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-   -   Simple eHERMS, following PJ's diagram w/ only 1 PID. (http://www.homebrewtalk.com/f170/simple-eherms-following-pjs-diagram-w-only-1-pid-221403/)

Squeeky 01-29-2011 02:39 PM

Simple eHERMS, following PJ's diagram w/ only 1 PID.

First off I would like to thank PJ, he truely is a genuine person. Back in 06' he helped me get started with my ebrewery which I never completed due to several issues beyond my control. Now I'm back at it :)

If I'm understanding this diagram correctly it will give me a very simple control panel, which will allow me to control 1 of 2 elements at a time. My question really is, do I need a second PID. I have yet to brew with a HERMs setup, but my understanding is a second PID would monitor MT output, while the first would control the Temp in the HLT. Since my setup will not be 100% automated, couldn't one just montior the temp in mash, and either increase/decrease flow through HERMS, or +/- temp in HLT to reach proper mash temp.

Once mash completed, it would just be a matter of switching PID to BK. Also from what I have read a temp probe is not needed when boiling as it is the duty cycle that controls the boil, is this correct?

I have to plan everything out and currently all my brewing items are over an hour away (damn conodo assoc.).

*I realize the diagram does not show temp probe leads, but they would be ran as well

P-J 01-29-2011 04:18 PM

Just discovered your thread. Thanks for your kind words.

You really only need a single PID. (Unless you intend to do back to back brews)

The temp probe would be placed in the HLT and there is no need to move it. You are correct that for the boil you would switch PID mode to percent of power delivered. The temp probe must still be connected for the PID to function, but it can stay in the HLT. No need to move it.

For the mash: Just monitor your HLT temp and circulate the HLT water through the mash. You will probably lose a degree or 2 at most. You will know the loss differential on your first brew session. I'd just use a standard thermomemeter to measure the mash temp during you first few sessions. Once you know the loss, you can adjust your HLT temp accordingly. Actually you will know within 5 minutes on your first session.

If you are using a cooler type of mash tun, there is no need to do recirculation at all.

If you use a keg or kettle type mash tun recirculation helps compensate for heat losses through the kettle walls. It also keeps the entire mash at your target temp. I suggest that you keep your hose line lengths reasonably short as this also helps minimize heat loss. You also would want to recirculate your mash through the HERMS coil for the entire mash time. Keep the flow at a reasonable rate so that you do not compact the mash bed.

I know you know all of this, but I hope it makes sense and helps.


Squeeky 02-05-2011 02:20 PM

Well after much consideration and debate I'm going to continue with this setup. I had debated using my current Omega PID w/o manual control and a 555 timer circuit to control the BK. This would save on cost, but add aditional room for wiring error. I plan on building this control panel into a toolbox as I would love the ability to make things portable.

Thanks again P-J for all your input, now it's time to start collecting parts.

P-J 02-05-2011 05:57 PM

Just sent you an e-mail. I hope you still have that address.
I think I can save you some $'s with a wiring design change.

Hope to hear from you.

shuie 02-05-2011 07:47 PM

This very similar to my build. Lots of help from PJ on mine, too. Help from Tiber, the Simple, TwentE2, concepts as well :)

I also have two vessels, but I'm using a single heating element and a single pump. My HLT doubles as my BK and I recirculate my mash and recirculating the mash through a HEX coil that sits in HLT/BK. My MLT doubles as an ice water tank and I swap the HEX coil over to that kettle while chilling. The RTD temp probe stays in the HLT full time and I monitor the mash temp on a couple of analog thermometers in the MLT and adjust the PID accordingly.

some pics...










Squeeky 02-07-2011 02:22 PM

After talking with P-J, the final diagram is as follows:

Squeeky 02-07-2011 02:35 PM

The biggest difference is cosmetics, who need Automation switches anyway. If I was building for BYO article or for a webpage I would be all about it, however I'm building to make good beer. If it's one thing I've learned of the years is good beer can come from some ugly breweries.

The DPDT center off switch P-J linked too is key, as it eliminates the need for the 2 contactors and saves a few $. If anyone plans to duplicate I recommend ordering early as it seems to not be stocked at Grainger and must be ordered in.

This control panel will also be rather small and compact which will work nicely to make it protable. It also uses only 1 PID, whose temp probe will stay connected to the HLT. When done mashing just flip the switch and use manual control on the PID to control BK.

I would recommend if you are going to use any illuminate switches, do it for the PID. With this design it is also the master on/off. As you can see without the PID on, there is no power going to either leg of the element. Assuming the grainger switch is set to center off.

Please keep in mind this is a work in progress as I will be building the CP, and later the HLT and BK. If you guys have any suggestions for enclosure or comments feel free to reply. I don't think I'll use a toolbox as it may be over kill due to the small footprint and design. I believe if using a 40a SSR, I can get away with a standard Heatsink and not have to mount outside of the control panel.

Big thanks to P-J again, as a thank you I am now a Premium Supporter of HBT.

Squeeky 02-08-2011 12:46 AM

To use JB Weld or Not
Debating using "The Pol's" JB Weld/stik method to create the connection from keggle to control box.

I realize members like Kal have a beautiful setup, however I'm looking to save cost and make things easy. Does anyone have a reason for me not to make the PVC couplings? Also when grounding the element to the kettle, so I need to have a hole through the ketlle, or can I just solder te ground like to the keggle?


Ordered the grainger switch and back ordered PID this evening. It's finally going to happen 5 yrs later. I will be selling all my extras after the build is complete.

P-J 02-10-2011 03:55 PM

Here is the box for your controller setup.
Project Box for 1/16 DIN controller
All of the components will fit inside of it.

Hope this helps.


Squeeky 02-10-2011 04:12 PM


I actually already placed my order from Auber, so I'll have to find a different box. I should be able to locate something at the liquidator I talked about of the phone. Thank you though.

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