Why won’t my MSR Pocket Rocket Deluxe ignitor work at 12000 feet?

[Stephen Seeber]

Works great, every time, at 5000 feet.  Never works at >12000 feet. Wind speed is not a factor. Temperatures are 40-70F.  Cannister brands and fuel mixtures do not matter. Matches or lighters are required at elevation.  Any ideas?

[Ryan Jordan]

I have the same experience. I’m guessing it’s a fuel mixture issue because of low oxygen. If the mixture at the ignition arc is too rich, it’s not going to light.

[John Vance]

Piezoelectric ignition is much less reliable as elevation increases.  My JB Ti will work fine above 11k but the piezo igniter can be very stubborn – particularly when it’s cold and damp.  I’m sure someone will chime in with the science surrounding the phenomenon.

[Todd T]

I’m more surprised it does work at lower elevations.  :-)  Piezo starters are in that class I call temporary features.

[Dan]

I have a very old (15+ years) MSR piezo igniter that still works perfectly at high altitude. I wonder if something has changed.

[JCH]

My 7 yo soto windmaster piezo has been 100% reliable. I rarely get above 3000’, but it did work at the young lakes in Yosemite.

[Jerry Adams]

reportedly, piezo lighters don’t work over 10,000 feet.  flint lighters do work

I just don’t go above 10,000 feet or I’d do an experiment.  I start getting this huge headache and immediately go down to lower elevation.

yeah, must be due to something like oxygen.

doing the google, there are contradictory reports, some claim they’ve got a piezo to work at 12K or 13K

Maybe a small piezo lighter doesn’t work as good as a stove which has more fuel flow?

I’ve used Soto and PRD piezos for years without problems

I bought these cheap piezo lighters on Amazon.  Some of them don’t work at all.  Some start being difficult but eventually work – I’ll replace before the next trip.

There are some brands of piezo stoves that are reported to quickly break.

[Stephen Seeber]

I called Cascade Designs customer service.  Cascade is the parent company of MSR.  Ryan got it right.  They immediately stated there was insufficient oxygen to support combustion.  I wonder if the Soto Windmaster performs any better at altitude?  I suspect duration of spark or temperature of spark could impact altitude related performance if these are actually variables.

[Dan]

I always find these conversations interesting, I’m just not sure what to say. A lot of theory and supposed confirmation from the manufacturer. And yet, I used an MSR piezo lighter hundreds of times above 12,000′ for more than a decade with a nearly perfect success rate. In recent years I’m more often using an alcohol stove with a mini-Bic. But last week, my wife and I camped for three nights above 12,000′ and I dug out a large pot and my old piezo ignited stove for the trip. It worked great as long as I “flicked” the lighter, which is my preferred technique. If I push it in gradually, I don’t always get a good result. I think that’s due to wear and tear on the lighter over the years, not altitude.

I had a conceptually similar experience on this forum, where someone told me with great certainty and supposed technical expertise that a particular repair tape wouldn’t work on a specific tent floor material, and yet I have had those exact repairs hold up for years with perfect water-resistance. What does one do with comments like these when I know that they are inconsistent with my first-hand empirical experience? It would be silly to argue, “Never wrestle with a pig. You both get dirty and the pig likes it.”

I guess we just have to accept that this is the internet and you can’t believe everything you read … do your own testing and bring a back-up. Maybe everyone is truly relating their own firsthand experience and the different experiences may be due to defective equipment or other variability. Or maybe some people are just posing as experts, but their apparent knowledge is more theoretical than practical, and therefore not always reliable.  I like to read these threads to get ideas, but I honestly approach the comments with skepticism, and accept that I need to do my own testing. And since you don’t know me, you should probably apply the same principle to my comments.

[Roger Caffin]

The problem with altitude is well-known and can be scientifically explained.

First of all, you can not light just any fuel/air mix. If there is a lot too much fuel or too much air, it won’t light. That is, if the mix is too rich or too lean. In fact, there is an optimum fuel/air ratio where ignition is easy. As you go away from the optimum, it takes more starting energy to get the mix to burn.

Second, the spark you get from a piezo-ignitor does not have a lot of energy. If you are close to the optimum fuel/air ratio, then the spark has enough energy and the stove lights. But if your fuel/air mix is a long way from the optimum, the spark may not have enough energy.
At altitude the air pressure is lower, and this changes the fuel/air ratio: it becomes very lean. This makes it hard for the tiny spark to light the mix. In the other hand, a Bic has lots of energy and will always light a stove.

Aha! Can you reach an altitude where the spark in a Bic can’t light the butane fuel in the lighter? This is less likely to happen (or more difficult), as the spark starts very close to the fuel and there is a wide range of mixture as you go through the stream. In most cases the spark will find a suitable part of the mix before it goes out.

Also, the flow from a BIc nozzle is at a much lower speed than the flow from a stove burner head. The high flow from a burner head cools the spark faster.

What this can mean in practice is that careful adjustment of the spark gap on the stove, plus a very low flow of fuel, can often be enough to light the stove. That is why many piezo-ignitors have their tips very close to the metal of the burner head.

I would imagine also that some ignitors have bigger piezo crystals than others, meaning they can put more energy into the spark. That seems logical, but it makes the ignitor more $$.

