STC-1000 replacing refrigerator thermostat

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passivestamina

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Ok so,
First post here and I'm a novice when it comes to electrical work, but here goes.

I bought a used fridge that functioned fine and I wanted to install an stc-1000 in the refrigeration area, and still maintain the ability to use the freezer. So my thought process was:
1. disconnect the fridge thermostat, and connect hot & neutral to the STC1000 cooling terminal.
2. splice hot & neutral to the STC1000 main power.
3. ferment beer.

So I cut a hole in the door of the fridge, took out the old fridge thermostat which looked like this.

Brown on the bottom is neutral, gray on the top was live from the defrost switch, green is ground, black is livee always on.

So I've
1) spliced black (live) to connect to the defrost timer and STC1000 main power
2) Spliced the brown (neutral) to the cool neutral and main STC neutral
3) Spliced the gray (live from defrost) to the STC 1000 cool live line

Plugged in the fridge, light turns on, fan turns on, STC turns on, cool timer blinks, wait 1 minute for timer to end, cool switch kicks on, STC resets (flashes all 8's on display), STC shows temp and cooling timer is counting down.

So I think the problem is the compressor is pushing too much (higher than 10 amps) through the STC and the STC is resetting itself.

I think if I ground the STC (is that possible?) or lower the amount of pushed through the STC (I think this would affect the compressor), it might work.

But... how?




https://drive.google.com/file/d/0B5rezoWE9YRjM3hFZkk5a2xOdDA/edit?usp=sharing
https://drive.google.com/file/d/0B5rezoWE9YRjM3hFZkk5a2xOdDA/edit?usp=sharing
https://drive.google.com/file/d/0B5rezoWE9YRjMHV5bEtTU21LRlU/edit?usp=sharing
https://drive.google.com/file/d/0B5rezoWE9YRjTlE1Q2tvZUFNd1U/edit?usp=sharing



IMG_20140319_162616.jpg


IMG_20140319_162619.jpg


IMG_20140319_162623.jpg


IMG_20140319_162631.jpg
 
.....Brown on the bottom is neutral, gray on the top was live from the defrost switch, green is ground, black is livee always on.

So I've
1) spliced black (live) to connect to the defrost timer and STC1000 main power
2) Spliced the brown (neutral) to the cool neutral and main STC neutral
3) Spliced the gray (live from defrost) to the STC 1000 cool live line

.....
There is no cool neutral. The STC1000 cool terminals are simply a switch that routes current from terminal 7 through a relay contact to terminal 8. Use this terminal pair to control the HOT that would normally be controlled by the existing thermostat.

I can't speak with certainty about the wiring because I can't really make out the difference between black and brown. And no photos of the as-installed STC1000 were provided. Is there a wiring diagram you could post?
 
By cool neutral I mean the white (not ground) line. Here's my fridges wiring diagram, and my own wiring diagram.

Hotpoint Diagram.jpg


STC WIRING DIAGRAM 1.jpg
 
There is no Cool/White/Neutral at the STC1000.

Based on the schematic:

Brown along the left is the HOT buss. This HOT should be used as the always live HOT to power the STC1000, let's say terminal 1.
Orange along the right is the Neutral buss. The only neutral connection to the STC1000 would be terminal 2.

Essentially, you want STC1000 terminals 7 & 8 to be connected to brown and gray with the thermostat removed.

Your Diagram:
I'm not sure what the color convention for you diagram is. Hot=black, Neutral=tan, or the opposite.
Regardless, it is incorrect. For example, in the schematic, the defrost timer does not have a direct connection to both legs of "line in". And the switched (terminal 7 to 8 ) line, by way of the defrost timer, cannot be the same as the fixed line into the compressor.

Keep in mind, that this modification may not result in the freezer maintaining freezer temperatures. The current thermostat monitors and controls freezer temperatures. The STC1000's probe, I assume, will be monitoring fermenting wort temperature.
 
Yeah...
I messed up that diagram. I made it without the gear in front of me.

But, the good news is I fixed it. Basically, I had the black and brown running to the main power of the STC 1000. The black line switched on the compressor from the brown line and turned off the STC when I had it connected. So I just ran it to the orange and brown on main power, and brown and black on the cooling switch.

So here's to hoping it stays up and running. Thanks for the help.
 
That's great you got it working. Just keep in mind that using brown and black on terminals 7 & 8 will bypass the defrost control, which may become a problem.

In addition, if the defrost control is still powered via the existing thermostat through the gray lead, the defrost heater will fight the compressor. The defrost timer can actually be back-fed powered via the black lead, although it shouldn't do much if it trips.
 
Any updates? I'm thinking of doing the same thing. Does the freezer still work? Does the lack of defrost control pose a problem?
 
Bump...

