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General Category => Pimp My System => Topic started by: xtrmnt on January 14, 2014, 02:21:34 PM

Title: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: xtrmnt on January 14, 2014, 02:21:34 PM
I must admit I was a little nervous about tearing into my two True GDM-12 glass door refrigerators. Though, the process of modifying them and building the BrewPi's was very rewarding and I am even more glad to have active fermentation going for a Dopplebock and Double IPA using the new BrewPi controllers. I love being able to be laying in bed and pull up the BrewPi management webpage and see what is happening or modify the fermentation profile. By By Johnson Controls, Hello BrewPi!

(http://i1314.photobucket.com/albums/t563/xtrmnt/brewpi1_zps5ddb1301.jpg)

(http://i1314.photobucket.com/albums/t563/xtrmnt/brewpi5_zps80883847.jpg)

(http://i1314.photobucket.com/albums/t563/xtrmnt/brewpi2_zpseb01a1ae.jpg)

(http://i1314.photobucket.com/albums/t563/xtrmnt/brewpi4_zpsbcd98f97.jpg)

(http://i1314.photobucket.com/albums/t563/xtrmnt/brewpi3_zps044dab39.jpg)

(http://www.brewpi.com/wp-content/uploads/2014/01/BrewPi-Case-2.0-with-sensors-and-actuators.jpg)

(http://www.brewpi.com/wp-content/uploads/2014/01/brewpi-web-interface-overview.png)

Of course, now you are wondering...

What is BrewPi?

BrewPi is a fermentation temperature controller for brewing beer or wine. It runs on Raspberry Pi and an Arduino. Compared to other temperature controllers, BrewPi offers much better temperature control and a lot more features like data logging, a web interface and graphs. BrewPi is open source and has an active community. BrewPi developers are working hard to support mash control (BIAB, HERMS or RIMS) in the near future.

BrewPi runs on two very popular boards: a Raspberry Pi and an Arduino. The Raspberry Pi is a credit card sized computer that runs Linux. In BrewPi it runs the web server and a python script to log data and manage settings. The Arduino is a microcontroller board that reads the temperature sensors and activates the cooler, heater and other actuators. It also has an LCD and knob to display and change settings.

Stability and flexibility

The Arduino runs the temperature control algorithm autonomously. If you don't care about data logging, it can control your beer without the Rasberry Pi. This makes this combo very stable: if the Raspberry Pi crashes, the Arduino will still keep your beer temperature perfectly under control. And being a simple embedded device, the Arduino just does not crash. If you want to run BrewPi on something else than a Raspberry Pi, you can! Any platform that has USB and can run a web server and Python will be able to run BrewPi.
Web interface

BrewPi runs a local web server that provides a great interface to change settings, view brewing data and to configure your controller. The web interface shows interactive graphs of your current brew and previous brews. You can easily start a new brew, view what the control algorithm is doing, check the logs, load/save temperature profiles, edit the active profile, etc.

Visit BrewPi.com (http://BrewPi.com) for more information.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: Stevie on January 14, 2014, 02:27:43 PM
I've been lusting after a brewpi for a while. Glad to hear you love it.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: klickitat jim on January 14, 2014, 02:44:52 PM
The log function out to prove or debunk a bunch of theories. They should give a couple to one of our experiment geeks.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: yso191 on January 14, 2014, 05:45:47 PM
An awesome setup.  I shopped for some time to find a commercial fridge like what you have but couldn't get within a few hundred dollars of an upright at Sears.  So I did that.  It sure would be nice to see the airlock/blow-off like you can.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: Pinski on January 14, 2014, 06:12:38 PM
Cool! What's Pepsi?
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: AmandaK on January 14, 2014, 06:58:37 PM
I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: Stevie on January 14, 2014, 07:46:58 PM

I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(

I hear what you mean. Look at the builds people post in his forum. Makes more since when you see how others did it. His personal build requires messing the the fridge wiring, but you can go so many ways with what he has done.

He has also streamlined the install and setup from what I can see.

I plant to use powertails instead of wiring the solid state relays. Powertails are basically power supplies with a cord and an outlet along with the inputs that the brewpi would us to tell it to turn on. Way easier that way.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: xtrmnt on January 14, 2014, 08:11:44 PM
Cool! What's Pepsi?

