Wifi Inkbird ITC-308 fluctuation temps!

[kydan47]

I've been using the Wifi ITC-308 in combination with a heat pad for controlling my fermentation chamber (a 5cf freezer with collar).

I've got 2 small batches going and wanted to maintain a temp around 70F so as to benefit both yeasts (Wyeast1214 & WL530). My TS is 70, my HD is 1 and my CD is 3. I would have assumed that the heat side would kick in at 69 and turn off at 70 but it doesn't. My cold side kicks in at 73 but takes it down to 68? I use tilts to monitor the temps. I use a thermowell for the probe.

I love that I can check in remotely to monitor the temps, but keep discovering that the cold side control goes down below my set point TS! The heat side goes over the TS as well! Inkbird on their website suggests the temps will turn off at the TS.

Anyone have a cure or a source for a better controller that shuts off at the TS?

 

[VTX1300]

I don't think the problem is with the controller but where you are measuring the temp. If you want the cold side to turn off at 70 the air temp of the wort may be at 70 but the temps in your FC are much lower, probably in freezing temps as you are using freezer with a collar. Same with the heat side. once the inkbird sees the proper temps in the fermenter the FC air temps are much higher so the temps continue to climb as it is a well insulated space. I always set my differential temps at 1 above and 1 below. that keeps my fermenter well within range for the yeast I am using.
Also, the yeast has a range it likes to work in. It does not have to be an exact temp. generally anything close to your target temps and it will do exactly what you expect. I never worry about a 3-4 degree swing in temps inside the fermenter. It just dose not have to be that precise. 10 degrees above or below, then I worry, not before then.
There are many things in brewing where you have to be spot on and many things where close is close enough. yeast is one, in my opinion and experience that close is close enough.
Hope this helps. Brew On!

 

[kydan47]

I appreciate the thoughts but don’t agree.

I’m measuring my temp in 2 places - both in the thermowell of the fermenter itself that is connected to the INKBIRD and from the tilt sheet reports. I don’t believe the ambient temp of the FC would account for the deviations. In fact, I have a 2nd freezer for serving/aging and controlled by a second Wi-Fi INKBIRD, and the ambient temps do not reflect the beer temps at all. The INKBIRD on the FC is not cutting off at the TS (set temp).

The WL530 has a recommended range of 66-72 which is what I kept striving for, but the tilts indicated a deviance. I set the INKBIRD TS at 70, a CD of 3, and a HD of 2. The cooling would take it down to 67 before the heat kicked in. The heat took it past 72.

The Wyeast 1214 has a broader range so it didn’t matter but the sheet temps confirmed the malfunctions.

INKBIRD help said it could be the special function.
https://community.inkbird.com/t/q-a-how-does-itc-308wifi-work/151

Thanks for trying.

 

[Peebee]

A less popular explanation ...

It certainly isn't a problem with the controller. The controller is not a "PID" or "PI" type device. So, it overshoots the set temperature. That is normal (thermal inertia).

Spend the bit extra on PID/PI if that is what you want.

 

[kydan47]

A less popular explanation ...

It certainly isn't a problem with the controller. The controller is not a "PID" or "PI" type device. So, it overshoots the set temperature. That is normal (thermal inertia).

Spend the bit extra on PID/PI if that is what you want.

I agree it is not a “tuned” PID (I have 3 in my brew system) but like the tuned PID it should turn off when set point reached. The creep would not be that great to move the 3-5 gallons of liquid if the controller shut off at the set point. I’ve had a Johnson controller which kept the temp range within 1-2 degrees. I gave it away unfortunately..

 

[Deadalus]

How well calibrated are the Tilts to the Inkbird? The way you described, you have two batches, each with a Tilt, but just one Inkbird with a thermowell. What type of fermentation vessels and where is the thermowell and probe reading at? How are you determining when the heat and cooling occurs? The Inkbird data won't tell you when the heating or cooling occurs nor the Tilts (meaning specifically turning on the heat or cooling). Are you collecting the data constantly? Do you have exactly the same amount of fluid in each fermentation vessel? Even so, two different yeasts with different size starting populations may not be fermenting at the same rate. This would make for different solutions of water and alcohol. I'm not saying that will cause noticeable differences but something to consider. The Tilts are somewhere at the top but the Inkbird probe is where in the FV?

I recently had one of my Inkbird wifi units flake out and return temps in the 180s. I've also had a different one die. So I recently bought a BN-link wifi unit. I didn't notice it was maybe the older version (very square) vs their unit that looks a lot like the Inkbird. I've used it for one brew and the temp variation has been very controlled around the set value. However it's a glycol chilled unitank with heater and just one batch. Their wifi app is poorly rated, like a 3 out of 5 stars but I had no trouble adding it and Alexa can see it too. I did not attempt any control through Alexa yet. My tilt inside needs calibration, it's like 3 degrees low. It was a consistent difference.

