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Reviews > Cook and Food Storage Gear > Stoves > Optimus Nova White Gas Stove > Test Report by Ben MansfieldOptimus Nova Plus Stove
Image from Manufacturer's Web site
Backpacking Background Over the past 15 years or so, I've tried to average at least one weekend trip per month year round, primarily in PA, WV, and VA. During the last 8 years, I've tried to take a weeklong trip somewhere further, but still usually in the eastern US. I consider myself a mid-weight hiker, preferring some luxury to an ultralight load. I am also an avid fly fisherman, mountain & road biker, and snow skier, and enjoy sailing my homemade dinghy. Initial Report
Product Description The Optimus Nova+ Stove (hereafter called the Stove or the Nova+) is a multi-fuel backpacking stove capable of burning most commonly available fuels, including white gas (NAPTHA), gasoline, diesel, and kerosene. The stove features a seemingly ingenious shut-off system by which the user simple flips the fuel bottle over, allowing air rather than fuel to flow through the hose. This serves at least two purposes: to put out the stove, and to depressurize the fuel bottle.
Three legs fold out from the sides of the stove to support the Nova+ off the ground. The legs also extend above the burner to serve as pot supports. The metal legs are a fairly heavy gauge metal and their curved shape means that supporting a large pot shouldn't be too much of an issue, provided the stove is on flat ground. The Nova+ does not use a priming cup like many liquid fuel stoves but rather has a small white (for now) absorbent pad located under the burner which serves to hold the fuel used to prime the stove. Hopefully, this feature will mean less spilled fuel and smaller priming flames than many similar stoves. The fuel control knob is an integral part of the fuel hose - there is a green plastic molded grip on the bottle end of the hose, which, when turned, actually rotates the entire hose down to where it connects to the burner. This would not be possible were it not for the quick-connect at the bottle end of the hose, which snaps into the pump assembly and allows the hose to rotate freely. The large grip on the fuel control knob makes me wonder if it can be adjusted while wearing gloves and/or mittens. From initial appearance, it would seem that gloved adjustment would be much more reasonable with this stove than with many others which feature small control knobs. The pump assembly is comprised of several parts. Inside the bottle, there are two tubes - a flimsier plastic tube responsible for transporting fuel out to the connector, and a rigid metal tube which houses the pump mechanism. Visible from outside of the bottle is the pump plunger, used to pump air into the bottle to pressurize the fuel, and the quick-connect to which the stove's fuel hose is connected. The majority of the pump body is metal, which means that although it may weigh a bit more than it would if it were plastic, it is probably a much more robust assembly and therefore less likely to break, leaving the stove inoperable. The main grip which is used to screw the pump assembly in and out has the word "On" molded into one side and "Off" molded into the other. Because of the location and orientation of the flexible fuel tube inside the bottle, fuel is allowed to enter the fuel tube only when in the "On" position - otherwise air is passed out of the bottle, extinguishing the flame and depressurizing the bottle. Although the stove came with an Optimus branded fuel bottle, the pump assembly does fit on many other commonly available fuel bottles thanks to a standard thread pitch and connection diameter. Spare parts included with the Nova+ are extra O-rings, lubricant for the pump and quick connect, and a spare fuel filter. The instruction manual does a good job of describing routine maintenance, as well as troubleshooting, and provides detailed diagrams showing an exploded view of the pump with each serviceable part noted. Basic maintenance is similar to many liquid gas stoves - lubricate the leather pump cup regularly, inspect and replace worn o-rings when they look worn or fuel leakage is experienced, and frequently (every use) clean the nozzle to ensure proper operation. The included maintenance tool serves many purposes. The first thing to note is the magnet attached to one end of the tool. This end, when waved under the stove, serves to wiggle the cleaning needle built into the stove, thereby clearing the fuel nozzle. At first glance, I considered this an interesting way to clean the stove and nothing more. Every other stove I have used requires either complete disassembly or physically shaking the stove to clean the nozzle. Then I realized that this magnet mechanism means that the stove could potentially be cleaned while in use. I'm not sure that I would ever need to do it, but it at least has some coolness factor and gives me something to brag about around the backcountry dinner table. The rest of the tool has a number of different sized wrench and screwdriver components such that any field tightening or disassembly can be handled by remembering to bring along a single tool (which should come along for the ride anyway, since it is necessary for cleaning the fuel nozzle). A basic windscreen is included with the Nova+ that I received, with appropriate cutouts for allowing the fuel hose, etc. to pass under the screen. The thin metal sheet is pliable such that it can be molded to an appropriate shape for the conditions, but rigid enough to hold the shape. Another nice feature of this windscreen (and most stove windscreens, for that matter) is that it can be used for all sorts of other purposes, from a makeshift frying pan to a snow shovel.
