New Plastic Conical Fermenter build

[rkhanso]

The Window A/C is going to be run off the SSR.
I'm going to use 10a project/arduino relays to run the cooling water pump and the flexwatt heat tape.

 

[rkhanso]

I'm having trouble using the motor controller driver board with my SSR. Not sure what's going on. I'm using one of the cheap motor driver boards from ebay.
I wanted to bump up the signal voltage from 3.3 to 5v to better switch the relays.
Using it with the mechanical relays is working fine, SSR is not.

I'm running 5VDC and ground from the PI Zero board to both the driver board and the relay board. Running ground from the RaspberryPi to the - pin of the SSR.
GPIO pins are run to the input of the driver board. The output of the driver board goes to the relay board. Lights on the driver board turn on/off when the output signals change and the mechanical relays are activated just fine. But if I hook up the SSR -As soon as I connect the +pin of the SSR to the driver board, the LED lights a little dimmer than when activated, but it's not switching properly. It doesn't matter what in/out channel of the driver board I use.

When using the driver board with the PI, when the GPIO is not activated, I get 3.38VDC on the output of the driver board. When I activate the GPIO, the output on the driver board goes down to .58VDC. The LED on the driver board operates normally though....when I don't have the SSR connected. This is confusing me.

But..... I must have 2 problems here. Or maybe just 1 problem that shows itself differently when I use the driver board or don't use it?

Ignore the following paragraph - this is due to the SSR leakage problem.
Even when using the GPIO only, not the driver board - the LED on the SSR operates normally, but there seems to be leakage on the output side of the SSR. When I plug my soldering iron into the outlet and the SSR is off, the LED on my soldering still lights, but it doesn't get hot. When I turn the SSR on, the soldering iron will get hot. It must be leaking. With the SSR off and the soldering iron plugged in, there's 40.5v AC there. It goes up to 117.7 when I turn on the SSR. Both of the SSRs I have do the same thing. Must it be a wiring problem then? Or a bad jack/outlet?

Am I wiring this wrong? How can I correct this? If I put the + pin of the SSR to the GPIO on the PI, it works OK (well, used to before I shorted the pins together). But I wanted the control to be at 5V to give a little breathing room over the 3.3v.

 

[rkhanso]

Could the SSR leakage problem be putting voltage backwards, out of the input of the SSR and back into the driver board, which is making the LED light up even when that channel is not activated?

 

[rkhanso]

More work on the control box. Almost done. Have to wire up the 2 indicator lamps and figure out how to run power to the PiZero.
I put the electrical tape on the pins to help keep them on. They have a tendency to come off.

 

[rkhanso]

I powered up my CraftbeerPi fermenter controller with the window AC unit connected to it for the first time today. The air conditioner is having a hard time starting up. The AC unit works just fine when I have it plugged directly into the wall outlet.

I checked the SSR output at the plug on the controller box and it's switching on/off (well, 117 VAC and floating at something less because of the SSR leakage). But when the AC unit starts up... it's "chugging" and trying to get going.

I thought ight my input cord on the controller box might have had too small gauge wiring, so I found a beefier cable. That didn't help. I thought I might be on PWM logic, but it's not - it's on GPIOSimple. Might my SSR be bad? I'm sure it's wired correctly since it switches on/off using CraftbeerPi.

Help?


EDIT - Got it fixed - a bum SSR. Brand new and couldn't take the current, I guess.

 

[501irishred]

Nice! That didn’t take long to figure out!..... if later you think it’s starting the same thing again, you might think about switching to a definite purpose contactor. I know SSR’s have come a long way recently, but there is a big difference running a resistive load (ie heating element) and an inductive load like a compressor. Is the SSR you’re using rated for inductive load?

 

[rkhanso]

Nice! That didn’t take long to figure out!..... if later you think it’s starting the same thing again, you might think about switching to a definite purpose contactor. I know SSR’s have come a long way recently, but there is a big difference running a resistive load (ie heating element) and an inductive load like a compressor. Is the SSR you’re using rated for inductive load?

About the SSRs - I've never heard of a difference. No idea if the one I have is meant to be used for an inductive load. It's just one of the normal cheap SSRs off ebay. How do I tell?

It's keeping pretty good temps on the chiller tank (I don't have the immersion coil connected yet). But I recently changed the offset for the chiller tank - Offset OFF at 1. Offset ON at 2. The tank can take wider temperature swings and I thought the wider range might be better for the AC unit - not cycling so frequently.

