DIY PID controller

[brew starter]

Hi there

Been brewing for a while now on a starter kit (painful). Next step is to invest or build a PID controller and this is not tricky. However, with this amount of liquid and heat losses it is difficult to determine the correct setup. In some off the shelf kettles they use 2.5kW element and state that it is very efficient. I want to opt for a 2kw element, 40A SSR(overkill), thermocouple and a PID controller setup. For mash and sparge separately (8L + 17L) this should be okay right? Maybe I should opt for a 2nd element is parallel giving me 4kW total but I dont know if this will be just stupid.

Any advice before purchasing parts will be appreciated. descriptions below:

Heating element 2kW typ M2kW
Typ K thermocouple
SSR 40A DA
PID Controller

 

[bjhbrew]

I built my own controller and had similar questions when I got started. Here’s a couple thoughts: make sure you know what you have available for power where you plan to brew, if you’re in North America then a 2kw element would require a 120v 20 amp receptacle which most newish homes should have in the kitchen. Elsewhere in the world where 220v is the norm it would probably operate safely on any breaker but I don’t know what the standards are. I used a 2.2kw element in a 10G kettle for my system making 5.5G batches. It is slow. I don’t mind the wait when heating up strike water for the mash cause I can do other things but waiting for the boil is annoying. What I do is put the kettle on a cheap induction cooktop for some extra oomph. I would recommend picking one of the schematics on this site before purchasing parts but yes you do have the basics listed; ssr, heatsink, temp probe and related ports, switches. If you are staying with 120v you won’t need contactors as long as your switches are rated for the amperage that they can expect to see. One bit of advice is to look into the Auber ez boil instead of a pid. The ez boil does an awesome job of controlling the mash and the boil with two separate modes, I love mine.

 

[Bobby_M]

Make sure whatever PID you end up with has a Manual or PWM mode for boil control. You can't vary a boil's intensity by using a temperature target.

 

[brew starter]

I built my own controller and had similar questions when I got started. Here’s a couple thoughts: make sure you know what you have available for power where you plan to brew, if you’re in North America then a 2kw element would require a 120v 20 amp receptacle which most newish homes should have in the kitchen. Elsewhere in the world where 220v is the norm it would probably operate safely on any breaker but I don’t know what the standards are. I used a 2.2kw element in a 10G kettle for my system making 5.5G batches. It is slow. I don’t mind the wait when heating up strike water for the mash cause I can do other things but waiting for the boil is annoying. What I do is put the kettle on a cheap induction cooktop for some extra oomph. I would recommend picking one of the schematics on this site before purchasing parts but yes you do have the basics listed; ssr, heatsink, temp probe and related ports, switches. If you are staying with 120v you won’t need contactors as long as your switches are rated for the amperage that they can expect to see. One bit of advice is to look into the Auber ez boil instead of a pid. The ez boil does an awesome job of controlling the mash and the boil with two separate modes, I love mine.

Thanks @bjhbrew , I am running 220V wall outlets as standard and many of standard devices in kitchen is already around 2kw from wallplug so 10Amps is probably standard trip switch but I will check in any case. Your brew size is same as mine but I have a 50L pot which is overkill and actually causing more losses during heating than a smaller vessel. I will use this vessel to add element, thermo couple etc. I can always rip it out if I decide on going more efficient but this exercise is more of a proof of concept than anything else. I cannot get this EZbrew in my country and with shipping to europe will exceed flimsy budget. Will look into @Bobby_M suggestion for PWM function with PID.

 

[brew starter]

I built my own controller and had similar questions when I got started. Here’s a couple thoughts: make sure you know what you have available for power where you plan to brew, if you’re in North America then a 2kw element would require a 120v 20 amp receptacle which most newish homes should have in the kitchen. Elsewhere in the world where 220v is the norm it would probably operate safely on any breaker but I don’t know what the standards are. I used a 2.2kw element in a 10G kettle for my system making 5.5G batches. It is slow. I don’t mind the wait when heating up strike water for the mash cause I can do other things but waiting for the boil is annoying. What I do is put the kettle on a cheap induction cooktop for some extra oomph. I would recommend picking one of the schematics on this site before purchasing parts but yes you do have the basics listed; ssr, heatsink, temp probe and related ports, switches. If you are staying with 120v you won’t need contactors as long as your switches are rated for the amperage that they can expect to see. One bit of advice is to look into the Auber ez boil instead of a pid. The ez boil does an awesome job of controlling the mash and the boil with two separate modes, I love mine.

