HERMS PID Burner Question

[mjackson]

Okay so I have been crunching some ideas and have a question. This might be a stupid question, and I am up for suggestions. Basically I want a low pressure LP HERMS rig with two burners.

I have seen a e-hems where the HLT and Boil Kettle both have elements and the control panel has three PIDs to control them. 1st PID controls the actual heat of the strike water, the second PID controls the same element as the first but the temp probe sense the heat of the mash as it recirculates to the MT. And the third PID controls the BK.

My question is can this same general set up be utilized in a low pressure LP stetting with two burners. Can i have a burner under my HLT with a Honeywell valve that is controlled by a PID for heating the HLT, and then have that same valve and burner controlled by a second pid that gets its temperature reading from the MT?

 

[wncbrewer]

I think most of the time the mash pid isn't actually controlling an element, but rather being used to monitor. For instance, Kal'selectric brewery (www.theelectricbrewery.com) is set up this way. I have a HERMS with both burners controlled via pid and Honeywell valve. The mash pid is multi purpose in my system. I use it to monitor the mash temp during the mash, then come boil time I set the set value to 212 and it fires my boil burner. This only requires that the set point be lower than your mash temp during mashing (otherwise the boil burner would fire) and higher than mash temp during the boil. This works well for me. My probe is at the mash return after the hex. Hope that makes sense.

 

[ajdelange]

Sure but as you are controlling the same element with respect to two different regulation points wouldn't it be less expensive/simpler to put together something which switches the input to a single controller connected to that element between two RTD's, one in the HLT and one in the mash?

 

[mjackson]

Yeah I think that does make sense to me. So when you mash at lets say 154 is your target mash temp. What would you typically set your HLT and MLT values at? So during the beginning of your boil it would still read the mash temp which should for sure be lower then the temp a firing boil kettle right?

 

[mjackson]

I like the Idea of less PIDs.

 

[mjackson]

ajdelange I just saw a post where someone had made a switch for their RTD's that would solve my problem I think.

 

[wncbrewer]

Yeah I think that does make sense to me. So when you mash at lets say 154 is your target mash temp. What would you typically set your HLT and MLT values at? So during the beginning of your boil it would still read the mash temp which should for sure be lower then the temp a firing boil kettle right?

You got it. The probe measures the mash temperature, but the pid controls the boil kettle burner. Kind of a shortcut method of using 1 pid and probe for two functions. No switch needed. May not be as ideal as having a switch, but I have had good luck with it.

On my system, I hold my hlt water at 3 degrees above the desired mash temp. If it is cold outside I sometimes have to bump that to 4 degrees because I lose a little heat in the lines. I have heard others give different values. It depends on the system.

 

[mjackson]

Wncbrewer, could you supply me with some pics of your setup? Im getting ready to start buying supplies for the build and honestly the only info I have is from reading threads on here. I currently do all grain but only use a 8 gallon boil kettle for both the BK and HLT with a 70 QT MLT.

 

[wncbrewer]

Wncbrewer, could you supply me with some pics of your setup? Im getting ready to start buying supplies for the build and honestly the only info I have is from reading threads on here. I currently do all grain but only use a 8 gallon boil kettle for both the BK and HLT with a 70 QT MLT.

Sure, if you need any more specific shots let me know. The pid on the left controls the hlt, the probe associated with it is located in a tee at the hlt outlet. The right pid monitors the mash temp as it leaves the hex and returns to the mash tun. The probe is located just before my line loc sparge tube this probe fires the boil kettle, as I said before. Gas valves are Robertshaw combination gas valves controlled by Honeywell hot surface ignition modules and glowfly igniters.

Hope this is what you were after. Look back in a couple weeks. In the middle of converting to all triclamp.

 

[mjackson]

Thank you!

 

[wncbrewer]

Also, Mr. Delange, thank you for all your hard work with water chemistry. You have done the homebrewing community a huge service