Issue with A419 and consistent temperature

[DSmith]

The controller is monitoring the carboy wall temperature under a lot of insulation. The 65F cut-out is my set-point (cut-out at setpoint). The cold air in the freezer + thermal mass of the freezer after it's powered off do not seem to decrease the carboy temperature any further.

I understand what you're doing with the probe in the air. I do the same thing for heating mode and the carboy temperature is VERY stable. I generally try to end all my fermentation in heating mode or just the basement temperature. I rigged a switch to transition between modes - pic below.

I like that the probe on the carboy approach is very hands-off; have been on work-trips when all this is happening. The probe in the air during active fermentation will need some set-point intervention and intuition. The Love TSS2 with a single probe looks like a better controller than the Johnson because it's the only one that can do differentials to 0.1F increments, heating & cooling is a big plus. I could attempt a fermenation your way and log it.

 

[DSmith]

So after not seeing any improvements with my manipulation of the probe insulated against the carboy I decided to tape the probes (uninsulated) against the side of the chest freezer a few inches from the bottom. I realize this method won't be the most accurate for exact fermenting wort temperature but so far it has been keeping much more stable.
I plan on insulating the temperature probe against the carboy while keeping the Johnson probe taped against the chest freezer wall. This way I will have a reading of wort temperature while being able to reduce compressor cycles with a more steady temperature controller reading. There still exists a 3-4 degree difference between the two displays taped against the freezer wall but I can take that into consideration when setting the Johnson settings.

The Johnson unit has an "offset" parameter that will let you adjust your 3-4F temperature difference. I've compared the Johnson thermistor probe to lab calibrated thermocouples/readers and haven't needed to use any "offset". It's entirely possible that yours needs adjusting and the "offset" parameter will let you do that so you don't need to think about it again when setting the set-point. The offset is applied differently to cooling vs heating mode so it has it's limitations.

EDIT: Looks like a jumper would need to be installed between the "BIN" & "COM" terminal for the offest to be active (see manual).

"Temperature Offset (OFS) establishes the value of setpoint-shift (in F° or C°) applied to Setpoint (and Differential) when a (user-installed) circuit is closed between the binary input (BIN) and common (COM) terminals. The offset value may be set from 0 to 50F° or C°.
The Temperature Offset function is used to reset the Heating Setpoint to a lower temperature (secondary) setpoint or reset the Cooling Setpoint to a higher temperature (secondary) setpoint by the temperature value set in Temperature Offset.
The BIN and COM terminals may be connected to a (user-supplied) external switching device, such as a time clock, that has a set of Single-Pole, Single-Throw (SPST) contacts. Closing a circuit between the BIN and COM terminals activates the Temperature Offset."

 

[Arod_3]

I did something similar with my controller. I have my probe in a small jug of water in the cooler. The temp in the cooler may change a couple degrees with a differential of -2. But the brew isn't going to realize this temp. So if you have a set point of 72 with -2 differential, your ambient might be between 72-70 but the water/brew temp is going to average between those around 71. I got the dual stage TC-9102D-HV and it took me a while to understand how the differential works. I just had to look at it after a few brews.

 

[Buna_Bere]

I like that the probe on the carboy approach is very hands-off; have been on work-trips when all this is happening. The probe in the air during active fermentation will need some set-point intervention and intuition. I could attempt a fermenation your way and log it.

That's a pretty cool setup you got there. I agree the attached insulated probe is probably the better 100% hands-off approach, I'm just not willing to settle for a +2 to 2.5 degree temp rise on every cooling cycle. It would be awsome if you could do a whole fermentation with the controlling probe in the air and log it, but really what I think would be more interesting would just be a graph showing the stability of the carboy temps, and the fluctuating air temps for say a 48 hour period after the wort temp has stabilized. You could do this with just a carboy full of water.

One benefit of the Johnson is it has the ASD(anti-short cycle delay) control, I don't think the Love has that.
My Johnson is set up with the cut-out like you use too.
my settings are
dif at 1
asd at 10
ofs at 0

I wish Blichmann would build a tower of power controller that could function as a fermentation controller too. I heard him talking on an episode of Brew Strong about how inaccurate the Johnson and Love controller electronics are.

 

[DSmith]

That's a pretty cool setup you got there. I agree the attached insulated probe is probably the better 100% hands-off approach, I'm just not willing to settle for a +2 to 2.5 degree temp rise on every cooling cycle. It would be awsome if you could do a whole fermentation with the controlling probe in the air and log it, but really what I think would be more interesting would just be a graph showing the stability of the carboy temps, and the fluctuating air temps for say a 48 hour period after the wort temp has stabilized. You could do this with just a carboy full of water.

