Automating Reflux Condenser Water Flow

Automated Dephlegmator Coolant Flow

Wiring a PID controlled mechanical ball valve for constant output temperature on a Reflux Condenser.

By Michael Cotherman
Cotherman Distilling, LLC


Power supply:

24VAC, at least 10VA (volt-amps)
I had an old doorbell brick laying around that worked perfect.

Sestos Controller:

4-20mA PIDcontroller
$30 on eBay (a comparable omron is several hundred dollars)


1PCS 0-400 ℃ 5M Type K thermocouple 150mm probe M8 threaded @ eBay
this one has a 5mm probe that fits inside my 1/4" thermistor thermocouple thermowells very nicely.
$8.50 on eBay

Johnson valve:

VA9104-GGA-2S (PDF)
(1/2" 2-way non spring return)
$40 on eBay


500ohm 1/2w (I used 510ohm, 1/4w)
old stock from 20+ years ago


'Carlon' 4x4x4 plastic box
~$8 at Home Depot


I marked the outline of the PID opening required using the backing ring. I then drilled a hole in the backside of the front cover with a step drill and used a jigsaw and file to get a nice square hole. Installed the PID into the cover, slip backing ring over, and tighten screws snugly.

I drilled 2 more 1/4" holes in the back bottom, one for the valve cable, the other for the smaller thermocouple cable and the power leads.

Route the valve cable, power cable, and thermocouple cable into the box. FYI - the valve needs to have both DIP switches switched to the UP position, for "Reverse Acting" and "2-10V".

Connect the thermocouple wires to terminals 3 and 4, observing polarity.
Connect the 24VAC power supply wires and the power leads of the Johnson valve to terminals 9 and 10 of the PID.
Connect the grey wire of the valve and the resistor to pin 8.
Tape off the orange wire from the valve.
Connect the other end of the resistor to terminal 6, also run a black jumper wire to the terminal that has the black wire from the valve.

Resistor notes: if you wanted exact value and more power handling capability, 2 1K ohm resistors in parallel would work.
You may have fun fitting all the wires in the terminals, I added a blob of solder to the resistor lead to help the terminal grab it.

Tuning the PID:

I tried Autotune, it went for 10 minutes, and did not seem to work well.

P - proportional - the further away , the harder it tries to correct... I chose a small number, like 30.

I - Integral - Sestos calls this M50 for some reason.... this parameter pushes harder the longer you have been off of the target temp.

Because of the time lag between opening the valve and the outlet temp reducing, compounded by the slowness of the valve, the Integral value has to be pretty big (it is a 1/i, so a big i means small affect.) I ended up using the factory setting of 1000, may be able to go lower.. I tried to turn off the integral altogether, but as predicted, the steady-state always had an error, when set to 75C, it went to 78C and stayed there.

D - Derivative - Sestos calls this t, or 'Hysteresis time' for some reason.. default is 120, I have it at that.

Ctl - Control period default is 4, I have it set to 10

the Ctl value has been noted by some on forums to be screwy:

Ctl Period
40 = 40s
20 = 20s
10 = 10s
 8 =  8s
 6 =  8s
 4 =  8s
 3 =  8s
 2 = 70s
 1 = 70s
 0 = 70s

Sestos look amazingly similar to Auber (PDF), they have the similar default values, and this helped determine that t was in fact derivative.


  • Rock On!

    What are you seeing in terms of the opening percentages during the run? Sitting middle, high, low? Are you maxing out or closing at any point?

  • Nice Howto, look forward to seeing how this performs for you. I have my still set up for automation and enjoy watching the tech work, I recently upgraded all of my sensor to detachable Auber sensors and couldn't be happier. I find the solenoids work really well for me and once I get into the run they seem to hold things pretty stable. I will bookmark this thread =)

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  • This is a great thread. I'm planning on doing something similar using Sestos PIDs and Johnson valves. They came in a few weeks ago and I didn't notice until I took them out of the box yesterday. These things only read in °C... guess I'm working in dual units from now on.

  • yep, the only downside... let me know on this thread if you have questions...

  • I've salvaged a new Omron E5CN from work the other day, just need to figure out how best to use it :-)

  • it needs to be a E5CN-Cxxx to have 4-20mA output..

    E5CN-C2MTD(24vac input that matches the valve power supply) is best
    E5CN-C2MT is the 100-240vac model..

    Basic-type Digital Temperature Controller (48 x 48 mm) E5CN, E5CN-U @ OMRON Industrial Automation

  • @CothermanDistilling My valves didn't come with wires.

    Since you only use 3. Do you think something like 18/3 Thermostat Wire would work? Or are your wires thicker than that?

  • Looking at @CoterhmanDistilling 's pictures, that's what it looks like. Honestly, for the signal cables and/or only one valve, it's plenty.