Cheers

[Jerry Adams]

“…I like to read these threads to get ideas…”

Yeah, exactly Dan

Even different stoves of the same model are different.  And how people use them are different.

Contradictory results are a good thing.  That shows the range of experiences so I know what to evaluate.

And if I voice an experience that’s different than someone else’s, it’s not a personal attack, it’s just another data point.

[Stephen Seeber]

Thanks all for your comments.  My question is answered and we all now know something about the Pocket Rocket Deluxe that some of us did not know before.  Dan’s comments suggest that  a piezo ignitor can work at higher altitudes.  The fact that the the Pocket Rocket Deluxe does not may be because designers had to make some engineering trade-offs that precluded high altitude ignition.

[John Vance]

Roger – very interesting comments and counter intuitive to my oxygen depleted thinking above 11k feet.  I am going to try turning DOWN the fuel when attempting to light via the piezo in an attempt to get a “hotter” spark.   I’ve been blaming the piezo all these years but perhaps something else is afoot.

[Jon Fong / Flat Cat Gear]

FYI –  From the web

At real altitude, the barometric pressure of the atmosphere is significantly less than that of sea-level environments. The result is that oxygen molecules in the air are further apart, reducing the oxygen content of each breath incrementally as one goes up in altitude.

ALTITUDE (FEET)   ALTITUDE (METERS)   EFFECTIVE OXYGEN %     SIMILAR LOCATION
0 – Sea Level               0 – Sea Level                       20.9%                                      Hypoxico HQ, NY

5,000                            1524                                     17.3%                                        Boulder, CO

10,000                          3048                                     14.3%                                        Leadville, CO

[NoCO-Jim]

https://youtu.be/xHmcwNPr_to

[Stephen Seeber]

Hi NoCO:  I actually ordered one yesterday from REI. Only $10.  I should be able to duplicate the test some time next week.  Interesting that it seemed to work best in the video at low fuel flow rate, as suggested by Roger.  Thanks for posting the video.  I found a couple others that demonstrated the same device, but neither at altitude.  Perhaps this is the one that Dan was using.  I believe it was introduced in 2012.

[Roger Caffin]

Found it! The graph which explains all this.

At altitude, when the amount of oxygen falls, the fuel/air mix becomes richer and the operating point heads to the right – which means you need a lot more energy to ignite the mix. Most cheap piezo-ignitors simply do not put enough energy into the spark.

Cheers

[Dan]

That’s an interesting application of the ignition energy curve, Roger!  From an engineering perspective, I generally think about it in the context of process safety, but of course it is equally relevant here.

[Stephen Seeber]

Problem Solved.  Today I went on a trip up Mount Evans, which tops out at 14200 feet.  Beginning at 8000 feet, I lit the stove with the piezo ignitor at 1000 foot elevation intervals.  It lit at every interval, right up to the top!  The secret:  above Roger stated : Also, the flow from a Bic nozzle is at a much lower speed than the flow from a stove burner head. The high flow from a burner head cools the spark faster.   Today, each  time I lit the stove, I opened the fuel valve until I could begin to hear gas flow.  At low flow, it lit each time.  At 13000 feet, I did have to press the ignitor a couple of times.  At 14000 feet, the first time I attempted ignition, it failed.  I then installed the windscreen I purchased from FlatCat Gear, and it ignited.

So, it appears that the secret to ignition at high altitude is a very low gas flow rate at the burner.  If you have too much ambient noise to hear a low flow rate, keep you Bic handy.  Also, as altitude increases, elevated wind speed will exacerbate the issues of ignition arising from high elevation.

[Dan]

Which route did you take on Mt Evans? It has been a while, but I used to love that route from Guanella Pass that starts through the willows and then climbs the gully to the left of the sawtooth ridge from Bierstadt. It’s long but you don’t run into anyone until the very end. And you’ll almost always see the goats.

BTW, I have always had a habit of lighting my propane stove at a low flow rate and then turning it up once it’s lit, so maybe that’s why I haven’t had problems. I always just thought I wasted less fuel that way and it seemed a little safer since my fingers are near the burner when lighting it.

[Jerry Adams]

Nice experiment Stephen!

 

[bradmacmt]

I have always had a habit of lighting my propane stove at a low flow rate and then turning it up once it’s lit

That’s always been my practice and I’ve always just assumed that’s the correct way to do it. It never occurred to me anyone did it differently, which is sort of a silly notion in retrospect. I’ve never had a problem above 10,000′ including this past weekend’s trip.

[Roger Caffin]

Of course, if you turn the stove on a fair bit before you light it, and then you fumble the lighter, you may end up with a small fireball . . . . This could be exciting.
Caution is always wise.

Cheers

[Roger Caffin]

Interesting gas canister with handle in Ukraine. See at 0:38 in the following.
https://www.ukrinform.net/rubric-ato/3555858-eyes-of-artillery-on-the-approaches-to-zaporizhzhia.html
Kettle on for morning tea? The windshield is NOT UL! Saucer as lid on kettle too.

Cheers

[Daryl and Daryl]

My sister lives in Evergreen Colorado.  I asked her about this problem.  She said the piezo works every time at 7300 (Evergreen).  Never  works at 10,000 or higher.

[Author]

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