Auber PID Probe Issues

[ddtdustin]

All
I have an OBS with Dual Elements and Auber PID Dual probes.  I am having issues with my cook temperature probe intermittently swinging +/-20 degrees.  On my original install I did some testing and this probe worked great with a temperature variance less than +/-2 degrees.  I also verified the temperatures with a Maverick ET-732.  I have only used this probe for two smokes and have been very care to not get any water in the top side of the probe.  I use foil to cover the armored cable so I only have to clean the tip of the probe and discard the foil.  I have also unscrewed the plug and checked wire connections visually (no issue).  Does anyone think this could be an issue with the thermocouple?  I switched to the meat temperature probe and it is stable.  I see the issue now with no load in an open OBS.  Does anyone know why the meat temperature probe measures about 10 degrees higher than the cook temperature probe?  Are they the same type K thermocouple?
Thanks
DDT     

[beefmann]

has the probe been placed in the same location on every smoke and same orientation as  under the bottom rack  in above the elements horizontally vs. .  the middle of the bottom rack and dangling? .. if it has been the same .. you  may  have a probe going bad,

if it has been moved  so much as an inch it changes the TC sensor location causing different temp swings  like you are  experiencing. ..

try a few more  smokes paying attention on how the probe is setting .. do the best you  can to keep it exactly the same and monitor the temps,,, if at this  point you  still have  temp swings do an auto tune again  then proceed with more  smokes .. if it settles down then you  have cured the  issue by keeping it at the same location or close to it

the TC can be sensitive to location and orientation 

[ddtdustin]

The probe orientation is vertical, front side of smoker, just under the bottom rake.  When I first saw the problem I thought it might be grease dripping on it.  However the problem has continued and I have paid care attention to make sure the food was far enough back that drippings can't touch the probe.
As for different locations I have moved the probe with similar results but the swings happen after the temperature is stable and the probe is not being moved (just intermittently, and then the Controller will try to follow, even though the temperature is not really changing)
DDT

[Habanero Smoker]

Make sure the tip of the probe is about 6-inches from the meat. If the tip of the probe is too close to the meat, that can give you lower temperature readings. Moisture evaporating from the meat cools the surrounding air and can initially lower your temperature readings up to 40°F.

[Mr Walleye]

DDT

I would shoot Suyi at Auber an email about it. It does sound like you have a probe going bad. It could also be the connections on the sensor inside the the PID cabinet. If you send Suyi an email he will help you trouble shoot. Just use the email addy off the web site. He's usually really good at getting back to you even on weekends.

Mike

[viper125]

I would remove probes and bake in a 350 degree oven. Usually about 2-3 hours will do it. Then retry. I postion mine more on a horizontal plin and th wire running down hill of the probe. This way any juice or condensation runs away from probe.

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[ddtdustin]

All
I sent an email to Suyi and he very quickly sent me a replacement probe, however once I receive this probe and setup to make Jerky I had the following issues.  So here are some more details in case it helps.
The probes are not thermocouples, they are thermistors. The resistance of it should be around 50kohms at room temperature. The problem may because of bad solder point or bad connector.
When I connected the new probe to the controller it displayed -H-. After unscrewing the connector I thought it was the strain relief shorting out the red wire.  I verified it was shorted with an ohm meter.


I found the nut on probe 2 receptacle loose. I tightened it back up (with my fingers) only to find it loose again when I put a probe back in it. After looking a little more I found the nut on the receptacle split. So I brought my controller inside and carefully re tightened the nut and inserted the meat probe in it. However, when I move the probe just a little the temperature is jumping around and switches to -H-. I believe the wires connected on the inside of box have probably came loose or are coming loose.




Here are the instructions to open the WS controller.
Open the instrument.





2) Check the problem.


3) Put the instrument back to its original by reverse the steps. Slide the cover on first.
Install the back panel. In this step, screw the left up screw with the ground wire first.
After the screw is half screwed in, slide the panel into the right location and install the
other screws.


Here are the picture of what I found
On the bottom was probe 2 with half of the strands loose.


On the right was probe 1 with possible cold solder junction.


It does look like the red wire was shorted to the strain relief on the thermistor. I also think some of my problems were the connection between the eyelet and the center probe conductor on the connector. I dropped a small amount of solder between these two points.


Thanks again to Suyi
DDT

[Mr Walleye]

Nice job DDT!  ;)

Suyi is good to work with and he definitely responds quickly to any questions.

Thanks for reporting back and sharing!

Mike

[beefmann]

nice repair job