@bjhbrew , you mentioned schematics available on this site. Could you share link or topic header as I am struggling to find? Thanks a million

 

[brew starter]

Make sure whatever PID you end up with has a Manual or PWM mode for boil control. You can't vary a boil's intensity by using a temperature target.

Hi @Bobby_M , struggling to find PID with built in PWM mode. Could you provide links? I don't think I am yet at that stage where I need to vary the boil intensity. I just need to set mashing temp and then PID should keep it around that temp +/- a degree or two. And same for mash out and boil. I can see that at the boiling end it might be tricky to maintain a constant boil if element is switching on and off every few seconds but wort temp should stay around 210F which should be good enough I hope.

 

[bjhbrew]

@bjhbrew , you mentioned schematics available on this site. Could you share link or topic header as I am struggling to find? Thanks a million

I find it’s easier to search using Google with Homebrewtalk inthe key word. Here’s a thread that popped up:220V eBIAB Design - Wiring Diagram Review on post number 3 there is a good schematic for a single vessel controller (element output and switchable pump outlet) it’s very similar to the one I built. I would look for schematics drawn by doug293cz he does an awesome job. This schematic uses contactors to isolate the switches from the high voltage path. At 220v 10amp you could probably find switches that are rated high enough to not need to use contactors but don’t quote me on that. They do add an extra layer of safety and open up some interesting possibilities like making sure you can’t power on the controller if the pump or element switch are in the on position. As you can probably tell, one post will not give you all the info you need. I highly encourage you to take the time to do the research and understand the components before making any decisions. There is very real danger when working with electricity in this application. That being said, many hobbyists have been successful before you and much info is available here on HBT and elsewhere.

 

[brew starter]

I find it’s easier to search using Google with Homebrewtalk inthe key word. Here’s a thread that popped up:220V eBIAB Design - Wiring Diagram Review on post number 3 there is a good schematic for a single vessel controller (element output and switchable pump outlet) it’s very similar to the one I built. I would look for schematics drawn by doug293cz he does an awesome job. This schematic uses contactors to isolate the switches from the high voltage path. At 220v 10amp you could probably find switches that are rated high enough to not need to use contactors but don’t quote me on that. They do add an extra layer of safety and open up some interesting possibilities like making sure you can’t power on the controller if the pump or element switch are in the on position. As you can probably tell, one post will not give you all the info you need. I highly encourage you to take the time to do the research and understand the components before making any decisions. There is very real danger when working with electricity in this application. That being said, many hobbyists have been successful before you and much info is available here on HBT and elsewhere.

Thanks for info. This seems above my pay grade and now serious shock and possible death as imminent. I have built a few simple pid systems in the past for other applications but never for brewing. I was hoping to get away with this simple setup.

 

[doug293cz]

Hi @Bobby_M , struggling to find PID with built in PWM mode. Could you provide links? I don't think I am yet at that stage where I need to vary the boil intensity. I just need to set mashing temp and then PID should keep it around that temp +/- a degree or two. And same for mash out and boil. I can see that at the boiling end it might be tricky to maintain a constant boil if element is switching on and off every few seconds but wort temp should stay around 210F which should be good enough I hope.

A good choice of PID with a manual PWM mode is the MyPin TD4. Don't confuse this with the MyPin TA4, which does not have manual mode.

I would avoid Fotek branded SSRs. They have more failure reports on HomeBrewTalk than all other brands combined. You will also need a heatsink for your SSR, which needs to be mounted on the outside of your control panel enclosure (unless you have inlet and outlet air vents, and an exhaust fan in your enclosure.)

You will need an enclosure for your controller, as well as some switching to control power to the components. SSRs are imperfect current switches (they leak current when off), and they do not remove voltage from the circuit when they are off. I always design with contactors or switches in parallel with the SSRs to provide positive current and voltage cut-off.

The heating element that you show may be a bit tricky to mount in a cylindrical kettle. You want it mounted horizontally rather than vertically so that it takes the minimum amount of water to cover, and also to have the minimum volume below any false bottom. Most brewers use stainless steel water heater elements. There are a number of suppliers that make covers for the electrical connections on these elements, but I don't know which ones might be available to you.

Brew on

 

[brew starter]

A good choice of PID with a manual PWM mode is the MyPin TD4. Don't confuse this with the MyPin TA4, which does not have manual mode.

I would avoid Fotek branded SSRs. They have more failure reports on HomeBrewTalk than all other brands combined. You will also need a heatsink for your SSR, which needs to be mounted on the outside of your control panel enclosure (unless you have inlet and outlet air vents, and an exhaust fan in your enclosure.)

