HERMs without temp probe in mash tun?

[Hello]

I think I made a mistake with my build, which may or may not cost me.

I'm about to install my HERMs coil in my HLT. Right now I have a temp probe in the water out valve of my HLT. My control panel has two PIDs and two temp probe connections. One is for the HLT the other for the BK. I never intended to have a PID for the MLT as I did not think I needed it. I don't intend to have an element in my MLT in the future.

Looking at the Electric Brewery again, I think I missed a step and I'm not sure if I can get away with the HERMs setup without actually building more into my panel.

It appears as though I can keep my temp probe in my HLT as it is in the water out valve, but that will only measure temps of the water. If I set that to 168F and recirculate my wort from my MLT though the HERMs coil, then there is no telling what the temp of the wort will be. Originally, I assumed if the water was 168F in the kettle then the circulation through the coil would rise to that same temp (not that I would mash that high). Now I'm thinking that's not right and I need to have a temp probe in the wort out valve of my MLT (or wort in valve of my HERMs). If that temp drops below what I want then the element in the HLT kicks on and starts heating the water, I guess.

I think I got lost somehow. Is there anyway to effectively run a HERMs system with just the two temp probes for the HLT and BK and two PIDs?

 

[crane]

You are correct that the mash tun may not be at the same temp as the water in the HLT. It would be beneficial to have a way to monitor the temp of the MT. At the very least you can add another temp probe and connect it to the BK PID during mashing, just to monitor the temp. You would still use the temp probe in the HLT to control the HLT water temp. If you find that the MT is a few degrees colder than the HLT then you can bump up the HLT to bring up the MT temp. Where you place the MT temp probe is up to you, I chose to mount mine to the MT itself so I am reading the temp of the contents inside the MT. This should be the same as the outlet of the MT. If you place it at the inlet of the HERMS coil it may be reading a few degrees colder than the temp inside the MT, due to temp loss through your pump/hose.

If you want more bling then you can add a third PID to your panel, just to monitor the MT temp. That way you would not have to change which temp probe is plugged into the BK PID between mashing and boiling.

 

[Hello]

You may have saved me then.so a PID for the mash temp is kind of unnecessary if I just use the BK PID. Also, if I set my mash temp on the PID to say 152 then if it drops temp then nothing really gets triggered anyway. I'd have to watch the temp and if it drops then set my PID on my hlt to increase the temp of the water and thus increasing the temp of my wort as it circulates, right?

 

[brrman]

I use a temp probe on the exit of the MT going to the herms coil. I want to know the temp of the actual wort, since the inside of the MT might have pockets of diff temps throughout.

I also a temp probe on the exit of the HLT going to the MT.

I have that third PID, but it is only to monitor temps on the MT exit. A simple temp readout from a physical thermometer inline would suffice - that would keep you from having to add to your panel.

 

[crane]

You may have saved me then.so a PID for the mash temp is kind of unnecessary if I just use the BK PID. Also, if I set my mash temp on the PID to say 152 then if it drops temp then nothing really gets triggered anyway. I'd have to watch the temp and if it drops then set my PID on my hlt to increase the temp of the water and thus increasing the temp of my wort as it circulates, right?

Correct, but you should find after some use that your MT temp will always settle x degrees below the HLT temp. This shouldn't change throughout the brew day, and in most cases it will be the same for every brew day. Thus you will most likely always set the HLT temp x degrees above the desired mash temp.

Most people don't use the MT temp to control the HLT element, but rather do as I described above.

Using the MT temp to control the HLT element can easily cause the HLT temp to fluctuate more than you want as there will now be a larger lag between the element firing and the MT temp rising. This could cause the wort in the HERMS coil to get too hot

 

[Hello]

Man, you all saved me. I really had a moment where I thought I had a serious misstep on the panel build. While there is room, I think, I add another PID, I would rather not. I like the inline thermometer idea a lot @brrman . I also am glad @crane that you mentioned I will eventually know that the HLT temp will give me X MT temp.

I've spent most of my time outfitting the second pump and making sure I had no leaks, so I'm saving the HERMs for another day so I can still brew today. I really appreciate the help from you both.

 

[Brad2287]

Here is my solution. It is a half inch npt dial thermometer on the output of my MLT right before my pump. The HLT is usually has to be a couple degrees above me desired mash temp. Not as cool as if it was on my panel but it gets the job done.

View attachment 1441565578400.jpg

 

[BigFloppy]

Mine is less than a degree different HLT->MASH .. each system will be slightly different, once you find out how your system plays, really is no need for mash tun monitor.

MAKE SURE you tune your pid controller though

 

[Hello]

I definitely tuned it. I need to calibrate the temp probe though as it reads about 4 degrees off. But I'm glad I can borrow the probe for now if I want.

 

[30Bones]

Just put a standard thermometer in the MT via the kettle itself on in the output via a tee? That's what I plan to do. I see no reason for a PID just to display temp and do nothing else.

