YM-2 "Watlow" Flame Control Question


New member
Apr 22, 2016
Hey There:
New to roasting, but own a shop. We have a 2016 YM-2 that runs well. We've just run about 10 batches thru it and we're getting used to the flow of things. I had a friend who was #2 roaster at Seattle come by to help me dial in the process. He was trying to kill the flame when we charge and let the batch "soak" thru to the turn, then cut the fire back on high to climb back toward charge temp. With a Watlow controller on this unit, I couldn't figure out how to kill the flame except to hold down the down-arrow until it goes below 150 so I'm safe from it cutting on at turn temp. Then try and increase it fast for it to cut back on (but then there's a bad delay in the flame).

One issue is that I may not have my flame knob on the front panel adjusted right. I had Amer help me, from Ambex, via Facebook video, but when I turn the knob to "0", should it turn the flame off? (giving me manual control?) Right now, it just lowers the flame a lot...then going to 100 increases flame to full.

Just looking for more manual control. Any help appreciated!

Thanks from a newbie:)
Last edited:


Super Moderator
Staff member
Aug 14, 2003
Boca Raton
I haven't used a 2.5 kilo in long time. I know the older models you couldn't adjust the airflow...have they changed that yet? If so why not adjust temp with airflow? I do not adjust my flame unless I am doing smaller batches I rely on airflow for temp.


New member
Apr 22, 2016
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Hey Topher, thanks for thoughts! I mistaningly typed 2006 but it’s a 2016. Yes u can adjust airflow on it. I realize most people leave gas on thru beginning of roast, but like I said, my friend is suggesting that flames go off from charge thru turn. He calls this “soaking”. He did win #2 roaster in the country last year, so I feel like it’s worth a try. He says acidity really increases when there is no flame on during the temp drop. So I’m trying to figure out how to cut off flame and back on with punching up down buttons on Watlow.


Well-known member
May 11, 2014
Kansas City
Soaking is a theory that Scott Rao has been discussing the last year or so. I have yet to find any significant difference in flavor profile using the soak method. The only time I find soaking useful is when I was doing really small loads on my 12K. I only utilize this because the heat output on my roasted can be simply too much when I'm roasting 3-5 lbs. I give it a minute soak on the lowest flame setting.

Regarding flame and '0' settings - any roaster I have scene it simply means the lowest heat setting possible. The burners need to maintain some gas flow in order to stay lit. I assume there is a minimum flow that gas control valves require.. otherwise you would risk having gas flowing with no flame which could lead to bigger issues.