How to control the boil with a heating element

[wilserbrewer]

... so in the meantime my thoughts were to use a 5500 watt element @ 240 with no controller to get it close, then switch it to 120 which would drop it down to 1375 to hopefully maintain a boil. ...

5500 / 4 or 1375w is not enough or even close. If you are going 240v, I would try the 3000w or 3500w element for a 5 gal batch. They are less than 10 bucks a piece.

 

[wilserbrewer]

I know this is getting a little complicated but still simple enough. Why not use two separate elements one 2000W and one 5500W both with the capability of switching between 240V and 120V. Surely with the eight possible wattage configurations you could get to a boil quickly and then maintain it and even be able to do different batch sizes.

At this point...may as well fashion a controller, no?

 

[gunner65]

As simple as a PWM or PID circuit is why in the world would a person not want the control?

If you already have the 240v outlet you are looking at less than $100 to build a somple controller like the one mentioned above. The ability to turn the system on/off while standing at the kettle is very important to me.

And my opinion is no matter the batch size go with the 55kw element if you are controlling it. The cost nill compared to the other elements and you are already capable of upgrading your system to a larger boil.

 

[Tiber_Brew]

I have full intentions on building a control panel eventually, but I don't have the funds or the time to build what I want right now... so in the meantime my thoughts were to use a 5500 watt element @ 240 with no controller to get it close, then switch it to 120 which would drop it down to 1375 to hopefully maintain a boil. Then when I have the money and time to put into a control panel I can.

That being said, I doubt 1375 will maintain my boil though even if I insulate by pot...

Wiring a PID would be almost as simple as wiring that switch you're talking about. If you're willing to wire up a switch in a small enclosure, why not save up the $50 or so dollars to skip right to a PID? The added benefits are exponential to the added cost/wiring.

I think some people are a bit discouraged by looking at some fancy control panels here, but I promise you that wiring a simple PID setup is far easier than all the beginners think. Trust me, I've been in those shoes before.

TB

 

[Ohio-Ed]

OK Guys, I agree completely, that having a controller to precisely power the boiler element works very well I am sure. The point I am trying to make is that I am uncomfortable with it being represented that the only way to make an e-kettle work successfully is to use a controller. I boil around 10 gallons w/ 4000w without a controller. Of course some people have the time, knowledge, money, and technical savy to build a better more sophisticated system, but IMHO a simple e-kettle works pretty darn good for what it is.

Here is a list of various elements available, they're cheap.
http://www.plumbingsupply.com/elements.html

A simple e-kettle w/out a controller can work very well, of course this simple stripped down approach is not for everyone.

I've seen posts from folks doing the same thing... so I know it can be done.
I've also seen posts where folks wire in a switch or plug/unplug the element as needed.

I haven't built one, but I think the next step up is a PWM circuit. It requires some fairly inexpensive parts and a bit of assembly but they are VERY effective in a Boil Kettle... Basically provides you a knob to dial in the power you want to apply. I'm pretty sure Walker posted about building one, if you want to go searching. If you have a few bucks to put toward it and feel like tinkering, you might look into it.

Ed

 

[nm999]

At this point...may as well fashion a controller, no?

I personally am waiting to get a PID before going electric with my boil kettle but maybe relays and switches work better for some people.

Oh, anyone want to trade a Johnson controller for a PID and SSR. https://www.homebrewtalk.com/f16/johnson-analog-temp-controller-215505/

 

[gunner65]

I've seen posts from folks doing the same thing... so I know it can be done.
I've also seen posts where folks wire in a switch or plug/unplug the element as needed.

I haven't built one, but I think the next step up is a PWM circuit. It requires some fairly inexpensive parts and a bit of assembly but they are VERY effective in a Boil Kettle... Basically provides you a knob to dial in the power you want to apply. I'm pretty sure Walker posted about building one, if you want to go searching. If you have a few bucks to put toward it and feel like tinkering, you might look into it.

Ed

My first controller was PWM it was $7.99 from http://www.bakatronics.com/shop/item.aspx?itemid=383

That ans a wallwort are all that is necessary to fire the SSR you can put the entire setup into a plastic box from home depot for $20. They work VERY well.

