Advice on Another Abbot Steam Generator / Level Switch Wiring Q's for the Experts

edited January 2017 in General

Hey all, I am in the process of building a self filling steam boiler based on the @Telluride design, and I was hoping someone could clarify the wiring diagram on this level switch for me.

Red is the common 12v for the LED and the circuit, and white completes the LED circuit, so then do I run the black to my water-in solenoid (which has one pole wired to the -12vdc source?). Here is the wiring diagram to make it more clear than the picture:

ELS-1150 Series Electro-Optic Level Switch (Carbon Steel & Stainless Steel) (PDF)

Second, on both diagrams it shows a load or resistor at the LED, how do I tell which type of resistor to use?

I know this is a basic question, but my brain has been turned to mush by this head cold and just want to confirm. Thanks all!


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  • the resistor is just to keep the LED from burning up... back int he 80's, my teacher wouls say they are like a puppy and current is like the food... you can literally feed a puppy to death.... and a LED....

    lets say your resistor can handle 10mA, and you have 12VDC..

    here is a handy page I found by googleing:

    How Voltage, Current, and Resistance Relate

    here is the formula for finding resistance:


    So if we put in 12V and 10mA (0.010A), we get 1200ohms...

    alternatively, a relay coil or SSR will be what you use to open a solenoid valve... they do not need a resistor...

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  • edited January 2017

    Gotcha, thanks as always @CothermanDistilling so then to fire the solenoid, I would wire the signal side of the ssr to the white and black cables, with the output controlling the solenoid?

    My other concern is that because it is optical, it might be prone to interference with the polished stainless spools I am using. I also ordered one of these:

    LS-77700 Series – Bent Stem Switches Provide Greatest Buoyancy Of Any Side Mount Version (PDF)

    which looks like it might be more reliable, anyone have any experience using optical level sensors in this kind of application?

  • Just remember that the level sensor can not be in the boiler.

  • edited January 2017

    Thanks @grim, I was honestly reaching out to you and @CothermanDistilling as my gurus. I am attaching a picture of my current workup for the boiler setup (note: I know it aint pretty but its put together with what I have on hand). The black lines are the copper equalization lines once I get the proper fittings. I come from a commercial brewing background and love steam in all of it's flexibility. Initial plans are to use the boiler for corn flour mashing, then work on implementation for jacketed/direct distilling or at least stripping applications.


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  • edited January 2017

    I also forgot to mention, the first usage of this boiler will be in conjunction with one of these steam eductors to mix and mash flour slurry washes.

    From there I plan on trying to use direct steam injection for the stripping run as well. I am still not 100% convinced of the efficacy of this side, so based on the pilot results I may move to an internal coil, calandria or external steam jacket for the strip and sticking with electric for the spirit run. I'll keep everyone apprised once my eductor lands. Cheers!


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  • edited January 2017

    I suspect the 3/8" eductor may even be too large for your steam generator.

    I use a single 3/4" on the mash tun - and it will easily consume the entire steam output of my 15hp boiler. That's easily in excess of 125kw, north of 500lbs of steam an hour.

    Here (PDF) is the sizing tutorial.

    Just remember - a pound of water is a pound of steam. Boiling off an entire gallon in a minute is 8.3 pounds of steam.

  • 5.5kw/h element = 18,766btu/h

    Vaporization - 970 btu per pound Heating - 1btu per pound per degree

    Say, 70F water heated to 212F and then completely vaporized.

    212 - 70 = 142 btu per pound to heat, then another 970 to vaporize, so 970 + 142 = 1112 btu per pound.

    At 18,766btu/h on tap - we've got 16.88 pounds per hour heated and vaporized (18,766/1,112).

    That's a little over 2 gallons an hour.

    Assuming mashing 100 gallons from the same 70f to 190f for gelatinization (corn, etc) - that's 190-70 = 120 btu per pound of water.

    We can just assume water=mash=SG=1.0 to keep things easy.

    100 * 8.3 * 120btu = 99,600 btu required to heat 100 gallons of mash from 70 to 190.

    With a 5.5kw steam generator, we're talking a bit over 5 hours, and this assumes 100% efficiency.

    I think what's obvious here is that anything you can do to pre-heat your mash water, boiler feed water, or even wash for distilling/stripping is going to significantly reduce time.

    Just for giggles, lets say you setup a hot liquor tank and preheated all the water you needed to 150f. Let's say you started it the day before, filled it, let the element take it's sweet time heating the water overnight or when the lights were off.

