STC 1000 "Ebay" Temperature Controller Build

I appreciate the advice. I'll think about it as I build the collar. Since the Johnson controller is already on the way with other components I may just return this one to my friend. I don't like the thought of buying and connecting power outlets to it.

 

This is the device I'm talking about. It looks nearly identical:


Well if two in series isn't a good idea, I'll probably just use the Johnson controller, since I already paid for it, I don't want to deal with purchasing/wiring power outlets, and its display is in Fahrenheit. I appreciate the advice. Thanks!

 

That is the STC-1000, not the single stage unit.

Wiring one controller downstream from another really is a bad idea for many reasons, and if you're not totally comfortable with wiring outlets, that's even more reason to just use the johnson. Good luck!

 

Dang... now the chinese are knocking off their OWN products! I wonder how many places in china make these things???

 

Anyone know if the STC-1000 will push enough amps to start up a Holiday 7cu chest freezer set up in my garage?

Here are some specs from the back of the freezer:
Voltage: 115v~60Hz
Amps:1.70A
Startup Amps: 12A

 

You should be fine. There is some debate about the actual rating of the relay, but either way it's close enough to 12A that it shouldn't be an issue. If the running load were close to the rating, then it could be an issue, but the startup draw only lasts a split second. I popped the cover on my controller, and the relays say 15A @ 125V.

 

How'd you get the cover off? I'm still considering returning it so i dont want to break it or void a return policy somehow.

 

I honestly don't remember, it was a couple years ago. I do remember that I had to slice the wiring diagram sticker on top of the unit, so it will be apparent that it's been open if you try to return it. I think someone has directions with pics for taking it apart in the main STC-1000 thread (for replacing the transformer for those who ordered the 220V unit on accident), but that thread's 3,000+ posts long.

 

In order to get the cover off you must either cut or remove part of the label on the top of the STC-1000. Cut it where the front section joins up to the cover. Then carefully spread the tabs on each side and slide the cover back off the unit. There isn't a way of doing this that is not obvious to anyone looking at the unit that it has been disassembled.

 

That rating is at 220v, is it still 10 amps at 110v?

 

Most of the relays are rated for 15A @ 125V. The rating of the contacts and other components at lower voltages is debatable, but should be at least 10A, and probably slightly more.

 

Here is a question from a total novice. Why do you go through all the wiring joining and use the ground as neutral? Can't you just run power to the unit, one set of in wire, and then one set of wires from cooling to the plug as well as the heating to plug? I note there is not ground wire used.

 

On my diagram, all grounds are connected, all neutrals, and all constant hots. The only neutral that goes into the controller is to power it. Everything else is constant or switched

 

I see all that now, thanks! On this setup you were going to run a frig and fan. Run the frig on the cool cycle and the fan on the heat? Or run both on the cool? Or wire one outlet constant on and run the fan constant on?

 

I have mine set up to turn the fan on during cooling cycle

 

Ok I’m on the hunt for an old fridge to use as a fermentation chamber for my 1 gal batches and have this device on the way from HK. I’m going to follow these wiring instructions and I think this will be an easy build. Now I have some dumb questions. So you set the fridge temp to the max (warm) and then use the STC1000 to control the cold to keep it at your desired fermentation temps? My fridge will be outside here in GA. So it won’t get too cold this winter but I can see some dips into the 30s. Will I need to run some sort of heating device on the heat outlet or will the fridge maintain a constant 58-70 degrees? I think I understand what this device will do but want to make sure I have it set up properly to maintain my temps. I will have to re-read this thread.


Now reading the post above why would you have a fan on the cooling cycle? I thought you would want your fridge on this outlet. I guess this is where I get confused??

 

I have two outlets, one for heating and one for cooling. The fan is plugged into the cooling outlet with the fridge. If you're gonna get down to the 30s I would definitely get a heater. Walmart sells a personal heater that'll work for around $11. You have to make sure it's not computerized otherwise it'll need a user to manually turn on and won't work for this application

 

You'll almost certainly need a heat source in the fridge then as well, unless your ferments are putting out a lot of heat.

If you use a duplex outlet for each function (heat and cool and maybe one constant hot) then you can plug two devices in - so the refrigerator and fan can both be on the cool circuit.

 

Thanks for the replies all. Would something like this work instead of a fridge?

http://augusta.craigslist.org/hsh/3255214447.html

 

Sure, but you'll want to either cover the glass with foil or something else to block the light, or use completely opaque fermenters. UV light will skunk a beer in no time.

 

Oh that looks neat. I don't see why you couldn't use that. You can also probably get the thermostat in it just set where you want, at least for the cooling. Naturally would still need a heat source as well if the ambient temp is going to be below your desired ferment temp. That style might be easier to use for 1 gallon batches because of the shelves.

 

Ahh yes that makes sense. It will be in my garage which doesnt get much light. Cool.

 

Anyone know what kind of temp probes these use?

 

Believe it to be a simple thermistor. It includes the probe. It's definitely not an RTD.

 

NTC thermistor, 10k @ 25°C, 3435 beta.

 

Be aware that some EBAY sellers have jacked the price 10X because "low supply". I asked the question and he answered.

 

That's a good piece of mind. I happened to order one from him a few hours ago for a build.

 

I pick one up from amazon and it came straight from china. It took maybe ten days to get to my door. Same price as the ebay one and free shipping.

 

I will be running the standard build of this unit on a GE 7 Cuf chest freezer. Should I also be adding a 10a fuse before the unit? I read through A LOT of the megathread and never noticed anyone mentioning adding a fuse.

Thanks

 

In this application, a fuse isn't really necessary, since you have the upstream breaker at 15A or 20A. Obviously you would need to bear in mind you wouldn't really want a continuous load of more than 10A on it. The relays apparantely say 15A on them, but that doesn't necessarily mean the screw connectors and solder traces on the board can handle that much. You could certainly put in a fuse if you want to. Some people like to have a 1A fuse going to the STC's control power. I would imagine it has a fusible link on the circuit board anyway for the control power though I could be wrong.

 

Side note on the STC-1000: I compared the temperature reading to a much more expensive instrument, and the STC-1000 was within 0.2C at room temperature. That's much better than I expected at this price.

 

That is nice. And if you did happen to nice a relatively constant offset vs a calibrated source in your target control range, it has an offset you can set to compensate for the displayed value.

 

oops, should have read the rest of the thread before posting. I see others have already pointed out the schematic errors.

The relays on this diagram appear to me to be hooked up incorrectly. The coil and contacts seem to be reversed from what they should be.

 

Hello All, this may have already been posted in this thread, but I purchased two of these from Amazon for $49 on 07 Nov and they shipped that day and arrived in my mailbox today from China.

 

Yep. Mine came with a bunch of Chinese writing on it and customs declaration. Made it across the pacific and to Texas in something like 9 days. Pretty remarkable.

 

Yea some if those companies are really quick.

 

Ok, so I got my temp controller built and it seems to be working good but I have one question. Can you drill into the side of a fridge? Just the old school fridge on bottom and freezer on top fridge. I want to mount my controller to the side of it but don't know if I will drill into lines and destroy my fridge. Any input would be helpful.

 

I think that the coolant lines in a fridge are generally in the back... but I am not sure and I wouldn't drill. Maybe you can find a service manual for your fridge?

You could also consider using industrial-strength Velcro. That's good stuff.

 

Velcro is a good idea. Thanks for the help

 

Just got my STC-1000 today, working on the project box tonight. Can't wait to fire up that craigslist freezer and actually have controlled ferments instead of the texas closet temp!