boiling water in winter with canister stove

[egilbe]

https://www.outdoorgearlab.com/revi...g/backpacking-stove/msr-whisperlite-universal

Is what I use. I've never converted it to white gas. Works just fine in deep cold.

 

[sierra]

And don’t forget that eye dropper!

I always had one in my kit.

 

[ChrisB]

BethW... So how did it go???

Did you survive and thrive below Zero?

 

[DayTrip]

I always had one in my kit.

I think I missed this idea in my initial stove inquiry last year. So the eye dropper is for what? You put a few drops of fuel on the burner so you don't have to open the valve and use too much fuel and make an impromptu facial hair removal? That is a great idea. Nice consistent way to get the amount right every time (give or take for the temps). I'll have to track down an eye dropper from something to use. Does the fuel do anything to degrade the plastic over time?

 

[DayTrip]

I prefer to prime mine with the throttle set at 1/2 open. This creates more flare-up than I would tolerate inside of a vestibule, but it prevents over-pressurizing and it eliminates the need of catching the prime at just the right time. Also, this priming approach means I can start the stove with a fire-steel 99% of the time (just start the priming bowl and the burner will self light), which has benefits in the cold winter of avoiding dealing with finicky lighters.

Do you mean the gas valve is ON when you say half open, as in the fuel supply valve? You don't add some fuel and close to burn off? I'd like to be able to light mine with a fire steel for the exact reason you mentioned and find lighters can be really irritating to use in cold weather and I like the safety margin of having a steel which will throw sparks in just about any weather. I actually use the strike plate of my magnesium starter with old metal cutting hack saw blades and it throws a ton of sparks with very little effort, even better than a fire steel (at least the ones I've used). Appreciate it if you could expand on this thought.

 

[JoshandBaron]

I think I missed this idea in my initial stove inquiry last year. So the eye dropper is for what? You put a few drops of fuel on the burner so you don't have to open the valve and use too much fuel and make an impromptu facial hair removal? That is a great idea. Nice consistent way to get the amount right every time (give or take for the temps). I'll have to track down an eye dropper from something to use. Does the fuel do anything to degrade the plastic over time?

Some folks put alcohol in the dropper instead of WG. It's a bit less volatile but does the job the same as long as you keep it warm.

 

[JoshandBaron]

Do you mean the gas valve is ON when you say half open, as in the fuel supply valve? You don't add some fuel and close to burn off? I'd like to be able to light mine with a fire steel for the exact reason you mentioned and find lighters can be really irritating to use in cold weather and I like the safety margin of having a steel which will throw sparks in just about any weather. I actually use the strike plate of my magnesium starter with old metal cutting hack saw blades and it throws a ton of sparks with very little effort, even better than a fire steel (at least the ones I've used). Appreciate it if you could expand on this thought.

The SVEA works a little differently than a WhisperLite. It's essentially a white gas cannister stove. The unit is totally self-contained and self pressurizing. The heat from the burner keeps the fuel tank under it pressurized. To prime you dump some gas/alcohol in/on the prime cup built onto the tank and you can just throw a spark at the unit. As the prime burns it warms up the tank and pressure starts to build. When pressure builds enough that the wick brings fuel to the half open burner it will light itself off the prime flame and prevent overpressurizing the tank. In very cold temps you'll often need to double prime to get enough pressure for operation. Some people use carbon felt on the tank to avoid having to double prime. I've never used his method, I usually keep the valve closed while pressure is building, but after sending my Svea across camp from overpriming I might give it a shot.

 

[hikerbrian]

Hey JoshandBaron, what's your take on the Svea's performance in windy conditions, and is there anything special you do in those circumstances? I was out on a pretty chilly and windy night a couple years ago at Kinsman (IIRC), and one guy had a Svea. It was taking forever for him to melt snow because he didn't want to use a windscreen for fear of overpressuring. Can you use a windscreen? Is there any indication you're getting close to overpressuring before boom!? Can you judge with experience based on what the flame looks and sounds like? I'm not expecting to switch from my Reactor anytime soon, but I like to help people troubleshoot when I can.

