When your Inkbird controller decides to have a 6° offset and you're cold-crashing - UGH

CornyKegs 728
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passedpawn

passedpawn

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I set my fermentation freezer to 33°F and closed it for 2 days. When I looked, they were nearly frozen (including the jar of starsan solution in which I hang the temperature probe).

The two pale ale fermentors froze and heaved spectacularly. The brown ale there was a little higher ABV and didn't freeze completely.

Anyway, My Inkbird 308 now has a 6° offset - I've been testing at room temperature and with salt-ice slush. I also suspect that I might have been fermenting 6 degrees higher than I wanted.

I went into the controller settings and adjusted the temperature offset from 0 to -6 and it seems to be reading correctly now. But I'm not sure if I trust it anymore.

upload_2019-6-17_9-46-6.png
 
Last edited:
... and now, even after I added the correction, it's drifting 15° high. I'll probably disassemble tonight and see if the problem was the sensor (maybe lost it's waterproof-ness).

I'll probably buy another - I've got a could of other types of controllers that I like less.
 
Did you change the offset in the proper direction? If the beer froze when it reads 33 degrees, then the reading is too high and the actual temperature is too low. But then you mentioned potentially fermenting higher than expected? If anything, I would think you were fermenting lower than expected.

Either way, that sucks! It would be bad enough with one batch - but four different fermenters...ouch!
 
Carolina_Matt said:
Did you change the offset in the proper direction? If the beer froze when it reads 33 degrees, then the reading is too high and the actual temperature is too low. But then you mentioned potentially fermenting higher than expected? If anything, I would think you were fermenting lower than expected.

Either way, that sucks! It would be bad enough with one batch - but four different fermenters...ouch!
Click to expand...

Yes, I did. I made the correction while it was side-by-side with another thermometer, and the correction fixed the inaccuracy. But then it didn't. I don't know what it's doing, but I have ZERO trust in it now.
 
I had this happen recently (froze my kegs!), but found out it was because the temp probe was too high in the keezer, where the temps are warmer—moved it to the middle and got the right reading again.

I should really get a fan in there.
 
This same thing happened to my inkbird about 2 - 3 weeks ago during the “hot” spell we had. Lucky for me it was the one on my keezer. All of my kegs froze solid. Temp read out never said below 43 and the thing must have run for 48 to 72 hours straight before I noticed.

I messed with the probe for about 2 days and never could get it to read correct temps again.

I swapped it for the one on my fermentation freezer as it’s empty at the moment. 5 mins after dropping the new probe in temps were reading spot on. The one that went bad is about 3 years old. I was just guessing that’s the useful life I should expect out of these controllers. Or should I be expecting better useful life?
 
deadwolfbones said:
I had this happen recently (froze my kegs!), but found out it was because the temp probe was too high in the keezer, where the temps are warmer—moved it to the middle and got the right reading again.

I should really get a fan in there.
Click to expand...

During my thaw out when mine froze I decided to add a small fan at the bottom along with an Eva-Dry. Temps seem to stay more consistent even in this summer heat now. I have the fan wired to come on only during the cooling cycle so it’s not running 24/7.
 
Is this the rubber probe or the metal one?

I think the metal one is not supposed to be waterproof.
 
This is when I like my Tilts. During cold crash I can closely monitor if anything is starting to go wrong with beer temps. Once I put the inkbird thermo-coupler directly in the carboy thermowell and caught it in time before the outside started to freeze. Probe goes outside!
 
Funny you mention this . Yesterday my inkbird was set to 68 and it was 63. I set it for 2 degree difference. I didnt know if they get too wet in the freezer it could Jack em up.
 
Hello, everyone. Thank you for supporting and sorry for the inconvenience. Our metal probe waterproof level is IP68，and all our products have 1 year warranty. If there is any problem with our product, please PM us with your order ID#, we will try our best to help.

And we keep improving our probe and product, if the probe is getting too wet, sometimes it will affect the interface( between the probe and the cable). Coated the waterproof tape to the interface, it will help. And we recently release a updated plastic probe and a detachable probe, here is the link for your reference. https://www.amazon.com/dp/B07R195CQF

We will report to our engineering team, sorry again for the inconvenience.

Inkbird
 
Last edited by a moderator:
inkbird said:
Hello, everyone. Thank you for supporting and sorry for the inconvenience. Our metal probe waterproof level is IP68，and all our products have 1 year warranty. If there is any problem with our product, please PM us with your order ID#, we will try our best to help.

And we keep improving our probe and product, if the probe is getting too wet, sometimes it will affect the interface( between the probe and the cable). Coated the waterproof tape to the interface, it will help. And we recently release a updated plastic probe and a detachable probe, here is the link for your reference. https://www.amazon.com/dp/B07R195CQF

We will report to our engineering team, sorry again for the inconvenience.

