Inkbird ITC-308s - A Comprehensive Review

As many of you already know, @marina29 from Inkbird has been running prize giveaways, and offering discounts to all GC members.

I was fortunate enough to win the last prize giveaway, and thought it would be useful to do a product review for those of you who are considering buying one. The model that I won was the ITC-308s

Before I commence, it is worthwhile pointing out that I tested this product in the house and not in the greenhouse - I haven't been feeling well for the past few days, so doing this out in a warm greenhouse was a non-starter. However, I have tested it thoroughly, and for both heating and cooling.

The unit arrived, well packaged in a nice compact cardboard box, and further cardboard protection inside. It was pleasing to note that there was no polystyrene or excessive packaging, which shows that some thought has gone into the environmental footprint of the product.

The main unit



The unit itself is very clearly laid out, and is of plastic construction that feels durable and of good quality. At the top of the main unit, there is a key-slot hole that would allow you to hang it from a suitable screw or hook.

Both the mains in and the mains out cables are nice and thick, and certainly capable of handling the maximum output of 10A. Cable strain relief is of a very high standard, which should see the unit perform flawlessly for a long time to come.

There are two displays, and three buttons, all nicely laid out.

The top display (PV - Process Value) shows the ACTUAL temperature being measured. The lower display (SV - Set Value) shows the TARGET temperature desired.
The three buttons comprise a 'SET' button, and two arrow buttons (up and down)

The key slot can be seen easier when looking at the rear of the unit:


Worthy of note, the 13-amp fitted plug is of high quality, and conforms to current British standards, with the correct depth of shielding on the live and neutral pins, and the earth pin fully unshielded. This may seem an odd thing to point out in a review, but there are MANY products being imported into this country now that are supplied and fitted with mains plugs that are not to standard, and are in fact downright dangerous (check out BigClivedotcom & John Ward on YouTube for more information - two excellent channels).



The temperature probe is detachable, which will allow for easy replacement should it get damaged in any way; should there be a fault with the temperature probe, or if you power the unit up with it disconnected, an alarm will sound. Connecting the probe is child's play, as it uses a standard 3.5mm stereo jack plug and socket arrangement. The probe end appears to be made of stainless steel:





This probe worked perfectly well for me in free air, cupped in my hand, dipped into fluid, and even with a bag of frozen chips wrapped around it

The potential uses for this probe are massively varied, and can range from taking air temperature in a greenhouse or room, through to measuring soil/compost temperatures, or even fluid temperatures if you are into home brewing (as many of us here are); NOTE - whilst the construction of the probe is of very high quality, I would STRONGLY advise that it is not submerged any further than the first indent up the probe - submerging it too deeply would likely see fluid ingress into the joint between the probe and the wire strain relief which would almost certainly kill the probe completely.

The mains output sockets are of a similarly high quality, and do have the correct guarding for the live and neutral sockets, which confirm to current British safety standards - this guarding effectively means that nothing can be shoved into the live or neutral connections accidentally, and the guarding only drops when a suitable three pin plug is inserted. Again, this may seem a strange thing to note here, however like the mains plugs there are many imported products that do not have this feature and are downright dangerous.



As you can see, the Heating and Cooling sockets are clearly marked, and again the strain relief is excellent. The rear of the sockets has two key slots to allow you to hang them up on a suitable screw or hook.



How does it work?
To set the desired target temperature, simply press and hold the 'SET' button until the top display shows 'TS' (Temperature Set), and then use the up or down arrows to alter the temperature in 0.1º steps; once you have the desired temperature on the display, press and hold the 'SET' button once more to store that temperature.



There are other parameters that you can access by pressing and holding the 'SET' button for three seconds until the display shows 'TS', then simply pressing and releasing the 'SET' button will cycle through those parameters. Remember, if you change any of them, you must press and hold the 'SET' button to commit it to memory. These parameters are:

HD - Heating Differential
How much below the desired target temperature do you want the unit to switch the heating power on - this is set in 0.1º steps. Simply put, if you have set a target temperature of 20.0º and have set the Heating Differential to 2.0º, then the area will be allowed to cool to 23.0º at which point the heating will come on.

CD - Cooling Differential
Yes, you guessed it - how many degrees over the desired target temperature before the cooling power is switched on. Again, in 0.1º steps.

Temperature rising:


Temperature now over the desired temperature by more than the set differential value, thus turning on the cooling power:


AH - Alarm High
This allows you to set an upper temperature limit, that once reached or exceeded will sound an alarm to warn you that things are too hot.



I set the alarm temperature to 32º and then shoved the end of the probe in my mouth, as soon as the actual (PV) reading got to 32º as set the alarm went off. The alarm will continue to sound until such times as the temperature drops back below the set value.

AL - Alarm Low
In exactly the same way as the alarm high, this will sound an alarm once the temperature has dropped below your preset temperature and the alarm will continue to sound until such times as the temperature rises back above that set temperature.



PT - Compressor Delay
I am not 100% sure what this does, but I think it is a time delay in minutes between the desired temperature being exceeded and the actual power coming on, to prevent damage to refrigeration compressors (such as those you would find in an air conditioning system). I suspect that this is to allow a compressor to come to a complete rest before another duty cycle is started....

CA - Temperature Calibration
If you think the displayed temperature (PV) is not accurate, then you can calibrate the unit +/- in 0.1º steps.

CF - Celsius or Fahrenheit
Exactly as you would expect, change the displayed values between ºC and ºF

So is it accurate?
In a word, yes. I tested the temperatures using a known calibrated digital thermometer, and this unit was absolutely on the money. Any change in temperature is quickly shown on the display, with an accuracy of +/- 0.1º

In summary
The ITC-308s is one of the most impressive bits of kit I have seen in a long time; build quality is excellent, the features are genuinely useful, and it is extremely easy to use.

By simply attaching a fan to the cooling socket and a heater to the heating socket, you will have a 'set and forget' temperature control for any environment (greenhouse, kennel, chicken coop..... I could go on!). The ONLY criticism I have would be the instructions that are provided - the print size is a little small, and they are not the clearest instructions I have ever seen. However, I would like to bet that given ten minutes or so with the unit, that almost everyone would be able to work it fully without even referring to the manual.

If you need temperature control for anything, do yourself a favour and get one of these - for the money (especially with the generous discounts that @marina29 offers to GC members), the Inkbird products cannot be beaten!