 

[JoshandBaron]

Hey JoshandBaron, what's your take on the Svea's performance in windy conditions, and is there anything special you do in those circumstances? I was out on a pretty chilly and windy night a couple years ago at Kinsman (IIRC), and one guy had a Svea. It was taking forever for him to melt snow because he didn't want to use a windscreen for fear of overpressuring. Can you use a windscreen? Is there any indication you're getting close to overpressuring before boom!? Can you judge with experience based on what the flame looks and sounds like? I'm not expecting to switch from my Reactor anytime soon, but I like to help people troubleshoot when I can.

I almost always use one of those tall folding windscreens with it. I find it helps with both priming and boiling efficiency. The Svea is a pretty vocal little guy and it's very apparent when the pressure is up. Sounds like a B52 taking off and will kind of spit a bit. I wouldn't be worried about blowing one up in cold or windy conditions for melting snow, just remove the wind screen and let nature cool it off a bit. When I blew mine it was in calm, warmer conditions and from closing the valve while it was overpressurized instead of letting it burn off. The bottom of the tank popped out which probably prevented the stove from exploding. I don't think pressure would ever build enough in the stove to actually explode with the valve fully open but I'm not sure I want to test that theory.

 

[DayTrip]

The SVEA works a little differently than a WhisperLite. It's essentially a white gas cannister stove. The unit is totally self-contained and self pressurizing. The heat from the burner keeps the fuel tank under it pressurized. To prime you dump some gas/alcohol in/on the prime cup built onto the tank and you can just throw a spark at the unit. As the prime burns it warms up the tank and pressure starts to build. When pressure builds enough that the wick brings fuel to the half open burner it will light itself off the prime flame and prevent overpressurizing the tank. In very cold temps you'll often need to double prime to get enough pressure for operation. Some people use carbon felt on the tank to avoid having to double prime. I've never used his method, I usually keep the valve closed while pressure is building, but after sending my Svea across camp from overpriming I might give it a shot.

OK. I did not realize that. I thought he was talking about a liquid fuel stove.

 

[dave.m]

Do you mean the gas valve is ON when you say half open, as in the fuel supply valve? You don't add some fuel and close to burn off? I'd like to be able to light mine with a fire steel for the exact reason you mentioned and find lighters can be really irritating to use in cold weather and I like the safety margin of having a steel which will throw sparks in just about any weather. I actually use the strike plate of my magnesium starter with old metal cutting hack saw blades and it throws a ton of sparks with very little effort, even better than a fire steel (at least the ones I've used). Appreciate it if you could expand on this thought.

DayTrip,

To reiterate, I'm talking about my Svea 123R (it has a cleaning needle), not an MSR. I believe the same basic tricks might be applied to an MSR stove but am not sure.

First, priming material. I prefer priming materials that are stable relative to movement. That is, I want the ability to pick the stove up while the priming fuel is lit with confidence that the fuel will stay put, so I can put the windscreen on easily. Without having carbon felt on the vaporizer stem, the best option I've found is fire starter paste, such as Mautz Fire Ribbon or Colghan's paste. It's sooty, but it stays put.

With the carbon felt/wire wrap on the stem (as shown in the YouTube I referred to), you can use either alcohol or white gas to prime. The felt acts as a wick that holds the liquid fuel in place sort of like a candle or better, like a wick fed lantern. Once the priming fuel is lit (and sloppy excess has burned off), you can pick the stove up and even hold it sideways and the priming flame will stay put. Very handy.

For winter, I like either fire paste or white gas, as they put out more BTUs and of the 2, I prefer white gas because it lights more easily with a fire steel.

Next, adding the priming fuel... I use a Trangia fuel bottle, which IMO is the best bottle I've found to pair with the Svea. The nozzle makes filling the Svea a snap and better yet, it makes it very easy to add just a splash of white gas in the priming bowl/felt. No need to carry a dropper or straw.

So to start things off, I fill the cool stove with the Trangia bottle and then replace the filler cap on the stove. Then I put a splash of gas on the felt/in the bowl.

Next, I use a fire steel to light the priming fuel. As you might expect, the vapor of the white gas takes a spark exceptionally well. I wouldn't put my face too close.

