My STC Build (with pics!)

[DethApostle]

I'm putting a full write up on my website later today but thought I'd post a short version here too.

The shopping list:
•220V STC-1000
•3 20mm IP68 Weatherproof Cable Gland
•Plastic Electronics Project Box (216 x 130 x 85mm)
•2 Trailing Mains Extension Sockets
•15 AMP Block Connector Strip
•13 AMP Fused 3 Pin Plug
•1.5mm 3core Flex Cable
•1ft Electric Tube (Greenhouse) Heater
•Under-counter fridge
Total cost c. £70 (including £20 fridge off ebay)
The bits!

Drill the holes. (Buy. A. Dremel.)

Wiring Diagram

My wiring!

All done! Simples!

Once the build is complete the probe itself needs to be calibrated against a known temperature such as boiling water or in my case I used a thermometer that I had already verified as accurate.
The STC has 4 settings:
•F1 – Temperature Setting
•F2 – Temperature Variance Setting
•F3 – Compressor Delay
•F4 – Probe Calibration Value
F1 is set to the temperature you require (19C in my case for fermenting an IPA).
F2 allows you to define how accurately you want the STC to get to that temperature. For example a setting here of 0.5 degrees will send power the cooler when the temperature reaches 19.6C, a setting of 0.2 will turn the cooler on at 19.2C.
F3 controls the delay in turning the fridge compressor on and off. Rapid switching the compressor on and off can reduce its working life, a setting of 3 minutes is pretty standard here it seems.
F4 allows you to calibrate the probe. I found that the default probe was reporting 3.5C lower than my trusty thermometer so if I set my STC to 19C with no corrections I was actually only holding a temperature of 15.5C inside the fridge! Not ideal for fermenting beer! This was corrected by setting F4 to -3.5 and now 19C is actually 19C!
And that’s all there is to it!
DA

 

[TheRedDarren]

Great stuff! Will be doing this at some point this week and I'm a bit nervous about the wiring, what's the link to your website so I can read the full write up?

 

[DethApostle]

Here you go.
http://demonvalleybrewing.co.uk/2015/08/31/diy-stc-fridge-controller/
It's supposed to be on my profile but that's not working as intended it seems! :P

Just copy that wiring diagram perfectly and it is easy enough. That's the bit I was most bothered by but it turned out a lot easier than I thought!

DA

 

[Bunglebrewsbeer]

Where did you get the temp probe from?

 

[TheRedDarren]

The earth goes to the heater/cooler socket, is that a double socket to two wired in series?

 

[Labowner]

I think the temp probe normally comes with the stc 1000 on eBay. I'm guessing that the earth is wired in parallel to two separate trailing sockets but I could be wrong.

 

[ManseMasher]

That's the way I did mine - the diagram should have two earth leads coming out of the connector shown, one for the heater socket, the other for the cooler one. The STC does indeed come with a temperature sensor.

 

[TheRedDarren]

Great, thanks guys

 

[Bunglebrewsbeer]

I'm confused as to the wiring? Is that diagram incorrect then from what has been said? ( I'm no electrician ).

 

[Pirate_Pete]

Mine is wired slightly different, but with the same end result.
The wiring is quite simple really. If I can do it.......

I have read (I think on the Coopers forum) that some STC's have the heating and cooling in different positions. I haven't seen that though. Mine is the same as above.
I have a second one on it's way. I'll take a look at that, but it should be the same as I bought it from the same ebay seller.

 

[Pirate_Pete]

I'm confused as to the wiring? Is that diagram incorrect then from what has been said? ( I'm no electrician ).

As I said I wired mine slightly differently, but with the same result.
Take a look on youtube. There's heaps of videos and watching a video
might make more sense. I'm not say follow this one, but take a look.

[ame]https://www.youtube.com/watch?v=30TvX1Zz1-Y[/ame]

 

[Bunglebrewsbeer]

Not watched it yet. But I see a soldering thing. Not used one of them since at school. Was useless with it then. I doubt I've improved with 20 years of not touching one since!

 

[Pirate_Pete]

Not watched it yet. But I see a soldering thing. Not used one of them since at school. Was useless with it then. I doubt I've improved with 20 years of not touching one since!

I didn't use solder. I just used connectors.
Sorry I was thinking that you should watch the video for the wiring
rather than the soldering. I'll take a pic of mine later and post it.

Labowner has built one. He says he's a sparky. Maybe ask him for a pic.
But honestly, it's not hard.
http://www.thehomebrewforum.co.uk/showthread.php?t=56422

 

[Bunglebrewsbeer]

I'm thinking of getting one to convert a chest freezer to store some cornys and a few taps ( I dream ). I take it I wouldn't need a heat source for this just something to flip the freezer off when it had chilled down to a set temp. Or am I totally wrong?

 

[ManseMasher]

I'm thinking of getting one to convert a chest freezer to store some cornys and a few taps ( I dream ). I take it I wouldn't need a heat source for this just something to flip the freezer off when it had chilled down to a set temp. Or am I totally wrong?

You'll only need a heat source if you want to use it as a fermentation chamber, I would think?

 

[Bunglebrewsbeer]

Not to ferment its to make a keezer

 

[ManseMasher]

Not to ferment its to make a keezer

Yep, understand that mate, that's why I think you won't need a heat source. When you set up your STC, make sure you adjust the cycle time setting with a bit of a delay, otherwise your freezer could be on and off like the undercrackers on a lady of the night....

 

[Bunglebrewsbeer]

I'm a bit off doing this so when I get to it expect some questions.

 

[ManseMasher]

Any time mate!

 

[Labowner]

I'm confused as to the wiring? Is that diagram incorrect then from what has been said? ( I'm no electrician ).

The diagram is correct except for the earth which should be shown splitting at the terminal (block connector) and continuing with two wires. One to the heat socket and the other to the cooler/fridge socket.
Hope that helps [emoji3]