The instruction manual, and an included addendum, provide detailed instructions on the operation of the Nova+. I'm really impressed with the quality of the instruction manual. Operation of the stove is spelled out in simple to understand language, and accompanying pictures serve to further clarify each operation. There is also an extensive maintenance and troubleshooting section, with tips for emergency repair and things you can do to use the stove in a pinch. One example is the suggestion that butter can be used to lubricate the pump leather in a pinch, if you happen to be out of other, more suitable, lubricants. Basic operation is similar to most liquid fuel backpacking stoves, and the instructions included with the stove are shown below.
The instructions also point out that the pot supports are designed to handle a pot with a diameter of no more than 11" (28cm) and combined weight of not more than 8.8 lbs (4 kg). This limitation sounds reasonable for most backpacking situations, though I will verify that the stove supports whatever I can think to throw at it that I would also want to carry in my backpack (My cast-iron skillet does not make the cut as something I would like to carry on my back for any period of time). Also included in the package was an addendum to the instructions which describe a potential problem with the stove and the method by which it can be fixed. Basically, if the control valve is closed too tightly while the stove is too hot, it can be nearly impossible to re-open by hand without damaging the hose. The addendum indicates that the metal components of the control valve become somewhat soft when hot and, if closed tightly at this point, can be difficult to loosen once they cool down and harden. The resolution proposed in the addendum is to use the wrench end built into the maintenance tool to loosen the control valve, rather than otherwise twisting the hose, banging it with a rock, or throwing it off a cliff when it can't be opened. The addendum is also careful to point out that following steps 9 and 10, above, will eliminate the problem. For my toothbrush-shortening friends out there, a more detailed breakdown of the weights of each individual component is shown in the table below. Note that while drilling holes in your toothbrush may save a little weight, drilling holes in the Nova+ windscreen will diminish its usefulness (kind of like plucking the bristles out of your toothbrush).
Field ReportField Conditions I have had the good fortune to be able to use this stove on a number of outings, as well as run it through its paces at home in a somewhat more controlled environment. Soon after receiving the stove, I had a chance to test it out in early November in the very colorful Allegheny National Forest. Temperatures during this trip ranged from around 50 F (10 C) down to freezing or a little below at night. Friday and Saturday were those picture perfect days that make most people want to hike forever, Sunday brought in a few clouds and some misty sprinkles of rain. Leaving was made easy on Monday with a little rain (ensuring that once again, all my backpacking gear went home needing to be dried out). I had another chance to try out the stove during a local day hike in the Cuyahoga Valley National Park in early December. I left the house at sunrise, planning to have a hot breakfast and lunch on the trail to further test the stove. Weather during this hike was chilly, around 30 F (-1 C). Field Observations So far, the stove has performed exceptionally well. Setup is quite easy and is accomplished by simply snapping the quick-release on the fuel hose onto the receptacle on the pump, pressurizing the fuel bottle, and priming and lighting the stove according to the manufacturer's instructions. Like any liquid fuel stove, initial priming is required to get the fuel hot enough to vaporize on its way to the burner. Also like many liquid fuel stoves I've used, it's not all that difficult to start quite a blaze when priming by making too much fuel available. The first time I lit this stove, I failed to close the supply valve fully and, upon connecting the hose to the pressurized bottle, managed to let quite a lot of fuel out into the priming pad (and then some). Luckily, I choose to use white gas (or NAPTHA, Coleman Fuel, etc.), which evaporates quickly. I let it sit for a few minutes before lighting, but still had an exciting experience. Many liquid fuel stoves have an issue where some unburned fuel is left in the supply hose and the burner nozzle when the stove is shut off. When this happens, much of it evaporates, leaving behind the impurities and sludge-like residues. Over time (and especially with less pure fuels), this residue will clog