Replacing the Temperature Controller on my Freezer

[_TheTrevster_]

In this thread I will describe the steps I took to replace the stock temperature controller that came with my Chest Freezer with an aftermarket controller. Most of the temperature controller threads I have seen involve creating an outlet that the controller turns on and off, plugging the freezer into that outlet, and then hanging the probe inside the freezer. My preference was to utilize the existing space to create a cleaner and simpler design. I initially intend to use the freezer as a fermentation chamber, and have future plans to modify it further into a Keezer. The steps I took for this project were gathering supplies, removing the old controller, and installing the new controller in its place.


Step 1:Supplies

• Chest Freezer (Mine is a 7.0 cubic foot GE Chest Freezer (model FCM7SUBWW).

• Temperature Controller (http://www.newegg.com/Product/Product.aspx?Item=9SIA1NV1055349).

• 12 gauge stranded copper wire

• Twist-on Wire Connectors

• 6" x 6" Junction Box, I chose this part is for aesthetics only, as I plan on painting the Freezer in the future. (http://www.amazon.com/dp/B000HEIX6W/?tag=skimlinks_replacement-20)

Step 2: Removing Old Temperature Control
First I removed side vent, which let me access the clips on the back of the front face plate. I removed the clips, and was able to detach the face plate from the freezer. The connection I had to unplug were the positive/negative for the ‘Power On’ light (Red/Black & White/White), the positive/negative for the temperature control unit (Red & Black), and the natural ground (green).

The only connection left was the temperature probe, which came inserted into a plastic tube into the bowels of the freezer. I pulled this out and removed the entire controller. This left a hole in the front of the freezer where the previous controller and faceplate were.

Step 3: Installing the New Temperature Controller
The first task was to remove the connectors from the ends of the wires for the old controller, which looked like this:

I cut them off and stripped them. Next I cut four 6” lengths of wire, stripped them, and inserted them into the new controller. I now had bare wires coming out of the freezer, and bare wires coming out of my new temperature controller. All that was left was to connect them. This diagram outlines the connections I made.

Using the stencil that was included in the instructions, I measured a spot for the controller on the lid of the junction box. I cut out the stenciled shape with a coping saw, though a Dremel or other power tool would have been much easier. I set the junction box lid, now my new faceplate, into place and primed the screw holes with a drill. I inserted the new controller into the freshly cut lid, and connected the loose wires to the freezer’s wires using the twist-on wire connectors. I inserted the new temperature probe into the plastic tube that housed the old probe. Before I screwed the new face plate onto the freezer, I tested to make sure everything was working properly.
Success!

 

[NTXBrauer]

Nice job. I built a temp controller, with an external utility box, using the same digital controller you have. I like how you were able to integrate it into the front of the freezer where the original control panel was.

 

[Seven]

Nice job. Does that controller allow you to set a temperature range to prevent short cycling the cooling unit?

 

[_TheTrevster_]

Thanks for the feedback!

@Seven: Yes the controller does allow you to adjust the temperature range. The default is 2 degrees, but I upped mine to 3 degrees to reduce the number of cycles. It also lets you specify whether its heating or cooling, delay the start, and offset the temperature for any corrections that may be needed. Here is the Diagram that comes with the unit.

CP is the temperature range, i've heard this referred to as the hysteresis cycles, but the manufacturer classifies it as "Slewing Range".
CA is the temperature correction, I have mine set 3 degrees, because my probe is built into the wall of the unit, not hanging free in the freezer.

Hope that helps, it's an amazing unit for the price. You could defiantly get a higher quality one with more features, but at $14.66 you can't lose.

 

[dbrewski]

Well done. I have a Frigidaire I want to use as a fermenation chamber and a very similar controller. This is a very clean way to do it, hope I have the same panel.

 

[TNugent]

Nice work, thanks for the write-up!

 

[Oddball]

I did the same thing with mine, but I haven't added a nice plate like yours (haven't got to it yet). The temp controller is just hanging out in the opening for now. The only problem that I have without the added heat source is that sometimes it gets too cold when I am lagering. If the temp is set very low the compressor will come on and end up dropping about two degrees lower than what I set it. I think maybe the censor recognizes that the temp has reached the target but because it is a new unit the combination of the compressor working very hard and the insulation ends up dropping it a bit lower.