 

[bgrubb7]

My first controller was PWM it was $7.99 from http://www.bakatronics.com/shop/item.aspx?itemid=383

That ans a wallwort are all that is necessary to fire the SSR you can put the entire setup into a plastic box from home depot for $20. They work VERY well.

OK.. I'm sold on that one! Hell I even feel like an idiot now. I was reading about that PWM board on another thread about controlling the speed of a March Pump and never even though about using it to fire an SSR... Thanks Mr. Obvious, I guess I never "made the connection" :cross:

Here's the post about Walker's PWM if anyone's interested.

 

[gunner65]

OK.. I'm sold on that one! Hell I even feel like an idiot now. I was reading about that PWM board on another thread about controlling the speed of a March Pump and never even though about using it to fire an SSR... Thanks Mr. Obvious, I guess I never "made the connection" :cross:

Here's the post about Walker's PWM if anyone's interested.

Just a thought you have to replace one of the capacitors in that circuit to slow down the timer in order to control otherwise the pulseing is way to fast for boil kettles. Do a search as I cannot remeber the exact value of that.

This is why we were banging you over the head about not wanting control...because it is this cheap and easy. Good Luck!

 

[wilserbrewer]

Also, if you just want to boil, you can probably skip all control and just plug it in. I have a 5500W element in my BK and a pulse modulator to control it, but I brewed the last three batches with the PWM cranked up to 100% on the boil. I could have just plugged it in and let it roll.

Interesting finding...."I could have just plugged it in and let it roll."

 

[bgrubb7]

Just a thought you have to replace one of the capacitors in that circuit to slow down the timer in order to control otherwise the pulseing is way to fast for boil kettles. Do a search as I cannot remeber the exact value of that.

Are you talking about the Bakatronics PWM kit or Walker's design?

 

[Ohio-Ed]

Interesting finding...."I could have just plugged it in and let it roll."

In that post, Walker didn't specify his boil volume.

And 2 posts later he mentioned that 100% power results in a "Violent Boil" that shakes his entire stand.

 

[bgrubb7]

Oooh... lookie here. Would this one work without an SSR? According to its rating, it would work for a 4000w or lower element at 220v.

 

[gunner65]

Are you talking about the Bakatronics PWM kit or Walker's design?

Bakatronics

 

[bzomerlei]

Guys,

I'm building an electric setup very close to Kai's, but I'm using the BCS-460 instead of a control panel. (by the way Kai, I'm going to owe you alot of beer for that info) My question is how do you control the boil with a 5500W element? If I wanted to brew a small 6 gallon batch I would have to imagine the boiloff would be too much without some type "dimming" solution.

I have the BCS-460 controlling a 5500 watt element and it is super easy to control the boil. I can boil 5 or 10 gallon batches and control a hard or light rolling boil.

The simplest way I found was to set the target temperature for the boil kettle and set the control to 'PID' instead of 'duty cycle'. When I set the temp to 208, I get a nice rolling boil. The BCS allows you to set this value on the fly so it is easy to adjust the boil as needed.

Any suggestions on what PID I could use?

The BCS 460 is the PID, so having the BCS controlling a pair of SSRs is all you need to control the heating element.

Brent

 

[Ohio-Ed]

I have the BCS-460 controlling a 5500 watt element and it is super easy to control the boil. I can boil 5 or 10 gallon batches and control a hard or light rolling boil.

The simplest way I found was to set the target temperature for the boil kettle and set the control to 'PID' instead of 'duty cycle'. When I set the temp to 208, I get a nice rolling boil. The BCS allows you to set this value on the fly so it is easy to adjust the boil as needed.



The BCS 460 is the PID, so having the BCS controlling a pair of SSRs is all you need to control the heating element.

Brent

Brent,

You may find that controlling the boil by temp is not real reliable. The problem is that there is no temp difference between rolling boil and violent, off the hook boil. When water reaches boiling temperature, it converts to vapor (steam), and doesn't get any hotter.

Duty cycle will allow you to adjust the boil by adjusting the amount of energy going into the kettle. With my BCS, I find that once I reach boiling, I set the duty cycle to about 65% with a 5500watt element to maintain a nice rolling, vigerous boil.