  • edited May 2015

    The current draw is small, if you have 18/3 that's fine, you could even go smaller.

  • 22 gauge, even 24 gauge, such as alarm, doorbell, or ethernet wire ... 20 millamps... I don't think you can buy wire that is not heavy enough!

    edit - that is signal wire, the power wire has to be able to handle what, maybe 10va or something?, ~1 amp , so 26 gauge is OK...

  • edited May 2015

    Or, if you have some spare ethernet cable, just twist together the two wires in a pair and use that as a single conductor.

    It's something like 5va at 24v - I'm including the power supply as well.

  • edited May 2015

    I was thinking 18/3 because it's cheap and relatively sturdy.

    I'm wiring a couple of these, so I'm going to panel mount my RTD and valve connections. Do any of you have a preference between XLR and RTD connectors?



    I'm leaning towards XLR because they say it's sturdier.

  • I bought 4 of these 3 pin ones and will use 4-conductor wire to do 2 temp probes per connector(I currently do this, but just have 4 wires going through a hole in the box...

    with three pins, perfect for pid valve controller using common.

    Waterproof Aviation Plastic 2~9Pin Connectors SP13 13mm Panel Mount Connectors @ eBay


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  • I like those, they seem comparable to XLR. I need the 4 pin connectors for the 4-wire RTDs, I was using the lighting XLR (aka DMX) - but they are damn expensive.

  • I'm using M12 connectors.

  • The valve I'm using has a type A plug so I got a typeA valve to M12 plug jumper and a M12 socket for the control box from IFM

  • don't tease on how you got end-to-end, give us links and pics on each piece....

  • A heap of these in the panel. These for the Burkert valves and some of these for the flowmeters and analogue temp transmitters.

    For the RR bit I'm using some of these paired with these and I was going wire them up using headphone jacks.

    Enough links? :)

    Anyone got a good link for me?
    I want to get multiple DS18B20's on the same signal wire not using parasitic power for an Arduino.
    I found an easy way to have each on its own data pin without the need for a library but ideally I'd like one plug going into the box for all of them.

    More mucking around programing-wise but a much neater end product.

  • Looked somewhere else and found it

    Got three working working now :)

  • edited January 2016

    Great post. Thanks a lot guys. I'm currently buying parts to build a dephlegmator control. Will this PID from Auber work?

  • That one looks like it will run a solenoid. Are you looking at a proportional valve or solenoid?

  • Or a proportional solenoid valve :)

  • Haha yup that too!

  • A selonoid. Maybe this isn't the right thread.

  • I have collected the parts and i am getting ready to wire up this set up so i can try it out, but i have a couple of questions before i do. I am reading the description and looking at the photo of the wiring on the back of the controller and something does not look correct. I am assuming the photo is the correct way to do it but i wanted to ask first. As far as the resistor goes it says to wire it from terminal 8 to terminal 6. but if i am seeing things in the photo correctly it is going from terminal 8 to terminal 10 is this correct? And as far as the jumper wire is concerned does that go from terminal 6 to terminal 10 ? Thanks for any help

  • One other observation i am trying to figure out, is the photo looks as if the black wire of the valve goes to terminal 6? is this correct? My understanding of the worded directions is that the red and black wires from the valve would go to the power terminals of the p.i.d along with the power wires of the power supply? Again just trying to sort this out before i go wiring things up and plugging in the power. Thanks

  • (whoops, I meant to post this months ago, luckily it was saved)

    A follow up on this, I am currently very happy with my setup for making really, really good vodka. It will never truly make up for more plates, but it can take some work out of the process of keeping the ABV exactly where you want...... now I set it to about 60 degrees C and let it go... (actually, it is better to say I set it for a 70F delta-T)

    It stays at a real 190.5-190.8 measured with calibrated, NIST traceable hydrometer and thermometer and I get 10-15L/hr. I think I should get more, but I am happy for now... I can put my product next to a mega premium product and taste flaws such as a small amount of heads in Grey Goose..

    380L direct electric, 24 CD ProCap plates, 11kw heat during run

  • you have to understand the relationship between voltage and current... if the PID puts out 4-20mA and the valve reads 2-10 v, that is a .5kohm (500ohm) resistor... the PID will error out if it does not see something within a reasonable range.

    By connecting the 500ohm resistor across 6 and 8, the PID creates 10v across it when you put 20mA through it. Funny thing happens when you go to actually connect it though, and only have a good place to put 2 wires, one each side of the screw... SO... since 6 and 10 are connected together, it may look like 8-10, but it is really 6-10 because 6=10. "Connect the other end of the resistor to terminal 6, also run a black jumper wire to the terminal that has the black wire from the valve."


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