Bypassing fridge thermostat. How?

Yorg · 08-28-2008, 07:11 AM

Bought myself a fridge, and have an external controller for it.
But let's say I want to lager at 0 Celcius / 32 F.
The fridge's own thermostat would turn the power off, and I would never get to 0.
So how do you bypass it?

BarleyWater · 08-28-2008, 07:16 AM

Not sure if this is possible, and it would likely be dependent on the make and model of the unit, but I would also like to know how if it is.

Most people use freezers that have no problem getting down that low, most fridges can't quite get there.

brewjunky · 08-28-2008, 07:49 AM

It is possible you just have to know what you are doing and I can't help you with that. I want to do the same thing to a fridge that I have.

You have to find the wire that leads from the thermostat to the compressor and tie the power out into it from the controller.

Then you have to find a wire that is always hot to keep the controller on for the power in. If you do that you will by pass the thermostat but I have no clue where to find that when I attempt it Im going to be trying to figure it out.

**Bobby_M** · 08-28-2008, 02:55 PM

I'm going to assume the stock controller works as a switch just like the external controller. It makes or breaks a connection. You should find two wires leading into the controller. Cut them both and wirenut them together. This effectivly turns the fridge into a deep freezer given no external controller.

**IrregularPulse** · 08-28-2008, 06:09 PM

Is it possible that the compressor on a fridge versus the compressor on a freezer simply wouldn't be rated to cool to temps that low? Or do you think/know that the compressors used in fridges and freezes are the same and just capped by temp control? With your fridge there should be heating and cooling specs. maybe could even pull the model number off the compressor being used and google it to find a spec sheet on it, Not the specs of the fridgedaire/whirpool/magic chef system. This would tell you what the compressor was capable of. as far as wiring in the controller look the the schematic included with the fridge manual and sub in the controller switch for the thermostat switch. If you don't understand electricity don't attempt yourself. People under estimate 110V because it's everywhere, It's still plenty to kill you.

BarleyWater · 09-04-2008, 08:13 AM

OK, so I figured it out with my fridge. I'm using a Haier Wine Cooler, it fits a carboy just right.

My fridge's thermostat only allowed the compressor to run until the temp reached 40ish, with the lowest setting at 45, and let it warm back up to 48 before the compressor kicked back on. I found the wire leading to the thermometer, and discovered that it was right behind the backplate of the fridge. After removing the backplate and CAREFULLY bending it aside, I was able to detach the thermometer from the back of the unit.

I ran the thermo out from behind the backplate, took off the dome light and lined the inside with foil, and put it back on with the thermo inside the dome. Now, I have it so the unit will turn on and off with the help of a Ranco or Johnson control (haven't purchased yet). When it turns on, the light turns on, but doesn't expose the beer to any light because of the foil, and heats the inside of the dome light where the thermo is. Inside the fridge can get as cool as I need now, while the internal fridge thermo reads in the 90s.

Weizenheimer · 09-04-2008, 01:29 PM

Hmmm...I was trying to figure that out with an old fridge i'm about to purchase. It has a freezer compartment on top of the frindge compartment. Can I not just cut out the bottom on the freezer and the top of the fridge and make it one chamber. Then install a temperature control?

brewjunky · 09-06-2008, 08:44 AM

O.k I just did this on a fridge from 1956 and it was a nightmare but I finally got it going.

On my fridge on the back where the compressor is there was a relay that turned the compressor on and off.

This wasn't your run of the mill Relay it had about 8 wires going to it and was really confusing.

I decided to bypass the relay and use the love controller after many combination's of wiring I got it going.

So it is possible i'm thinking on a newer fridge it would have been a little easier.

I'm mounting the love controller n the door I will post pics after

HopnHooch · Today, 02:42 AM

I researched a lot, and was a bit worried about cutting the wires, but installing my temperature controller took about 5 minutes once I got to it.

The fermentor/kegerator I have is a Kenmore 5.7' model, no ice compartment, its part number is 9588.

This model has a digital display on the front, and control for the stock thermostat. To keep that and the light active you don't want to just plug the fridge into the controller.

So, after probing some wires and finding the compressor (which is conveniently inside a hatch/door near the back), I figured I could just wire the Ranco controller directly to the compressor. By keeping the other wires intact the rest of the fridge works the same.

With three twist connectors and a couple snips it was all done. I just cut an extension cord in half and hooked the white and black wires to the compressor, the green to ground, then plugged it into the Ranco controller.

The other connections that were on the compressor, I just made sure were intact, except for the control lead (a red wire from the control board).

Done. Do it. The fridge was off by about 5 degrees, so I am happy I just decided to control the fermentor this way instead of turning the fridge on and off to do a diactyl rest!