# DIY Temperature Controller



## Chiumanfu (Apr 2, 2012)

*Description*
In this thread, I'm documenting another project that I've hacked together. The only area available for me to brew wine is in my poorly insulated garage. The temperature in my garage fluctuates quite a bit. During the winter it can drop to 5C and in the summer it can be 30C. I bought a cheap temperature controller on eBay that does the job perfectly. For heating, I have a brew belt although I am contemplating trying an aquarium submersion heater just because it will be so much more efficient. For cooling, I have a small freezer that can hold 1 23L carboy perfectly.

*I am not responsible for any damage or injury caused by the use of this information.*

*Parts list*

1 x STC-1000 Digital Temperature Controller. $24.95CAD shipped to Canada. Do an eBay search for STC-1000. I got mine from a seller named skiesmall360. Just make sure the one you get is the correct voltage for your region. For north America, that means 110VAC.
1 x Standard electrical wall outlet.
1 x Old repurposed electrical cord. I used an extra one from a PC.
1 x Velcro strap that will go all the way around your carboy/primary.
1 x Chunk of closed cell foam.
Total damage = $24.95CAD

*Wiring It Up*






Here you can see how the connections are made. The temperature controller is simple but the connections are not as straight forward as you would think because the outputs are actually relay contacts. Wire it up using proper gauge wire for the load you will be using. A brew belt only draws about 25 watts so you can get away with samller wire if you must but the freezer is a power hog so I suggest using #16 gauge to cover all possibilities. The outlet labelled Heat goes to your brew belt and the outlet labelled cold goes to your fridge/freezer if you are using one. 

*The Sensor*








Attaching the sensor to the primary/carboy can be as simple or complex as you like. I experimented with thermowells and heat transfer paste and aluminum tape but nothing really changed the accuracy. In the end, I found that simple is best. I used a 2" x 2" close cell foam block and sandwiched the sensor directly to the carboy/primary wall with a long velcro strap. You can find the long velcro in a garden supply store. Press the foam block as compressed as you can and wrap the velcro around it. As the foam expands, it creates a good insulation seal.

I also suggest wrapping the carboy in a thermal blanket just to save energy. It really makes a significant difference.

*Programming the Controller*





The controller is pretty simple to program but the instructions are written like a typical chinese manual so it can confusing at first.

Press and hold the "S" button for 3 seconds.
Press the "Down Arrow" until F1 displays.
F1 is the setting for the maximum temperature that you want. Press and hold the "S" key and at the same time use the up and down arrows to adjust the setting.
Press the "Power" key to save the setting. If you do not press the power key, the setting will not be recorded.
Repeat steps 1-4 for "F2". This is the difference value. Default is 0.5C. If you max temp is set to 18C and your difference is set to 0.5C then the heater will turn off when the wine hits 18C and the cooler with turn on. When the wine temp drops to 17.5C the heater turns back on and the cooler turns off. You can set this value down to 0.1C but I suggest keeping it at at least 0.5C so that there is a little hysteresis in the system, especially if you are using a fridge or freezer which needs time for the compressor to kick in.
Repeat steps 1-4 for "F3". This is the compressor delay time. Default is 3 minutes. This setting provides a delay to switch on/off the cooling unit so to avoid damage to the compressor.
Repeat steps 1-4 for "F4". This is the temperature calibration setting. If you find that the sensor temp does not match, you can set in an adjustment value here.
The display will show the current temp. If you press the up arrow, it will show you what you've set the max temperature for. If you press the down arrow, it will show you what you've set the difference value to.

*Conclusion*
I use this temperature controller to maintain a constant temperature on the primary. With EC-1118, the optimal temperature is 15C-25C. I set the controller to the lower side (18C) so the ferment is a little slower and steadier. When the fermentation really gets going, it generates it's own heat but the cold garage keeps it in check. During the summer, I may have to put the primary in the freezer to keep it within the optimal temps.

For bulk aging in carboys, I set the controller for 16C. This keeps the temp nice and stable. Temp swings are bad for aging wine, before I got the controller I was measuring swings up to 5C between day and night.


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## ibglowin (Apr 2, 2012)

Looks like it would work pretty well. 

Does your electrical outlet have some type of cover to hide the exposed 110 electrical connections so you don't get shocked?


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## Chiumanfu (Apr 2, 2012)

I just used a couple layers of electrical tape and nice clean connections.


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## olusteebus (Apr 2, 2012)

Great. I was just about to post something that some may not have seen, a product that does the same thing for $100. I am going to do what you did. I don't think I have to worry about my cellar getting too hot but It may get colder than I would want so I will use just the heat source. Thanks.


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## robie (Apr 2, 2012)

olusteebus said:


> Great. I was just about to post something that some may not have seen, a product that does the same thing for $100. I am going to do what you did. I don't think I have to worry about my cellar getting too hot but It may get colder than I would want so I will use just the heat source. Thanks.



Make sure you don't overload it. The max amps is 10 amps.


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## vacuumpumpman (Apr 2, 2012)

I have a similiar product - store bought though - it can handle up to 16 amps for my freezer. I do like the idea for the heating belt.
http://www.grainger.com/Grainger/RANCO-Electronic-Temperature-Control-3ZP77?Pid=search

thanks steve

http://allinonewinepump.com/


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## Kev (Apr 2, 2012)

I would look for a temperature controller with better accuracy.

http://www.omega.com/ppt/pptsc.asp?ref=CN4000_Series

Thermistors are good for freeze protection, but not much in my opinion.
I would suggest something that uses an RTD input and specifies accuracy or repeatability.

