Is the SVEA 123 still a viable stove option for winter?
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Zorg Zumo
(BurnNotice) - F
Re: Is the SVEA 123 still a viable stove option for winter? on 05/16/2013 15:37:50 MDT Print View

Well I've got one on order. It is going to seem strange with a little pulsing blow torch after so many years of nothing but Alcohol stoves.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Does automotive fuel clog it? on 05/16/2013 16:19:14 MDT Print View

Hi Zorg

Sorry, but no.

Liquid fuel may come out of the jet when it is starting up (priming), but then the stove gets hot and it's all vapor coming out.
The pulsing is oscillation in the pipe leading to the jet. The wick should reduce that a bit.
And the fuel does not get 'cooked' at all - just vaporised.
Seems there may be some myths running around out there. Happens.

Cheers

Dan S
(nunyabiznes32)

Locale: Pacific NW
Re: Is the SVEA 123 still a viable stove option for winter? on 05/16/2013 16:20:20 MDT Print View

Used a SVEA 123 for years, in all conditions. Never failed. Its biggest plus is that it doesn't require any pumping, like other white gas stoves. Everyone's already stated the specifications and there are trade offs for the convenience (BTU and weight). I've switched to a Jetboil for winter outings, but I still have fond memories of being in the mountains with the sweet sound this blast furnace makes.

Edited by nunyabiznes32 on 05/16/2013 16:23:29 MDT.

Zorg Zumo
(BurnNotice) - F
Re: Re: Re: Re: Does automotive fuel clog it? on 05/16/2013 17:41:57 MDT Print View

Thanks for the explanation :)

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Re: Re: Re: Does automotive fuel clog it? on 05/16/2013 18:11:09 MDT Print View

Yes. There are additives (octane boosters, oxygenaters, detergents) in Auto Gas that will eventually plug things up with "varnish." WG doesn't have any of that stuff in it. Using WG after autogas will clean it out, but it may take a full tank run through it to work at 100% again.

If you are using Auto Gas for long term, add a bit (~10%) methanol, ethanol, or isopropynol to help clean out stuff. Even the 123R version can get badly gummed up after a few tankfulls of regular auto-fuel. Using the alcohol in the autogas will insure that deposits are washed out as quick as they are created. 10% toluene, or acetone will also clean it out In the US, most autogas has 10% alky, anyway, so it tends to keep stuff a bit cleaner. In other countries, you may still find leaded, with no alcohol added, auto-gas. So, this is mostly for those that travel world wide, anyway.

I believe everywhere has auto fuel, with a few exceptions like antarctica.

Edited by jamesdmarco on 05/16/2013 18:19:18 MDT.

Zorg Zumo
(BurnNotice) - F
A question about fireballs - overheating on 05/19/2013 11:19:32 MDT Print View

So there are a few stories on net of SVEA 123's overheating and blowing the pressure relief.

Is the stove really that sensitive or did these folks screw up?

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: A question about fireballs - overheating on 05/19/2013 11:29:41 MDT Print View

If you put a wide pot on it and a closed wind screen around it you can create a mini-oven that will heat the tank. The pressure then overwhelms the valve, and the growing flames deter any further efforts to shut things down.

You can accomplish the exactly same result with a canister stove.

Common sense goes a long way towards prolonging one's lifespan.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: A question about fireballs - overheating on 05/19/2013 11:43:44 MDT Print View

Not disagreeing that common sense should avoid problem, but

with SVEA, the way it works is you heat up the tank to get pressure for it to work so may be more likely to overheat

with canister you normally do not heat it up

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Re: Re: A question about fireballs - overheating on 05/19/2013 11:54:35 MDT Print View

I'll bet there a more than a few folks who have inadvertently had a runaway canister from to "to tight" wind screen...

It's the correlation between "normally" and "common sense" that is sometimes missing.

"I didn't do Anything different, but it just wouldn't shut off...."

Edited by greg23 on 05/19/2013 11:57:50 MDT.