I'm looking at bypassing my Frigedaire's thermostat (Fridge with top freezer) with the STC-1000.

It is a very similar project to this thread and would like to see how it worked out.
 
From my perspective, if the thermostat is functioning. Just plug the refrigerator or freezer into the STC-1000 set the temps you want and turn the temp control in freezer/refrigerator to coldest setting , done! Freezer/ refrigerator will attempt to keep running and the STC will control temp.
 
From my perspective, if the thermostat is functioning. Just plug the refrigerator or freezer into the STC-1000 set the temps you want and turn the temp control in freezer/refrigerator to coldest setting , done! Freezer/ refrigerator will attempt to keep running and the STC will control temp.

It is a simple setup..but here's my question:

What effect does the defrost timer have in using the STC-1000? Should it be bypassed - requiring a manual defrost every once in a while or will that damage the compressor?
 
Just an update, looks like I won't be needing a temperature controller. After modifying the existing Thermostat's set screw, I was able to get it down to about 38 degrees. I'd prefer 36, but I'll take as cold as I can get.
 
From my perspective, if the thermostat is functioning. Just plug the refrigerator or freezer into the STC-1000 set the temps you want and turn the temp control in freezer/refrigerator to coldest setting , done! Freezer/ refrigerator will attempt to keep running and the STC will control temp.

Until the fridge decides it's time for defrost. I had to bypass my fridge thermostat (pretty much just bridged the wiring) so that it would allow lagering temperatures and not kick back up to 40°F in defrost mode.
 
Quick, perhaps silly question. Does hot vs neutral matter when wiring the stc-1000? I seem to find a lot of conflicting opinions.
 
I have a Frigidaire FFTr1715LBF (freezer on top, one thermostat, thermostat controls both chambers and freezer adjusts with a baffle)

I want to replace the existing thermostat control and temp probe with the STC1000 since now at its warmest setting it is still at 48-50 degrees and I want to be able to hold it at 55-60 for fermentation of my ciders. Plus is seems to vary WIDELY from 45-55 every time I open the door to look at the temp ( I have a digital thermometer inside to check temp )

I just bought a STC1000 but have NO CLUE how to work around the auto defrost issue, (and of course, the freezer will probably not be cold enough but I can live with that unless you know another way)

Could anyone possibly advise me on the wiring ?

Many thanks

WIRING DIAGRAM FROM Frigidaire attached
 
ALWAYS switch the hot as was said before. Switching neutral can get you lit up, as components will be hot when not running. If ground is ify you can touch metal cabinet barefooted on garage floor and find yourself tossed across the room. Nothing worse than a piece of equipment that lost neutral.
On the bypassing of defrost: Is this necessary? There is a defrost terminator on all of them that shouldn't close untill below freezing. Should have temp stamped on it somewhere with a differential as to when it reopens. Unplugging an end of the element would work also for anyone whos fridge isnt in the heat, as I wouldn't think the 30-40 min defrost time shouldn't change fridge temp much without a load on it.
 
From my perspective, if the thermostat is functioning. Just plug the refrigerator or freezer into the STC-1000 set the temps you want and turn the temp control in freezer/refrigerator to coldest setting , done! Freezer/ refrigerator will attempt to keep running and the STC will control temp.
I don;t believe you have assessed the set up you proposed correctly.
I can't see how you can have two thermostat probes controlling one compressor; that's why most write ups include warnings:
To disconnect the existing fridge thermostat.
Accept that controlling the fridge internal space (where the kegs are) will have unpredictable results on the freezer section if such is present.
I can't say this for certain, as I am just now doing the STC 1000 install.
 
I don;t believe you have assessed the set up you proposed correctly.
I can't see how you can have two thermostat probes controlling one compressor; that's why most write ups include warnings:
To disconnect the existing fridge thermostat.
Accept that controlling the fridge internal space (where the kegs are) will have unpredictable results on the freezer section if such is present.
I can't say this for certain, as I am just now doing the STC 1000 install.

System works, fridge does not know what is trying to occur. Unit is told to keep running. The external control turns power on and off as needed with controls to keep unit from cycling too soon. Have one running this way for nearly a year now without incident. External control probe is under a quart jar of yeast slurry.
 
I don;t believe you have assessed the set up you proposed correctly.
I can't see how you can have two thermostat probes controlling one compressor; that's why most write ups include warnings:
To disconnect the existing fridge thermostat.
Accept that controlling the fridge internal space (where the kegs are) will have unpredictable results on the freezer section if such is present.
I can't say this for certain, as I am just now doing the STC 1000 install.

"Well, actually"...I reckon 8 out of 10 folks using external controllers do exactly the same thing: set the oem fridge/freezer control to its lowest temperature setting, then plug the line cord into the external controller.

fwiw, I've been running two fridges and a freezer like that for years...

Cheers!
 
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