ebay aquarium temp controller build

-1 insulating probe.

 

Good tip. Will do.

 

Most of your comments are contrary the laws of thermodynamics and control theory. The only one that is correct is that the secondary body (beer) will "follow" the primary body (air), if the probe is placed in the primary body (air again), but that is not a good thing in our case (more later). It can get complicated when the body being controlled has a lower thermal mass than the heat/cool input, but that is not the system (usually) we deal with when using a fridge/freezer for what we do.

The most stable and accurate temp (of the beer/wort, which is what we are concerned with, not the air temp) will be maintained by placing the probe on the keg/fermenter and insulating it (the probe) from surrounding air, or placing the probe in the keg/fermenter (thermo well) and using a conductant (oil, water, etc.) inside the well.

For a kegerator/keezer where active fermentation is not happening, putting the probe in a container of liquid sufficient.

Not following this strategy for a fermentation chamber, the beer/wort temp will always "follow" the air temp, but may never get there and could vary considerably during exothermic phases. It will also cause more frequent cycling of your heat/cold source which in the case of your compressor which will shorten its life, and the various starter circuit fiddly bits.

 

Yes it is complicated! I still stand by what i said and without getting into credentials lets looks at the scenero. I'm slightly sleep deprived and i've been wrong before (more right than wrong usually! ) so i'm not trying to suggest i'm more knowlegable about this but i would like to seek some clarification because i'm curious as to what the best method is going to be, obviously.

SO your heating your air and it will continue to heat until your beer has reached temp 'cause thats where your probe is, right? Now your air temp is going to be several (if not more) degrees higher than your beer because your beer has a greater thermal mass than that of the air. Now your probe turns off the heater and the air is still hotter than the beer so it will continue to heat your beer until your beer gets to a temp where your set point is to cool, now you will start to cool and that will take your air lower than your set point is because your probe is in the beer which will take some time to actually cool since again it's a larger thermal mass than the air....

If your heating the air its easier to just keep the air at say 20C and your beer will follow, i have a 1 degree differential and my beer stays pretty much on mark this way.

Now i understand that your beer is going to give off heat durring fermentation 'cause its 'exothermic' but isn't this kind of trivial when your dealing with a small volume like a carboy? I could see it being an issue with a 1000 gallons of beer, but not a carboy.

I mean to be technical its kind of an improvised method what we are doing in the first place. Breweries use fluid filled jacketed fermenters and they heat and cool the fluid, so if you want to get real technical, thats what we should do too.

 

In the early stages of fermentation, you can get close to a 10 degree difference between ambient temp and what's going on in your fermenter.

I'd much rather have the thermostat keeping my beer at the proper temp than the air around it. If I have to keep the air temp at 55 to keep the beer at 60, that's what I want it doing. As the ferment slows down and less heat is generated, the freezer will adjust automatically because you're measuring the temp of the beer.

True, the ambient temp in the chamber is going to overshoot the temp of the beer, but 5 gallons of beer does have quite a bit of thermal mass and isn't going to change that quick. Say you're heating the chamber because it's in your garage in the winter. You want your beer at 60 and the temp has dropped. The heater will run until the beer gets back to 60. By then the air in the chamber might be closer to 70. Once the heater shuts off, it's going to start cooling down again. The beer might only gain another degree or two before the air temp inside has dropped to meet it.

 

this last bit is not true. say the air temp is ten degrees warmer than the beer - the amount of energy contained in the air for this temp difference is too small to heat something with the heat capacity of water up much at all. the heat will be lost through the insulation etc as well. I would explain better, and possibly even bring out a heat transfer textbook from my shelf, but I'm typing on an iPhone which isn't easy...

 

I finally wired mine up today. works great with only one issue... the tightening screws for the cold wires will not tighten at all. so the wires wiggle a bit. since they are solid core, 14 gauge, they are quite stiff, so I keep it in contact with the terminals by jamming a piece of corrugated cardboard underneath the wires. works for now, and it will keep working as long as I don't jostle it too much, hopefully.

 

OK i think i'm starting to see how that works now, thanks for the clarifying. Although i feel more questions brewing as a result of this information. Do you set your temp and forget it or adjust it at all during the ferment?

Does using a space heater with a larger thermal mass change anything?

 

After doing some analysis, the behavior of the system is more complicated than I thought, but still favors putting the probe next to the fermenter (or in a container of liquid for kegerator situations). For non-fermentation scenarios, monitoring the air may keep a more stable and truer to setpoint temperature, but will cause more cycling and wear out your compressor and/or controller solenoids prematurely. Who cares how precise storage/serving temps are anyway? Maintaining fermentation temp is what is most critical.

As for heater size/mass- if you are still clinging to the probe in the air idea, a massive (thermally) heater will reduce the offset between air/probe temp and beer temp for a given ambient vs. ferm temp. An offset will still be there and will vary with changes in ambient vs. ferm temp/heat input for fermentation temp control. You won't know what to set your controller to without keeping a logbook of a variety of variables (outside temp range, batch size, Spec Grav, yeast, etc.).

Or, you could give in to peer pressure, conform to the will of the masses, and just put the probe in/on your fermenting beer already.

Having said that, a heater that when on full time provides just enough heat to maintain proper ferm temp is the perfect size. Practically this can only be realized by using a PID and SSR controlled heat source.

A overpowered non-massive high-output heater is the worst choice for a heat source, by the way.

As for adjusting the temp during fermentation- If the probe is on the outside of the fermenter, some set the temp slightly lower at first to compensate for the slightly inaccurate/lower reading. Setting the proper temp, and forgetting is sufficient. The temp on the outside of the fermenter should be very close to the internal temp, if get good contact and insulate it (conform!). You can change the temp to make the yeast do tricks for you- like raise it at the end of fermenting to keep the yeast going for a drier beer, or step the temp for different ester profiles.