In the pics the MT is on the left and BK on the right.

 

[ChocolateMaltyBalls]

It's always a good idea to use another thermometer to periodically calibrate the PIDs. I use this setup with a camlock (like 30Bones) to check temps as well as the output from my plate chiller. You could easily use it to monitor your MLT till you get a feel for the system.
https://cdn3.volusion.com/htxqr.ysuzo/v/vspfiles/photos/Pcomp1-3T.jpg?1436787057

 

[Hello]

Just put a standard thermometer in the MT via the kettle itself on in the output via a tee? That's what I plan to do. I see no reason for a PID just to display temp and do nothing else.

In the pics the MT is on the left and BK on the right.

Yeah, thanks to everyone, this is exactly what I'll be doing. I'll use a thermometer with a short probe (I think I'll need to get it from @Bobby_M again) and then monitor my wort out at the MT. I should be okay.

It's always a good idea to use another thermometer to periodically calibrate the PIDs. I use this setup with a camlock (like 30Bones) to check temps as well as the output from my plate chiller. You could easily use it to monitor your MLT till you get a feel for the system.
https://cdn3.volusion.com/htxqr.ysuzo/v/vspfiles/photos/Pcomp1-3T.jpg?1436787057

What thermometer is that? It looks neat.

 

[ChocolateMaltyBalls]

It's the CDN Bobby sells, I got it and all the parts from him. Very convenient to use.

 

[Hello]

It's the CDN Bobby sells, I got it and all the parts from him. Very convenient to use.

Did you cut the probe or something? Seems shorter.

 

[ChocolateMaltyBalls]

No need to cut, it's all in how you orient the tee. If you put in the straight its short, if you put the probe in the 90* then the thermometer sticks up a few inches.

 

[Dcpcooks]

I use probe on the outlet side of my herms coil. I played with several variations and this gave me the best control. You may want to circulate the HLT liquor to improve heat transfer. I run about 3 degreesF hotter in my HLT than the wort. It's at least double that with circulation around the coils

 

[Hello]

These are data points I'll have to definitely learn. I just bought a thermometer and I'll be working towards determining placement. I don't need to be fancy with a third PID. For me, it really is going to come down to learning the appropriate temps and adjusting accordingly.

 

[cantrell00]

I think I made a mistake with my build, which may or may not cost me.

I'm about to install my HERMs coil in my HLT. Right now I have a temp probe in the water out valve of my HLT. My control panel has two PIDs and two temp probe connections. One is for the HLT the other for the BK. I never intended to have a PID for the MLT as I did not think I needed it. I don't intend to have an element in my MLT in the future.

Looking at the Electric Brewery again, I think I missed a step and I'm not sure if I can get away with the HERMs setup without actually building more into my panel.

It appears as though I can keep my temp probe in my HLT as it is in the water out valve, but that will only measure temps of the water. If I set that to 168F and recirculate my wort from my MLT though the HERMs coil, then there is no telling what the temp of the wort will be. Originally, I assumed if the water was 168F in the kettle then the circulation through the coil would rise to that same temp (not that I would mash that high). Now I'm thinking that's not right and I need to have a temp probe in the wort out valve of my MLT (or wort in valve of my HERMs). If that temp drops below what I want then the element in the HLT kicks on and starts heating the water, I guess.

I think I got lost somehow. Is there anyway to effectively run a HERMs system with just the two temp probes for the HLT and BK and two PIDs?

Went back to your original post...

My system is a 3 vessel, single PID that I alternate between the HLT & kettle.

I have a dial gauge on my HERMS & a dial gauge with a 6" probe that measures the mash bed temp.

The best place to put my PID was on the return into the HLT/HERMS. This resulted in only a 1-2 degree deviation between the mash temp & the HLT temp.

The two dial gauges are invaluable when you are trying to check the various input & output temperatures relative to one another.

I can only rationalize two PID's max and only while running two elements at the same time.

 

[Hello]

I do have two PIDs and a 50a panel to be able to run back to back batches if I wanted to in the future. That is where I figured all that jazz would come into play. That being said, the third PID never occurred to me and with everyone's responses, I can see that I did not make a truly bad decision. I like your idea on using the PID on the return of the HERMs.

 

[cantrell00]

I do have two PIDs and a 50a panel to be able to run back to back batches if I wanted to in the future. That is where I figured all that jazz would come into play. That being said, the third PID never occurred to me and with everyone's responses, I can see that I did not make a truly bad decision. I like your idea on using the PID on the return of the HERMs.

No problem. I tried everywhere else and that was the location that resulted in the most narrow delta.

Measuring in the mash resulted in the worst variance for me.

Yeah. If doing back to back, I can certainly see the need for two & two elements.

I only have a 20 amp, 240 volt service so my setup HAD to be simple. Hardly no room for error, over amperage, etc. It works though.