Keezer Thermostat

[dante42]

So I decided that the time had come to get serious and build a keezer. I build it and it seems to be good. I tried to do the turning screw method of adjusting the thermostat, but no dice. Or more accurately, no screw.

So I ended up order a new thermostat. One of those that the freezer plugs into and has it's own probe. Of course it came with no directions. But really how hard is it to drill a whole and push a probe through it.

The problem is that the keezer will not cool down. I have the thermostat set to 30 degrees, but the freezer will not drop below 50 when connected to the thermostat. I'm not sure what I need to do, so suggestions would be appreciated. The ideas I have are:

• Time - The thing has been running for 18 hours. Maybe it needs more time to cool down, but it did not change temp after running all night.
• Location - I put the probe in the freezer and the thermostat box outside on the back. Maybe the thermostat box needs to go inside the keezer too?
• Water - I have read that some people put the probe in water to get the beer temp to match the water. But the ambient temp should not be affected by that.
• Bad - The thermostat is just bad.

So, suggestions? Anyone had this problem?

 

[novahokie09]

The first thing I would check is your deadband range setting. Without knowing your model, it's hard to say what it is, but my Ranco ETC has an adjustable range from 0 - 30F. I set mine between 2F - 5F.

However, if my setpoint was 30F and had a deadband of 20F, then it would make sense that the freezer wouldn't go below 50F because the thermostat would stop transferring power to the load (compressor) at that temperature.

Also, does your freezer get below 50F without the controller?

 

[dante42]

Yes, the freezer gets very cold (-something) without the thermostat.

Deadband huh? I had to look that up. I did not know that was a thing. The thermostat came with no instructions. So that means I have no idea how to adjust a deadband. This is the model that I bought. Now that I look at it, I am concerned since it does not seem to have a brand.....

 

[rekoob]

The "dead space" is really called the differential. As nova said, on some controllers you can set the differential to what you want, that prevents the freezer from coming on to fast. I don't see online directions for that controller, are there any other adjustments on it other than the main set point on the front?

What you could try to make sure your controller is working how you think it should, plug in a light to it and adjust the temp set point to ambiant temps and see if the light comes on/off when you adjust the set point. Then, you can hold the probe in your hand to make the light turn on after a few seconds of warming up the probe.

I would think it's a set point on your controller that is just not right.

 

[novahokie09]

I wasn't able to find the answer either from the Amazon link and a google search didn't really come up with useful results either.

Also, thermostats actually work with hysteresis, not deadband. Sorry for the misinformation, but the concepts are similar in that once it gets to a setpoint it changes the voltage. Hysteresis will only be on/off whereas deadband can give different output voltages depending on the signal.

 

[socalboomer]

Is your temp controller in Celsius? Mine came default at 20deg but 20deg C is 68deg F so it may not actually DO anything!

 

[dante42]

Still no joy. The thermostat dial clearly says Fahrenheit. I came downstairs to find the freezer light off signifying that is was not receiving power. The interior temperature is 50.

I am assuming that I do not need all 10' of the probe coil in the freezer, right? Even if I did, it should read warmer, not cooler.

 

[IFMracin]

You do have the freezer's built in thermostat set at its lowest setting, correct?

 

[socalboomer]

As in coldest setting. . . When I said that to a buddy he was like, "you don't want it to cool?"

 

[SpookyAlmond]

Do you have a fan in there to move the air around? When I built mine there was a serious temperature differential from top to bottom in the freezer. A PC fan spliced into an old cell phone charger solved that pretty quick.

 

[bmc1313]

you drilled a hole through the side? are you sure the freezer still works without the controller?

 

[FuzzeWuzze]

you drilled a hole through the side? are you sure the freezer still works without the controller?

This, drilling a hole in the side is a bad idea, for all you know you hit one of the condenser lines and thats why it wont cool anymore.

 

[Junkster]

Try putting the probe in a container of ice water, and plug a lamp into it. See if it trip on / off near the low end of the dial and play with it warming the probe to see if it works at all. Maybe you got a dud... Some mechanical 'stats have a differential adjustment - either a slider or a screw arrangement, so check that as well.