Heat Exchanger Pot setups

Please add a picture of your setup. Yes, starving the Kovea Spider of oxygen will cause it to sputter. My guess is you can test this by lighting the stove and setting it to the lowest level possible. Increase the flowrate and see when it sputters. Best wishes.

Do you have air intake holes at the bottom of the wind screen? If not, try that first. I like to place 1/4" holes about 3/4" apart, and I place the first one close to the space you created for the hose to run through. I just go 1/2 way around the screen so that the other side can be aligned to block the wind. I usually do two rows of holes, or even three. Also, how much space is between the pot and the wind screen? You want about 1/2" space to allow the combustion gases to escape properly.

I use this:

1.3 oz. aluminum flashing. Provides a fair amount of heat exchanger and windscreen functionality.

1) you need more air gap around the pot, at least 1/4 clear all around
2) the image does not look like a Kovea Spider, a side view would be beneficial.
3) if that gap is open on the bottom, I would suspect that burnt gas is creating a zone of oxygen depleted gas around the stove intake as well.

Just as a data point when I use my kovea spider, I use it with a evernew .9 and a caldera sidewinder. I do not experience sputter, so I suspect the cone has enough holes to allow enough air for the stove to perform well.

Yea…that wasn't me. That DIY windscreen/HE is interesting. Lots of things going on there.

I'll get a pic shortly, and can try the sputter test. My first field test was at 9,000' It wasn't cold, so I didn't invert the canister. Does the altitude affect it as well. We ran through a small 4oz canister much quicker than I expected, much faster than I remember my old gigapower stove, but I was cooking for four.

More vents below seem to make sense. It almost seems like more vents at the HE level would make sense to streamline the hot air flow out, but that would seem to compromise the wind shield performance. It looks like the MSR windburner has escape vents for the HE, but they also have some fancy HE fins.

Thanks all for your help

Here's a pic of the kovea stove and windscreen and one with the pot. I need to take back one comment from an earlier post – when I used this at 9,000' it was a MORS 1.8L pot, wider than this one, and it sputtered. I had previously tried the setup with the Olicamp (as shown) at home at a few hundred feet altitude, and had the same problems. The solution in both cases was to prop the windscreen open on one side, but it's not ideal, and partially defeats the purpose in my mind.

Hole punch vents go all the way around the bottom, but none at the top. There's a finger's distance between the windscreen and the side of the pot.

Thanks again for the help and feedback.

-Bob

I am pretty sure that you could 2X and 4X the number of holes around the bottom and it will work fine. A simple test would be to prop the bottom of the windscreen up using a tent stake on each side. I'ld bet a $1 that it would work just fine, even in the wind. The windscreen is important to keep the burner flame constant and in contact with the stove. The base of the the Kovea Spider Burner is also pretty high off the ground. Because the gas is jetted out, the flame is much more stable than with an alcohol flame. The tent stake test will tell you a lot. Best regards

In an ideal world those holes might be enough, but I suggest you double their diameter. That would 4x the area, and should suffice.

Cheers

I am pretty sure that you could 2X and 4X the number of holes around the bottom and it will work fine.

+1

Canister stoves need a LOT more air than alcohol or Esbit.

Looking at the gap between pot and windscreen, seems to me it needs no holes at all at the top. Once there is adequate airflow at the bottom, the hot exhaust will take care of itself.

But it might be a bit more fuel efficient if the windscreen were a little taller. Easy to test.

Bob, based on timed tests a few of us ran with the olicamp heat exchanger pot, I'm going to suggest you have the wrong stove to get the most efficiency from the Olicamp pot. We found the best design was one with a burner that has a small surface area, and points exactly upward (not angled like yours) giving a more concentrated flame. The MSR Pocket Rocket or Olicamp Vector are two that worked most efficiently.

Interesting, my experience is the opposite. I find the Optimus Crux (large head) to be a better pairing with the XTS than the Soto Windmaster (small(er) head).

Good input all.

I am going to try to elevate the windscreen, which would raise the shield and also allow plenty of air-flow from the bottom. The design I saw in another post here had holes in the screen that fit onto the Kovea pot stand (credit goes to Jon at Flat Cat Gear- he sells it as well, which may be the way to go.

Since it fits on the pot stand horizontal segments, it will have a smaller diameter than the current one. I think I could go a little smaller for the Olicamp XTS pot, but I also have a MORS 1.8L pot, that also suffered with a sputtering Kovea. I'll need to experiment to see if the elevated windscreen is better for both pots, or if I should just add more holes to this windscreen for the MORS pot.

I appreciate the feedback on the stoves, and won't rule out a stove change but I was really looking for a remote canister setup, and I think all the suggestions were canister mounted (vertical) stoves, which would be less stable and a tricker add-on windscreen. If the Olicamp/Spider combination doesn't work with a modified windscreen, or if windy performance suffers with the venting needed, then I'm back to the drawing board. I might try a MSR Windburner in that case.

I added a second row of vents with 5/16# McGill punch I got from Amazon. The kovea seemed to work across the range without sputtering. Test boil took 3.46 but I was messing with the nob. Sorry no specifics on water or air temp. I'll do another comparison when I make the flat cat style screen.