I often get sloppy and overfill the priming bowl, so I let any of the excess burn off before putting the windscreen on. But once it's settled down, I pick up the stove and put the windscreen on. It took me a bit to trust that the carbon felt works as a wick and really prevents white gas from moving around.

As for lighting the burner, this is a trick I picked up from one of the BernieDawg videos and wish I new this decades ago. It works when you have a really strong priming flame burning under the burner head.

The classic way to start the Svea is to let the priming fuel burn to heat the stove up while the valve is fully closed. If you time things perfectly, the priming flame will die down and the stove will be perfectly preheated so that when you open the valve, you'll get a strong hiss of vaporized gas. The trick here is to light your lighter or match and to hold it over the burner BEFORE you open the valve, otherwise the hiss of the gas can blow out the match as you move towards the head. Needless to say, this approach isn't ideal for using a fire steel as the you'll need to open the stove and then grab your fire steel and by that time, you may of lost the prime.

The BernieDawg trick avoids this. The Svea 123R has a priming needle and if you open the valve too far, the needle will actually rise up and extinguish the flame. On my stove, the range of motion of the valve key is less than 1/2 of a turn from fully closed to the cleaning needle being fully up. It's pretty pretty easy to turn a closed valve to where it stops as the cleaning needle comes up and thus it's super easy to find a valve setting roughly between the 2 extreme positions.

Getting back to the stove, which has the windscreen on it and a robust priming flame fueled by white gas, this is what I do next. I put the valve control key on the stove (never leave it on!!!). I turn it counter-clockwise to till it stops to find the fully "open"/cleaning needle up position. And then I turn the key back clockwise to a position 1/2 way between the 2 extremes. Then, I sit back and wait.

The nice thing about the classic approach of priming a Svea is that with practice, you can light the stove with no flare up. So, if you're brave and it's your buddy's tent, you can light the stove in a vestibule with low over head clearance without burning a hole in the fly. Usually.

The start the stove with the valve open approach I'm describing invites and embraces flare up as a feature, not a bug. Don't use this approach under a vestibule and don't hover over the stove with a GoreTex jacket. I use a flourless MegaMid in the winter and a flourless tarp/tent in the summer, so this isn't a concern for me. Anyway, here's what happens...

In fairly short order, the priming flame will heat the stove enough to drive out liquid white gas, which will immediately catch fire from the robust priming fire. The priming fire needs to be tall enough to reach the burner head. The fuel coming from the burner will flare up and surge, creating dramatic waves of yellow flame (and soot) but it won't be uncontrolled. It also won't be long lived. Soon, often quite soon, the burner flame will keep trying to pop to vaporized blue flame and at this stage, there will be a fight for O2 between the 2 fires. The priming fire will eat all of the local O2 for a second and the burner fire will turn big and yellow and then the burner fire will snap back to small and blue and this dance will continue as the stove comes up to full heat and, more importantly, the priming fire runs out of fuel. At that point, the stove will be running with a small, hot blue flame.

Summarizing: Add white gas to the felt, light the felt with a fire steel, put the windscreen on, open the throttle valve to 1/2 open and then do another camp chore while the stove comes up to heat and a full flame (with no further need to light anything).

All this noted, there are times when I do need to light the stove in a fully primed state. So, I do, in fact, practice lighting a vaporized Svea with a fire steel and it is very possible. Slow is smooth and smooth is fast. And toss good sparks. Lastly on this point, I do carry a back up Bic lighter or better, a Zippo with a Thunderbird refillable butane insert.

Sorry for the length but it was a boring meeting I was listening to and hopefully something here helps.

 

[dave.m]

I almost always use one of those tall folding windscreens with it. I find it helps with both priming and boiling efficiency. The Svea is a pretty vocal little guy and it's very apparent when the pressure is up. Sounds like a B52 taking off and will kind of spit a bit. I wouldn't be worried about blowing one up in cold or windy conditions for melting snow, just remove the wind screen and let nature cool it off a bit. When I blew mine it was in calm, warmer conditions and from closing the valve while it was overpressurized instead of letting it burn off. The bottom of the tank popped out which probably prevented the stove from exploding. I don't think pressure would ever build enough in the stove to actually explode with the valve fully open but I'm not sure I want to test that theory.