 

[rkhanso]

Full test today - not brewing, just with water.
I filled the conical with about 10 gal of water (it's from the outside spigot and came in at 55F).

I connected the heater power, cooling pump power, put in the SS Chiller coil and it's all on automatic right now. I'll track the temps over the next day or two. It's going to be a cool day, so I don't expect much need for the cooling system. The heat is on now.

 

[rkhanso]

Nice! That didn’t take long to figure out!..... if later you think it’s starting the same thing again, you might think about switching to a definite purpose contactor. I know SSR’s have come a long way recently, but there is a big difference running a resistive load (ie heating element) and an inductive load like a compressor. Is the SSR you’re using rated for inductive load?

I've been reading a little about the inductive-load type SSRs. It appears that I can simply add a single component to the SSR - a varistor, to accomplish this same task. A .pdf online tells me I can add a 240-270V Varistor with surge resistance of 1000A minimum. It looks like I can put it right across the load of the AC unit - jump across hot and neutral, right? Or is something else needed?

 

[501irishred]

On any mechanical relay (including contactors) they are clearly labeled. There is typically about a 10A difference between load types. I went to look for similar info on SSR’s and it seems not to exist...... Not sure if that’s because it truly doesn’t matter, or if the typical use is for a resistive load so they are rated as such.
Regardless, it sounds like it’s working well, so i’d Just keep an i (and ear) on it and just make sure it doesn’t have a hard time starting again.

 

[rkhanso]

I have the fermenting temps pretty dialed in now with CraftbeerPi.

Finding that my cooling coil must be pretty efficient, because I can't keep my chiller tank too cold or it overshoots on the fermenter temperature. I'm keeping the chiller tank only about 4F cooler than the fermenter set point. This is a "test brew" using about 9 gallons of just water, so once I really brew and have 11-12 gallons in the fermenter. I suppose the real-world overshoot might be a little less due to more volume.

Some graphs below from 7/11/19 to 7/15/19 - and the temp in my garage where the fermenter/chiller is located is currently only 77F but has been as high as high 80s.

Fermenter tank (only .6F difference in swing from high to low temp and takes 1-2 minutes to drop that temp):




Chiller/cooler supply tank:

 

[rkhanso]

Looking at racking arm options for this, I ran across THIS POST and wondered if that's a rotatable arm. If you scroll down, you can see a picture of that racking arm.
I'd like to get a rotating racking arm in my fermenter for a brew soon.
I'm not yet catching yeast/trub with a catcher at the bottom. Maybe it would be easier to just go that route?
I don't mind plastic parts if I can get them at the local home supply store. Maybe upgrading to real homebrew parts in the future.

 

[rkhanso]

I think I have hit the bottom temp possible with my setup. I kept lowering the temps to see how it reacted.
40F seems to be the lowest I can get the fermenter, even if I lowered the "glycol" cooler down to 30F (no glycol in it yet. Just water). Ambient temps were 80F and humid.

Fermenter




"Glycol tank"

 

[501irishred]

Very nice! A glycol solution, Fall ambient temps, and a low set point should get you lower if you just have too, but that sounds good enough for the 99.9% for sure!

 

[rkhanso]

Finishing up a brew - Dragonmead Final Absolution Belgian Tripel - and will bottle in 2 days (8/31/19). Cold crashing now.
The glycol chiller (well, water only for now) performed perfectly for the 20 days in the fermenter so far.
Never strayed more than .5F above or below the set temp. And was usually within .25F above and below the set temp. There are a couple glitches in the graph below, but that was me messing with it.

I started fermenting 8/10/19, but had trouble with the Raspberry Pi and had to reboot and clear the logs on 8/12/19.

Cold Crashing with water only - I'm able to maintain 37F. It has been a bit cooler here the past couple days though.

 

[rkhanso]

After cleaning the plastic conical out really well with water, and then pumping in some Star-San water and doing my best to spray up and under the lid/lip area - it looks really clean. But it sure still smells like Belgian Tripel. I suspect this is normal and won't be a problem for future brews as long as it's sanitized. Right?

I've also noticed little tiny flies in my garage after that last brew. I don't see them in the fermenter though. You know, at the last brewery I was at, I saw a couple tiny flies there. Maybe it's me.

I'm hoping I don't have sanitation issues in the future. I'm hoping to brew a Pumpkin ale in the next week or two.

 

[501irishred]

That’s just the joy of plastic. Brewing in buckets, I always expected contamination from batch to batch, but it has never materialized. Even after brewing a mild beer right after a super dank one, I've never perceived an issue in the final product.