Refrigerator thermostat wiring

[danm1]

I have the top loading Adler Barbour freezer and adjacent fridge on my Hunter 356. The freezer thermostat is frozen and won't adjust. I want to replace it with a digital STC 1000 if possible, but I don't understand the wiring
Can anyone identify the positive, negative or load by color in the attached pics? Are these all the wires I need? Thanks.

 

[marcham]

Tstat is a simple on/off circuit, there should only be 2 wires.

http://sailing.mit.edu/wikiupload/7/7e/Adlerbarbour_manual.pdf

 

[Rich Stidger]

I have wired this same controller to my refrigerator and I have a second one to connect to my freezer. The wiring is simple.

The two wires on the original mechanical controller simply close the circuit to power the compressor to start cooling.
Here is a picture of the controller connections:

Simply connect the existing thermostat wires to terminals 7 & 8 (no polarity).

Connect the sensor to terminals 3 & 4 (no polarity). I placed the sensor in the same spot as the original temperature bulb so that the temperature of the plate will be controlled. This means that the temperature that is displayed is that of the plate and not the temperature of the box. You will have to experiment with the controller set-point to determine the setting to achieve the box temperature that you want. I used a differential setting of 4 on my refrigerator controller. That should be a good starting point for you.

Connect 12V power to terminals 1 & 2 (no polarity). I connected this power input to the compressor input power so that when I turned on the refrigerator the controller would power up as well.

There are no connections to terminals 5 & 6.


Easy-peasy. Good luck. It is a great upgrade.

 

[danm1]

Easy is relative. Are the green wire and the connection wrapped in red the "existing thermostat wires"? Are there 12v wires there or do I have to run them from somewhere else (the compressor)? If so, any trick to getting them thru into the back of the freezer without disassembling the boat?

 

[marcham]

Your existing TStat is mechanical, not electronic, thus it does not have 12VDC input. Your new electronic TSTAT will not be located i the fridge/freezer. You'll need DC power from the compressor unit to the TSTAT, you'll need a temp sensor from the fridge/freezer to the TSTAT. And you'll need to redirect the two control wires from the old mechanical Tstat to the new digital one. Drill the fridge/freezer, pull the temp sensor, then seal with duct seal compound (grey putty available at home depot).

Did you review the manual and associated wiring diagram I posted above? It has several examples of electronic thermostat wiring....

Do you have the spillover fan option in your existing install? If so, you'll have to make sure that wiring is maintained.

Is there a resistor between the yellow wire and the red spade connector? Resistors are covered in the installation manual.... this may have been a modification by the previous owner, so you may have to assess your install prior to proceeding.

Why not just replace with a mechanical unit though? They are super reliable from a mechanical standpoint and relatively cheap.

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www.rparts.com

 

[danm1]

I didn't realize the mechanical replacement was available for so little. I'll probably do that and go sailing. I haven't opened the spillover fan control . Is it the same part?

 

[Hayden Watson]

For what it is worth, I converted my mechanical tstat to digital and it made very significant reduction in the total energy used.

 

[bugsboat]

I added a computer fan, to circulate air and reduce frost build up. I also have a temperature sensor inside the box to make sure the box stays below 38 degrees

 

[jviss]

I know this is an old thread, but it's one of my favorite topics.

Regarding where to get the 12V for the Inkbird STC1000 thermostat, note that the wires for the old thermostat plug into a four contact RJ-11 connector on the control board. Two of those pins are for the t-stat to call for cold, and the other two are - dah dah! - 12V. See the manual.

 

[Hayden Watson]

I know this is an old thread, but it's one of my favorite topics.

Regarding where to get the 12V for the Inkbird STC1000 thermostat, note that the wires for the old thermostat plug into a four contact RJ-11 connector on the control board. Two of those pins are for the t-stat to call for cold, and the other two are - dah dah! - 12V. See the manual.

Exactly.
I just grabbed an old phone chord from my old cables box and cut the end off and used that to wire the Inkbird into the fridge. I left the old mechanical T-stat installed with the wire still running out to the compressor. If the Inkbird ever dies, it is a simple matter of unplugging the new chord and plugging in the old one.