Josh,

If your Svea popped like that, a couple of things to think about.

First, I would either replace the Pip and service the safety release valve in the filler cap, or I would replace the filler cap entirely. The FettleBox and A&H Enterprises are my sources for both. The safety release valve in the filler cap is by far the most important part of the Svea and I'm surprised you didn't get the traditional 4 foot flame. I've over heated my Svea once and got it and it was spectacular in a horrible way. But it was controlled. That your stove popped might indicate that your valve is jammed in some way.

Second, I would do a dunk test to verify that the pop out, pop back in cycle didn't create any cracks along the bottom of the tank. Empty stove and remove the burner head and windscreen. Put the empty stove and cap in the freezer for an hour. Then fill a bucket or large pan with hot but not scalding water (you'll need to put your hand in it safely). Once the empty stove is at freezing temperature, put the cap on it snugly and then dunk it in the hot water. The hot water will heat up the air in the tank which will expand and if you find any escaping bubbles, your stove has a leak. I check the jet (indicates a worn valve), the valve nut (indicates a worn valve bushing), the safety valve on the filler cap (worn pip or pip spring), the base of the filler cap (worn washer), the threads at the burner/tank junction (worn or crossed threads), and OF CONCERN FOR YOU I THINK the junction of the tank floor and tank sides along the bottom of the stove.

Lastly, to avoid this problem in the future, I shut my 123R off by opening it fully till the cleaning needle comes up to kill the flame. Then I return the stove to half open for a bit to bleed off pressure before closing the valve fully.

Hope this helps.

 

[JoshandBaron]

Josh,

If your Svea popped like that, a couple of things to think about.

First, I would either replace the Pip and service the safety release valve in the filler cap, or I would replace the filler cap entirely. The FettleBox and A&H Enterprises are my sources for both. The safety release valve in the filler cap is by far the most important part of the Svea and I'm surprised you didn't get the traditional 4 foot flame. I've over heated my Svea once and got it and it was spectacular in a horrible way. But it was controlled. That your stove popped might indicate that your valve is jammed in some way.

Second, I would do a dunk test to verify that the pop out, pop back in cycle didn't create any cracks along the bottom of the tank. Empty stove and remove the burner head and windscreen. Put the empty stove and cap in the freezer for an hour. Then fill a bucket or large pan with hot but not scalding water (you'll need to put your hand in it safely). Once the empty stove is at freezing temperature, put the cap on it snugly and then dunk it in the hot water. The hot water will heat up the air in the tank which will expand and if you find any escaping bubbles, your stove has a leak. I check the jet (indicates a worn valve), the valve nut (indicates a worn valve bushing), the safety valve on the filler cap (worn pip or pip spring), the base of the filler cap (worn washer), the threads at the burner/tank junction (worn or crossed threads), and OF CONCERN FOR YOU I THINK the junction of the tank floor and tank sides along the bottom of the stove.

Lastly, to avoid this problem in the future, I shut my 123R off by opening it fully till the cleaning needle comes up to kill the flame. Then I return the stove to half open for a bit to bleed off pressure before closing the valve fully.

Hope this helps.

Thanks for the tips. I'll do some tests tonight. I used it last weekend for the first time since the incident and it performed as it always has but I don't want any surprises. I have all the replacement parts on hand. This stove was manufactured in the 70's and is still running original everything except the washer on the fill cap.


As to the gas blowing out your flame when you light it using the traditional method, if you light from under the burner you don't have that issue. I usually do everything with the windscreen/pot stand on and put my lighter through the largest slot on the screen.

 

[Andrew]

Love all this talk about the Svea 123 as it's a beauty and a classic. When I started backpacking my friend and mentor had a 123, I wanted to be cooler and got an MSR multifuel, but could never match the convenience and boiling speed of my friends stove. After many other stoves I went and bought myself a 123 within the past 10 or 12 years - although with my wife's gear and a kid in the mix now, our tame adventures bring along the Pocket Rocket.

I used to love that purr you would hear from the Svea 123 early in the morning quiet of the forest.
It used to be quite the pyro performance at meal time when most everyone had liquid stoves.