Pepsi is the Dopplebock and the other fridge with the "Coke" handle has the Double IPA.  :)
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: xtrmnt on January 14, 2014, 08:27:14 PM

I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(

I hear what you mean. Look at the builds people post in his forum. Makes more since when you see how others did it. His personal build requires messing the the fridge wiring, but you can go so many ways with what he has done.

He has also streamlined the install and setup from what I can see.

I plant to use powertails instead of wiring the solid state relays. Powertails are basically power supplies with a cord and an outlet along with the inputs that the brewpi would us to tell it to turn on. Way easier that way.

Yes. There are many ways to do it. Initially both refrigerators were connected to Johnson Controls which would control heating or cooling, but not both. The BrewPi handles both heating and cooling. Also to note in comparison, the BrewPi will hold the beer temperature within a 0.1°F. This is significantly different than the Johnson Control that will hold the beer temperature within a range of 2-4°F (or whatever differential you set it to). Because the BrewPi acts like a PID, it is capable of amazing temperature control. By setting up a beer profile within the BrewPi web management page, you can easily step up for a Diacetyl rest, make a slow step down for cold crashing, or do slow temperature steps if wanting the beer to self rise but not get out of control.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: morticaixavier on January 14, 2014, 08:29:09 PM

I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(

I hear what you mean. Look at the builds people post in his forum. Makes more since when you see how others did it. His personal build requires messing the the fridge wiring, but you can go so many ways with what he has done.

He has also streamlined the install and setup from what I can see.

I plant to use powertails instead of wiring the solid state relays. Powertails are basically power supplies with a cord and an outlet along with the inputs that the brewpi would us to tell it to turn on. Way easier that way.

Yes. There are many ways to do it. Initially both refrigerators were connected to Johnson Controls which would control heating or cooling, but not both. The BrewPi handles both heating and cooling. Also to note in comparison, the BrewPi will hold the beer temperature within a 0.1°F. This is significantly different than the Johnson Control that will hold the beer temperature within a range of 2-4°F (or whatever differential you set it to). Because the BrewPi acts like a PID, it is capable of amazing temperature control. By setting up a beer profile within the BrewPi web management page, you can easily step up for a Diacetyl rest, make a slow step down for cold crashing, or do slow temperature steps if wanting the beer to self rise but not get out of control.

isn't the intent of the differential more to protect your compressors from the effects of rapid cycling? (sweet setup by the way)
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: xtrmnt on January 14, 2014, 08:40:44 PM

I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(

I hear what you mean. Look at the builds people post in his forum. Makes more since when you see how others did it. His personal build requires messing the the fridge wiring, but you can go so many ways with what he has done.

He has also streamlined the install and setup from what I can see.

I plant to use powertails instead of wiring the solid state relays. Powertails are basically power supplies with a cord and an outlet along with the inputs that the brewpi would us to tell it to turn on. Way easier that way.

Yes. There are many ways to do it. Initially both refrigerators were connected to Johnson Controls which would control heating or cooling, but not both. The BrewPi handles both heating and cooling. Also to note in comparison, the BrewPi will hold the beer temperature within a 0.1°F. This is significantly different than the Johnson Control that will hold the beer temperature within a range of 2-4°F (or whatever differential you set it to). Because the BrewPi acts like a PID, it is capable of amazing temperature control. By setting up a beer profile within the BrewPi web management page, you can easily step up for a Diacetyl rest, make a slow step down for cold crashing, or do slow temperature steps if wanting the beer to self rise but not get out of control.

isn't the intent of the differential more to protect your compressors from the effects of rapid cycling? (sweet setup by the way)

You are correct regarding the differential. Within the BrewPi, the minimum cool time is set to 5 mins and the max idle time is set to 5 mins. This setting is hardcoded into the software to protect the compressor. Of course, even with a 5 on 5 off setting, the compressor cycles a lot, but due to the thermal load of the conical/beer, especially on a large batch, the idle times can be pretty long. The compressor would be cycling more often during the most active part of the fermentation. For instance, my Dopplebock is currently set to 48°F, but due to the low end of the yeast temperature, the activity is steady but not spiking all the time. In this case, the compressor doesn't come on that often.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: morticaixavier on January 14, 2014, 09:04:57 PM
[...]isn't the intent of the differential more to protect your compressors from the effects of rapid cycling? (sweet setup by the way)

