Another request for thermostat wiring & STC-1000 help!

[Beer0clock]

I just ordered an STC-1000 because I was really unhappy with the temperature swings of my Danby Designer mini fridge.

I'm trying to read up on how exactly to install the thing so that I'm ready to do it as soon as it arrives.
It seems that theres 2 main ways to use the STC-1000:

1) wire it "in line" with the existing thermostat

2) wire it so that it bypasses / replaces the existing thermostat

I want to do option #2, because frankly I dont even understand how #1 even works. Why would you want the crappy Danby thermostat in the picture at all? Why not let the fancy STC-1000 do its job?

It seems to me you absolutely need to "hot-wire" the Danby thermostat to be always on, then let the STC-1000 have complete control over when to power on the fridge. Thats option #2.

Anyway, I know this must have been anwered a dozen times already on the forum but I'm having a hard time finding exactly what I need.

Please see the attached pic. I know nothing about wiring or elictricity stuff. I'm pretty confused as to why I'm seeing 6-7 wires here. How can I completely disable the Danby thermostat, thereby making the fridge always pumping cold air? I have a feeling its just a matter of joining 2 of these wires together, but I dont know which 2.


Thanks!!

 

[revco]

I think you're going about it the hard way. You don't necessarily need to integrate the STC into the freezer's internal wiring in any way, especially if you're not doing a thermostat replacement. (Which I'm not even sure works with the STC, as it's a particular type of T-stat.) The STC will come with a probe, which you bring into the keezer/fermentation chamber and measure either ambient or liquid temps by insulating it against what you're trying to measure.

From the power side, you'll have an input to bring in power from the wall. There are also two relay outputs that are designed to switch cooling sources and heating sources, based on what is needed by the STC programming. If you simply wire the freezer's power input to the STC, you'll be set for cooling. Then, if you want heat to warm things up if they get too cool, you would wire the heat into the heat side relay. The STC relays will usually switch the hot side of the circuit, whereas neutral is shared between the STC and the power for the freezer or heater. You're just simply applying power to heating or cooling, depending on which the STC senses it needs from the temp probe.

A nice, handy way to do this is via one of the kits seen in the sponsor showcase section. I built my own kits originally, but it didn't turn out as nice as the pre-fabbed kits you can get relatively inexpensively. Brewsbysmith is who I went with, simply because he had them in stock ready to ship and was willing to work with me to get exactly what I wanted. It does take some soldering, but it's super simple to do. From there, you just plug in your freezer and heater plugs to the kit and route the temp probe where you want it, and voila, full dual temp control down to a degree.

Just an FYI, it is far more stable to measure liquid temps than ambient air temps. Ambient air will change significantly in a freezer, whereas the liquid has higher thermal mass and won't change nearly as quickly. This is usually what we want to control anyway, so I think it's the way to go.

 

[Beer0clock]

I think you're going about it the hard way. You don't necessarily need to integrate the STC into the freezer's internal wiring in any way, especially if you're not doing a thermostat replacement. (Which I'm not even sure works with the STC, as it's a particular type of T-stat.) The STC will come with a probe, which you bring into the keezer/fermentation chamber and measure either ambient or liquid temps by insulating it against what you're trying to measure.

From the power side, you'll have an input to bring in power from the wall. There are also two relay outputs that are designed to switch cooling sources and heating sources, based on what is needed by the STC programming. If you simply wire the freezer's power input to the STC, you'll be set for cooling. Then, if you want heat to warm things up if they get too cool, you would wire the heat into the heat side relay. The STC relays will usually switch the hot side of the circuit, whereas neutral is shared between the STC and the power for the freezer or heater. You're just simply applying power to heating or cooling, depending on which the STC senses it needs from the temp probe.

A nice, handy way to do this is via one of the kits seen in the sponsor showcase section. I built my own kits originally, but it didn't turn out as nice as the pre-fabbed kits you can get relatively inexpensively. Brewsbysmith is who I went with, simply because he had them in stock ready to ship and was willing to work with me to get exactly what I wanted. It does take some soldering, but it's super simple to do. From there, you just plug in your freezer and heater plugs to the kit and route the temp probe where you want it, and voila, full dual temp control down to a degree.

Just an FYI, it is far more stable to measure liquid temps than ambient air temps. Ambient air will change significantly in a freezer, whereas the liquid has higher thermal mass and won't change nearly as quickly. This is usually what we want to control anyway, so I think it's the way to go.

I may very well be going about it the hard way.. But just to clarify because I'm not sure you understood what I was looking for.
Basically my Danby minifridge thermostat is trash because its fluctuating everywhere between 35F to 60F and I have it set to the lowest/coldest setting.

The general advice is to let the STC-1000 turn on and off the fridge, and set the fridge to the coldest. The assumption is that the coldest setting on the fridge is colder than you would ever need. But as I said, the fridge sometimes only cools to 60F. So I want to jumper the stock thermostat to be "always on" and then let the STC-1000 have complete control. I know that I only have to join 2 wires together to bypass the thermostat, however there are 6 wires there so I dont know which 2.

 

[Beer0clock]

Ok well I managed to get the compressor running by joining the black and red wire, and leaving all the others disconnected.

Now I'm looking at my STC-1000 and the voltage is something I've never seen before.

I bought the 110VAC model, and it says 110VAC for the input power, however the Heating and Cooling both say 220VAC ! Whats up with that, is that bad?

 

[badandy519]

Ok well I managed to get the compressor running by joining the black and red wire, and leaving all the others disconnected.

Now I'm looking at my STC-1000 and the voltage is something I've never seen before.

I bought the 110VAC model, and it says 110VAC for the input power, however the Heating and Cooling both say 220VAC ! Whats up with that, is that bad?

Never noticed that before... Just looked at the exact one I have and a few others on Amazon that have decent pics and they're all the same. You should be fine.

 

[ChuckO]

Ok well I managed to get the compressor running by joining the black and red wire, and leaving all the others disconnected.

Now I'm looking at my STC-1000 and the voltage is something I've never seen before.

I bought the 110VAC model, and it says 110VAC for the input power, however the Heating and Cooling both say 220VAC ! Whats up with that, is that bad?

The heating and cooling mention of 220VAC simply means that the relays are rated to be able to switch up to 220VAC without problems. The key word is "up to".