 

[_TheTrevster_]

@Oddball: I believe the way this unit (and the STC-1000) works is that it cools/heats until the probe reaches the set temperature. I know this sounds obvious, but if you have your controller set to 34 degrees to lager, the compressor will be on full blast until 34 degrees. This may account for the temperature dropping below freezing. I suggest initially setting your controller to a higher setting (40 degrees?) and then dropping it down in the increment that your "slewing range" is set to.

 

[fleetmack]

new poster to homebrewtalk here. I've read many posts on how to install one of these STC-1000 and, until this thread, it has appeared that people have been adding an STC-1000 to work in tandem with the existing temp. controller. So the STC-1000 will tell the existing controller when to turn on the compressor.

It appears your method is to remove the OEM temp. controller altogether, and simply install the STC-1000 as your sole temp. controller. So my questions:

1) Am I correct in what I am seeing here?
2) Am I over-thinking this? This method seems way more simplistic than using the STC-1000 in tandem with the OEM temp. controller. Why don't more people do this?
3) What are the pros/cons of this method vs. using the OEM temp controller + the STC-1000?

I should note that I'm only interested in cool temps to chill my beer, not heating the unit.

Thank you!

 

[day_trippr]

fwiw, I'm pretty sure a wire is transposed in the "after" diagram.

The black wire from the plug should be going to the controller pins 3 (power) and 1 (or 2) for the relay to the compressor. The other black wire should go from the relay pin 2 (or 1) to the compressor.

As drawn the controller would never power up...

Cheers!

 

[_TheTrevster_]

fwiw, I'm pretty sure a wire is transposed in the "after" diagram.

You're absolutely correct! Thanks for keeping me honest.

Corrected diagram below.

 

[_TheTrevster_]

1) Am I correct in what I am seeing here?
2) Am I over-thinking this? This method seems way more simplistic than using the STC-1000 in tandem with the OEM temp. controller. Why don't more people do this?
3) What are the pros/cons of this method vs. using the OEM temp controller + the STC-1000?

Welcome! I'm new myself and happy to help.

1) Yes you are correct, the only temperature controller in the unit is the aftermarket one.
2) It is more simplistic! There certainly isn't a right way, but I prefer this method.
3)Pros: Simple!, no external plug needed, no surge protectors were harmed in the modification of this freezer.
Cons: Less freedom with probe placement, more difficult to revert to factory settings, buttons are near the ground?

I would be interested to read what others, who have tried different methods, can add to this pros/cons list.

 

[fleetmack]

Thank you! I'm not really concerned with being more difficult to revert to factory settings; I'm pretty sure when I paint it black it's going to void the warranty anyway Got a GE 7.0 for $157ish ($189 Black Friday + $10 Coupon + 10% Discover Cash Back) brand new, it gets delievered next week and I've already got all my parts and my temp controller. Just trying to figure out how to best paint it and best hook up this temp controller.

I love the idea of fully replacing the existing temp controller, and I love the idea of placing it in the original spot, rather than in the collar. Being a chiller only, I can't imagine I'm going to be changing the temperature all that often. I'm far from an electrician, so I'm going to spend a bit more time looking at your diagram. Thanks for posting, this is a very clear depiction of what I need to do, your post & responses are much appreciated!

 

[ZombieCat]

Nice job! I ended up doing the same thing with my chest freezer, pull out all the factory wiring and wire the STC-1000 directly. I am fairly lazy after a "job" is done so I never got around to doing a thread on it.

For mounting the STC-1000 I cut my mounting plate (from an old plastic food tray) to the shape of the opening where the factory controls were. I was thinking of all sorts of ways to avoid drilling screws to hold it in place so as to keep a nice flush look. I finally ended up super gluing it then on the back use duct tape. Some real fine engineering there

For the wiring, I ended up drilling a hole in the bottom of the freezer and running my temp probe and heater power lines through it and sealed the hole with spray installation. It took some time to find a spot to drill but using a very dull exacto knife, I slowly poked away the foam making sure there were no cooling lines until I got to the metal bottom of the freezer floor. Even though there were no line, I was still nervous when I pulled out the drill.

