Heat Exchanger Pots Dangerous At Altitude?

[Jerry Adams]

Somebody gave me a heat exchanger pot and when I looked at it, the first thing I thought was the flame would be so far away from the bottom that it wouldn’t get good efficiency.

I was figuring out how to get the bottom closer to the flame by putting the arms down into the fins.

I haven’t got any further than thinking yet.  Who knows whether I’ll go further : )

[David D]

I think having the same gap between stove head and pot bottom on an hx pot will produce much  more CO than on a non hx pot.

The stash stove to stash pot gap is 27mm.  The PRD to flat bottom gap is much smaller. Cutting the stash pot bottom to have the PRD to stash pot gap the same as the PRD to non hx pot will generate a lot more CO

[Jerry Adams]

That makes sense

[Roger Caffin]

I reasoned that Jetboil has likely done Co2 testing and wouldn’t be putting out a dangerous product going on 2 decades. Dunno.
Forgive me, BUT
I think that is an extremely dangerous expectation.

When MSR, a much bigger company, first released the Reactor stove, I don’t believe they had done ANY CO testing. I did the testing, sent the results to MSR, and they cancelled the release – immediately. They tried to re-engineer the design, and succeeded in reducing the CO level SLIGHTLY. It remains deadly.
https://backpackinglight.com/stoves_tents_carbon_monoxide_pt_3/

Jetboil started with a claim that their first stove had a fantastic boil time. From a science point of view, the claim was impossible. Testing by BPL showed that the claim was completely false. A factor of 2x sticks in my mind.
It would seem likely that Jetboil had started with relatively warm water and timed to when bubbles started to appear. But those bubbles were a sign that the water was degassing (losing dissolved oxygen), and boiling is a long way beyond that. So expecting the Jetboil founders to have done CO testing is, to my mind, sheer fairyland.
(Note: the founders of Jetboil sold out many years ago.)

My 2c.
Cheers

[bradmacmt]

Jetboil started with a claim that their first stove had a fantastic boil time.

Not following you – with its HE pot Jetboil did have a “fantastic boil time” (whatever that means). Its boil time was ahead of any other canister stove at the time.

extremely dangerous expectation

I’m not worried. It’s not a radiant burner.

Would also add, JB’s have been in use worldwide for over 20 years, including by myself (I got my first in 2005). You can find dozens of climbing videos with JB’s roaring away at altitude in tents. As far as I’m aware, no one has reported a CO death. Of course it pays to be careful with any stove in a tent, but there are a lot of things I pay more attention to here (like grizzly bears).

[Roger Caffin]

Iirc, they were claiming a boil time half that of the opposition. That was not technically possible. In fact, when staff at BPL measured it at the Outdoors Rec show, its boil time was no different from the opposition under matching conditions. It may be possible to find the report in the BPL archives, probably under an OR heading.

Cheers

[David Thomas]

The electronic aviation CO detectors are vastly more sensitive than the UL-rated ones for home use.  UL decreased the sensitivity early on because so many people were calling the fire department when worrisome levels were reached for short periods, so it now takes higher concentrations for longer times to trigger them.  And it’s just an idiot light – no read out.  Or, at least the ones I’ve played with, even if it has a digital display, the display is delayed and time-weighted averaged.

General Aviation planes are often heated with an exhaust-gas-to-cabin-air heat exchanger (think VW Bug) which is a pinhole away from really high CO going into the cabin.  And it’s hard to step out of the cabin for fresh air.  Hence, the aviation ones have a real-time readout.  I was transporting one in my car to investigate some “sick building” complaints and backing my car up 30 feet through its own exhaust was enough for it to alarm (cold engine, rich mixture, catalytic not to temperature.   One current one is the Tocsin 4 at $190.

Then there are the multi-gas meters all over Amazon for $30-$40.

Or, the most UL option, is your father’s aviation CO detector with color-change spot.  

A slight graying of the spot indicates the presence of CO. The spot turning black indicates sufficient concentration to cause sickness. The spot will return to normal color after exposure to fresh air.  Adhesive backing.  Useful life is 90 days once opened; 3 years unopened.  $5.  Size and weight of a credit card.

[bradmacmt]

Good stuff David! I’d forgotten all about Sporty’s. We had their catalog’s around the house when I was growing up (my now 96 yo father was an airline pilot).

The reality is most of us in this country cook with NG or LP cooktops in our homes – something far more problematic than a little burner boiling 16oz’s of water for 3-5 min on a backpack trip.

[David D]

Now that’s cool, thanks for that.  I might pick one up to throw in my winter emergency kit

https://www.aircraftspruce.ca/catalog/pspages/asaCO.php

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