2 PID brew panel used for fermentor control when not brewing

I did a search but couldn't find exactly what I'm thinking. I'm in the process of figuring out my partial e-HERMS brewery. I think my brewery panel will have 2 PIDS, one timer, and alarm. Nothing fancy. The HEX would be a standalone unit, not a part of HLT. Because of this smaller HEX, I would only use 120v.

My thought was after a brew session, I could unplug my HEX, pumps, etc from the control panel and move it to where my fermentation fridge is. Use the same PIDs to control the cold/hot of the fridge.

Is this feasible? I'm sure it is. A better question is if anyone has done this with PID. I read people using BCS in this way, but I think I want to go down the PID path.

I figured, I only brew so often. Often my last batch has completed fermentation before I start my next one.

I tried using a PID through an SSR for fermentation control a while back. It will not work. The PID rapidly cycles the SSR on and off when it is near its set temp, so it is never able to get the compressor on the fridge to turn on when it is near your set temp. Though you could use one of the alarms on the PID to control the fridge, if the relay on the PID can handle the amperage of running the compressor.

This is one reason I went the BCS route.

Bsquared said:

I tried using a PID through an SSR for fermentation control a while back. It will not work. The PID rapidly cycles the SSR on and off when it is near its set temp, so it is never able to get the compressor on the fridge to turn on when it is near your set temp. Though you could use one of the alarms on the PID to control the fridge, if the relay on the PID can handle the amperage of running the compressor.

This is one reason I went the BCS route.

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It maybe the PID you're using, while searching on this topic I found this thread.
https://www.homebrewtalk.com/f51/love-vs-pid-fermentation-temp-control-143937/#post1646095

The poster said you could change some of the settings to allow a wider temperature range and keep the power on for 60 seconds to reduce the cycling. So I didn't think the limitation was the PID. But I haven't played with one so it maybe overkill for this application, but I figured if I could put it to work while not brewing.

I never tried that with the PID I bought, I ended up running my freezer through the High alarm relay on my PID, and put the SSR in to my control box for the brewery.

It looks like that would work, though you would most likely want to reprogram the power settings when you brew, or when you ferment. I might also be concerned about (if I was reading coad rages post correctly) that for controlling the fermenter the PID would be cycling on 60sec off 60sec, this might be rough on the compressor.

I think though you could set it up so the PID SSR runs the brewing side, and you run your fermenter through the High alarm of the PID. You would just need to turn off the fridge during brewing, and move the temp probe. Or rig up a selector switch that can switch between a probe in the fermenters or for brewing, and switch off the fridge during brewing.

You can use a PID for controlling ferm chamber. You just have to put the PID into a different mode (on/off mode instead of PID mode) to avoid the rapid cycling that bsquared talks about.

I see what you're saying with the alarm.

Bsquared said:

I think though you could set it up so the PID SSR runs the brewing side, and you run your fermenter through the High alarm of the PID. You would just need to turn off the fridge during brewing, and move the temp probe. Or rig up a selector switch that can switch between a probe in the fermenters or for brewing, and switch off the fridge during brewing.

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The fridge is in a separate place in my house. I was thinking this control unit would attach to my brew stand (still in planning phase). After the brew detach it (and plugs & temperature readings) and hang it on the wall near the fridge and attach temp probe & plugs.