thermowell, wet or dry?
- Thread starter Minbari
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I was in industrial instrumentation for 40 years. We always installed the wells so they were dry. As long as the thermocouple is firm against the wall, temperature measurement will be fine.
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IIRC the probe that came with my inkbird is not supposed to be immersed in liquid. I have inadvertently had a thermowell full of starsan, which I only discovered when packaging of course. No problems to date, but I do have a spare just in case it ever acts up.
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I do it dry. The diameter of my temp probe is only slightly smaller than the inside diameter of my thermowell so I seem to get decent heat transfer, if my probe was much smaller I might consider going wet.
Industrial temperature probes are generally threaded into thermowells and spring loaded to ensure good contact between the tip and the well. The measurement relies on the very small thermal mass to conduct any changes in temperature quickly.
Our consumer grade probes often just have a wire. So, to make sure that I have good contact between the probe and well, I push the probe in and put a small piece of tape over the well. This holds the tip in firmly and provides a good response rate.
Our consumer grade probes often just have a wire. So, to make sure that I have good contact between the probe and well, I push the probe in and put a small piece of tape over the well. This holds the tip in firmly and provides a good response rate.
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Ya kinda what I was thinking. Tape or clip to hold it in place. When my new PID controller gets here I will be testing
Dry, mushed in there well and held with blue painter's tape.
However I did find that with an inkbird 308 controller probe in the thermowell, the temperature swings of the wort (measured by the Tilt) were 2 or 3 degrees above and below the set point, whereas taping the sensor to the outside of the fermenter with some felt padding over it for insulation keeps the wort temperature withing a degree or two at the most. Spike Flex SS fermenter in a fridge. Because of that, I don't use the thermowell any more.
However I did find that with an inkbird 308 controller probe in the thermowell, the temperature swings of the wort (measured by the Tilt) were 2 or 3 degrees above and below the set point, whereas taping the sensor to the outside of the fermenter with some felt padding over it for insulation keeps the wort temperature withing a degree or two at the most. Spike Flex SS fermenter in a fridge. Because of that, I don't use the thermowell any more.
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And the temp agrees with your tilt that way?
I have a thermo well that goes right down the middle about 8 inches deep. It usually agrees with the tilt and keeps a +/- of 0.3°F. I don't have feementer fridge though. Instead use a glycol chiller
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May I ask @Donoroto and @Bubba Wade where does the tape come into play? In my case the thermowell is deep in the wort, and the probe is in the thermowell, not sure where I would put any tape... this is a little dimly lit, but that is the black cable leading to the probe.
Here’s a top view of my fermenter. The tape is not absolutely necessary. It just helps to hold the probe firmly in the well.
My Tilt and my temp controller will vary by a couple of degrees. That is due to the nature of my cooling system. I am using the Brewtech with the heat exchanger coil. The thermowell is at nearly the same elevation as the coil. So when chilled water is pumped through, the thermowell probe changes pretty quickly. The Tilt takes a little while to catch up as the temperatures in the top and bottom of the fermenter take a little while to equalize.
@Craigerrr My thermowell is in the side of the fermenter. The tape holds the wire so the sensor probe doesn't fall out easily. A lot like Bubba's photo above. I kind of mush a little (1/4"?) extra wire down the 4" deep hole so the sensor tip stays pressed against the inside end of the thermowell.
Well, I used to. Don't use it any more...
Well, I used to. Don't use it any more...
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In mine I just made sure the metal touches the bottom, I wedged something in there to keep it from coming loose but at the same time I'm an extensive tester and have only found a small variance between touching the metal and laying lose, the key is to get a long thermowell
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Mine is 18" long. About 8-10" is submerged
No glycol, just chilled water. I have my keezer next to it and have a reservoir made of 4" PVC drain pipe. Since the keezer is set to 36 degrees, it does just fine keeping the fermenter at temperature, even in these Southern regions.
