Keezer Thermostat Bulb Hanger?

[Sixbillionethans]

Does anyone have a particularly good method of mounting their Johnson Controls thermostat bulb in their modified chest freezer? I've looked through threads and didn't find anything.

Details:
- I've got a 7cu.ft. chest freezer with a 4" collar.
- Thermostat is fed into freezer thru hole in collar.
- Currently, I've just got bulb dangling in there.
- I've heard and would like to adopt the suggestion to submerge the bulb in some freeze gel goo.

What I'm looking for is a nifty way to combine all the above into a sturdy package mounted into corner of freezer. I'd like a sturdy mounting device to protect wire & bulb when I move kegs in/out, move hoses around, take bottled beers out. Anybody have a good solution?

 

[jaja]

I run mine down thru the collar and into a small glass of blue goo from one of those cheap ice packs you get for sports injuries. I heard of problems with the bulb not being stainless and not being suitable for being submerged but I've not had any problems and it prevents the freezer cycling a whole lot.

It come in from the back and into the glass in the corner and doesn't get in the way at all with the way my kegs sit, in fact I rarely touch it.

 

[Gritsak]

I'm also interested in this. I've got a mini-fridge and just hang mine from the top, but i've seen others use the blue goo. I'm wondering if this keeps the temps more consistent?

 

[Sixbillionethans]

I unexpectedly had some time to work on this last night, and came up with a nice solution. If I see any activity on this thread, I'll post a pic.

- I used a 12" long vertically-oriented 3/4" copper pipe with a cap soldered to the botom.
- I filled the pipe with the blue goo from a freezer pack and put the thermostat bulb down into it. This is my "thermowell".
- I capped (press-fit) the top of the copper pipe with a 3/4" pvc cap with a slot sawed into it (to allow the thermostat wire to pass thru).
- I used a "copper bell hanger" from Lowe's and a standoff to mount this contraption to the freezer collar so the bottom is sticking down into the freezer.
- Finally I used some staples to secure the thermostat wire to the collar.

What I like about this:
- It secures the bulb and wire so they aren't just hanging there, just waiting to get knocked around. (I've read that the thermostat wire is slightly fragile.)
- The copper pipe is a nice thermal conductor, while the blue goo serves to dampen the temperature swings of freezer.
- It puts all the business into the back corner so it's totally out of the way.
- And, most of all, it only took me 10 minutes at the hardware store and 20 minutes of actual work.

 

[JesseRC]

I thought the temperature probes were not water proof?

 

[Sixbillionethans]

Gonna have to look into the waterproof-ness of the probe/bulb.

Anyone else have any experience?

If necessary, I'll swap out the thermowell goop with some dry media. Or I'll remove it entirely. The copper pipe should be good enough for temperature modulation. Opening the freezer wouldn't cause the motor to kick on immediately.

 

[JesseRC]

From the Ranco store:

"The 1309007-044 sensor is a negative temperature coefficient (NTC) thermistor sensor. The sensor resistance decreases with temperature increase. It is .25"X1.94" long with 8 feed of #22 AWG cable. The thermistor has a reference resistance of 30,000 ohms at 77°F(25°C).

This sensor can be used to replace the one that came with your Ranco ETC digital temperature controller or multiple sensors can be wired for average temperature sensing. See the instructions for your controller for wiring instructions and recommendations. Instruction for then Ranco-ETC-1110000 can be found here.

Note: The manufacturer does not recommend the sensor be directly submersed in liquids. They recommend using a thermal well (bulb well) to protect the sensor."

They sell a a heatshrink thermowell for submersingin aquariums:
http://www.rancoetc.com/etc-sensors-c-24.html

 

[Sixbillionethans]

Thanks for input JesseRC

I've got a Johnson Controls thermostat and the instruction manual really doesn't say anything about water applications...

HOWEVER

I did dump out the blue goo and just used the copper pipe as my temperature modulator. Here's a pic of the setup.

 

[JesseRC]

Looks nice. What is the Tee connection at the top for, is that what holds it in place? Yeah the probe looks like my analog control I have, that may be safe to submerse. I'd do some research and if its safe, I'd put the blue jell back in. Good job.

 

[kinison_fan]

Nice clean setup.
Even without the blue stuff, the copper pipe should protect the probe from quick temperature swings.

The only thing I noticed is it may still be too close to the wall of the freezer which will turn the unit off sooner (before it reaches the target temp for the air space).

 

[Sixbillionethans]

Looks nice. What is the Tee connection at the top for, is that what holds it in place?

The Tee is a copper bell hanger which is screwed into the collar thru a short length of copper pipe as a standoff. It holds it close to the wall of freezer to stay out of the way, but is rigid enough to keep it from touching. (About 3/4" on both sides)

The only thing I noticed is it may still be too close to the wall of the freezer which will turn the unit off sooner (before it reaches the target temp for the air space).

Good point, I've been keeping track of air temperature to check if there is an offset.

 

[jetlink1983]

I'm trying really hard to type this with a straight face. Wrapped my probe in a trojan and stuck it in the blue goo. It only cycles a few times a day and holds temp perfectly!