the fuel injection nozzle and hinder the performance of the stove. Optimus has designed two potential solutions to this problem. First, their magnetic needle and cleaning tool serves to shake any soot out of the nozzle. Second, the stove is extinguished by flipping the fuel bottle over. This not only depressurizes the bottle making it safer for transport, but also forces the air in the bottle through the hose and out the burner nozzle, effectively blowing any soot or sludge out. The whole process takes a minute or two, depending on how much fuel and how much air was in the bottle when it was flipped over. A subtle hissing sound is made as the air escapes. The stove gets red-hot very quickly, but cools down relatively fast as well. This is important, because breakfast is usually one of the last things I do before leaving camp in the morning. I don't want to wait around for the stove to cool off so I can pack it up. The Nova+ cools in the amount of time it takes me to clean the residual oatmeal out of my pot, and finish stowing gear in my backpack. Packing the stove in the included stuff sack continues to be a bit of a challenge. The bag is just a little too small for its intended use, and though the organizational pockets are an interesting idea, I just can't manage to get everything stowed such that the bag is useful for me. At one point during the Allegheny National Forest trip, the maintenance tool slipped out of the stuff sack and found a new home deep down in a dark and scary corner of my backpack. I've since swapped the manufacturer's stuff sack for a somewhat larger but lighter off-the-shelf version. Temperature control is about as good as can be expected for a liquid fuel stove. Fuel flow to the nozzle is regulated by turning the control knob which is built into the fuel hose. This is a little bit strange - if there is no weight on top of the stove (such as a pot of water, then turning the control knob will also turn the stove on its side if great care is not taken. This can be somewhat minimized by keeping the hose as straight as possible, though this is not always feasible, depending on the surface that the whole thing is sitting on. This really isn't a big deal, since there's nearly always something on top of the stove. The only time it becomes a pain is when I'm trying to let a precise amount of fuel out for priming, when there's nothing sitting on top holding the stove down. The control knob is operable while wearing gloves without much difficulty. The stove simmers well provided the bottle is sufficiently pressurized, and boil times are fast. Lab tests are still ongoing, but early trials show boil times in the sub-three minute range. Full lab results will be posted in the long term report. For the majority of my backcountry meals, I need a stove which will boil water quickly and without much trouble. This stove accomplishes that extremely well. As I continue testing, I will try to expand my meals into things which require more precise temperature control. So far, I'm very pleased with the stove. There's been no maintenance to report, save for the occasional waving of the magic wand under the needle to clean the jet. It packs down small and is in my acceptable weight range for a full-featured stove. It has plenty of neat features to brag about around camp. The stuff sack leaves a little to be desired, but that is easily remedied. My only real complaint at this point is actually only a small one. That is, the gas flow control knob is a little funny. The fact that the whole hose has to turn causes its operation to be a little difficult. The reason is understandable, however, since moving the control close to the bottle means that not only the fuel nozzle gets blown out when the bottle is flipped over, but the hose is drained of its excess fuel as well. Long Term ReportLong Term Observations I put a few more trips worth of meals on the Nova+ since the Field Report. One trip in particular was a three day, two nighter to Zaleski State Forest in southern Ohio in early February. Conditions were cold at night, with temperatures hovering around 18 F (-8 C) at night with some scattered snow and plenty of wind, warming up during the days to around 40 F (4 C), with some sum peeking through and the wind subsiding in the afternoon. Because of the short days, it was generally dark when cooking dinner. I tried to take some artsy pictures of the stove glowing blue against the night sky, but pictures without a flash came out either dark (with a short exposure) or blurry (with a long exposure and no tripod). Pictures with the flash came out fine, except that the flash washed out the flame almost entirely. I'm sure it was the camera's fault, not the photographer's.
