PID reading the same temp...always Whats wrong ?

[day_trippr]

Gotta be silicone, probably reinforced...

Cheers!

 

[doug293cz]

it will be mash at around 190 degrees F

You got me curious now: how is this system configured, and how does it operate?

Brew on

 

[Mike Vogan]

Its pretty simple and basic First part of this year I thought I would like to try an electric still So Im converting my 15 gallon LP heated still over to electric If it dont work I will just put it back to LP burner It has 2 1500 watt electric heater elements, wired parallel , hooked to my PID with the probe in the side of the tank Which works perfectly by the way..after a test run with water I got to thinking yesterday that maybe I do need a recirculating pump to move the mash so it will heat more constant and even Thats one thing Im not sure about Thats it If theres anything else I need to know just tell me cause it wont hurt my feelings It took 45 minutes to heat to 190 With series wiring it would still heat but would take longer due to the fact the elements would be drawing half power

 

[doug293cz]

Why are you using a PID to try to maintain a constant temperature in the boiler? The boiling temp is fixed by the ratio of alcohol to water in the boiler. There is nothing you can do to change the boiling temp. The only ratio that boils at 190°F (87.8°C) is 22.5 ABV alcohol and balance water. Lower alcohol will not boil at 190°F, and higher alcohol will boil lower.

Normally boil vigor (which determines rate of vaporization and thus still output rate) is controlled with a power setting (manual mode on the TD4) not PID mode.

If you wanted to control the temp at some upper location in a fractionating column, then PID control is probably appropriate for that.

Finally, recirculation of a boiler is not necessary, as the convection currents during boiling stir things up very well. You might want to recirculate on heat up to boiling, if there is significant solids content in your wash. This is so that the solids don't settle on the elements and scorch during heat up. Once boiling, solids won't settle on the elements.

Brew on

 

[Mike Vogan]

Thanx Doug But you lost me at " why are you using " I didnt know changing over was going to be so confusing I dont understand all this I just might go back to the lp tank

 

[doug293cz]

Thanx Doug But you lost me at " why are you using " I didnt know changing over was going to be so confusing I dont understand all this I just might go back to the lp tank

Mike, you can use your MyPin TD4 in manual mode to set a specific power level that will give you the vigor of boil that you need to get the still throughput you want. Using PID mode to control a boil is hard enough when the boiling point is fixed, but if the boiling point is changing, like during distillation, it's pretty much impossible.

Running with the TD4 in manual mode is fundamentally the same as controlling the gas valve on a burner, except instead of turning a knob on a valve, you push up and down arrow buttons on the front of the TD4.

Brew on

 

[Mike Vogan]

Thanx Doug Now I believe I understand Think I will give it a try and see what happens Might still go back to the ol tried and true method