Johnson A149 lagering chamber setting

[TimelessCynic]

Just bought a danby designer 10.2 cubic foot chest freezer to use for lagering. I have my Johnson digital thermostat setup to it. Any suggestions on how i should set it. I currently have it set to 33 F with a 3 F differential. I want to keep my beer around 30 F to keep it as cold as possible without freezing. I am also trying to set it so the thermostat does not turn on every 15 minutes. If the freezers thermostat is rated for 100,00 cycles than it will burn out in around 3 years. I also have vacuum sealed hops in there so i would like to keep them as close to freezing without freezing my beer. I don't quite understand the temperature differential setting. Of i set SP to 30 and a differential of 5 would it shut off at 25 and turn on at 35?

 

[day_trippr]

In Cooling/Cut-Out mode, if the temperature reaches Setpoint + Differential the compressor will turn on and drive the temperature down to Setpoint, where it will turn off. So if you have Setpoint at 30 and Differential at 3, the chamber temperature should stay between 30 and 33.

As for compressor cycling, you can affect this directly by using the ASd (Anti-Short Cycle Delay). It has a range from 0 to 12 minutes, so you could set it to the maximum which will assure that no matter how you screw other things up, the compressor will sleep for at least 12 minutes between on cycles...

Cheers!

 

[TimelessCynic]

Thanks for the input day tripper. I set it to 30 F with 3 F differential. I went down this morning and noticed it showed 28 F
I am gonna toy with thermostat probe location or tweak SP up a little to get to my 30 F minimum temp. I don't want my beer freezing. I guess the evaporator still has cold energy stored up and releases it into the freezer after the thermostat turns off.

 

[day_trippr]

Yes, the overshoot on shut-down is a real phenomenon and the cause is exactly as you thought. You'll especially see that effect if you're dangling the probe in free air below the ring of evaporator coils - and in an empty freezer it'll be most apparent...

Cheers!

 

[chemman14]

I plan on attaching my probe to the side of the kegs I am lagering. Is this not advised? I figured this is the most accurate way to get the temperature of the keg I want.

 

[day_trippr]

I plan on attaching my probe to the side of the kegs I am lagering. Is this not advised? I figured this is the most accurate way to get the temperature of the keg I want.

Absolutely the best way to go. Cover the probe with a good insulator (I use inch thick closed cell foam scavenged from random product packaging) and strap it to keg or fermenter and you'll isolate the probe from ambient influence...

Cheers!

 

[chemman14]

Absolutely the best way to go. Cover the probe with a good insulator (I use inch thick closed cell foam scavenged from random product packaging) and strap it to keg or fermenter and you'll isolate the probe from ambient influence...

Cheers!

Yep, thats my plan. Currently I use a piece of padded shipping envelope for my fermentation chamber. What do you use to strap it to the keg? I just use the strap from my brew hauler but that isnt an option here.

 

[TimelessCynic]

In Cooling/Cut-Out mode, if the temperature reaches Setpoint + Differential the compressor will turn on and drive the temperature down to Setpoint, where it will turn off. So if you have Setpoint at 30 and Differential at 3, the chamber temperature should stay between 30 and 33.

I think mine came set differently i toggled my settings to 35 F and 5 F differential. It turns on at 35 and turns off at 30.

Great idea about attaching the probe to a keg and insulating it. Much better than dangling in mid air like i have been doing.

 

[Curtis2010]

I took a little different approach than Ive seen posted on my set up. I have an older manual johnson control in series (on the power side) with the A419. The manual control's probe is inside the freezer and set to the lowest temp I want in the freezer air space. The A419 probe is in a thermowell in the wort.

This prevents the freezer air space from getting too cold due to lag when cooling the wort. For example, if I want to chill the wort to 40F then I set the manual control slightly lower like 35F. If freezer air space hits this temp then power is shut off to the A419 (and thus the compressor) until the temp rises (no problem here in the tropics).

This keeps the chamber from getting too cold and allows me to set it and forget it rather than gradually tweaking the temp down.

The limiting function of the manual controller only comes into play when making large temp drops. Once the wort reaches its target temp then the manual controller typically does not cut out and the A419 just does its thing.

This is easy to do out of the box w 2 controllers. With a little more effort you could get fancy and use the "binary" connection on the A419.

 

[TimelessCynic]

Curtis,

Do you use your setup to control your fermentation temperatures more accurately?

 

[Curtis2010]

Curtis,

Do you use your setup to control your fermentation temperatures more accurately?

That's the purpose yes.

 

[day_trippr]

I think mine came set differently i toggled my settings to 35 F and 5 F differential. It turns on at 35 and turns off at 30.[...]

You're running your controller in Cooling/Cut-In Mode then. In that mode the output relay is energized at Setpoint and de-energized at Setpoint - Differential. It works just fine that way as you've found, it's just a bit less intuitive (imo) as you have to do math to calculate your target temperature

You could switch to Cooling/Cut-Mode by moving the Jump2 jumper so it covers both pins (connecting them together). Right now that jumper is only on one of the two pins so the circuit through them is "open". See page 7 of the manual...

Cheers!

 

[TimelessCynic]

Thanks day tripper, That's what I figured. Strange they would ship it as cut in mode by factory default instead of cut out. I intuitively set it thinking it was in cut out mode. I am eager to try the stuck on insulated probe.

Curtis you using a chest freezer as well? I understand your need for two controllers if so. I just use mine for cold storage. I use my standup fridge for lagering. When set to the warmest temp i get 50 F inside then I can usually adjust it with the built in controls with accuracy anywhere down to 45 F so it works well for me. BTW i ordered parts for two spunding valves based on your build.

 

[Curtis2010]

...

Curtis you using a chest freezer as well? I understand your need for two controllers if so. I just use mine for cold storage. I use my standup fridge for lagering. When set to the warmest temp i get 50 F inside then I can usually adjust it with the built in controls with accuracy anywhere down to 45 F so it works well for me. BTW i ordered parts for two spunding valves based on your build.

Yes, I have a small one for ferm (w the two controllers) and a big one for storage w just one external controller. Built in tstat would work fine for this since it covers fridge and freezer range, but I already had the extra controller and its handy to actually dial in a specific temp. I sometimes use the big freezer for ferm too if the small one is in use. Planning to add a second small one next season so I can have two ferm chambers.