Temperature probe is reading 90F off of true temp

[Hello]

I had an issue with my panel, sent it back and it was gone for months. I finally got it back and while it "works" the temperature probe on my HLT reads 95F when the water is actually 185F. I have my probe in my ball valve and water runs through the pump back into my HLT while it heats to my strike temp. I checked the probe connection to my panel and it is fine. I also auto tuned the PID, twice. I'm brewing today so I'm just keeping an eye on temps the good old fashioned way, but I'd like to figure out the issue. The PID shows the increasing temp, but it's way off. Number one reason per the guide the panel came with was a bad connection between the probe and control panel and to check the connection. That's the only thing that was mentioned. With that not being the case, I wonder if this is an easy fix and I'm just not seeing it.

Thanks.

 

[microbusbrewery]

Try immersing the probe in a different containers filled with different temps of water and see if it's reading those correctly. If it's reading correctly there, my guess is you have an air bubble where it's positioned in your HLT. If it's not reading correctly with that method either, I'd look at connection again. After building my stand I was getting weird temp readings until I realized the panel mount connectors (simple mono audio connectors) were causing problems because they weren't insulated from the grounded metal control panel. When the connectors weren't mounted, they read correctly. When they were mounted, they read way off. Could be something similar in your case.

 

[The_Bishop]

A picture of the setup (where the probe is located) would help.

 

[dmcman73]

What type of probe is it (RTD?) and what are you connecting it too (PID? What model?)

If you are using a PID controller with an RTD type temp sensor, you first need to verify that the PID is programmed with RTD and not a Thermocoupler. Next, pull the temp sensor out and place the probe into a mug filled with crushed ice and water (should look like a slurry). The sensor should read around 32 degrees F. If it's off, the PID has adjustments within it to calibrate the senor you are using, read the manual for it. I had to adjust my setup a few values up in my PID.

 

[Hello]

A picture of the setup (where the probe is located) would help.

Would you like a pic of the set pup or inside the panel?

 

[The_Bishop]

The setup of the probe. Also, did you ensure the temperature controller is correctly configured?

 

[Syncman]

Mine was off 16 deg. Followed this instructable. Ice/water mix should read exactly 32 deg.

[ame]https://www.youtube.com/watch?v=-cKa_EWRIQY[/ame]

 

[Photopilot]

I doubt any setup location could be responsible for a 90 degree error unless it was not touching the liquid being measured in any way.

Auto tuning is just the PID setting the algorithm to your vessel to heat the water to the set temp without overshooting. My guess is you need to calibrate the unit. Start with Syncmans video and let us know what happens.

 

[Photopilot]

It has been a long time since I set my PID up but I remember there are different type of probes available and the PID needs to be configured to the correct probe. Read your instructions and make sure the PID is configured to the proper probe before you calibrate.