Inkbird ITC-308 Problems

[MarkA]

I recently got one of these for my brewfridge but haven't been particularly impressed with it so far. I think it's a great idea for a product, and no-one that I've read has had any problem with it, but I've found the following issues with mine;


A - The temperature is way out when compared to my Hannah Checktemp1 Thermometer. It is out by 1.6 degrees (this is with both sensors immersed in water at the same position). I have re-calibrated the Inkbird using the CA setting, which isn't a problem, but......

B - Say the unit is measuring the liquid at 17 degrees, but my thermometer reads 18 degrees, then I adjust the CA value by one degree. Simple. BUT, when I press and hold the set button, and it returns to the main readings, the temp reads 17.8 (or 17.7) instead of just adding 1 degree on and reading 18

C - The sensor is next to useless when insulated and taped to the outside of my plastic fermenter. The readings are all over the place. I'd rather not have the sensor immersed in liquid but understand that I'll have to so I get a decent reading

D - In normal working mode, it's set to 18 degrees. The fridge is in my cold garage. I've set it so the heater switches on when it's dropped by 0.5 degrees. So, it gradually drops from 18.0 to 17.5 and the heater comes on. It heats back up to 18 and switches off. Exactly how it should work. I leave the garage for 20 minutes, come back, and the unit is now reading 18.6 and the fridge is on. The fridge is set to come on once the temperature has risen by 1.3 degrees. If it carries on like this, it's going to be cycling between heating and cooling all the time

- Another quirk it has is that it will be sitting steady at a temperature, then it will suddenly rise by about a degree and drop back down again, reaching the original temp in about 10 seconds. The first time it did this, the fridge sprang into life, and switched off again after 10 seconds. Hence why I've set it higher at 1.3 degrees, I would rather the difference was only about 0.5 or 0.6, just enough for the liquid to rise a bit without it switching on all the time

**All the above were tested using water in a fermentation bucket, so there's no CO2 or exothermic reaction to mess with the readings**


I have contacted Inkbird and they have suggested I set the compressor protection value (PT) to 0, and the temperature calibration (CA) to 0 to see if it sorts out the problem. I am currently fermenting so won't be touching any of them for now but, even after that, I'm loathe to mess about with it. I do not want to ruin my fridge as it could well switch on for 10 seconds, off again, on again very quickly, depending on how temperamental the unit's feeling. Also, I think it will be virtually impossible to guess the correct temperature if I set the calibration to 0 as it changes each time it is used and I can't just rely on adding 1.6 to the figure that's showing due to the point made in B

Has anyone else had any problems with it?

Is the sensor faulty?

Replacement product or money back?

Am I missing something blindingly obvious?

[vacant]

Just a few random thoughts:

Once my fridge gets going it continues to drop the temperature when the compressor switches off because the cooling pipes are still very cold. SImilarly when your heater switches off, the temperature may continue to rise for a while.

Does the fridge have it's own compressor protection? This may prevent you testing the Inkbird compressor protection if it hasn't been bypassed.

Lastly, doesn't setting CA to 0 imply the heat circuit is ignoring the CA value (i.e. firmware bug)? You could try a very large adjustment to test this.

[Secla]

Any temp controller will over shoot your set value
When you turn the heather off it doesn't instantly stop heat, same with the cold

Keeping the fridge in a low ambient temp won't help either

[Kev888]

Given the accuracy specs (when new) of your two measuring devices, there could be up to 1.2c difference in the readings as standard and before any other factors at all come into play, so an extra 0.4c in practice is disappointing but I wouldn't say that was 'way' out of expectation, probably not enough to indicate anything horrendous is wrong.

I don't have the inkbird so can't help much on the calibration, but it sounds like your setup has heating and/or cooling overshooting the target and so chasing each other in a cyclic attempt to correct. This will happen with any on/off thermostat if there is sufficient delay between the temperature change beginning and the change reaching the sensor, which there typically is. That is why most thermostats that we use have a dead-band that you can alter in which neither heater or controller operate and allow the system the opportunity to even out and stabilise. I'd guess that your dead-band is set too narrow for the response of your system.

Setting the compressor delay to zero (if thats what the setting means) could actually make things worse, and if you measure the air (which can change relatively quickly) it could cause unnecessary cycling and strain on the compressor without the delay to protect it, so best keep an eye on things of you try that. Setting the calibration to zero seems sensible as a test though, in case the calibration went wrong in some way and is actually making things worse.

[MarkA]

Thank you for your replies.

Once fermentation is over, I'll reset the calibration to zero and see if it makes a difference. I'll also give it a big adjustment to see how that affects the reading and behaviour.

I understand that the liquid will continue to heat up once the heater has switched off, but figured that having a headroom of 1.3 degrees before the fridge clicks in would be enough. I've been keeping a regular eye on it over the weekend and haven't noticed the fridge switching on or the numbers rapidly rising and dropping as they were before.

I don't think the fridge has its own compressor protection so won't be able to set the unit protection to zero for any length of time, but will give it a try just to see if it makes a difference (whilst keeping a close eye on it, obviously).