 

[dave.m]

Hey JoshandBaron, what's your take on the Svea's performance in windy conditions, and is there anything special you do in those circumstances? I was out on a pretty chilly and windy night a couple years ago at Kinsman (IIRC), and one guy had a Svea. It was taking forever for him to melt snow because he didn't want to use a windscreen for fear of overpressuring. Can you use a windscreen? Is there any indication you're getting close to overpressuring before boom!? Can you judge with experience based on what the flame looks and sounds like? I'm not expecting to switch from my Reactor anytime soon, but I like to help people troubleshoot when I can.

Heat and windscreens produce some interesting trade-offs in deep cold. The issues are that both fuels and fittings and seals behave differently at different temperatures.

With traditional canister stoves (burner head attached to the bottle) and traditional (non-MSR-style) white gas stoves (like the Svea, the older Optimus "box" stoves, and the Coleman Peak 1s) the fuel tank is attached to the burner head and generally you have to manage the heat of the burner and the tank concurrently to manage performance. Open flame alcohol stoves aren't fundamentally different in terms of striking a balance of retaining heat but not too much. It's possible to over heat an alcohol stove to a dangerous level to where a slight tap will cause the flaming fuel to "boil" over. For all of the stoves in cold weather, you want to the stove to be warm, but not hot.

For all of these stoves, you want an insulated base under the stove to keep conductive heat loss to the ground/snow to ruin performance and to prevent a warm stove from melting into the snow pack. I use a thin circular bit of plywood. Some folks add insulation.

You also need some form of windscreen around the stove to control convective heat loss to the wind. These also tend to reflect heat back to the stove. Without the windscreen, you'll get terrible performance. Use it wrongly and you can overheat the stove to dramatic consequences.

My advice to any stove owner with any stove is to make coffee/tea with it daily for month in your back yard so that priming and performance cues become second nature to the point that you can operate the stove when you're totally hammered with exhaustion and cold. They're like stick shifts in a car. You need to use them to get good with them. And to the point of managing heat, you need to be able to learn when a stove is starting to over heat.

I don't recommend courting disaster but I'm glad I've crashed my stoves a few time because I've learned some of the warning signs. I've managed to over-heat my Trangias 3 or 4 times - each time producing either a dramatic pond of flame or a scorched picnic table. The heat output rockets and it gets noticeably loud and at that point, it can super nova. I've over-heated my Svea once and it produced a 4 foot flame out of the safety valve. I was able to shut the stove down safely (albeit gingerly).

Specifically with the Svea, the performance of the stove gets better as the stove heats up. You can learn the sound of the Svea much like you can learn the sound of a car motor. There is a fluttering quality to the roar of a Svea when it is cool and that disappears into higher frequency and louder roar as it gets hot. You can also see the heat in how red first the burner plate and second the burner head gets. If the burner head is red, the stove is hot. I also will touch the stove tank occasionally to get a feel for how hot it is.

In terms of practicalities, I use an MSR style aluminum windscreen with my Svea. It's taller than than the stove - enough to stop convective/wind loss at the burner head - which is important. I've cut 1" tall, triangular holes along the bottom edge. In most cases, that allows enough air in, even on the windward side. In really bad wind, I flip it upside down to eliminate wind at the very base. I always put the valve control on the leeward side. When the stove is cold, I'll keep the windscreen closer and as the stove warms up, I'll open the windscreen more on the leeward side to bleed off heat.

I'm sure at this point, the above sounds like an add for using an MSR-style white gas stove to keep the fuel tank away from the burner head but in deep cold, that has its own issues. The problem is that the fittings and seals in the pump assembly don't work well in deep cold. It's the o-ring problem on the Challenger problem. Luckily, the Optimus Nova seems to have avoided this problem and MSR has finally come out with a different pump for deep cold use. But I've seen several MSRs catch fire at the fuel tank in deep winter.

Bottom line for me is that if I test the stove at home to ensure the seals are in good shape and if I use a windscreen responsibly, the Svea has proven itself as 100% reliable in the winter for me and to be a great performer.