 

[jviss]

Exactly.
I just grabbed an old phone chord from my old cables box and cut the end off and used that to wire the Inkbird into the fridge. I left the old mechanical T-stat installed with the wire still running out to the compressor. If the Inkbird ever dies, it is a simple matter of unplugging the new chord and plugging in the old one.

Hey Hayden, where did you mount the Inkbird, in the box, or outside?

 

[Hayden Watson]

Hey Hayden, where did you mount the Inkbird, in the box, or outside?

I mounted the Inkbird on the bulkhead over the ice box so that it is easy to see from most anywhere in the main cabin. Having a digital display of the box temperature would be enough to go to this setup. The fact that it also makes the power usage go down significantly is a huge bonus.


The probe has a 3' wire and passes through a small hole drilled through the box. I used a zip tie to attach it so that it is on the bottom of a shelf in the box. That way, it is always exposed to the air in the box rather than being pressed against so heat sink. I do not have a photo that shows the probe but it is under the tape measure in this photo.

 

[jviss]

Very nice, thanks. Yea, I don't really have good place to mount it within view of the cabin, without cutting holes in things which I am shy about doing. Plus, I'm mounting two of these; I modified a low voltage disconnect to give me a relay closure when the system voltage is above a set point, i.e., a charging source is present, so that the second t-stat can drive the box colder in that condition. I'll set the primary at something like 38º to 40º, and the secondary to 32º or 33º.

 

[duck21]

What make/model low voltage disconnect are you using/modifying?

I recently rewired my Adler Barbour unit and realized that with my setup I may not be protected against running the batteries down with the compressor fan/pump (I believe the controller is supposed to do that, and will with the compressor, but with my current wiring layout I think the fans will continue to run regardless).

Between that and your idea of dual thermostats I like the idea of a similar setup with a voltage disconnect to manage temperatures and protect the battery.

Doug

I modified a low voltage disconnect to give me a relay closure when the system voltage is above a set point

 

[Hayden Watson]

If you need to have the display farther away, you can add a longer length of wire. The only downside is that changes the total resistance and in introduce a small error to the temperature. You can calibrate the probe with the longer wire so that it is corrected. After changing the wire length, put the probe into a bowl of ice water. Any time that you have water and ice in the same container, it will be 0ºC 32ºF.
To get the greatest accuracy, use distilled water for both the water and making the ice

 

[jviss]

What make/model low voltage disconnect are you using/modifying?

I recently rewired my Adler Barbour unit and realized that with my setup I may not be protected against running the batteries down with the compressor fan/pump (I believe the controller is supposed to do that, and will with the compressor, but with my current wiring layout I think the fans will continue to run regardless).

Between that and your idea of dual thermostats I like the idea of a similar setup with a voltage disconnect to manage temperatures and protect the battery.

Doug

It's an XH-M609 module, available on eBay for $2.39, qty. 1; they get cheaper if you buy more.

XH-M609 D C 12-36V Battery Over Discharge Protection Module US

Now before anyone gets upset, no, it's not a "marine LVD," by any stretch; nor is one necessary in this case.

To modify it as I have to run the second thermostat:

• cut the traces that connect the negative “IN” to negative “OUT,” and the positive “IN” to the relay contact terminal
• connect a wire from that relay contact terminal to the negative “OUT” terminal.

This mod will give a relay closure across the “OUT” terminals when the voltage is above the LVD setpoint. Use this to connect the output of the second tstat to the output of the first tstat, so the second overrides the first when there's a charging source present; in other words, the outputs of the two tstats are "WIRED-OR." ("OR" as in Boolean logic.).

Then use another, unmodified LVD to either interrupt the power to the fridge.

 

[Hayden Watson]

What make/model low voltage disconnect are you using/modifying?

I recently rewired my Adler Barbour unit and realized that with my setup I may not be protected against running the batteries down with the compressor fan/pump (I believe the controller is supposed to do that, and will with the compressor, but with my current wiring layout I think the fans will continue to run regardless).

Between that and your idea of dual thermostats I like the idea of a similar setup with a voltage disconnect to manage temperatures and protect the battery.

Doug

You could use something like this but the control signal would need to go to a relay because its working capaicty is not large enough to handle the loads from the compressor. It has more functions than you need with the delay start timer but you can just set that to 1-second.

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