STC1000 Calibration

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SergeMarx

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hey guys,

I use an STC1000 for controlling the mash in my electric urn, but with a string of brews recently failing to attenuate, after ramping up the yeast and oxygen to no avail, I wondered if the calibration was out. I'd checked it last maybe 18mths ago and brought it in line (was 4c) out, but now it seems it's a whopping 15c out. So, attenuation probably explained, but how to fix? You can only correct the readings up to 10C. I've purchased a new sensor lead on ebay today - so that may help, but thought i'd ask if anyone has had similar issues and how they were solved?

Thanks
 
While you're at it may as well order a whole new unit from the evil bay, they don't cost much and it's not a terrible thing to have a spare of.

The probe may well do the trick.
 
SergeMarx said:
now it seems it's a whopping 15c out.
Woah!

I should probably check mine more often then.

With yours, I'm almost certain it'll be the sensor and replacing it will solve your problem.
 
In the end I had three different thermometers in boiling water and they all showed different readings. TRUST NO-ONE!
 
I don't use an STC for mash temps but I do calibrate it once every month or two to make sure the fermentations are where they should be. It's usually fine but sometimes it creeps a degree or two. Probably a good idea to do it regularly especially with mash temp measuring. I've never had one 15C out though!
 
Exact same problem and same delta!! Last week in fact.

Was for my keezer.... froze my beer at the reported 2degC.

Calibrated it against my PID

Wound it to -10 in the adjustment and have the PID supervising. Now it is 3 degC on the STC and -0.2 on the Omron.


Not good enough for me. I'm thinking of going down the warranty Avenue. I bought a spare so will try that first.

Always have a spare STC-1000 ;)

I'll try and find who I bought it from. Some eBay crowd
 
Have a look at where the sensor wires go into the STC, a bit of corrosion can cause all sorts of corrupt data.
I usually crimp on a straight connector so the junction isn't wire to screw terminal, rather a metal to metal connection.
Mark
 
A mate just bought a new STC1000 so i grabbed his sensor lead to see. Problem solved - now just a +1C calibration required. I'm sure sure there's a lesson in all this somewhere...
 
That makes sense. I'll try the other sensor lead I have and see if it happens with that one as well. Might not though as they were bought at the same exact time and could be a batch problem.

I liked MHB's idea above. But i've also found to the opposite to be true. A crimp on an especially fine wire can be a source of wildly varying impedance, especially when PT100s and other RTDs move micro-milliamps. But if the gauge of the wire is thick enough then a crimp should be of no electrical consequence and benefit the reliability of the junctions.

It's always metal on metal in electrical / controls / signals

https://www.youtube.com/watch?v=jDC2e6i6Quw
 
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