If you are recording continuously you could plot your three readings together. You could also run a regression between your Tilt and Inkbird temps for the same vessel (plus other combos). You could do the same if you had fewer data points as long as you were grabbing the temps about the same time from all instruments.

It's possible you may have a lag and possible there's a malfunction.

 

[kydan47]

How well calibrated are the Tilts to the Inkbird? The way you described, you have two batches, each with a Tilt, but just one Inkbird with a thermowell. What type of fermentation vessels and where is the thermowell and probe reading at? How are you determining when the heat and cooling occurs? The Inkbird data won't tell you when the heating or cooling occurs nor the Tilts (meaning specifically turning on the heat or cooling). Are you collecting the data constantly? Do you have exactly the same amount of fluid in each fermentation vessel? Even so, two different yeasts with different size starting populations may not be fermenting at the same rate. This would make for different solutions of water and alcohol. I'm not saying that will cause noticeable differences but something to consider. The Tilts are somewhere at the top but the Inkbird probe is where in the FV?

I recently had one of my Inkbird wifi units flake out and return temps in the 180s. I've also had a different one die. So I recently bought a BN-link wifi unit. I didn't notice it was maybe the older version (very square) vs their unit that looks a lot like the Inkbird. I've used it for one brew and the temp variation has been very controlled around the set value. However it's a glycol chilled unitank with heater and just one batch. Their wifi app is poorly rated, like a 3 out of 5 stars but I had no trouble adding it and Alexa can see it too. I did not attempt any control through Alexa yet. My tilt inside needs calibration, it's like 3 degrees low. It was a consistent difference.

If you are recording continuously you could plot your three readings together. You could also run a regression between your Tilt and Inkbird temps for the same vessel (plus other combos). You could do the same if you had fewer data points as long as you were grabbing the temps about the same time from all instruments.

It's possible you may have a lag and possible there's a malfunction.

The tilts were calibrated to the FG of the 2 worts (single batch w/ the 2 yeasts as well as to water. I used 3-gal Fermonsters and the probe is a modified pu tube silver soldered on the end and reaches about 2-3 inches from the bottom. The tilts report gravity & temperatures of the respective yeasts every 15 minutes. The probe with the thermowell is in Wyeast 1214. The temps of both have been close but not exact especially during the initial krausening/fermentation. I checked both sheets from the tilts and noticed swings in temps beyond my TS of 70. If excessive I would open the INKBIRD app and would adjust the TS. Often finding the heat on when over the TS of 70 and the cooling on even when below the TS.

Someone suggested it was the inertia but I just checked my new keg freezer temp history. Where I have a new tilt mini pro sitting in a 3 gal open keg of water with the probe insulated and taped to the lower side (The new tilt is much more responsive to temp changes). The new freezer is 8.8cf better insulated and the FC is slightly older 5cf. The drift on the new Wi-Fi inkbird is 5hrs from the low end to the peak. TS of 36, CD of 3, HD of 1. I don’t think it is inertia.

I’ve got 3-4 regular INKBIRDs so might try of those to see if they cut off at the TS.

Thanks for responding.

 

[CascadesBrewer]

I've got 2 small batches going and wanted to maintain a temp around 70F so as to benefit both yeasts (Wyeast1214 & WL530). My TS is 70, my HD is 1 and my CD is 3. I would have assumed that the heat side would kick in at 69 and turn off at 70 but it doesn't. My cold side kicks in at 73 but takes it down to 68? I use tilts to monitor the temps. I use a thermowell for the probe.

I love that I can check in remotely to monitor the temps, but keep discovering that the cold side control goes down below my set point TS! The heat side goes over the TS as well! Inkbird on their website suggests the temps will turn off at the TS.

You can look at the controller to see when it kicks on and off. That should be able to tell you if it is working correctly.

Personally, I have one fermenter with a thermowell, and I find I get better results taping the probe to the side of the fermenter with a layer of foam for insulation. In the thermowell, I just see it constantly fluctuating from heating to cooling as it overshoots in both direction. It likely depends on your chamber setup, but I find that my chest freezer builds up a lot of cold mass before the center of the beer changes enough and the same for the heating pad. Having the Inkbird probe on the outside of my fermenter helps to account for both the temp of the beer and the temp of the chamber and results in less overshooting and cycling.

I have some Tilt hydrometers. During active fermentation, the temp of the Tilt and the Inkbird match very closely. When not actively fermenting, I do find there can be a difference of several degrees from the bottom of the fermenter to the top. At this point, my Tilt is reading at the higher temperature.