As far as durability is concerned, the Nova+ has shown no signs of wear other than the normal coating of soot and field grime. I have not experienced any seizing of the control valve as indicated in the instruction addendum I discussed in the initial report, although I have been careful to allow the stove to cool before closing it entirely. Because of the method of flipping the fuel bottle over to extinguish the flame and depressurize the bottle, this has not caused any issue. The heavy gauge metal used to form the pot supports does take a little longer to cool than other stoves I've used in the past, but this has not been an issue for me. In the field report I noted that I have replaced the included storage bag with an off-the-shelf nylon stuff sack. I have continued this practice, and the nylon stuff sack has not shown any major signs of wear. This is likely due in part to the way that the Nova+ folds up so that the number and size of sharp points protruding from the stove are minimized. Lab Results I hoped to be able to provide a detailed lab report showing average, min, and max boil times for a number of different fuels, with water temperature trended over time. Indeed, this seems like it would be a really good idea. The fact of the matter is that when I performed the tests, the differences were so small that the results are really not interesting. In the end, I tested the stove with white gas (NAPTHA), kerosene, and diesel fuel. My fuel of choice when it mattered (in the field) was the white gas. In general, all the fuels boiled a liter of room temperature water in my stainless steel pot (seen above in the pictures) in about three minutes. Perhaps this is because the heat content for all of these fuels is pretty similar - within a 10% span. The white gas did seem to burn the cleanest; both kerosene and diesel produced a lot of soot and made the stove a little grimy. Also, the three minute time may be a little subjective, since I did not leave the fuel valve open full blast, but rather modulated it so that the flames just licked up over the bottom of the pot. Different pots and/or insulating the system in some way would definitely change the boil times, though I question the magnitude of the improvement. I think the thing to point out regarding lab tests is that in the field, on very cold and windy nights, the stove performed well with the white gas fuel I was using. Of a group of four stoves being used by myself and my companions, the Nova+ was the fastest stove to boil noodles at night or water for coffee and oatmeal in the morning. I guess when it counts, how a stove performs in a lab is really secondary to how it works when you're hungry and tired, or when you need your caffeine fix in the morning. Final Conclusions In general, I'm really pleased with the Optimus Nova+ stove. I'm a water boiler probably 7 times out of 10, so what I look for in a stove is a fast boiling, no nonsense heat maker. The Nova+ provides that, and adds some neat features like the self-depressurizing fuel bottle and magnetic cleaning needle. If I were Optimus of Sweden, I might redesign the storage bag that is included with the stove. It's a good concept, but a little undersized and a little overweight for the function that it performs. There is also some room for improvement in the fuel control. With no weight on the stove (i.e. when lighting), the stove body itself tends to turn when you turn the control valve (which in turn rotates the hose). This is not a major issue for me, and I accept it as the price I have to pay to get the unique shutoff and depressurization system that it provides. The only other improvement I'd suggest would be to change the "On" and "Off" text on the fuel pump which shows me what position the fuel nozzle is in - it's nearly impossible to read in the dark. Maybe just a dot of paint on one side or the other would do the trick. I'll likely raid my wife's nail polish to add a little red dot to the "Off" side. These issues are really just nitpicks, however. The stove is an excellent piece of gear which performs its designed function admirably and without a lot of nonsense. The capability to depressurize the fuel bottle and extinguish the flame by flipping the fuel bottle is really innovative and saves me from either packing a bomb in my backpack or getting my hands and other gear covered with liquid fuel. The moving parts of the stove are solidly built and easy to maintain. In the end, I will continue to use this stove as my primary backpacking stove, which is all that really needs said about the quality and functionality of the Optimus Nova+. In total, I used the stove in the field for 8 days worth or meals, plus a number of meals cooked at home (my wife was not impressed by my jerky stroganoff) and a bunch of lab testing which took place in my garage and my basement.
I would like to thank Optimus of Sweden and BackpackGearTest.org for the opportunity to test this fine stove. Read more reviews of Optimus gear Read more gear reviews by Ben Mansfield Reviews > Cook and Food Storage Gear > Stoves > Optimus Nova White Gas Stove > Test Report by Ben Mansfield | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