What is the minimum the compressor protection should be set at?

I think I may be expecting too much from this system so will just calm down and go back to basics!

[marinali29]

Hi Mark,

This is Marina from Inkbird.

I know that you contacted us for help before, but it seems that we still have not settle you doublem, sorry!

For the temperature differences, it's hard to save which is more accurate (your thermometer or the inkbird controller), please kindly understand.

For on/off thermostat, it controls a temperature range, if you need more accurate one, I think PID temperature controller is better.

Maybe you can change you setting and have a try more.
TS=20,HD=2,CD=3,CA=0. You told us that you set PT=10 mins,it's too long,maybe you can set it shorter,the default value is 3 mins.

TS=20,HD=2,CD=3,CA=0.
When measured temperature is higher or equal to 23°C（TS+CD）, system enters refrigeration status;
When temperature decline to 20°C(TS), stop refrigeration;
When measured temperature is lower or equal to 18°C（TS-HD）, system enters heating status;
When the temperature raised to 20°C(TS), stop heating.

In case the time interval between two refrigeration is less than PT, please refer to user manual on 5.3.

Could you please try again? I checked and found there's something wrong on your setting as mentioned above. If any questions after tired,please feel free to contact Inkbird CS team or let me know here, we are pleased to solve it, do no worry!

Regards

[MarkA]

Thanks Marina, I'll be resetting and trying again next week (once fermentation has finished on my current brew!)

[marinali29]

Thanks Marina, I'll be resetting and trying again next week (once fermentation has finished on my current brew!)

It's a preasure. Please keep updating if any news.

[Kev888]

What is the minimum the compressor protection should be set at?
I think I may be expecting too much from this system so will just calm down and go back to basics!

The compressor delay is really only protection to stop the compressor switching on/off rapidly, causing damage and excessive strain/wear. In our application twenty-odd litres of wort does not change temperature at all quickly so if the probe is in or against the wort (and insulated) the delay isn't normally necessary, however a 3min delay is not significant either so IMO it is prudent to have in case something goes wrong (say the probe falls out and dangles in the air). If your probe is measuring the air (either accidentally or intentionally) which can change more quickly then the delay is slightly more meaningful, but also more important to protect the compressor so I'd still be reluctant to reduce it too much except as a trial.

There is probably some tweaking to do to get things stable and check nothing odd is happening, but TBH I wonder if your expectations may be unrealistically high. Its only a fridge and heater plus a simple on/off thermostat with a claimed accuracy of +/-1c. Even if the thermostat were more accurate, air is a very poor conductor of heat and so when used for heating and/or cooling wort with a large thermal mass then the system itself has limits on how responsive it can be. The measurement is also a compromise, you are cooling/heating the air and either measuring the wort which are different things (and this essentially insulates the probe from knowing accurately what the air is doing), or else you measure the air which allows for tighter control of heater/cooler but then the probe doesn't see the extra heat generated by the yeast during fermentation. The former is more accurate, the latter more stable wrt wort temperature. Some people hedge their bets by putting the probe in a small jar of water or a lump of copper or something as a compromise, which could either be the best or worst of both worlds.

You can use PIDs which learn and predict the response of the system and so can act accordingly, and you can use more direct/responsive means of heating and cooling, like recirculating cold water through immersion coils in the wort. But really, unless you want to get very enthusiastic about things your current setup will be fine (when its stable), lots of people use this type of thing very successfully - light years ahead of having no control and 90% of what considerably more complex setups will gain.

[Mhall2016]

Just got mine the other day. Noticed going into settings then saving them the temp read out changes. If you do it multiple times it changes each time. Did you ever figure it or get any support. Had trouble adjusting CA setting as well. Each time I set the off set it would be off.

[MarkA]

Just got mine the other day. Noticed going into settings then saving them the temp read out changes. If you do it multiple times it changes each time. Did you ever figure it or get any support. Had trouble adjusting CA setting as well. Each time I set the off set it would be off.

The temp readout should only change if you've set the calibration, does it change when saving any of the settings? It's probably best to email Inkbird as they do reply, or reply to marinali29 above.

I have set my heating differential to 1.4 degrees, as the unit does still occasionally throw a wobbler when the display rapidly rises up by a degree then settles back down again. I wouldn't normally set the HD so high, but it does stop the fridge from switching on for just a second or two when it does this. Also, another thing I changed was the shelf my fermenter is sat on as I originally had it sat on a piece of wood with holes drilled in it, but I think the heat was taking ages to get through to the wort, which caused the temp inside the fridge to get hotter than needed, the wort would the continue heating after the heater switched off and the fridge would kick in to cool it back down (causing it to cycle on and off). After changing the base to one with a lot more gaps, the temperature only over-shoots by 0.3 degrees at the most and the fridge rarely switches on. All in all, I'm pretty happy with it now

[Cqr]

I've had mine about 7 months, I've had no problems at all
I'am getting a second fridge and inkbird soon
Hope yours get salted soon