One benefit of the Johnson is it has the ASD(anti-short cycle delay) control, I don't think the Love has that.
My Johnson is set up with the cut-out like you use too.
my settings are
dif at 1
asd at 10
ofs at 0

I wish Blichmann would build a tower of power controller that could function as a fermentation controller too. I heard him talking on an episode of Brew Strong about how inaccurate the Johnson and Love controller electronics are.

I'll set up a carboy of water and do it your way with setpoint of 65F tonight. The difference in active fermenation is that the setpoint will need to be adjusted based on measuring the insulated-over carboy wall temperature.

I've done this with heating mode and the probe in the air, the result is +/-0.2F insulated-over carboy wall temperature.

 

[Buna_Bere]

I'll set up a carboy of water and do it your way with setpoint of 65F tonight. The difference in active fermenation is that the setpoint will need to be adjusted based on measuring the insulated-over carboy wall temperature.

I've done this with heating mode and the probe in the air, the result is +/-0.2F insulated-over carboy wall temperature.

Wow +/-0.2F with the heating. I'd call that pretty damn stable.
The amount of manual adjusting needed for the temp controller to match the rising and falling active fermentation isn't as much as you would probably think. That will be awsome if you do that experiment, then I think we can finally put to rest which method holds temps more stable.

 

[DSmith]

Cooling experiment without fermentation underway. 12 hours will probably be enough to see a trend because I mixed tap water to 65F to start out (same as set point).

 

[DSmith]

Here's about 13 hours of data for cooling with the probe in the air (graph below). The freezer cycles every 100 minutes, where if the controlling probe was on the fermenter it would have cycled about every 600 minutes. The contents of the carboy stayed very smooth, but took a while to get to the actual set-point. I'll try my next fermentation control this way.



Conclusions for Cooling with the A419:
1. I think it's better to insulate the probe to the fermenter to get to pitching temperature quickly.

2. You can expect 2F-3F temperature swings if you insulate the probe on the fermenter wall. It can be the most hands-off method. The freezer is efficient at achieving the set-point within the 2F-3F range (long periods between cycles). This method seems sufficient for a kegerator or lagering chamber to extend the life of the equipment.

3. A controller with a smaller differential (<1F) would reduce the temperature swings than the Johnson A419 for control with the probe insulated-over on the carboy wall. The Love TSS2 could be an option but the setting would have to be realistically set to avoid over-cycling the freezer.

4. Controlling with the probe in the air results in very smooth fermenter temperatures. The fermenter will lag behind the set-point for hours so you need to have some instinct where to set the controller based on how active the fermentation will be (lager vs Belgian...). The set-point will need to be modified during fermentation. A differential >1F may be a good idea. You need a second accurate temperature probe insulated-over on the fermenter wall to determine what to do with the set-point.

Conclusions for Heating with the A419:

1. Heating inside a chest freezer can be done with the controlling probe in the air to maintain very steady temperatures. Cycling a heating pad only puts wear on the controller's relay. Controlling with the probe insulated over on the carboy wall will result in 2F-3F temperature swings.

 

[Xpertskir]

Problem is the amount of time the ambient temperature takes to cool the beer. By then the air around it is very cold. It stays cold, continues to cool the beer, so you end up down around 60F even though you only wanted 65.

Set the differential down to 1 degree. That way the temp swing is recognized more quickly and gives it less to deal with. The 12 minute cycle delay will protect you from cycling the compressor too often.

This explains why I only have a problem with mine when I first put my carboy in the freezer and attached the probe to the side, insulated. I cool to high 60's post boil and then set the a419 for 68(i usually set 3 degrees higher than my where I want the temp to be). The freezer starts cooling the wort and then the ambient air temp is cold enough to take the wort even colder once it reaches its goal.

One thing I have found that has generally helped consistency is having the actual freezer set on one of its lower cooling settings(although I dont know how this will affect the longevity of the compressor).

Is there a good thread about reprogramming the a419? I have looked around, and not found what I am looking for.

 

[canihaveurpants]

Dsmith,
Did you track any with the probe touching the wall of the chest freezer? Looks like ill be sticking with this method as it keeps my Johnson controller at the most consistent.