You are correct regarding the differential. Within the BrewPi, the minimum cool time is set to 5 mins and the max idle time is set to 5 mins. This setting is hardcoded into the software to protect the compressor. Of course, even with a 5 on 5 off setting, the compressor cycles a lot, but due to the thermal load of the conical/beer, especially on a large batch, the idle times can be pretty long. The compressor would be cycling more often during the most active part of the fermentation. For instance, my Dopplebock is currently set to 48°F, but due to the low end of the yeast temperature, the activity is steady but not spiking all the time. In this case, the compressor doesn't come on that often.

cool.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: xtrmnt on January 16, 2014, 12:21:06 AM
The BrewPi developer ask me to post this on his behalf:

"Regarding the idle zones for the beer temp and cycling, in the BrewPi control algorithm there are a few things to prevent cycling and to protect the compressor:

- There are hard coded minimum OFF times (5 minutes) and minimum ON times (3 minutes) to protect the compressor. These are not user configurable, on purpose.
- For the fridge temperature, you can set the idle zone (upper and lower limit) in the web interface. The default is -1 and +1 degrees Celsius, compared to the fridge setting.
- For the fridge temperature, BrewPi estimates the overshoot that will occur and turn off the compressor in advance.

- The goal of course is to control beer temperature and not fridge temperature. So when BrewPi is set to 'beer constant' or 'beer profile' mode, it will adjust the fridge setting dynamically. To do this, it calculates the proportional, integral and derivative error in beer temp and adds these to the beer setting. The result is the fridge setting. You can adjust this calculation to match your setup. Please refer to this image: http://www.brewpi.com/wp-content/uploads/2014/01/control-algorithm.png
- By controlling the fridge temperature to adjust the beer temperature, the beer temperature fluctuates a lot less. Here is an example where the beer is generating heat, so the fridge temperature is below the beer temperature constantly: http://www.brewpi.com/#jp-carousel-1098

I am working on a different way to calculate the derivative for the beer temperature, so the fridge setting will have less spikes. The spikes are caused by the digital sensor: when the least significant bit toggles it seems to rise quickly.

Cheers!

Elco"
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: morticaixavier on January 16, 2014, 04:31:57 AM
The BrewPi developer ask me to post this on his behalf:

"Regarding the idle zones for the beer temp and cycling, in the BrewPi control algorithm there are a few things to prevent cycling and to protect the compressor:

- There are hard coded minimum OFF times (5 minutes) and minimum ON times (3 minutes) to protect the compressor. These are not user configurable, on purpose.
- For the fridge temperature, you can set the idle zone (upper and lower limit) in the web interface. The default is -1 and +1 degrees Celsius, compared to the fridge setting.
- For the fridge temperature, BrewPi estimates the overshoot that will occur and turn off the compressor in advance.

- The goal of course is to control beer temperature and not fridge temperature. So when BrewPi is set to 'beer constant' or 'beer profile' mode, it will adjust the fridge setting dynamically. To do this, it calculates the proportional, integral and derivative error in beer temp and adds these to the beer setting. The result is the fridge setting. You can adjust this calculation to match your setup. Please refer to this image: http://www.brewpi.com/wp-content/uploads/2014/01/control-algorithm.png
- By controlling the fridge temperature to adjust the beer temperature, the beer temperature fluctuates a lot less. Here is an example where the beer is generating heat, so the fridge temperature is below the beer temperature constantly: http://www.brewpi.com/#jp-carousel-1098

I am working on a different way to calculate the derivative for the beer temperature, so the fridge setting will have less spikes. The spikes are caused by the digital sensor: when the least significant bit toggles it seems to rise quickly.

Cheers!

