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disney7 11-20-2012 05:10 PM

HERMS temp probe placement help
I am working on a HERMS system and have decided to place the temperature probe in the mash tun at the point where the wort dumps back into it from the heat exchanger. Feel free to comment on the wisdom of this approach.

My question is, how are you guys installing the temp probe? I am trying to think of a good way to install it and keep it covered by wort.

Right now, I'm thinking of using a 1/2" Tee. The probe goes in the top, the wort enters from the side, and a nipple is used on the bottom to create back pressure and make sure the T and line stay full of wort and not wort/air.

Also, I have a couple of different probes. Both are K type. One is just a bulb on the end of a wire (water proof) and I don't know how I can install that and seal it up. The other (less accurate specs) is a stainless threaded collar and the probe is free to rotate in the middle of that. It is obviously made to screw into something, but I don't know how it would be water-tight unless the probe bulb contacts something and forces it backwards to make a seal.

So anyway, post pics if you have 'em. I can post some later if I've been unclear on the descriptions of what I have. I don't mind buying something else if it is a good solution.

Monster Mash 11-20-2012 05:49 PM

If you put it where it comes out of the HERMS you will be getting a higher temp reading then what the mash actually is, you have to remember it cools when it hits the mash. I put mine near the output of the mash so when it reads 168 I know the mash is that temp since the liquid has to pass through it to get there.

I would build a thermowell out of a keg dip tube or any stainless tubing. I cut a dip tube, stuck in a ball of foil about 1/4" deep in one end and filled it with JB Weld. That has held a seal for over 4 years now.



diS 11-20-2012 07:47 PM

I placed my probe half way to the middle of MLT (and half way vertically), it is 4" RTD probe mounted in welded bung, but I started to hate it because it's pretty tough to stir the mash equally, especially bellow the probe..

After some thinking I decided to shift it, make thermo-T couple (like Lonie Mac did it on Brutus ten) and use it to measure input temperature. I measured this temperature before with K-type thermometer placed in drilled hole in MLT input tubing, but now I be able to use RTD probe for other measurements too, like output of HEX when cooling wort (I use CFC and HLT filled with ice for chilling).

I would like to keep measuring my mash temperature too, so I will leave welded bung (1/4") on MLT so I can pull K-type probe trough it to measure mash temperature when i want to.
Problem is to secure wort from leaching outside of MLT and I came to an idea: mount 1/4" ball valve on bung (usually used for gas) and put wide rubber ring on outside of ball valve. Ring has small hole in center, but large enough to pull probe trough it.
I imagined it like this: inserting the probe- when top of probe is behind the rubber ring I'll open valve and push it to the end. Ring should prevent leaks when probe is in.
To take out the probe- drag it to pass the valve, shut off the valve and pull it off.

This way I should be able stir mash without taking care of the probe, measure temperature in middle of mash when I want without taking lid of, and also continue to monitor input temperature. Besides that, I think T couple w/RTD probe is nice solution to take temperature readings in several places.

This is just an idea, but I hope I will realize it until next batch.

disney7 11-20-2012 08:11 PM

That's interesting, might have to look into that approach.

When you spoke about Lonnie's build, I looked it up and found this picture:


Does anyone know how he made that? It's obviously a 1/2" pipe thread plug, but then what did he do with the probe? Epoxy/JB Weld it in?

diS 11-20-2012 09:04 PM

No, Lonnie's probe is inserted in thermowell.

I am using auberins RTD probe with a spring lock:
http://www.auberins.com/index.php?main_page=product_info&cPath=20_15&produ cts_id=107

Monster Mash 11-20-2012 09:21 PM


Originally Posted by disney7 (Post 4607661)

Does anyone know how he made that? It's obviously a 1/2" pipe thread plug, but then what did he do with the probe? Epoxy/JB Weld it in?

The thermowell is connected with a compression fitting and the probe is inserted into that.

It is kind of like mine but his thermowell is flush with the compression fitting.

Here is how I made my compression fittings, there are other ways but this was cheap and fits any size tubing.

1/2" compression to NPT with cap and o-ring

Drill holes in the caps to match the size of the thermowell...

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