Zorg Zumo
(BurnNotice) - F
Re: Re: A question about fireballs - overheating on 05/19/2013 17:45:26 MDT Print View

Thanks - I assumed that if there was a real problem with the SVEA 123 it wouldn't be so darned popular after all these years.

I was just wondering if it was sensitive to pot width as I intend to use a wide tea kettle most of the time.

Nick Gatel
(ngatel) - MLife

Locale: Southern California
Re: A question about fireballs - overheating on 05/19/2013 22:13:32 MDT Print View

"Is the stove really that sensitive or did these folks screw up?"

Follow the instructions and maintain it and it will never fireball or overheat. Buy some gaskets for the cap and replace periodically.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: A question about fireballs - overheating on 05/19/2013 22:26:27 MDT Print View

The only Svea that I saw burst into a fireball was the fault of its owner. He had no idea at all of how to prime it. A little experimentation at home helps.

--B.G.--

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Re: Re: A question about fireballs - overheating on 05/20/2013 06:42:10 MDT Print View

Well, this involves a piece of physics when you use the stove.

You do NOT actually apply heat to the tank, except as needed to prime the expansion chamber. The expansion chamber is the brass valve/burner assembly on top of the stove, there really is no expansion chamber, except in function. This heats the WG to evaporation (boiling.) The pressure sends the fuel out of the jet to be mixed with air & burned, AND, sends pressure back into the tank. Temperature and pressure are directly related in a closed system, so, the pressure is condensed in the liquid fuel, warming it. This supplies more fuel to the "expansion chamber." It sounds kludgey, but it works quite well. In open air, no pot, no windscreen, the tank warms as much from this as well as conduction through the metal parts (a given.)

This is the same mechanism as boiling water. Note that steam is created near the bottom, then, as bubbles rise through the water, they disapear and are re-absorbed into the water, releasing heat. Another, perhaps better example: The capuchino maker on many small expresso machines supplies steam to the milk. This will warm the milk simply by the milk absorbing some steam.

Anyway, it only requires a small bit of combustion to do this since the heat causes some expansion forcing raw fuel into the "expansion chamber."

Overheating is typically caused by large pots over a SVEA while using a wind screen. The simplest solution is to pour a bit of water on the stove. I know, this is counter to pouring water on oil flames, but we are not dealing with liquid fuel, here. Rather fuel vapour that is being vented. The water will simply reduce the heat in the tank, reducing the amount of vapour pressure, from overheating, being produced to vent out the safety valve. Hence, will pretty much reduce the stove output to normal conditions. The safety valve may stick, though. but it will eventually extinguish the stove, or, allow you to turn it off. Even the pot of water on the stove will be fine, boiling water is much cooler than the stove, IFF (if and only if) it overheats.

Did you ever boil-over a pot? It will put the stove out. I have done this several times, since I use a wind screen all the time. The stove will NOT explode. I recommend only low heat when using a wind screen. This is OK with me, since, lower heats are very efficient with fuel, anyway.

Generally, on low, fireballs cannot not happen. Even on 100F days in the sun, the stove will not overheat on low before you are done heating water. I have never gotten the stove to overheat with only a pot on top. Using a windscreen can cause ANY canister type stove to overheat. Canisters of compressed gas are much more risky, since, they have NO safety valve, like a SVEA has. Compressed gas canisters under the same conditions can explode, the SVEA will simply vent excess pressure, preventing the explosion.



You have to really misuse the SVEA to vent the safety. It is not recommended to use a wind screen, I do anyway. Knowing the parameters for any stove is the key to safe operation.

USA Duane Hall
(hikerduane) - F

Locale: Extreme northern Sierra Nevada
A question about fireballs - overheating on on 05/20/2013 11:29:13 MDT Print View

I've heard of one guy who primed his 123 by just pouring some fuel over the whole stove, of course after numerous times doing this, his stove was black. Like cold canister fuel, you can heat the tank/fount on the 123 to create some pressure, then light, or use the pressure to push some fuel out to use as primer.
Duane

Nick Gatel
(ngatel) - MLife

Locale: Southern California
Re: A question about fireballs - overheating on on 05/20/2013 11:51:30 MDT Print View

There is a small indentation on the top of the tank where the stem to the burner connects (priming bowl). You need to put some fuel there and then light it. If your timing is perfect, when you open the fuel key just as the priming flame extinguishes, it will ignite the burner.

