controlling both fridge and freezer separately?

[bierandbikes]

I am about to purchase a refrigerator or freezer for a fermentation chamber. There are obviously pros and cons to each. The freezer is an easy plug into an external controller like the STC or Inkbird, but requires finding one without an automatic defrost (I want an upright).

A refrigerator does not have the issues of defrosting but may have difficulty getting down to 32F for a lager.

My ideal set up would be a standard over/under refrigerator/freezer with the larger fridge section wired for beer and the smaller freezer section wired for cheese.

This is where the questions begin. Can these be controlled separately with an external temp controller? If both compartments are cooled by a single compressor, how do I deal with this? Are they typically cooled by a single compressor with separate coils? Assuming that I could control them separately, would I need to wire the temp controller into the appliances original system, essentially replacing the factory thermostat? Seems easy enough to wire in a new, more precise thermostat, but what about a heat cycle if I need to raise the temp?

I am sure that I am not the first person to ponder this issue, but did not find a thread on point. If there are existing resources, please direct me to them.

 

[stoneBriar]

Every fridge I have ever seen cools the freezer section down really damn cold and occasionally pumps cold air into the fridge section from the freezer. In this set up there is no way to independently control the fridge and freezer (that I can think of).

 

[Brettomomyces]

You would need to separate the thermostat from the damper that allows cold air into the fridge section and control each independently, but if you're shooting for a cold fridge and warmer freezer this won't work. But this is just spitballing, never tried it myself.

 

[Shockerengr]

Except for the really high end fridges, here's how they work:

There is usually (not always) two knobs to control temp.
The knob for the fridge portion contains the "thermostat" and turns the compressor on and off. setting it colder makes the compressor run more.
The knob for the freezer portion controls an air damper between the fridge and freezer section. setting it colder lets less air into the fridge from the freezer (keeping the freezer colder) Some of the cheaper fridges omit this adjustment.

If you want to control the two better, you'll need to mechanically modify the fridge to get control over the airflow between the two sections.

 

[PlexVector]

Except for the really high end fridges, here's how they work:

There is usually (not always) two knobs to control temp.
The knob for the fridge portion contains the "thermostat" and turns the compressor on and off. setting it colder makes the compressor run more.
The knob for the freezer portion controls an air damper between the fridge and freezer section. setting it colder lets less air into the fridge from the freezer (keeping the freezer colder) Some of the cheaper fridges omit this adjustment.

If you want to control the two better, you'll need to mechanically modify the fridge to get control over the airflow between the two sections.

My side by side has the thermostat controls in the frig section. The freezer section is controlled by a thermostat that it's temp probe is in the freezer and controls the compressor.

The frig thermostat controls a fan and/or damper door that pulls the cold air from the freezer section into the frig.

In this case you just need run the fan from your own controller and use the freezer as a freezer set lower than usual or run each with its own controller.

Or you can run the freezer section at 35F as a keezer since it is going to be a lower temp, and the frig section as fermentation since it is higher. Of course that's with both hooked to a controller.

 

[HObrew]

Except for the really high end fridges, here's how they work:

There is usually (not always) two knobs to control temp.
The knob for the fridge portion contains the "thermostat" and turns the compressor on and off. setting it colder makes the compressor run more.
The knob for the freezer portion controls an air damper between the fridge and freezer section. setting it colder lets less air into the fridge from the freezer (keeping the freezer colder) Some of the cheaper fridges omit this adjustment.

If you want to control the two better, you'll need to mechanically modify the fridge to get control over the airflow between the two sections.

Sorry to revive an old thread but would it make more sense that the freezer knob would control the compressor and keep the freezer cold and the fridge knob would control the fan and push freezer air into the fridge as needed until it hits temp?

The reason I ask is because I wanted to see if i could keep the freezer for my keg wraps and bottles but use a temperature controller in place of the refrigerator control knob to control the fan to the fridge so I can maintain temperature in the 60's for fermentation control (my house can hit the 80s in the basement in the summer.)

 

[Marcelo Medeiros]

I am about to purchase a refrigerator or freezer for a fermentation chamber. There are obviously pros and cons to each. The freezer is an easy plug into an external controller like the STC or Inkbird, but requires finding one without an automatic defrost (I want an upright).

A refrigerator does not have the issues of defrosting but may have difficulty getting down to 32F for a lager.

My ideal set up would be a standard over/under refrigerator/freezer with the larger fridge section wired for beer and the smaller freezer section wired for cheese.

This is where the questions begin. Can these be controlled separately with an external temp controller? If both compartments are cooled by a single compressor, how do I deal with this? Are they typically cooled by a single compressor with separate coils? Assuming that I could control them separately, would I need to wire the temp controller into the appliances original system, essentially replacing the factory thermostat? Seems easy enough to wire in a new, more precise thermostat, but what about a heat cycle if I need to raise the temp?

I am sure that I am not the first person to ponder this issue, but did not find a thread on point. If there are existing resources, please direct me to them.

Hi Buddy.

Did you ever got a solution for this?

Thanks

 

[robertlhawley]

I have a rig that essentially works like plexvector suggested. Side by side, the freezer section is wired into an stc-style thermostat, and set for my kegs. I installed a fan in the duct between the freezer and fridge sections, and that is wired to the cooling circuit of a brewpi to use the fridge side as a fern chamber. Unfortunately the pandemic put it on hold as we decided to use that space as extra fridge space for now, so I've never fermented in it yet.

But I can tell you that with the keezer side set at 35 F, the fan can get the fridge side down to about 40, but no colder. So cold-crashing will take longer with this system.

Hope this helps!
-- bob