 

[DSmith]

The probe controlling the air temperature was not touching anything. I zip-tied it to a rack in the freezer so it wouldn't move when I closed the door on the wire.

 

[Buna_Bere]

Here's about 13 hours of data for cooling with the probe in the air (graph below). The freezer cycles every 100 minutes, where if the controlling probe was on the fermenter it would have cycled about every 600 minutes. The contents of the carboy stayed very smooth, but took a while to get to the actual set-point.

View attachment 67183

Thanks for doing this Dsmith. You can really see how stable the wort(water for this experiment) temps were with the on off cycles, the +2-2.5 degree temp swings are gone.
I think you reversed the labels in the graph key, the purple line(with the big temp swings) I believe is the air temps, and the black line(smoothly dropping) the water insulated probe temps.
One other thing you can see is the wort(water again here) temp is still in the process of dropping to the setpoint. It would be nice to see the wort(water) temps for some period after the temps have stabilized at the setpoint.

Thanks again Dsmith, this is the best data I've seen for probe in the air vs insulated probe. I don't think there is any question now as to which method holds the wort temps more stable.

 

[DSmith]

Good catch, fixed the label on the graph.

It would just as stable (+/-0.2F) when the water reached the setpoint. I stopped this experiment already though. I will try fermenting an ale with the probe controlling the air temperature and post a plot in August with the set-point changes that were needed to maintain a 60F fermenter temperature.

 

[hulkavitch]

Interesting! However, i am not convinced with the water, we all know that a fermenting wort is much more dynamic than water. I will what for the actual fermentation experiment before I change my methods.

Another point, the first 24-48 hours are the most important to controlling fermentation. This method seems to take to long for the wort to stabilize. And with fermenting wort as opposed to a temperture stable bucket of water I hypothesize that the controller will be "chasing" the wort for well over 24 hours before it stabilizes. And when it does it will be because the yeast are less active and no longer raising the temperature.

 

[DSmith]

I agree the beer takes a long time to stabilize and the heat of fermentation complicates things further. You'd have to chill to below the desired fermentation temperature, move the probe to the air, pitch yeast and hope it stabilizes close to the temperature you want.

The Love TSS2 has very small differentials that wouldn't cycle the freezer too much if set well in cooling mode only. Incorporating heating seems to take more experimenting and understanding the unit's variables. I'm a fan of controlling with the probe on the fermentor and accepting the 2F-3F temperature swings with the A419 or moving to a unit the has a smaller differential. Attenuation has not suffered from those swings, 75%->90% lately.

 

[DSmith]

Here's a chart of cold crashing with the probe insulated-over on the side of the carboy. I believe this method is best to drive the beer temperature to the set-point quickly. The air temperature dropped to <10F and froze my vodka-filled airlock for a while. I opened the freezer and pulled the airlock stopper out for a second to equalize the pressure when the vodka was frozen.

The actual measured differential of 2F (1F set on the A419) is fine in my opinion for cold crashing and lagering. I don't keg, but I imagine that would also be more than fine for a kegerator. The freezer cycles every 3 hours.

 

[hulkavitch]

That is cool. Look like if you set your controller 2 degrees colder than what you want you will be right on.

 

[DSmith]

The A419 read 35F where my type k thermocouples and data logger show a little higher. There's always measurement error between devices, what's more interesting is the trends.

I'm going to place an order for the Love TSS2 & probe and see if I can utilize its smaller differentials to keep tighter control during fermentation using the insulated-over probe on the fermenter wall for control. The A419 has never short cycled my freezer and the actual differential seems to be 2-3F when the controller is set for 1F.

 

[DSmith]

I have the TSS2 controller working now and have logged equivalent data on the A419 and TSS2 each attempting to keep a carboy at 45F (cold conditioning a Belgian Tripel).

The A419 results in a 3F temperature rise (1F differential setting) with the probe insulated-over on the side of the carboy.

The TSS2 results in a 1.5F temperature rise (1F differential setting for cooling) with the probe insulated-over on the side of the carboy.

My TSS2 setting were a first-guess. I think they can be improved on and it's nice to have parameters that are not bottomed out. I plan on labeling the controller better, but the right outlet is always on, the left outlet is split for the 2 relays (protecting the controller with 15 amp and 5 amp fuses). The switches are defeats for the 2 relays, a fancy way of unplugging the freezer/heater to stop them from working. Fermentation should be the only time they should both work. My thought is that will decrease some of the parameter editing, especially in cases of cold pitching and letting the fermentation naturally rise to the setpoint.