Inkbird
Click to expand...

Just ordered, thanks.
 
I thought it was designed to put the probe into water . Looks like I better take it out . What about being in a glycol solution ??
Hmmmm
 
Timely thread (including the post about having a Tilt). My last beer was showing a lower ferm temp than expected on the Tilt, but it was the third batch on that set of batteries so I assumed it was dying batteries on the Tilt. Then I cold crashed. When I went to keg it 2 days later the beer in the fermenter was one solid block of frozen beer.

I messed around with it, but apparently the Inkbird is toast. It acts like it's getting no signal from the temp probe (or a signal that always says it's warmer than the set temp).
 
New controller and old one. The temperature probe is removable on the new one, which might be a nice thing if it gets damaged.

I took the old one apart. It has a metal sleeve crimped onto the end of the temperature probe - I removed that. Under the metal, it appeared to be completely sealed in rubber. I don't see how that could have let water in. I cut through that and didn't see any problem with the sensor (which is a 10k thermistor I think). The thermistor was about 8.5k at my room temperature, which is correct. Inside the enclosure, there was no sign of moisture, corrosion, or any other problem.

Anyway, it's still reading way off, so I'm going to toss it. In conclusion, I have no idea what's wrong with it.

upload_2019-6-18_18-1-55.png
upload_2019-6-18_18-3-11.png
 
... and one more thing. I got curious about whether the cable was the culprit, so I soldered the thermistor right onto the board. It read the same (wrong) temperature as before.

I had a look at the ckt on the board and it looks like the thermistor is half of a voltage divider (other resistor is a 10k 1% to GND) with a ceramic cap in there for a little filtering, then right to the Holtek processor's A/D converter. The processor uses an internal reference voltage for the A/D (I checked the VREF pin and it had no voltage on it). Power supplies to the processor and the excitation voltage for the thermistor were exactly as expected.

So I conclude that somehow, the thermistor got damaged. Seems almost impossible since it's a simple resistive device.

upload_2019-6-18_20-40-3.png
upload_2019-6-18_20-39-57.png
 
Is the new thermistor compatible with the old one? I see that they connect differently, but maybe you could temporarily wire the new one to the old controller for fun just to see what happens.

I was actually going to suggest soldering every connection because I had a similar problem with my PID. If you care to read about it:

https://www.homebrewtalk.com/forum/...lmost-every-brew-day-why.652420/#post-8462052
 
kevink said:
Is the new thermistor compatible with the old one? I see that they connect differently, but maybe you could temporarily wire the new one to the old controller for fun just to see what happens.

I was actually going to suggest soldering every connection because I had a similar problem with my PID. If you care to read about it:

https://www.homebrewtalk.com/forum/...lmost-every-brew-day-why.652420/#post-8462052
Click to expand...

The connections in the old one were all soldered to the PCB. So that wasn't the problem.

I did attempt to connect the thermistor to my new unit, but ran into a snag. But I guess i could have done it the other way - hook the new probe to the old unit. I'll try that in a few minutes.
 
kevink said:
Is the new thermistor compatible with the old one? I see that they connect differently, but maybe you could temporarily wire the new one to the old controller for fun just to see what happens.
Click to expand...

OK, I connected the new probe up to the old Inkbird board. Worked fine (old unit with new probe = 85.0, new unit = 85.1). So the final (FINAL!) root cause is a bad thermistor.

upload_2019-6-19_12-36-20.png
upload_2019-6-19_12-36-24.png
 
kevink said:
Haha, nice! Now to find a new thermistor!
Click to expand...

nah, the thermistor was in the sealed end of the probe. I don't want this to happen again, so I need a fully-sealed probe. I'm tossing it and moving on.

(I could add one to my next digikey order, 50 cents. Maybe I'll do that, probably could use it for something else. )
 
inkbird said:
Hello, everyone. Thank you for supporting and sorry for the inconvenience. Our metal probe waterproof level is IP68，and all our products have 1 year warranty. If there is any problem with our product, please PM us with your order ID#, we will try our best to help.

And we keep improving our probe and product, if the probe is getting too wet, sometimes it will affect the interface( between the probe and the cable). Coated the waterproof tape to the interface, it will help. And we recently release a updated plastic probe and a detachable probe, here is the link for your reference. https://www.amazon.com/dp/B07R195CQF

We will report to our engineering team, sorry again for the inconvenience.

Inkbird
Click to expand...


I ordered a controller last week. Is there a way to retroactively use this probe. My controller doesn't have a detachable probe.
 

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