odd issue, need some help

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Bayoujeeper
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odd issue, need some help

Post by Bayoujeeper »

Brewing this morning and during my hold mash temp state, I hold the boil kettle at 155 (output 0) and temp 0. I use hystersis in the mash (temp 1) and the wort pump (output 1) set at 152. Once the temp drops in the mash it will recirculate through the BK to raise the temp back up. This part works, the odd thing is, the BK does not maintain the 155 temp. It never kicks the elements on.. Here is a screen shot of the process.
Image
Bayoujeeper
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Re: odd issue, need some help

Post by Bayoujeeper »

Actually what it looks like it is doing is the BK is using the 1 degree swing instead of PID. is this normal functionality? I noticed once the temp in the BK got below 154 it started heating and didn't stop until it went to 156..
JonW
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Re: odd issue, need some help

Post by JonW »

The PID output isn't using the 1 degree swing from the hysteresis output config. It's likely just normal over/under variance that is triggering the PID output. If you do some PID tuning, you should be able to narrow your PID trigger range.

Take a look at the PID Tuning utility here: http://embeddedcc.github.io/bcs-pid-tuner/
Bayoujeeper
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Re: odd issue, need some help

Post by Bayoujeeper »

On my previous brew I did not use the pump in Hysterisis mode, I basically just used the bk in Pid and set it a few degrees higher than the MT and turned the pump direct on. It held temps rock steady.
Using the pump in Hysterisis and the bk in Pid, it waited until it was a full degree low to turn the elements on and would overshoot by a full degree.
After the brew I turned it back to the old way of just Pid no pump and it held solid at my temp setting, not the huge swing I was experiencing during the brew.
I will try it again on my next brew and see how it goes.
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