Some people carry a small eye dropper and pull fuel from the tank and place it in the priming bowl.

Some people carry a small bottle of alcohol and fill the priming bowl with this.

Some people place fuel paste in the bowl.

Some people light a few pieces of scrap paper and hold the stove over this until the tank builds pressure.

The instructions say you can cup the tank in your hands to warm the tank, then open the fuel valve and WG will dribble down into the priming bowl -- this has never worked for me.

And then there are those who douse the entire stove with WG, throw a match on it and run away :) .... probably the same people who light campfires by dousing the wood with fuel.

Zorg Zumo
(BurnNotice) - F
wooo-hoo Buddy! This is fun! on 05/20/2013 22:33:11 MDT Print View

My wife told me my "weirdy stove" arrived (A little sooner than I thought). Way down in the corner of this big, lonely cardboard box was this little stove. Pretty un-exciting packaging and instructions - written in 4 languages all of which say the same: fill, prime, light, enjoy and don't burn up. I like that.

So I filled it, primed it by warming the tank with my hands until it gurgled up some fuel which I then lit and let it burn down. Then I lit it and away it went.

Not sure why folks say it is noisy - it isn't compared to other white gas stoves. Yes it is noisy compared to my alcohol stoves, but then so is most everything.

Boiled water like it is supposed to, and it simmers really well. I can get it down to below the level of boiling water and it stays there (it was pretty breezy). I'm going to use it with the Optimus Weekender HE .95L pot, (when it arrives), to make the most of the limited BTU output of the little guy.

The key is stupid, so I moved it almost immediately.

Cute little bugger - I can see how folks fall in love with them. It is so simple that it has just got to be reliable, and that is of utmost importance to me. I wanted white gas for the cold-weather BTUs, but the MSR stoves kind of turn me off because of the bits & pieces. There just isn't much to go wrong with the little SVEA 123R.

Wish I had picked one of these up earlier in life.

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Re: wooo-hoo Buddy! This is fun! on 05/21/2013 03:12:57 MDT Print View

You just outlined why I use the stove: Reliable, durable, simple, and efficient.

The key is usefull for field maintenence besides controlling the valve. It is certainly possible to use it without, though...never had a problem in the field in more than 40 years of use.

It is a bit heavy for the BTU output, but, that also makes it very efficient with fuel. My thought was to revamp the old design using totanium for all except the valve/jet assembly. The weight would go down a LOT. But the origonal is a very compact heating system.

Add a wind screen, but be carefull with the heat radiated down to the can. It can get quite hot if you don't watch it. On low this is perhaps the most effecient stove available.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: A question about fireballs - overheating on on 05/21/2013 05:37:07 MDT Print View

> there are those who douse the entire stove with WG, throw a match on it and run away

And there are those who open the valve slightly and stick the stove in the campfire until it is roaring.
I kid you not. We stayed a long way away though.

Zorg Zumo
(BurnNotice) - F
Last Question - really on 05/21/2013 10:13:52 MDT Print View

Just one more question and then we can let this thread die. Do you need an insulating pad under the stove on the snow, or does it work better without one? I'm wondering if the little bugger will run if the tank is heatsinked? I.e. is it ok running on wet ground or does it need to be sitting on something dry? Thanks for your help folks and I hope this thread is helpful to someone else considering one of these stoves.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Last Question - really on 05/21/2013 10:29:58 MDT Print View

If the snow is cold, then it has the effect of slowing down the pressurization of the Svea fuel tank. A good platform can be fashioned from a piece of plywood or Masonite. It doesn't have to be a fantastic insulator, but a stiff platform like that is very helpful.

For wet ground, it will work without any platform. OTOH, a piece of aluminum foil underneath it might help.

--B.G.--