Elco"

awesome! Thanks for posting.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: shoptoylife on September 11, 2014, 03:13:42 PM
I just came across BrewPi via Google search...then came back to HBA to see if anyone else tackled this.  The set-up in the chambers is insane!  I'm really impressed and curious about setting up something small to work with since I'm still in my early brewing days.

I have around 0% knowledge of wiring, so would it be better to tackle the wiring of a compressor in, say, a small fridge versus buying a flex heating / cooling element and installing it into a fridge?  At the bottom of the Fridge Hacking guide http://www.brewpi.com/fridge-hacking-guide/ (http://www.brewpi.com/fridge-hacking-guide/) they show some different options for heating elements which might be more beginner's speed.

Thanks!
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: Stevie on September 11, 2014, 03:38:21 PM
If you don't feel like wiring, you can get relays that are prewired. Basically the prewpi hooks up to those via a control wire and all of the electrical wiring is inside. You would need two if you are going hot and cold and I think you can skip the relays.

PowerSwitch Tail II https://www.amazon.com/dp/B00B888VHM/ref=cm_sw_r_awd_9eCeub0E064QD
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: xtrmnt on September 11, 2014, 03:39:06 PM
It would be better to tackle the wiring of the compression/thermostat. Even if you don't know much about wiring, it would be a good idea to physically see how the compressor is currently wired up in your refrigerator. Take lots of pictures before you cut anything as you discover wiring paths, from HOT to NEUTRAL to GROUND. You basically want to bypass your current thermostat and replace it with the cooling side / solid state relay of the BrewPi. I used paint can light bulb heaters in my BrewPi build to heat the chamber. This was connected to the heating side / solid state relay of the BrewPi. :) Cheers!
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: shoptoylife on September 11, 2014, 03:46:05 PM
Here's what happened the last time I tried to tackle any wiring - my wife and I were still living in Astoria, Queens.  I wanted to install a new ceiling fan / lamp in the bedroom we were renting fro, popped the old light off and saw there were at least 9 different wires in the housing.  After guessing on what to do I wired it up, turned on the switch and fried our building!  Luckily later that evening the giant underground transformer on our block blew up and caught on fire, so I blamed it on that  :D

I will take a stab at this and taking photos before I dig in is a killer suggestion, didn't think of that before.

Thanks!
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: biertourist on November 05, 2014, 08:52:04 PM
1. Anyone know where to get custom decals (for the top of the door) for a GDM-12 fridge like this?: http://www.brewpi.com/brewpi-feature-and-review-on-aha-pimp-my-system-and-in-linux-voice/ If you just remove the existing Pepsi/ True decals you're staring at a fluorescent / LED (depending upon age) light, which isn't nice either. 

I REALLY want to remove the Pepsi logo and replace it with something custom, but I can't get the Ones and Zeros guy to respond to where he got his...


2. Anyone know where you can get 3rd party after market casters for these True GDM12s? -The official casters for the fridge are like $280 from the manufacturer which is a level of crazy I never thought I'd see....


Thanks,
Adam
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: xtrmnt on November 05, 2014, 09:13:22 PM
I am the Ones & Zeros guy. Sorry for the late response.

1) The logo banner is a decal, the same van wrap material that is put on cars. I ordered the decals from here:

http://www.thesigncenterusa.com/


2) These are the casters you should get. Significantly cheaper. :D

http://www.ebay.com/itm/Threaded-Stem-Caster-1-2-13x1-Black-Polyolefin-Wheel-3-x-1-1-4-Plain-Bore-/400782398357?pt=LH_DefaultDomain_0&hash=item5d507e1395


Cheers!
Chris
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: Stevie on November 05, 2014, 09:27:52 PM
You want backlit material. Near any sign shop should be able to produce one for you.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: biertourist on November 05, 2014, 09:46:00 PM
I am the Ones & Zeros guy. Sorry for the late response.

1) The logo banner is a decal, the same van wrap material that is put on cars. I ordered the decals from here:

http://www.thesigncenterusa.com/


2) These are the casters you should get. Significantly cheaper. :D

http://www.ebay.com/itm/Threaded-Stem-Caster-1-2-13x1-Black-Polyolefin-Wheel-3-x-1-1-4-Plain-Bore-/400782398357?pt=LH_DefaultDomain_0&hash=item5d507e1395


Cheers!
Chris

So awesome!  Thanks, Chris.  I've been stalking you around the interwebs to get this information so apologies in advance: you're going to have a message from me on pretty much every email, online forum, and FB page you have.  ;-) 

-That's what you get when you build such an awesome setup: creepy internet stalkers! 