You will need an enclosure for your controller, as well as some switching to control power to the components. SSRs are imperfect current switches (they leak current when off), and they do not remove voltage from the circuit when they are off. I always design with contactors or switches in parallel with the SSRs to provide positive current and voltage cut-off.

The heating element that you show may be a bit tricky to mount in a cylindrical kettle. You want it mounted horizontally rather than vertically so that it takes the minimum amount of water to cover, and also to have the minimum volume below any false bottom. Most brewers use stainless steel water heater elements. There are a number of suppliers that make covers for the electrical connections on these elements, but I don't know which ones might be available to you.

Brew on

Thanks for detailed info @doug293cz . I will look into contactors and switches but no idea what specs I need to even look for as this stage. My knowledge is crap as you can see.
Okay I have opted for a more expensive 25A SSR with headsink. Of course a box with ventilation and fan. I am considering a different heating element that provides me a 2kW and a 1.5kW in one unit with two different plugs. Think this is good option to limit draw from one electrical outlet. The draw is 16Amps max so one SSR 25A should be enough? I see most split the into two SSRs but I will probably only be running both elements on. The only advantage is to have two outlets.
For the PID I seem to only get the TA4 and not TD4 in my country. Question is if it is REALLY necessary to opt for manual control or PWM? I know it will be better but I am young in the game and dont mind standing around the pot.

 

[brew starter]

@doug293cz If I look at you diagram it includes a pump which makes wiring a little more tricky as you have more checks in place. IF/AND gates if I remember something from electrical class I only have the heating element and thus is it possible to wire the main power switch in series with the contactor? Is it possible for you to show me how it will be wired?

 

[Brewdog80]

I use a MyPin for my lead melter for about 5 years now. Holds the temp within a couple if degrees at 725f. Inexpensive and works

 

[doug293cz]

Thanks for detailed info @doug293cz . I will look into contactors and switches but no idea what specs I need to even look for as this stage. My knowledge is crap as you can see.
Okay I have opted for a more expensive 25A SSR with headsink. Of course a box with ventilation and fan. I am considering a different heating element that provides me a 2kW and a 1.5kW in one unit with two different plugs. Think this is good option to limit draw from one electrical outlet. The draw is 16Amps max so one SSR 25A should be enough? I see most split the into two SSRs but I will probably only be running both elements on. The only advantage is to have two outlets.
For the PID I seem to only get the TA4 and not TD4 in my country. Question is if it is REALLY necessary to opt for manual control or PWM? I know it will be better but I am young in the game and dont mind standing around the pot.

You don't need vents and a fan, unless you want to put the SSR heatsink inside the enclosure. Most builders cut a hole in the enclosure that is slightly larger than the SSR, and smaller than the base of the heatsink, so the heatsink can be mounted outside the box.

You cannot control boil vigor with a PID, as it does not run with a fixed output, but rather continuously adjusts output to maintain a target temperature. You need a controller that allows you to manually set a fixed output, that gives you the desired boil vigor, since boiling happens at a fixed temp (depending on barometric pressure and liquid composition.) Thus ideally, you will have a controller that has both a PID mode and a manual mode.

With the element you have chosen, it might work out that you get a suitable boil vigor either running at a constant 1500W or 2000W, in which case you could set the PID target temperature at 120°C or higher, and turn off one of the element loops.

@doug293cz If I look at you diagram it includes a pump which makes wiring a little more tricky as you have more checks in place. IF/AND gates if I remember something from electrical class I only have the heating element and thus is it possible to wire the main power switch in series with the contactor? Is it possible for you to show me how it will be wired?

I can probably help with a diagram, but need to know some more information from you:

• What country are you in? Croatia?
• What is the amp rating on the circuit breaker(s) on the outlet(s) that you plan to plug into?
• What is the actual voltage measured at your outlets?
• Can you provide a link to the specification sheet for the heating element you have chosen?

Brew on

 

[brew starter]

Thanks for the replies and support. I almost pressed the green button on DIY version when I found a supplier making beer kettles for around 250$ from klarstein (germany). These are 3kW 30L SS temperature controlled vessels with heat exchanger and mash strainer/filter. Buying each of the DIY parts individually is significantly more expensive. I know part of the fun is building it yourself but I am working with food, liquids and AC electrical equipment here so not 100% comfortable. The purchased kettle looks neat and I can also sell eventually where the DIY version for sure wont.
Any reason you can think of why I need to build myself other than the fun of it??
Thanks