DIY Temp Controller for Freezer?

[CollinsBrew]

I was wondering if anyone had a less expensive way or could point me in the right direction of making a temperature controller for a freezer that I am going to use for lagering?

I can get a Johnsons for $50 at www.bevergefactory.com but am trying to not spend a whole lot more money on my setup than I already have this month. Any DIY's on this? Thanks!!

 

[Yuri_Rage]

Hmm...not sure if I can come up with one that's too much cheaper. Check eBay for Ranco ETC-111000 controllers - sometimes you can find them for around $30.

 

[Jaybird]

that rancho ETC works good as Yuri said SOMETIMES 30 bones but few and far. 50 bucks is a really good deal consider it my gift to you..... just send it to yourself COD
JJ

 

[tron]

you might be able to rig up a temp controller with a dial control for AC. I believe they go down to 50 degrees and you could wire that in to the thermostat that is in the freezer. i think this would be pretty easy if the thermostat for the freezer is simple like two wires, i have not done this only thought about it for future use. let us know if you decide to go this route.

 

[CollinsBrew]

I found this last night while looking through some other posts. He says something at the bottom of the page about not being able to hook up 120 Vac because it will blow the capacitor.

Would the relay he is talking about work for the power plug to the freezer and if it did would it be cost prohibitive? Also, is there any way to tell the temperature differential to keep the unit from clicking on and off constantly?

 

[Yuri_Rage]

EDITED (different relay part number)

You'll need a power supply (wall wart) capable of switching the relay. You could use a 12V relay and cheap power supply. I know, that doesn't help make it cheap, but if you want a relay that could be controlled by the batteries in your thermostat, it'd cost another $25.
Here's something to consider with that project - you'll need (assuming you have a soldering iron and solder):
RiteTemp Thermostat - $24
Relay - $7
Power supply - $6
Wire - ~$5 (I like to use short extension cords - they look professional and don't cost much)

Now you're up to $42, which is roughly the cost of a purpose-built temperature controller in the first place.

On the bright side, it looks like a fun project...

 

[Yuri_Rage]

Also, is there any way to tell the temperature differential to keep the unit from clicking on and off constantly?

This installation guide has a few good notes:

http://www.ritetemp-thermostats.com/images/8029B_installation_guide.pdf

It doesn't list the temperature differential, but it does indicate that it has a "4-minute minimum off time in COOL."

 

[CollinsBrew]

If I were to purchase a Ranco ETC that's not prewired how would I attach the power to the freezer to the controller?

 

[D2T]

If I were to purchase a Ranco ETC that's not prewired how would I attach the power to the freezer to the controller?

Look at the bottom of this page for a PDF that outlines wiring for the Ranco temp controller: http://www.honeyrunapiaries.com/store/goldline-sp30-replacement-ranco-p-88.html

It's not very difficult. Just take a short extension cord, cut it and wire as shown. Drop me a PM and I can supply some pictures of mine if that helps.

 

[Beerrific]

EDITED (different relay part number)

You'll need a power supply (wall wart) capable of switching the relay. You could use a 12V relay and cheap power supply. I know, that doesn't help make it cheap, but if you want a relay that could be controlled by the batteries in your thermostat, it'd cost another $25.
Here's something to consider with that project - you'll need (assuming you have a soldering iron and solder):
RiteTemp Thermostat - $24
Relay - $7
Power supply - $6
Wire - ~$5 (I like to use short extension cords - they look professional and don't cost much)

Now you're up to $42, which is roughly the cost of a purpose-built temperature controller in the first place.

On the bright side, it looks like a fun project...

I was going to do something like this for a fridge I have. I got a Ranco instead, the price difference would have been nothing because I was going to use the thermostat from my house and buy a new programmable one for my AC.

I went with the Ranco because of the probe, I can put it wherever, don't have to worry about the thermostat in the fridge or removing anything from it.

 

[CollinsBrew]

Alright, I have been scoping out the Johnson Controls Tem controllers on Ebay and am a bit confused on which model will work for freezer purposes.

The one I am looking at specifically is the A19ABA-40C. The guy said that this one can't be used for what I want to use it for because it is an DPST and not an DPDT. What the heck does that mean? Also, the temp adjustment is done with a screwdriver instead of the knob......big deal.

DPST= Dual Pole Single Throw
DPDT= Dual Pole Dual Throw

Now that I know that why do I need one over the other?