Adam
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: biertourist on November 05, 2014, 09:49:03 PM
You want backlit material. Near any sign shop should be able to produce one for you.

"Backlit material" -That's what I ask the sign shop for?  -And then just give them my graphics and dimensions?


Adam
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: Stevie on November 05, 2014, 10:54:09 PM

You want backlit material. Near any sign shop should be able to produce one for you.

"Backlit material" -That's what I ask the sign shop for?  -And then just give them my graphics and dimensions?


Adam
Yep. A FedEx Office, fast signs or local sign shop should be able to assist. Save your self some dough and set the files up yourself if you can. Illustrator would be my first pick. File manipulation can run as mush per hour as a mechanic.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: xtrmnt on November 05, 2014, 10:55:31 PM
Haha! (To your response about internet stalkers) Thanks for the compliment! If you call the sign center (from the link I provided), ask for Dave and tell him you want the same van wrap material that was used on the Ones & Zeros Brewing order. Hopefully he will remember. He's a nice guy anyhow and has helped me with decals / signs on other projects too. Good luck on your build! Post pics when it's done and friend me on Facebook. I'm the Chris Allen from Nashville, TN
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: biertourist on November 06, 2014, 06:38:59 PM
Haha! (To your response about internet stalkers) Thanks for the compliment! If you call the sign center (from the link I provided), ask for Dave and tell him you want the same van wrap material that was used on the Ones & Zeros Brewing order. Hopefully he will remember. He's a nice guy anyhow and has helped me with decals / signs on other projects too. Good luck on your build! Post pics when it's done and friend me on Facebook. I'm the Chris Allen from Nashville, TN

Thanks again.

Regarding FB: Already did and you'll notice a message from me there. (Told you I was stalking you.)  ;-)

Adam
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: biertourist on November 12, 2014, 06:49:42 AM
2) These are the casters you should get. Significantly cheaper. :D

http://www.ebay.com/itm/Threaded-Stem-Caster-1-2-13x1-Black-Polyolefin-Wheel-3-x-1-1-4-Plain-Bore-/400782398357?pt=LH_DefaultDomain_0&hash=item5d507e1395

Can anyone educate me on what all these numbers and terms mean on the casters?

I get what "threaded stem" means.  "Black Polyolefin wheels" -easy enough.

But what is "Plain bore"?

What does the measurement "1/2-13x1" mean?

I'm assuming that 3" is the wheel diameter, and then 1 1/2" is the width of the wheel?

Why don't these things come with wheels with brakes? -It looks like you buy and assemble the brakes separately.

--I'm trying to understand all the important stats on the casters mostly because this ebay seller charges 5x too much for shipping and I have Amazon Prime; plus casters are just something I know basically nothing about and I'd like to learn.


Adam

Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: biertourist on November 12, 2014, 06:55:01 AM
When I look at the original True caster set for this fridge (model 830275), the originals are 2 1/2" wheels by 1 3/4" wide, with a stem that it says is 1/2" -13 by 1" tall.   I'm so confused at what the 13 means.


Adam
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: biertourist on November 12, 2014, 07:13:02 AM
Ok I'm answering my own question, but UNC13 seems to be a standard for threads so you know that they'll work together.

I've found two options that I THINK will work on Amazon that are Prime eligible:
$8.93 a piece with 1/2" x 1" UNC13 threads- seems safest except I can't find an option with a brake and I need 2 with brakes...
http://www.amazon.com/Shepherd-Institutional-Diameter-Polyolefin-Threaded/dp/B009PFCLT4/ref=sr_1_1?ie=UTF8&qid=1415775465&sr=8-1&keywords=casters+2+1%2F2%22+stem+1%2F2%22+13+1%22

Here's one that's only 2" in diameter, the wheel is wider and it has a stem that's 1/2" x 1 1/2" Unc 13 and includes a brake for $6.65 a piece...
http://www.amazon.com/Shepherd-Diameter-Polyolefin-Threaded-Capacity/dp/B009PFC1R6/ref=sr_1_4?ie=UTF8&qid=1415775465&sr=8-4&keywords=casters+2+1%2F2%22+stem+1%2F2%22+13+1%22

The 2nd one is closer to what I want but possibly a bit risky with the 1 1/2" stem... Hmm...