I do notice that with my Wi-Fi Inkbird, when I change the set point it seems to ignore the cooling and heating differential value. Even if I just boost or lower the target a degree or two that should not cause it to activate the heating or cooling, it still does. At least that is how mine works.

 

[kydan47]

You can look at the controller to see when it kicks on and off. That should be able to tell you if it is working correctly.

Personally, I have one fermenter with a thermowell, and I find I get better results taping the probe to the side of the fermenter with a layer of foam for insulation. In the thermowell, I just see it constantly fluctuating from heating to cooling as it overshoots in both direction. It likely depends on your chamber setup, but I find that my chest freezer builds up a lot of cold mass before the center of the beer changes enough and the same for the heating pad. Having the Inkbird probe on the outside of my fermenter helps to account for both the temp of the beer and the temp of the chamber and results in less overshooting and cycling.

I have some Tilt hydrometers. During active fermentation, the temp of the Tilt and the Inkbird match very closely. When not actively fermenting, I do find there can be a difference of several degrees from the bottom of the fermenter to the top. At this point, my Tilt is reading at the higher temperature.

I do notice that with my Wi-Fi Inkbird, when I change the set point it seems to ignore the cooling and heating differential value. Even if I just boost or lower the target a degree or two that should not cause it to activate the heating or cooling, it still does. At least that is how mine works.

Wow! Thanks for the feedback. I’ve disconnected the heating pad since I’m close to final, will put the probe on the outside next batch. I can see the controller kick on and off outside of the differential values but often after I have adjusted the TS so maybe that’s the problem. I also found out from INKBIRD help that there is a special cycle where the differentials are ignored. Going to try some non-Wi-Fi INKBIRDs too.

 

[Peebee]

... but like the tuned PID it should turn off when set point reached. ...

And so it should be? But I have to admit, I "think" I've noticed 308s being a bit tardy responding to their set-point (reaching it the first time around, not subsequently?), but have ignored it because I was dealing with bigger fish (the 308's tendency to measure spurious, momentary, spikes of temperature which plays difficult-to-notice havoc on the cooling cycles in particular ... a bug that's been there for years and I'm not going to go on about here). And I also have to admit to misusing the term "thermal inertia" as an explanation ("thermal inertia" won't be the explanation).

But I've personally relegated 308s to duties like controlling cooling water temperature and leaving duties like pumping cooling water around beer fermenters cooling jackets to more advanced devices.

I'm always ranting about 308s. But they have one major advantage ... they're cheap! Trouble is, we home-brewers attribute them with mythical abilities, not helped by Inkbird allowing them to be configured for plus or minus 0.5°C (1°F) accuracy when plus or minus 2°C is a stretch-of-the-imagination (especially when cooling).

 

[wdavis2003]

If you are fermenting multiple batches in one FC, but are using one of the batches to control the entire FC, I would either do as @CascadesBrewer mentioned or place the probe in a jar of water or a flask to more accurately control the temp of the FC.

 

[kydan47]

If you are fermenting multiple batches in one FC, but are using one of the batches to control the entire FC, I would either do as @CascadesBrewer mentioned or place the probe in a jar of water or a flask to more accurately control the temp of the FC.

Update: I disconnected the heating pad relying solely on the INKBIRD w/TS of 72 and the probe in the fermenter and the temperature stayed at 71.7 for 16 hrs then jumped to 72.7 for the last 8 hrs. The 2nd fermenter had similar results. Prior to fermentation, I had placed the probe in a thermowell in a small container of 91% alcohol and the control was cycling often and did not reflect the fermenter temps at all and that’s when I used a thermowell for the fermenter itself thinking a larger mass.

 

[Peebee]

... and the control was cycling often and did not reflect the fermenter temps at all ...

That sounds like the "erroneous temperature spikes" I'm always ranting about. Few notice it happening (the cooler being triggered on before set-temperature reached, or the heating cut before set-temperature reached), but the bug isn't trouble for heating and only supposed to be trouble for cooling (excessive compressor on-and-off ... what "compressor delay" is supposed to prevent but in this case does not) but it doesn't seem to have the promised dire consequences? (Conclusion: All that "compressor delay" bobbins is utter drivel so ignore it).

 

[beren]

I thought about flashing the inkbird with Tasmota with the pid algorithm and trying that https://tasmota.github.io/docs/PID-Control/

 

[kydan47]

I thought about flashing the inkbird with Tasmota with the pid algorithm and trying that https://tasmota.github.io/docs/PID-Control/

Wouldn’t it be contingent on the number of kegs in the freezer eg 1 vs 4?

 

[beren]

PID controllers need to be calibrated for different conditions.