Ed

 

[Walker]

Just a thought you have to replace one of the capacitors in that circuit to slow down the timer in order to control otherwise the pulseing is way to fast for boil kettles. Do a search as I cannot remeber the exact value of that.

If you are talking about my PWM circuit...No, you don't need to slow it down. You can pulse that sucker WAY faster than I'm doing it with that circuit and it will work.

In fact, I wish I would have made mine pulse faster than it does. Mine pulses ever 2.3 seconds. If I run it it half power, that's 1.15 seconds on and 1.15 seconds off, and you can literally see the boil pulsing in the kettle. VROOM-off-VROOM-off-...

Interesting finding...."I could have just plugged it in and let it roll."

In that post, Walker didn't specify his boil volume.

And 2 posts later he mentioned that 100% power results in a "Violent Boil" that shakes his entire stand.

I pretty much always make 5 gallon batches. My boil volume at the start is about 7 gallons.

I have a single wrap of reflectix around my kettle (a converted sanke), and I can run the element (5500W) at 100% and nothing splashes out of the kettle at all. Yes, the boil is very strong, but it does not erupt.

And, yes, it does make my whole stand shake, but that's because my stand is a piece of crap. It's just an old lab table with thin square legs and no bracing down low on it, so it likes to shimmy back and forth. I need to put some braces at the bottom to stop this because I'm sure it's not good for the table's longevity.

 

[Walker]

When I set the temp to 208, I get a nice rolling boil.

I would argue that your temp probe is inaccurate. Wort shouldn't boil at 208*F.

And, like Ed mentioned, the temp of a boil is a constant. It doesn't matter if it's a nice gentle simmer or a table-shaking steam pumper.

 

[bzomerlei]

Brent,

Duty cycle will allow you to adjust the boil by adjusting the amount of energy going into the kettle. With my BCS, I find that once I reach boiling, I set the duty cycle to about 65% with a 5500watt element to maintain a nice rolling, vigerous boil.

Ed

Ed,
So far I have done three batches, two 5.5 gallon and one 11 gallon, and the PID control based on the temp set point seems to work pretty well. It could be the placement of my temp probe, it is not right next to the elements so there is a small but measurable delta in the temp of the wort as I approach boiling temp. I'll keep an eye on it though.

Two questions:

• Do you find that you need to tweak the duty cycle percentage based on boil volume? My starting boil volume is usually 7 gallons and finishes around 5.6 gallons. It seems like less volume would take less energy.
• Do you set the duty cycle via state change in the BCS?

 

[Ohio-Ed]

Ed,
So far I have done three batches, two 5.5 gallon and one 11 gallon, and the PID control based on the temp set point seems to work pretty well. It could be the placement of my temp probe, it is not right next to the elements so there is a small but measurable delta in the temp of the wort as I approach boiling temp. I'll keep an eye on it though.

Two questions:

• Do you find that you need to tweak the duty cycle percentage based on boil volume? My starting boil volume is usually 7 gallons and finishes around 5.6 gallons. It seems like less volume would take less energy.
• Do you set the duty cycle via state change in the BCS?

Yes, I have adjusted the %.

I have my BCS in PID mode until the BK reaches 209f (I think), then switch to Duty Cycle. From that point, I usually run the Boil in Manual Mode on the BCS, so it's very easy to adjust.

Ed.

 

[bzomerlei]

I would argue that your temp probe is inaccurate. Wort shouldn't boil at 208*F.

And, like Ed mentioned, the temp of a boil is a constant. It doesn't matter if it's a nice gentle simmer or a table-shaking steam pumper.

My probes were calibrated and the new Steinhart-Hart Coefficients put into the system. However, there are two factors that impact why I get a boil at this set point. First, as mentioned earlier in this thread, exact boil point is base on atmospheric pressure, since I am 500 ft above sea level, I'm boiling a a slightly lower temperature, like 211. The second factor is that this the the set point for the PID control. Once I am within 2 degrees +- of this set point the PID control cycles the power on/off in an attempt to hone in on the exact temperature. It is possible that the set point I selected is effectively resulting in a 65% duty cycle like Ohio-Ed uses above.

When I look at the data log, the recoded temp in the boil kettle is moving between 210-211 during the boil even though the PID set point is 208