Adam
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: biertourist on November 12, 2014, 07:19:30 AM
Ok I'm answering my own question, but UNC13 seems to be a standard for threads so you know that they'll work together.

I've found two options that I THINK will work on Amazon that are Prime eligible:
$8.93 a piece with 1/2" x 1" UNC13 threads- seems safest except I can't find an option with a brake and I need 2 with brakes...
http://www.amazon.com/Shepherd-Institutional-Diameter-Polyolefin-Threaded/dp/B009PFCLT4/ref=sr_1_1?ie=UTF8&qid=1415775465&sr=8-1&keywords=casters+2+1%2F2%22+stem+1%2F2%22+13+1%22

Found the option with the brake for $10.55: http://www.amazon.com/Shepherd-Institutional-Diameter-Polyolefin-Threaded/dp/B009PFCMF2/ref=sr_1_3?s=industrial&ie=UTF8&qid=1415776581&sr=1-3&keywords=unc13+caster+3%22+brake

Here's one that's only 2" in diameter, the wheel is wider and it has a stem that's 1/2" x 1 1/2" Unc 13 and includes a brake for $6.65 a piece...
http://www.amazon.com/Shepherd-Diameter-Polyolefin-Threaded-Capacity/dp/B009PFC1R6/ref=sr_1_4?ie=UTF8&qid=1415775465&sr=8-4&keywords=casters+2+1%2F2%22+stem+1%2F2%22+13+1%22

The 2nd one is closer to what I want but possibly a bit risky with the 1 1/2" stem... Hmm...


Adam
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: Roadraper on November 17, 2014, 04:50:43 AM
It would be better to tackle the wiring of the compression/thermostat. Even if you don't know much about wiring, it would be a good idea to physically see how the compressor is currently wired up in your refrigerator. Take lots of pictures before you cut anything as you discover wiring paths, from HOT to NEUTRAL to GROUND. You basically want to bypass your current thermostat and replace it with the cooling side / solid state relay of the BrewPi. I used paint can light bulb heaters in my BrewPi build to heat the chamber. This was connected to the heating side / solid state relay of the BrewPi. :) Cheers!
Nice setup! I was inspired and pulled the trigger on the BrewPi controller for fermentation control in a GDM-26. As far as I know it has the same condenser and thermostat wiring setup as the GDM-12. Could you post a pic or give me more detail on the way you wired yours? (thermostat only or at the condenser)... The fridge hack on BrewPi's site didn't help me much for the True GDM models. Thanks!!!http://www.homebrewersassociation.org/forum/Smileys/default/huh.gif
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: Stevie on November 17, 2014, 05:09:54 AM
I would recommend wiring outlets that you can plug the fridge into. The primary reason for "hacking" the fridge like Elco and others is to be able to use the light as a heat source. Not messing with the wiring will maintain the value of your fridge.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: Roadraper on November 17, 2014, 11:49:21 PM
I don't mind hacking on this build considering I bought 2 units (a little rough looking but work fine) for $400 in a restaurant closure sale. Certainly don't want to ruin the fridge, but really like the idea and want to try it.  Not sure if the cycle time issue discussed earlier would be resolved using the pigtail method or wired outlet. Would'nt that be an "all on or all off" situation...eventually leading to premature failure? Hell...what do I know. Thanks for the suggestions.
Title: Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
Post by: chrisjpryor on March 10, 2016, 11:38:36 AM
This build looks amazing and I am hoping to build something similar.

My concern though is with the lowest temperature that these display fridges can maintain. After re-wiring them for use with a BrewPi, can they actually get the fermenter down to 32°F/0°C? If they can, will the compressor be running constantly to maintain such a low temperature?