Temperature Coefficient Issues

Get help and insight.
oldskoolbrewing
Posts: 14
Joined: Fri May 26, 2017 7:55 am
Bot?: No

Temperature Coefficient Issues

Post by oldskoolbrewing »

I am having trouble getting my temps to read correctly on the low end of my 462. I have tried the coefficient calculator and such but still the probes bottom out at about 40 degrees when they should be at about 33. Any ideas?
JonW
Site Admin
Posts: 1726
Joined: Sun Jul 18, 2010 7:51 am
Bot?: No
Location: Huntington Beach, CA
Contact:

Re: Temperature Coefficient Issues

Post by JonW »

Did you log the resistance at different temperatures to get your coefficients? If so, did the resistance change as it went from 40 down to 32?

Is this the calculator you are using? http://calculator.from-ca.com/
oldskoolbrewing
Posts: 14
Joined: Fri May 26, 2017 7:55 am
Bot?: No

Re: Temperature Coefficient Issues

Post by oldskoolbrewing »

I did not log. Yes that is the calculator.
oldskoolbrewing
Posts: 14
Joined: Fri May 26, 2017 7:55 am
Bot?: No

Re: Temperature Coefficient Issues

Post by oldskoolbrewing »

If there is a write up on how to properly do this I can use I would appreciate. Thanks
User avatar
bbrally
Posts: 210
Joined: Sat Mar 27, 2010 3:59 am
Bot?: No
Location: Vancouver, BC
Contact:

Re: Temperature Coefficient Issues

Post by bbrally »

PM oakbarn. He wrote a how to on the use of the calculator and calibrating probes. Perhaps he will share that document if asked.

There is also lots of information on the web about calibrating thermistors. just google "thermistor calibration" or "determine steinhart-hart coefficients"
JonW
Site Admin
Posts: 1726
Joined: Sun Jul 18, 2010 7:51 am
Bot?: No
Location: Huntington Beach, CA
Contact:

Re: Temperature Coefficient Issues

Post by JonW »

oldskoolbrewing - are you using probes from ECC/Brewers Hardware? Your initial statement says the "probes" bottom out at 40 degrees - are you saying all your probes act the same? I ask because this is an unlikely scenario using BH probes.

The BCS firmware ships with the default coefficients for probes by Brewers Hardware. If you are using another brand of probes, then they should have given you default coefficients for them also.

If you are using BH probes and have the default coefficients loaded, can you tell us more about how they are wired and placed in the vessels?
oldskoolbrewing
Posts: 14
Joined: Fri May 26, 2017 7:55 am
Bot?: No

Re: Temperature Coefficient Issues

Post by oldskoolbrewing »

All three probes are acting exactly the same. I am using BH probes and the coefficients. The probes are mounted in three fermentors in triclamp adaptor probe protectors. Wiring is just a straight run to the 462 with the probe wiring into the temp inputs.
oldskoolbrewing
Posts: 14
Joined: Fri May 26, 2017 7:55 am
Bot?: No

Re: Temperature Coefficient Issues

Post by oldskoolbrewing »

Anymore ideas or thoughts?
JonW
Site Admin
Posts: 1726
Joined: Sun Jul 18, 2010 7:51 am
Bot?: No
Location: Huntington Beach, CA
Contact:

Re: Temperature Coefficient Issues

Post by JonW »

If the probes have a lot of air space around them in the thermowells, then they could be off significantly and not able to properly conduct the temperature to the probe. There is no logical reason that all of your probes are "bottoming out" at 40 degrees.
User avatar
oakbarn
Posts: 846
Joined: Thu Jan 05, 2012 2:28 pm
Bot?: No
Location: Texas
Contact:

Re: Temperature Coefficient Issues

Post by oakbarn »

Try running a test with an ICE Bath. See Thermoworks blog: http://www.thermoworks.com/learning/the ... an_icebath

Make the wiring as simple as possible. I personally use 18awg twisted shield pair (overkill for sure) and run an independent ground to each probe. This is especially true for a "test" to try to trouble shoot.

Also back up you BCS and then restored to factory defaults. Then do the Ice Bath.

Check all your probes.
Post Reply