A bit of bragging... We did a trip near Oceola years ago and were walking out to the road but were out of water with no streams nearby so we melted snow. A buddy had an XGK and I had my Svea. No contest, right? Actually, I kept up with and even did better than the XGK. Yes, I had to refuel the stove, but the XGK needed to be pumped regularly and that made the stove unstable when doing the pumping routine in the snow.

Hope something here helps



EDITED TO ADD: One must also consider the size of a pot one is using. Wider pots effectively act as windscreens from the top and reflect more heat downwards which can cause a stove to overheat faster. The pot and windscreen need to be considered to be 2 parts of a larger windscreen/heat-reflector system.

 

[TEO]

. . . and MSR has finally come out with a different pump for deep cold use.

Thank you, Dave M. for the heads up! If I were to go back 25 years ago or so and had known about the Svea 123R, maybe I'd have gotten it, but my Whisperlite International has served me well and if I don't have to buy another stove, I'd rather not. (I use a beer can stove for summer solo overnights.)

For my fellow MSR users, here's their "Arctic Fuel Pump."

P.s. Dave, do you have a new Pinner site?

 

[hikerbrian]

Great info Dave.m. I thought it would be the case that one could understand what the stove was doing based on how it sounded. I imagine even without experience, a careful observer could have some inclination that the stove might be overheating, especially if one touched the fuel reservoir from time to time, as you've suggested.

I had the o-rings on my Whisperlite fail many years ago. It was very cold that night, and I noticed a strong fuel smell right after I pressurized the bottle. Fortunately, I had an extra pump with me, and I guess the seals were new enough that they held up just fine. It always seemed to me the plastic and rubber parts on the pump were the most vulnerable to failure, so I always brought an extra. Short money and weight penalty for considerable insurance, and I was happy to have it that night. Like you with your Svea, I'm pretty sure I could prime and start that Whisperlite with my eyes closed - pressurize the tank, attach the burner, open the valve (it squeaks just a little when fuel is coming out). Close, light. Prime is complete when you hear a little bit of hissing. Open fuel valve a hair and then close immediately (i.e. burp it lightly, a couple times if needed) until there's no yellow flame, just a small blue flame, then open all the way. Never had a flair up doing it this way. The burping is key. I started that stove in my vestibule many, many times.

All this said, I don't see myself switching away from my Reactor probably ever. I've only had a single, easily fixed problem with that stove (the dancing blue flame issue), even in deep cold and wind. I trust that stove probably even more than my Whisperlite.

 

[DayTrip]

Heat and windscreens produce some interesting trade-offs in deep cold. The issues are that both fuels and fittings and seals behave differently at different temperatures.

With traditional canister stoves (burner head attached to the bottle) and traditional (non-MSR-style) white gas stoves (like the Svea, the older Optimus "box" stoves, and the Coleman Peak 1s) the fuel tank is attached to the burner head and generally you have to manage the heat of the burner and the tank concurrently to manage performance. Open flame alcohol stoves aren't fundamentally different in terms of striking a balance of retaining heat but not too much. It's possible to over heat an alcohol stove to a dangerous level to where a slight tap will cause the flaming fuel to "boil" over. For all of the stoves in cold weather, you want to the stove to be warm, but not hot.

For all of these stoves, you want an insulated base under the stove to keep conductive heat loss to the ground/snow to ruin performance and to prevent a warm stove from melting into the snow pack. I use a thin circular bit of plywood. Some folks add insulation.

You also need some form of windscreen around the stove to control convective heat loss to the wind. These also tend to reflect heat back to the stove. Without the windscreen, you'll get terrible performance. Use it wrongly and you can overheat the stove to dramatic consequences.

My advice to any stove owner with any stove is to make coffee/tea with it daily for month in your back yard so that priming and performance cues become second nature to the point that you can operate the stove when you're totally hammered with exhaustion and cold. They're like stick shifts in a car. You need to use them to get good with them. And to the point of managing heat, you need to be able to learn when a stove is starting to over heat.

