Help with Auber EZ boil giving incorrect temps

[Steve3842]

Hey guys,

I'm looking for a little help troubleshooting an issue I'm having with my new temp controller for my HLT. I am running a 4500 watts RIPP element controlled by an Auber EZboil and a PT100 RTD sensor. I'm quite happy that my first attempt at building the controller was quite successful and I can get my 10 gallons of water to boil. However when I started testing the accuracy of the probe I got some weird results. I am hoping I am just doing something stupid, as I built the system a while ago and only just got around to testing it recently. Anyway here are the results of setting the system to boil and measuring the probe temp on the display as well as the water temp with a thermo pen (temp in brackets). I've been using the termo pen for my brewing for a while and it matches other themometers I have in the house, so I'm quite sure that is the accurate temp. Please let me know if I need to do anything else to test or if I'm just doing something dumb (like not configuring etc.)

Outside temp ~9pm 66F (66F)
9.15pm - 68F (140F)
9.30pm - 106F (185F)
9.40pm - 204F (204F)
10pm - rolling boil 210F (211F)

EZboil
https://www.auberins.com/index.php?main_page=product_info&products_id=560

Liquid tight PT100 RTD sensor, 4 inch, 1/2 NPT Thread
https://ebrewsupply.com/products/liquid-tight-rtd-sensor-4-inch-1-2-npt-thread

 

[Steve3842]

A bit more info if needed. Using the DSPR300 version of the EZboil and a 3 wire sensor. Have confirmed it is wired correctly according the the manual.

 

[ancientmariner52]

Hello, Stezza. Where is your sensor located in relation to the heating element? Is it possible that both readings are correct, for that given location? When I installed a boil coil in my kettle, I noticed, to my great suprise, that the bottom of the pot was cool to the touch until full rolling boil started. I didn't record any numbers, but what you describe sounds similar.

 

[Steve3842]

It is located quite low, and it only protrudes into the HLT by less than an inch. However for this test I did briefly stir the water every 5-10mins to try and remove this as a variable.

 

[ancientmariner52]

I think you are seeing stratification. You would have to stir pretty vigorously to overcome it. I can't think of a way that your temps could start the same, diverge wildly in the middle range, then finish the same, unless that is actually happening. I suggest you heat up a pint or so of water in a saucepan or something, and put your rtd and thermometer in together. I'm not a betting man, but if I was.....

 

[augiedoggy]

It is located quite low, and it only protrudes into the HLT by less than an inch. However for this test I did briefly stir the water every 5-10mins to try and remove this as a variable.

4" rtd only protrudes 1/2" into the kettle? sounds like you mounted it in a tee or something (sight glass base at bottom of kettle?) which can cause incorrect temp readings in many cases unless your circulating the water through that tee to equalize temps.. if the probe jacket itself it being somewhat altered by cooler liquid in the tee this could happen.

you can blow into the sightglass to push the liquid out and slowly let off it and see if your temps jump up.. if they do you found your problem.

 

[Steve3842]

4" rtd only protrudes 1/2" into the kettle? sounds like you mounted it in a tee or something (sight glass base at bottom of kettle?) which can cause incorrect temp readings in many cases unless your circulating the water through that tee to equalize temps.. if the probe jacket itself it being somewhat altered by cooler liquid in the tee this could happen.

you can blow into the sightglass to push the liquid out and slowly let off it and see if your temps jump up.. if they do you found your problem.

Just reporting back after almost a year (winter brews I bring our the electric HLT). You were right and a combo of stirring and blowing in the sight glass gave accurate results. Have replaced with an 8” probe now! Thanks for your help!

 

[Mybuddypete]

Although it took you a year, I appreciate when someone posts they solved the problem and what the solution was.

 

[augiedoggy]

Yes it help those of us who search and look for info from old threads appreciate it.