Fridge Temperature Controller

[BeerCrisp]

Hi all,

After some help with a fermenting fridge I have, works great at fermenting temps, but when I go to cold crash it struggles to get below 8°C (46°F). After some reading on forums I decided removing the thermostat would result in the compressor running non-stop and my external temperature controller can maintain the correct temperature. Behind the temperature knob at the back of the fridge I cut the two wires to the thermostat and wired them to each other.

Sadly no luck, still not getting to the low temps. I then had a look at the main control unit diagram and noticed a temperature controller, so I cut these wires and wired them together making a loop and hoping to bypass it. Yet still no luck, compressor turns itself on and off only maintaining 8-12°C

I've attached the main controller diagram to this post. I'm not sure if temperature controller was the right thing to be bypassing? Maybe something to do with the compressor side, temp fuse? I'm not sure, would love to hear people's thoughts if I can get the compressor running 24/7 and let my extrenal temp controller maintain it.

 

[grampamark]

Maybe I’m overlooking something, but if you have an external temp controller, why are you mucking about with your fridge’s wiring? Set the fridge thermostat to max cool, set the compressor delay to 10 min on your temp controller, set the temp to ferment or chill with the external controller, and life will be good.

All of that said, before you started using this unit for fermenting, did it cool? Would the fridge cool to normal fridge temps, say, 34-40°? If not, you might be low on refrigerant, have a blocked condenser, or some other mechanical problem with the unit.

 

[BeerCrisp]

Maybe I’m overlooking something, but if you have an external temp controller, why are you mucking about with your fridge’s wiring? Set the fridge thermostat to max cool, set the compressor delay to 10 min on your temp controller, set the temp to ferment or chill with the external controller, and life will be good.

All of that said, before you started using this unit for fermenting, did it cool? Would the fridge cool to normal fridge temps, say, 34-40°? If not, you might be low on refrigerant, have a blocked condenser, or some other mechanical problem with the unit.

It was a friend's unit, they said it was working fine when they gave it to me. Though with fermzilla and gas bottle in it it's struggled to get to normal fridge temps. That's why I've been fiddling with the wiring, assuming the thermostat in the fridge isn't allowing it to get as cold as possible.

 

[grampamark]

It was a friend's unit, they said it was working fine when they gave it to me. Though with fermzilla and gas bottle in it it's struggled to get to normal fridge temps. That's why I've been fiddling with the wiring, assuming the thermostat in the fridge isn't allowing it to get as cold as possible.

OK, just to confirm, you were told it cooled, but did you try it before you started fermenting in it? A refrigerator doesn’t have to work very well to maintain ale fermentation temps.

 

[BeerCrisp]

OK, just to confirm, you were told it cooled, but did you try it before you started fermenting in it? A refrigerator doesn’t have to work very well to maintain ale fermentation temps.

Used it for a week with just beer bottles and it stayed at 34°F but this most recent ferment then cold crash it hasn't dipped below 46°F and I have no idea why. So I started reading and mucking about with the thermostat / internal temp controller. I might just bottle this latest brew and troubleshoot to see how low temp gets with nothing in it and what I can do to fix it.