 

[D2T]

I found this last night while looking through some other posts. He says something at the bottom of the page about not being able to hook up 120 Vac because it will blow the capacitor.

Would the relay he is talking about work for the power plug to the freezer and if it did would it be cost prohibitive? Also, is there any way to tell the temperature differential to keep the unit from clicking on and off constantly?

He said if you need to switch anything higher than 24V you need to use an external relay. Basically the temp controller triggers the relay coil and that will close the connection to your 120VAC connection, turning on your freezer.

His second-to-last picture looks like it might diagram that kind of setup. I can't enlarge it because work blocks photobucket though.

So you'd need a SPST relay tied into the hot line going to the freezer with the temp controller triggering the coil that throws the switch. (or DPST if you want to break both the hot and neutral lines to the freezer to be extra careful). And the external temp probe he makes earlier up in the article.

The way it's outlined in that link is very doable, but you must be careful because you're dealing with 120VAC and IT WILL KILL YOU IF YOU'RE NOT CAREFUL.

 

[CollinsBrew]

That I know....I've had had my fair share of 120Vac experiences. I do repairs on audio equipment (power amps and such) and learned real quick what points should and should not be touched.

 

[Yuri_Rage]

See here for a decent explanation of SPST, DPST, and DPDT.

DPST will work for your application and is a bit of overkill for a 120VAC circuit, assuming it has the load capacity to support your freezer. You REALLY don't need a DPDT controller.

At the risk of sounding harsh (I've been doing that a lot lately, I think), if you need to ask these sorts of questions, you probably shouldn't be wiring anything that you plan on plugging into the wall without the (hands on) help of someone a bit more knowledgeable.

EDIT:
The part number you gave appears to be an SPST controller - which is what I would prefer if I were wiring a controller up to a freezer.

 

[CollinsBrew]

It's not harsh...I can follow directions however and have some experience working with electronics. I'm more a hands on person so not being able to see it in front of me doesn't help. Not only that but the .pdf files I have been looking at on Johnson Controls website in reguards to these haven't shown me much in the way of wiring. Maybe someone has found something that explains it a little better. I was more so confused with all of the different model numbers of the A19 series....AAA, ABA, ABC --49C 24C blah blah blah.

Plus....I'm trying to learn.

 

[Yuri_Rage]

I know you're trying to learn, and we're here to help...I just don't want anyone to get hurt or start any fires. It makes me feel a little better that you mention some experience with house current.

This page should help a bit with the A19 series controllers. Note, none of them are double pole designs, so whoever told you about the controller either gave you the wrong part number or the wrong info. Almost all of them will work for your application except the SPST-open high design and the ones outside your operating temperature range. If you use a SPDT controller, you'll have to determine which side of the switch is open in a low temperature condition in order to wire it properly (look at the diagram at the top of the page I referenced...it's the Y-terminal).

 

[user 574]

Just tossing something out here. I got a Ranco ETC single stage (111000 model) for $53.10 and that included shipping off ebay. Company is Thermal Resources and that's their everyday price. In case you ended up being close to that price with the Johnson Control flavors, this group would probably recommend the Ranco over the JC. Only thing left to have is an extension cord to splice in. And there is help here on wiring.

 

[D2T]

Just tossing something out here. I got a Ranco ETC single stage (111000 model) for $53.10 and that included shipping off ebay. Company is Thermal Resources and that's their everyday price. In case you ended up being close to that price with the Johnson Control flavors, this group would probably recommend the Ranco over the JC. Only thing left to have is an extension cord to splice in. And there is help here on wiring.

Yeah, I spent a few bucks more from the place I linked earlier.

The main reasons I was willing to buy a ready-made instead of doing it myself:

- I prefer not work with mains power if I can help it
- My DIY setup wouldn't look as nice. If I spent the $ on a project box/etc. it'd probably end up costing more than the Ranco
- I had already dropped so much loot on my kegerator that $20 was just a drop in the bucket

And I always warn people regarding 120VAC in any forum/conversation I have regardless of how educated I think they are. Doesn't hurt to re-state an important fact! No disrespect intended.

 

[CollinsBrew]

After all of that searching it looks like my best bet is to buy the Ranco ETC 111000from Thermal Resources off of Ebay. I went ahead and about my extension cord today and will order the Ranco tomorrow. Until I start lagering I'll now have a full size upright freezer to keep all of my beer cold.......now if I could convine SWMBO that I *need another refrigerator kegging.