I don't recommend courting disaster but I'm glad I've crashed my stoves a few time because I've learned some of the warning signs. I've managed to over-heat my Trangias 3 or 4 times - each time producing either a dramatic pond of flame or a scorched picnic table. The heat output rockets and it gets noticeably loud and at that point, it can super nova. I've over-heated my Svea once and it produced a 4 foot flame out of the safety valve. I was able to shut the stove down safely (albeit gingerly).

Specifically with the Svea, the performance of the stove gets better as the stove heats up. You can learn the sound of the Svea much like you can learn the sound of a car motor. There is a fluttering quality to the roar of a Svea when it is cool and that disappears into higher frequency and louder roar as it gets hot. You can also see the heat in how red first the burner plate and second the burner head gets. If the burner head is red, the stove is hot. I also will touch the stove tank occasionally to get a feel for how hot it is.

In terms of practicalities, I use an MSR style aluminum windscreen with my Svea. It's taller than than the stove - enough to stop convective/wind loss at the burner head - which is important. I've cut 1" tall, triangular holes along the bottom edge. In most cases, that allows enough air in, even on the windward side. In really bad wind, I flip it upside down to eliminate wind at the very base. I always put the valve control on the leeward side. When the stove is cold, I'll keep the windscreen closer and as the stove warms up, I'll open the windscreen more on the leeward side to bleed off heat.

I'm sure at this point, the above sounds like an add for using an MSR-style white gas stove to keep the fuel tank away from the burner head but in deep cold, that has its own issues. The problem is that the fittings and seals in the pump assembly don't work well in deep cold. It's the o-ring problem on the Challenger problem. Luckily, the Optimus Nova seems to have avoided this problem and MSR has finally come out with a different pump for deep cold use. But I've seen several MSRs catch fire at the fuel tank in deep winter.

Bottom line for me is that if I test the stove at home to ensure the seals are in good shape and if I use a windscreen responsibly, the Svea has proven itself as 100% reliable in the winter for me and to be a great performer.

A bit of bragging... We did a trip near Oceola years ago and were walking out to the road but were out of water with no streams nearby so we melted snow. A buddy had an XGK and I had my Svea. No contest, right? Actually, I kept up with and even did better than the XGK. Yes, I had to refuel the stove, but the XGK needed to be pumped regularly and that made the stove unstable when doing the pumping routine in the snow.

Hope something here helps



EDITED TO ADD: One must also consider the size of a pot one is using. Wider pots effectively act as windscreens from the top and reflect more heat downwards which can cause a stove to overheat faster. The pot and windscreen need to be considered to be 2 parts of a larger windscreen/heat-reflector system.

Tremendous details as usual. Thanks for the very well thought out replies.

 

[DayTrip]

. It always seemed to me the plastic and rubber parts on the pump were the most vulnerable to failure, so I always brought an extra.

When I ultimately bought my stove two years ago I went with an Optimus over MSR because a lot of the parts on the MSR that were plastic were brass/metal on the Optimus. My thought was durability would be worth a small weight penalty but does this provide any advantage in relation to extreme cold and the fit of threads and o-rings or is the issue entirely the rubber properties of the rings and gaskets? Probably never be an issue for me but I was curious.

 

[hikerbrian]

When I ultimately bought my stove two years ago I went with an Optimus over MSR because a lot of the parts on the MSR that were plastic were brass/metal on the Optimus. My thought was durability would be worth a small weight penalty but does this provide any advantage in relation to extreme cold and the fit of threads and o-rings or is the issue entirely the rubber properties of the rings and gaskets? Probably never be an issue for me but I was curious.

I'm not sure, Daytrip. I will say the night the o-rings failed on my Whisperlite was nowhere near the coldest night I'd been out with the stove. I think the o-rings were just old. I'm not sure the cold had much to do with it, but again, I'm not sure. If you can keep the o-rings on the Optimus lubed, that probably helps. The issue with the plastic is separate. I had chunks missing from my oldest MSR pump assembly, but it still worked fine (until the o-rings incident). But I still thought it prudent to bring and extra pump in a hard case because the pump assembly felt more fragile than I would have liked.

My Reactor (FWIW) has very, very few moving parts. Part of the reason I trust the stove. I bring an extra burner assembly anyway and always also pack one extra 8 oz fuel canister. Again, short weight for a good insurance plan.