How to make glycol work

Okay, so I received my SECOND BrewPi today because I couldn’t wait for the multiple chamber support to be finished; I tried to wait, but I really love being able to watch what is going on with my beer from anywhere in the world and I just added a second fermenter to the mix. Unfortunately, I only have one chamber,so I’m moving the second one (and eventually the first) to a homegrown glycol chiller this weekend.

I was all excited as I left FedEx thinking about my weekend project. Then reality set in: BrewPi presently doesn’t handle glycol setups unless you let it control the temperature of the glycol itself as a direct replacement for the fridge temp. I don’t want to do this because I’m going to run two BrewPis off the same glycol chiller using solenoid valves. Ideally when muliple chambers are working I can let BrewPi control the glycol temp since it will be able to determine the lowest temperature necessary to satisfy all fermenters, but as far as I know, that’s not now.

The only way I’ve come up with to make this work is to use “Fridge Constant” and put the fridge probe in the thermowell of the beer.

The downside I see to this is that I would rather label my glycol temp as Fridge and my beer temp as Beer and this idea would have them backward. A small price granted, but I’m wondering if anyone on here has inside that could help me make this work better.

Thanks to the “Your topic is similar to…” field to the right of this message, I found sjbaker’s thread and I will look into that, but I’m not sure I’ll have time to play with it this first round.


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You are on the right path. The best way now would be to just chill your glycol and use fridge constant mode to control the pump/valve.

I think switching an immersion pump (or 2) would be much easier than controlling the valve.

You’ll want to lower the PWM period and the minimum on time.

I’m running a multi chamber arduino-based setup myself, with fans to draw cold air from an a/c cooled chamber. This is pretty much the same as using a central glycol chiller to cool several fermenters. You just have to place your chamber probe in the glycol jacket (if using jacketed conicals, that is). The PID will take care of keeping the beer temp in check by opening and closing the valve as needed.

The firmware linked in my thread works fine, but it is not for the casual user since so much of the config is hardcoded in the source. Temp control also isn’t near as precise as Elco’s method. It’s a stop-gap for me until the true BrewPi multi-chamber support is available.

Unless you are using the glycol setup that has the pump always on, Elco’s suggestion of two pumps is the best choice. The problem with actuating the valves is that you need to control the pump power when either of the valves are on. ANDs are easy to simulate with ladder logic, ORs not so much.

P.S. I am using my firmware currently to ferment a belgian strong.