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More smoke at lower temperature set points?

PostPosted: November 18th, 2019, 6:01 pm
by Alphonse
The Yoder 640S seems to make more smoke at lower temperature settings (e.g. 180F setting).

Knowing that the combustion air fan is constant speed/volume, how does the smoker produce more smoke at a lower set point? One could imagine that with a variable speed fan you could produce a smoldering pellet pile but the fan is producing the same amount of air that you'd get at a 500F setting.

The temperature set point is achieved with pellet flow (auger speed). The air flow is constant and not variable from one setting to the next.

Re: More smoke at lower temperature set points?

PostPosted: November 23rd, 2019, 9:55 am
by Alphonse
Hoping that @Yoder_Herb might respond to this.

BTW, I have a YS640s and should have put this post in the ACS Pellet topic area.

Re: More smoke at lower temperature set points?

PostPosted: November 23rd, 2019, 10:46 am
by Yoder_Herb
I am not sure what you are asking. The design and programming of the controller, coupled with the calculated air flow, pellet feed rates and the very large burn grate, allows the perfect fire to produce a transparent blue smoke throughout the entire temperature range of the cooker. This is assuming the use of the factory preferred pellet brand, BBQRs Delight.

Re: More smoke at lower temperature set points?

PostPosted: November 25th, 2019, 9:02 pm
by Alphonse
Thanks Yoder_Herb for your reply.

Perhaps asking a more direct question will help me and my son. We both bought YS640s grills quite recently and my post/question was driven by our observations.

Does the controller vary the combustion air flow? From our observations we are assuming that the combustion air fan is constant flow and not varied by the controller regardless of pellet feed rate.

Re: More smoke at lower temperature set points?

PostPosted: November 25th, 2019, 9:45 pm
by Yoder_Herb
Alphonse wrote:Thanks Yoder_Herb for your reply.

Perhaps asking a more direct question will help me and my son. We both bought YS640s grills quite recently and my post/question was driven by our observations.

Does the controller vary the combustion air flow? From our observations we are assuming that the combustion air fan is constant flow and not varied by the controller regardless of pellet feed rate.


The fans run at a constant speed at all times, so no, the controller does not vary the airflow.

Re: More smoke at lower temperature set points?

PostPosted: November 26th, 2019, 9:39 pm
by Alphonse
Thanks Yoder_Herb for the prompt response.

Now my son and I will have to try to figure out why we think we are observing more smoke at lower temperature settings (<200F).

With a fixed air flow rate, the only controlling variable is pellet feed rate.

Therefore one could can imagine that with a low temperature set point (and its corresponding low pellet feed rate) there is more excess air as compared to higher temperature settings. So wouldn't it actually produce less smoke at lower temperatures than higher temperatures (which seems to be the opposite of what we're seeing)?

Re: More smoke at lower temperature set points?

PostPosted: January 12th, 2020, 7:45 pm
by brockstwrt
Are you seeing more smoke?? I know I cook at low temps to expose proteins to smoke for longer but as far as visible smoke after initial startup temp changes produce minimal changes

Re: More smoke at lower temperature set points?

PostPosted: April 22nd, 2020, 6:52 pm
by Nomamm
I just did the upgrade. Way worth it. I used the old controller for about a year. Went through almost 1000 pounds of pellets, so you can say I use my Yoder. It is odd but, I also believe you get more smoke from the unit with the new controller. I can only guess that the auger drops more pellets at a time and snuffs the fire a bit. This is low smoking temps. About 180-200 it billows a good amount of smoke