found this nice chart that had max capacity for many, many stoves. So... when filling a tank, is the MAX fill 80% of max capacity? (for some reason had that number in my head).. or does it vary by tank design or fuel type? In particular, I am wondering about the Svea 123 (max capacity - 4.5 oz) and the Optimus 111T - (17oz). Thank you
Something like that, I think. Space needs to be left. I usually figure 75%, very roughly. I pour in some fuel, look through the fill aperture, wiggle the stove so I can see the fuel surface, and apply dead reckoning.
@NW Lady Tank capacity is fraught as sometimes the listing is the volume of the tank, and sometimes the amount of fuel recommended to go into a tank (which will be a smaller volume than the capacity of the tank). The rough rule is fill the tank to 3/4 to 7/8 full; or to 1/2" to 1/4" below the bottom of the filler tube. Somewhere in my shed I have a list of approximate volumes for various stoves. When it stops blowing a gale I'll go out and check what I wrote for the 111 and 123 - of course it will be metric in my case. Cheers Tony
Thank you, Ed and Tony. Sounds like 75% of capacity is a good target. I think the list I saw was on the Fogas or the Base Camp website.
I have not encountered a situation where the pressure relief on a stove is activated but the fill level followed correctly will proactively help prevent it. Here's an example of a simple check on fill levels.
Generally if they dont have a fill line ie msr etc then fill the stove level and thats it. even tilting to fill then turning back level to check can result in an overfilled stove
Personally I fill up to the opening of the filler tube without tilting the tank. I do not find it so important how much it is in the tank exept that it must have a gas pillow on top of the fuel. Just now I unload a railway waggon with 60 ton of liquid SO2 to a tank that have a V85% as specification so I would say 85% should be OK. Michael
Hi, this post gives a bit of background for the need of airspace in the fuel tank of pressurised fuel stoves: https://classiccampstoves.com/threa...ler-patent-primus-took-out.30659/#post-311218
Hi, Like Tony, "somewhere" I have a home made chart of capacities for my Svea 123, Optimus 8R, recently added Primus 51, and a couple of Coleman products. I used the bottom of the filler neck for "max capacity" and then calculated 75% of that as "usable" capacity for the Swedish stoves. As I recall, the Svea numbers came out about 150ml and 110ml. If I fill at home before a trip, I'll measure. In the field, I just kinda eyeball it. BTW, that 75% figure works nicely for my wicked "storm" lanterns, too--a couple of the tiny ones (Feuerhand 175 Super Baby) will blow themselves out as they warm up if overfilled. All my Coleman stuff just gets fuel to the bottom of the filler neck (level) as there is built in air space in those tanks so they can be pressurized properly. Rick C
Rick C, you hit that spot on! Coleman stoves and lanterns need the air space to generate a fuel/air mixture for lighting and preheating. Now, having said this, I've also found out if I overfill the tank to maximum capacity on my 502 stove, I can light it "the UK way", using the dished area in the center of the burner as a preheat cup, and start with NO pressure, and valve wide open, and after a minute or two of preheating, give it a few pumps, and off it goes! This lets me tilt the tank when filling it, and take advantage of the full capacity of the tank to start with, and I have to carry much less fuel as such. Murph
My original Svea 123 instructions—there are copies of Svea 123 instructions in the Stove Reference Library—gave ⅔ of the tank as the fill level. I filled the tank to the bottom of the cap opening, emptied the fuel into a measuring cup—6 ounces was the result. I fill with four ounces of fuel; the stove runs well—47 years old with original jet. The fuel cap should be opened and closed each time before the stove is lit to equalize pressure in the tank; otherwise, starting it will be challenging. Overfilling the stove also will create starting difficulty because there isn't sufficient area to build effective pressure. Just empty some out then try again. Coleman Fuel or its equivalent is my choice to use. Hardware store vm&p naphtha also works.