 

Do you put the probe in a jar of water so you don't have to hassle with placing it on the fermenter each time you ferment? It seems less precise than putting it on the fermenter. You posted that you compensate for initial ferm temps offsets due to probe placement. If the probe was on the fermenter, you wouldn't have to remember to change the controller temp for various stages of fermentation.

 

I am thinking of making a thermowell that gets down into the center of my beer. would making it out of copper be a bad idea? thing is copper is cheaper and more readily available than stainless tubing.

you would be getting a reading of what the internal temp of the fermenting beer is not, air in the fridge/freezer or little cup sitting next to fermenting beer.

-=Jason=-

 

one of these is on the way to my house. looking forward to a new DIY.

For those using a terminal block instead of wirenuts, how are you mounting the block inside the project box?

 

Yes, copper is a bad idea. Contact with copper before the fermentation (wort chiller, etc) is OK because the yeast will consume the trace amounts of copper and the finished beer will have none. Contact with copper after fermentation will leave trace amounts of copper in solution.

http://en.wikipedia.org/wiki/Copper_toxicity

 

I would like to have it in my wort. I just dont have a sanitary means to do it and its another sanitation step. I forgot to mention, I do have my thermometer sticker on the side of my carboy to read the temp of wort. I like the thermowell idea so just use the jar of water with idophor which also keeps my ferm chamber from turning on and off constantly. One of these days I'll get one I can put inside the carboy, but Its not a priority. My system works great as is.

 

ok then..

I just found a killer deal on some 3/16" OD tubing on amazon.
http://www.amazon.com/dp/B00137QJP4/?tag=skimlinks_replacement-20

OMG... free amazon PRIME shipping. with 36" long I can make two units out of this maybe 3. thermowells and a ss bottling wand adapter.

-=Jason=-

 

Nice find. what are you going to seal it with?

 

take a hammer and smash the end flat, drop some flux and solder down the tube and heat the bottom to create a sealed end piece.

-=Jason=-

 

The thermowells offered by brewershardware.com are about the finest on the market. Very high quality construction.

16" thermowell



Couple that with a #6.5 two hole stopper and you can have a combo thermowell and airlock. It would be similar to the one sold by ETC Supply but a much higher quality





I have a temperature controller on order and I plan to use it along with the thermowell/stopper combo to monitor my fermentation temps.

 

thats not a bad price at all, however you'd have to pay shipping.

with the amazon piece you get TWO 18" long pieces FREE shipping if your a PRIME member and the stopper from LHBS for a couple bucks.

I am going to fashion my own DIY thermowell and use it with my blow off tube setup. no stoppers for me.

-=Jason=-

 

How about Stainless Steel brake line from an auto parts store and some Epoxy?

 

I don't see why not, but why epoxy? to seal the end? I wouldn't trust epoxy. just pound the end shut and drop some solder down the tube and heat it up.

just make sure its Stainless and not some other metal.

-=Jason=-

 

Yes the Epoxy to seal. I just thought that it would look better than a smashed down end. And easier for some that don't happen to have solder around.

Me I'll just TIG the end of an old Corney dip tube.

 

Wow that looks awesome! Must build!!

 

Cant link the page, on my stupid phone, but they have 60 inches of 5/16 304 stainless on amazon for 7, has an id of .2. They also have 1/4 with an id of .12 for 3. Just ordered the 5/16 for my bottle filler.

 

Ok, My interest in this is peaked a bit more. Like I really need something else to make.

 

Epoxy

 

so my temp regulator is all mounted in a box, and works like a charm. BUT: the screw downs in 7&8 don't work, so the wires are loose. while the outlet works, if I jostle the box, the connection flickers.

not a big enough issue to exchange over, but still annoying. does anyone have an idea about how to keep the wires tight without the tightening screw?

any help much appreciated.

 

Take the wires out, and turn the screw to the other way (loosen). It's random how the screw downs are installed - some closed, some open.

 

I am ready to build one of these but don't know which one, and from which seller, I need. Can someone post a link for ebay for the 120V one and from a good seller?

Also, can you set the temp to the decimal point, say 15.4, or can you only set it to 1 degree C?

Thanks

 

Counter clockwise loosens clockwise tightens. The terminals look deceptively open when they are closed.

Someone else had a problem, so maybe it was a manufacturing error? He suggested using some cardboard to make up the void, i would further go as to say maybe strip twice the amount of wire you need and bend it over the cardboard to have a connection on both top and bottom. I'd make sure your terminals are infact open first though. Hold the whole plastic terminal when tighten or untightening though, i imagine a good bit of torque with the screw driver would break the whole terminal strip off from the solder joints on the inside.

 

that was also me wig the cardboard. I tried again, and tried twisting it the opposite way - it worked better enough for me to get rid of the cardboard, but still not perfect. but at Lear there is no potentially flammable paper product in my project box now!!

 

Can this be wired directly to the controller with no plug involved?

 

Not understanding your question. Can "what" be wired to the controller?

 

qualitylink2000 or globalconn are good sellers.

All adjustments and displays are in 0.1*C granularity.

 

I would like to use this controller with out wiring in the outlet. I will be using a small heater and a fan on the cool side. I want to cut the plug off of the heater and hard wire it directly into the controller. Will this cause issues?

 

Yeah, you could wire the hot line from your heater directly to the thing and wirenut the neutral to your incoming power feed or something if you wanted to, I suppose.

The electrons don't care if you use a receptacle and plug. The receptacle is just a convenience.

 

Well put "electrons" I am going to mount the controller into the side of the ferm chamber and use a junction box on the inside for the cords. Everyone tends to over complicate things on here, lights, receptacles , bells and whistles. Give me function K.I.S.S.