    You would be able to push a higher volume of steam, probably closer to 18-19 pounds per hour. Now, while this wouldn't necessarily change the total energy you are still limited by the 5.5kw element), the additional steam would aid agitation, and any little bit more pressure you can throw at an educator or injector results in big benefit.

    Big savings is on the mash heatup time, since now we're talking about 100 * 8.3 * 40btu = 33,200 btu - now we're at under 2 hours heatup with steam injection. Really though, you are just trading off time and energy into the HLT earlier.

  • edited January 2017

    Worth noting, if you are mashing corn flour, why not just heat up your water to 190 and dump the flour? I doubt you really need any steam injection at all. What you'd need is a good mixer/agitator, and maybe some sort of hydrator or high speed mixer to keep the dough balls from forming (which would be wicked dumping right into 190).

  • Thanks for all the input @grim, this is all great stuff to think about.

    I got the ss eductor for about $15 so i figured it'd be worth the experiment, and if it proves too big for the steam I can push currently, I may just use it as an agitator run with my little giant pump and fab up a more simple steam manifold. This is all for a POC pilot scale system no larger than 30gal, mostly 15 and below so I have some wiggle room, and our home hot water heater has a max output of about 140f, so that should help things along as well.

    Also curious, what kind of boiler you are using that can provide clean steam as I move in to bigger gear.

  • edited January 2017

    I use a big 2" piped Spirax Sarco CSF26 steam filter. It's a 2.8 micron filter to provide culinary grade steam. It's what the FDA would require for food contact in the states.

    We use no chemicals or additives in our boiler.

  • I saw a small pro ditsiller use sankey kegs with 2 5500W elements each, pipe the outlet through copper pipe that he ran through the mash in a coil, then out of the mash into a bucket with 1-2 foot of water in it... easy-peasy.. maybe a limit swithc, or maybe know that you can boil 2gal per hour per element...just fill back up after the run...

    now producing very stable steam source for a continuous still, that needs that fancy steam generator.... mash does not need precise...

  • Quick update. I ended up purchasing another, smaller 1/4" eductor that may work better for my scale, but I'll give em both a go and report back when I get this all finished.

    One quick question for the water in feed: should I have a check valve after the solenoid or just count on city water pressure to be higher than the boiler?

  • Getting closer to the maiden voyage and wondering if anyone had any input on the question above? I'll be using city water, so should the main pressure be enough to compensate the generator at 10psi or should I throw a check valve inline to be safe? Thanks all

  • Just for sixpence info, ... I have recently been reconsidering the use of a steam generator. Got a quote form PREFLY in China .... 50 kg/h for USD 1,550.- FOB.

  • @richard, i dunno where you are located, but here a steam generator is considered a boiler which:

    needs to be certified annually (I think that's the right frequency),

    the operator needs to hold a ticket to operate it +

    the lines etc need to be cleaned periodically (descaled)

    I'm not trying to rubbish the idea, however for a commercial operation, they need to be considered especially if the unit you are looking at hasn't already been certified in your country (you'll need engineering drawings etc and get a suitable engineer to sign off = $$$ & time.

    Sure the energy and efficiency is awesome, just there are a few cons to go with them.

    Horses for courses

  • And how do they view a retort Croz?

    StillDragon North America - Your StillDragon® Distributor for North America

  • sorry, i don't know

  • They would have no idea what a retort was - but would generally look at the still as a single unit. Trick question I think.

    A boiler - like pornography - you know it when you see it.

  • edited May 2017

    smaug, I think I misinterpreted your query earlier. let me clarrify as I think you are referring to boiler and kettle (retort?) as the same thing eg Steam Jacketed Pot Belly Kettle @ StillDragon North America where as I'm referring to boiler as a stand alone steam generator eg Electric Steam Boilers @ Simon Boilers AU

    Over here, if the kettle (as distinct from the actual boiler) will be heated by steam even low pressure, it also needs to be certified and inspected to AS4343.

    hope that clarifies

  • edited May 2017

    I just saw this thread and noticed the bit about the sensor and solenoid. A solenoid coil when activated could draw an initial spike current of up to 200mA depending on the solenoid coil. That could make the driver transistor in the sensor burn out.
    Adding to that, when the solenoid is deactivated the collapsing magnetic field can generate a voltage of up to 300V which will most likely also blow your sensor. You need a protection diode to stop this.
    This circuit will solve these problems.


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