Needle valve/manometer/regulator issue - seeking advice

Discuss roast levels and profiles for espresso, equipment for roasting coffee.

#1: Post by CoffeeHound »

Greetings fellow roasting enthusiasts!

Over the holidays, I upgraded to a Kaldi wide 400, and I have been loving it (after about a year with a Fresh Roast 540 and a Behmor), but I'm having some issues fine-tuning the setup that I hope folks here might be able to help with.

For heat, I got the GasOne burner that a lot of people recommend (I believe it's the 8000 BTU model). I started working with just the knob on the burner and have produced a few dozen mostly great roasts this way - using Artisan with the Center 306 package that comes with the roaster.

Recently, I have tried to set up a needle valve/manometer system for more precise gas control. After many orders and trips to the hardware store, I finally got things more or less working -- BUT, the burner seems way underpowered with this setup.

Specifically, I can run things so that I'm putting a steady 30+ "inches of water" of pressure into the burner (with the burner knob opened full), but even there (and a little past that) I am getting both lower temps, and a kind of weird flame that seems like it's too yellow (very different from just having the knob at what feels like max power for roasting). This is, mind you, after some spectacularly underwhelming runs in a more "normal" pressure range in which something around the 4.5kpa zone would seem to be "max power." And by underwhelming, I mean FC at, like, 15 minutes, and ROR never gets much past the teens, as compared to roasts where FC is somewhere around 8 or 9 minutes, and the roast is done (usually I go about 30-45 seconds after FC) before 15 minutes, and most important, they taste way better.

My theory is that the problem has to do with the regulator at the end of the little extension hose that comes with the GasOne. Specifically, with the needle valve, I have things set up like this:

Propane tank -> needle valve -> T-junction with 0-30" of water manometer (was a lot cheaper than a kpa gauge but seems to cover the right range) -> into the GasOne hose with the regulator -> into the stove

Is my problem:

a) that the regulator should be ahead of the needle valve and the rest, rather than behind it in the chain


b) that the problem is in the stove's knob setup, and I should really just get a Cajun Cooker or something simpler for heat if I want to use this metered needle valve system


Something else?

I've seen posts where people discuss using a needle valve with this or similar stoves before, so I'm kind of leaning toward the first theory, but curious what others think or know about these things.


#2: Post by aabud »

FYI - may be relavent... I have the 15KBTU burner, and when I took a look internally (e.g. underneath) at how the gas is inserted in the air stream in the burner I was kinda suprised how cheap and loose/wobbly/imprecise/random it was. On mine, it was just a bent over piece of metal attempting to hold the "gas jet" in place. I feel like a did alot of good with a pair of needle nose pliers aligning and tighting up things underneath the burner.

I modded the internals so my new needle valve bypasses the existing "knob" and is connected directly to the copper tubing that is the gas jet, bypassing the built in hose/regulator thing that came with the GasOne. I have a standard low pressure regulator as part of the hose that connects to the propane tank, as would be typical with a gas grill.

My gas pressure maxes out at about 2.8 kpa, which is, not suprisingly very close to the standard max pressure for "low pressure" propane.

I'm using a Kaldi Home, so smaller drum than the wide, but think I could do 4 or 5 minute roasts if I wanted... way more heat than I need.

I also have the 8K BTU burner and have done roasts with it. Honestly... I didn't really feel like there was that much difference between the two. I chose the 15K in the end for my mods because of the way it was constructed internally - mods seemed a little more staight forward with it.

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#3: Post by okmed »

a) is your problem.

By the way, a yellow flame (not orange) is an indication of improper combustion and is creating carbon monoxide.
Make sure you have a clean blue flame through your entire range of adjustment.

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#4: Post by hankua »

This is a a setup I made for another machine, instead of the Camco regulator I switched it out for a 1psi Gas One (without the knob) around 10$ on amazon. ... BTYGVS6

The bare hose barb goes to the machine. Camco regulator uses a 15" wc gauge, 1psi Gas One uses a 30"wc gauge.