PJ's Diagram modification help

[duckdogs]

I am in the process of building a new system 50 amp service. I found one of PJ's diagrams that is perfect but I would like to be able to use the BK pid to cycle one of the pumps on and off to maintain the mash temp by running it threw the HLT coil when not being used to boil. Using the temp probe in the MT sense it's not needed for the boil using manual mode

I believe this can be done by using 2-3 position switches, the first on the positive out put lead of the pid switching it either to the pump ssr or the Bk ssr.

pos. 1 (left) pump, pos. (switching on the pump ssr pid contorled) 2 (center)off, pos. 3(right) BK element ssr.
The second 3 pos. switch would run the pump -
pos. 1(left) pid controlled pump, pos. 2(center) off, pos. 3(right)manual pump on.

It looks like I would just need to add another ssr to apply the power to the pump when being controlled by the pid that would be switch to via the first 3 pos. switch. Hope this makes sense

and thanks for any input

 

[atoughram]

Sounds like you already know the solution! Thats exactly what I would do also - two position selector switch - BK/HERMS, another SSR or a relay, and associated wiring. The only issue with this is that you will have to reprogram the PID when using it for a pump vs using it for an element. You dont want to turn a pump on and off that fast.

I'd do away with the BK PID all together and install an SSVR to run it's element. I'd then put the pump on a switch and run it all the time while mashing - It really helps to clear the wort up.

 

[Bobby_M]

I wonder how popular this method of HERMS is anymore. I know that it was "THE" way to do HERMS for a while but it's more prevalent to see constant recirculation these days. The main concern with cycling a pump is that you have no way to know if the probe is sitting in a pocket of stratified temp meaning you never know if the PID knows about the actual average temp. It would be a little silly, but quite effective, if you could rig a way to have the temp probe at least moving back and forth in the mash by even 2 inches of travel.

 

[duckdogs]

I wonder how popular this method of HERMS is anymore. I know that it was "THE" way to do HERMS for a while but it's more prevalent to see constant recirculation these days. The main concern with cycling a pump is that you have no way to know if the probe is sitting in a pocket of stratified temp meaning you never know if the PID knows about the actual average temp. It would be a little silly, but quite effective, if you could rig a way to have the temp probe at least moving back and forth in the mash by even 2 inches of travel.

It sounds like its a better option to just leave the pump on as is. As far as the temp stratification, I was thinking the way to get around that was just to put it in line directly outside the MT then it's always in moving fluid. Then there's another issue of how much difference in temp is there between the top of the grain bed and the bottom....


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[jeffmeh]

There are a number of ways to place the probes (and at least as many arguments), but many successful eHERMS systems use Kal's method, with a probe at the output of the HLT recirculation loop to provide PID temp, and a probe at the output of the MLT (feeding the HERMS coil loop) to monitor mash temp, with constant recirculation for both. http://www.theelectricbrewery.com/temperature-probes