I am told yeast don't like temperature swings.

I am going to get something my self soon, to extended the brewing season.


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## robie (Apr 2, 2012)

vacuumpumpman said:


> I have a similiar product - store bought though - it can handle up to 16 amps for my freezer. I do like the idea for the heating belt.
> http://www.grainger.com/Grainger/RANCO-Electronic-Temperature-Control-3ZP77?Pid=search
> 
> thanks steve
> ...



I bought this one, too. It has worked out well and the 16 amps is much better.
It is a more expensive, though.


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## Chiumanfu (Apr 2, 2012)

Kev said:


> I would look for a temperature controller with better accuracy.
> 
> http://www.omega.com/ppt/pptsc.asp?ref=CN4000_Series
> 
> ...



Omega is a great brand but a little overkill for my little experiment. The accuracy you gain is not worth triple the cost IMHO. Thermistors are actually more accurate than RTDs over a narrow band. The temps that we are talking about are well within that band. The benefit of RTD is that they can measure accurately well below freezing and above boiling point.



Robie said:


> I bought this one, too. It has worked out well and the 16 amps is much better.
> It is a more expensive, though.


The STC-1000 relay is spec'd for 10A @ 250VAC. I've never seen a fridge or freezer draw more than that. Even my folks ancient chest freezer only draws 5A when the compressor kicks in and 2A after the first 30 seconds. If you are running a big appliance with the controller, you should definitely check what you are drawing.


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## vacuumpumpman (Apr 3, 2012)

The STC-1000 relay is spec'd for 10A @ 250VAC. I've never seen a fridge or freezer draw more than that. Even my folks ancient chest freezer only draws 5A when the compressor kicks in and 2A after the first 30 seconds. If you are running a big appliance with the controller, you should definitely check what you are drawing.[/QUOTE]

you mentioned 250 VAC - I believe that most freezers in the states run on 110 volt and usually recommend a 15 amp service

if the relay is designed for 250 volt and 10 amps if you are only running 1 leg in it (110 volt ) it should be able to handle 20 amps correct ?

thanks steve


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## Chiumanfu (Apr 3, 2012)

Your logic is correct but that it not really the case. The contact rating for relays are always based on current capacity (to prevent burning) while the contact spacing or separation dictates the voltage rating (to prevent arcing). They are separate ratings and must be obeyed individually.


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## robie (Apr 3, 2012)

vacuumpumpman said:


> The STC-1000 relay is spec'd for 10A @ 250VAC. I've never seen a fridge or freezer draw more than that. Even my folks ancient chest freezer only draws 5A when the compressor kicks in and 2A after the first 30 seconds. If you are running a big appliance with the controller, you should definitely check what you are drawing.


 
you mentioned 250 VAC - I believe that most freezers in the states run on 110 volt and usually recommend a 15 amp service

if the relay is designed for 250 volt and 10 amps if you are only running 1 leg in it (110 volt ) it should be able to handle 20 amps correct ?

thanks steve[/QUOTE]



No, that is the total amps, period. Amps rating has nothing to do with voltage.


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## vacuumpumpman (Apr 3, 2012)

take a look at this formula
http://www.ohmslawcalculator.com/ohms_law_calculator.php


amps are directly realated to voltage


check any ohms law and it will change the output of amps if the resistance stays the same - but only the voltage changes

thanks steve


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## robie (Apr 3, 2012)

vacuumpumpman said:


> take a look at this formula
> http://www.ohmslawcalculator.com/ohms_law_calculator.php
> 
> 
> ...




This is not really related directly to Ohm's law.

The idea of a rating like 250V at 16 amps says you should not exceed 250volts, nor should you exceed 16 amps.

If you go over 250V you may get arcing.
If you go over 16 amps, you will likely burn the surface of the contacts. So if you have only 12 volts, but 20 amps, you will likely burn the contacts.


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## vacuumpumpman (Apr 3, 2012)

Thanks for the clarification !

steve


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## JetJockey (Feb 27, 2013)

Chiumanfu,
Why break the tab on the white side of the outlet, since you are jumpering to the other white screw? Wouldn't it be the same if you use one white wire from the controller to one white screw terminal on the outlet and both white screw terminals will be connected via the tab?

I understand that you have to break the black side tab to control the heating and cooling independently.


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## Chiumanfu (Feb 27, 2013)

Yes you are absolutely correct. If you know what you are doing you can leave the neutral side tab intact. I just found it easier to show in the diagram with a wire jumper.


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## olusteebus (Feb 28, 2013)

Would you put an aquarium submersion heater directly in the must?


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## vacuumpumpman (Feb 28, 2013)

olusteebus said:


> Would you put an aquarium submersion heater directly in the must?



Yes that is what I do


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## olusteebus (Feb 28, 2013)

vacuumpumpman said:


> Yes that is what I do



That being the case, I will definitely get me that temp controller.

Thanks


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## Chiumanfu (Feb 28, 2013)

A submersible aquarium heater already has a thermostat built in so you will not need a temp controller if you are putting it directly into the must. My only suggestion is that you use one of the ceramic types. The old style glass heaters are prone to cracking if exposed to air and it's very possible that will happen as you are stirring and racking.

Aquarium heaters do work well for the primary bucket but they do not work so well for a carboy. Some people put the carboy in a large bucket filled with water and then use the aquarium heater to heat the water which heats the carboy.


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