I am not the best at using a dremel so I want to redo it at some point. Looks great from a distance but not so much up close.

Sorry, I did not mean to hi-jack your thread. I was just going to make a couple comments but ended up getting a little carried away.

 

[_TheTrevster_]

Sorry, I did not mean to hi-jack your thread. I was just going to make a couple comments but ended up getting a little carried away.

No problem!

I would like to drill a hole in the "side hump" for my probe someday.

One recommendation, my first Russian Imperial Stout's fermentation was so vigorous that it blew sanitizer out of the blow-off vessel. This left the floor of my freezer covered in krausen, water, and sanitizer. This wasn't a problem since the floor of my freezer is all one piece (except for the drain), but I wonder if a similar scenario will cause that hole you drilled to leak. I see you used spray insulation, but I suggest ensuring that those holes are 100% sealed so your floor/electronics are not ruined.

 

[ZombieCat]

I wanted to drill threw the side hump as well but everything I read was saying the floor was a safer bet. It all worked out as my probe was plenty long enough to go under the freezer, through the hole and into the thermowell of my carboy cap.

Now that is a seriously vigorous fermentation! I always use a blow-off tube into a 1 gallon water bottle which should be safe enough. I will definitely need to look into sealing the hole better just to be safe. Thanks for the info!

 

[_TheTrevster_]

I finally pulled the trigger and drilled through the compressor hump

:rockin:

The method I used is similar to ZombieCat's:
1) I carefully sliced a small hole in the metal with a razor.
2) I pushed a screwdriver through the insulation to probe for freon lines.
3) Once I reached the inside of the hump, I punched the screwdriver through with a hammer.
4) I insulated the inside hole with some of the sealant 'goop' the sealed the stock probe in the factory location.

Now the probe reaches inside the freezer, giving me some more options.

I also replaced the first temperature controller I purchased with an STC-1000.

I was having an issue with the old unit. It would hold any temp above 40 F but if the probe sensed below 40 F, it would drop the unit to -20 F and keep it there. I couldn't troubleshoot the issue any further so I just bought an STC-1000.

 

[ZombieCat]

I finally pulled the trigger and drilled through the compressor hump

:rockin:

Braver man than me! Glad it work out for you and that looks so much better coming out the side than through the floor.

I never got around to resealing my hole. I got my 1/4 bbl sanke fermenter up and running awhile ago and have had zero issues with blow off. Only CO2 comes out of the blow tube. So I see no need to worry about it.

 

[frechetn]

TheTrevster,
The temp controller only does one mode at a time, right? You specify the mode as either heating or cooling.

Just looking for clarification.

Thanks for the feedback!

@Seven: Yes the controller does allow you to adjust the temperature range. The default is 2 degrees, but I upped mine to 3 degrees to reduce the number of cycles. It also lets you specify whether its heating or cooling, delay the start, and offset the temperature for any corrections that may be needed. Here is the Diagram that comes with the unit.

CP is the temperature range, i've heard this referred to as the hysteresis cycles, but the manufacturer classifies it as "Slewing Range".
CA is the temperature correction, I have mine set 3 degrees, because my probe is built into the wall of the unit, not hanging free in the freezer.

Hope that helps, it's an amazing unit for the price. You could defiantly get a higher quality one with more features, but at $14.66 you can't lose.

 

[_TheTrevster_]

Paint job, stained oak collar, faucets, and plumbing. Well worth it.

 

[bembel]

I know others have asked and for those of you who understand the schematics and such this must be like explaining how to turn a computer on or off, but I feel like I am riding the short bus on this and would really appreciate some help!

Like most, I just want to hardwire an Inkbird 1000F in place of the freezer controller on the plate, which I can take off, and unplug the existing wires so nothing needs to get cut. The existing temp probe is a wire running up into a tube so I will pull that out as far as I can and cut it, then figure out putting the probe through the compressor hump.

This is a Frigidaire 8.8 model #25316949108

The power on / off switch is not on the panel but rather on the back hinge of the lid, which is why the wiring is different that in the great pics that Trevster posted.

Can any one look at these and tell me what goes where and if I need to add an extra wire to power the unit and how?

MANY thanks in advance!!!!