Dual Stage Custom Fermentation Chamber
To my surprise the ferm project was a rousing success and Im quite proud. The wiring was easy for me as Im from a science/electrical background but I often screw up the mechanics of measuring drilling, cutting project boxes and the like. Id like to share the project with you in the hopes it might be helpful.
I want to thank HUACO for main design ideas, marinosr,PDX_T,itinerantbrewer for help! for their help in the planning without which this would not have been possible.
Will post pictures as soon as I have time. Should have taken more in retrospect but just wanted to get it done.
Basically this setup uses a chest freezer with a temperature controller providing both internal heating and cooling.
This is long but Im hoping itll be helpful. Please note this is not an official guide. ELECTRICITY IS DANGEROUS AND CAN KILL. I do not accept any liability for any damage to persons or property attempting to follow the procedure I followed. Be sure you know what you are doing and also have a qualified electrician either do the work for you or inspect it upon completion. Incorrect implementation can result in injury including death and/or fire.
2. Basic Setup
All in including tools, chest freezer (off Craigslist for $100) and cab rides to pick up freezer ($60) as well this came to $600. I already had screwdriver, powerdrill, multimeter, wirestrippers but bought everything else. I also bought some cabling and bought a lot off amazon for convenience. You can probably do $450 easy or better. If not marked otherwise I probably got in on amazon.
-Chest Freezer roughly 35 x 35 x 22. Unmodified. I talked to the manufacturer a bit who claimed there is no auto short cycle, but there is. This is a delay between the freezer turning off and on but in general this shouldnt be a problem as if youre cycling on that fast youre going to burn out the compressor anyways.
-Flex Watt Heat Tape Reptile Heater 11 x 5 Feet (BigApplePetSupplies.com).
This hooks further into a thermostat to regulate temperature as recommended by manufacturer.
Do not confuse this with thermal tape which is an adhesive used to stick this heater to the inside walls of the freezer. This thermal tape is electrically conductive unlike electrical tape but can also withstand higher temperatures than electrical tape can.
I chose the Control Products TC-9102D-HV Dual Stage High Voltage Digital Temperature controller with standard thermal probe. Make sure to choose the 120V AC version. In retrospect the STC-1000 that a lot of homebrewers like to use may be the better choice provided your freezers startup current doesnt fry the internal relays
Project Enclosure (8x6x3)
Power drill w/ dremmel cutting disk attachment and conical sander attachment
Screwdriver. Standard Philips for most of the work and then smaller for project enclosure box. I dont remember what size but if you have a standard set youll be fine
Quality Solder (I bought some cut rate stuff and started melting components and still got garbage flow) [I used Alpha Fry AT-31604 60/40 rosin core in the end with great results)
Wire Ripper (Klein Tools 74017 NM Cable Ripper 8-14 AWG)
Wire strippers for size 14WG and 18WG. (This is standard)
14/2 AWG NM cables (dont use UF like I did, its hard to strip) wires for internal wiring
18 AWG for connecting light indicators to GFCI load side
25 feet 3 prong extension cord (US Wire 65025 12/3 25 Foot SJTW Orange. This one is heavy duty and I love it)
120V green and red lamps (Radioshack) (part # : 2720708,2720712)
Single pole double throw toggle switch (any rated for 15A will do)
Thermal tape (Arctic Alumina Thermal Adhesive: Note this is thermally and electrically conductive)
Wire nuts for 14 WG and 18 WG
2 x GFCI outlets with dual mounting plate
Box wire clamps (Sigma electric 446600 ¾ inch clamp type connector ) 3 pcs
Spiral wrap (plastic to protect wires going through back of freezer door)
2. Basic Setup:
Extension cord goes to TC-9102D-HV box, 2 x 14/2 cables exit the bottom and go to project box, thermal sensor comes out the bottom of temp-controller box as well. Project box has light indicators to indicate status of switched power as well as a switch to prevent power from the heating GFCI. The biggest portion of the project is cutting the holes in the Temp Controller and Project box and filing them down. The wiring in the project box is a cinch but inside the temp controller box there is very little clearance and its quite frustrating. Make sure also to drill the hole high enough so that the clamp connector nut can fully turn.
The STC-1000 is small, self enclosed with contacts on the outside making it perfect for mounting in a hobby box.
However after contacting the freezer manufacturer regarding the startup current (which is higher than steady state current) I wanted to ensure the relay contacts could handle it so I instead went with the TC-9102D-HV which can handle up to 30 A
The TC-9102D-HV has more buttons in terms of settings available
The TC-9102D-HV also had a full manual in English whereas the STC-1000 has a pathetic and confusing one pager written in Engrish
The problem is that you have to open the TC-9102D-HV box itself for internal wiring. The box is quite large and inside it there is a mounted PCB connected to the touch pad top of the box. This makes it seemingly impossible (though I could be wrong) to mount this inside a reasonable size hobby box and you have to do the wiring inside and take outputs to a separate box. This makes my solution not as sexy as a single box that you could get with STC-1000 or similar.
To say this is frustrating with the very small clearance is an understatement. My fiancée was making small talk while I was working on getting a single wire into one of the outputs for 25 minutes plus and I got so frustrated I almost took my anger out by yelling at her for absolutely no reason. Basically if you want to carry any reasonable current youre going to have to use 14 WG wires and have some wire nuts in there and this box has so little clearance for maneuvering the wires into the contacts and so little internal space that I could barely close the box back up.
This led me to think the cheaper STC-1000 might have been the better selection for clearance reasons, ease of use, cost etc but again I dont know whether it could have handled the start up current. STC-1000 is also in Celcius only and I think has less things to set so overall Im happy.
Cutting the TC-9102D-HV box
-Marked holes for top and bottom (side) of box for extension cord power entry (top) and 2 x 14/2 cables and thermal sensor (bottom)
-Marked holes for fuse on side top
-Cut/file/and sand (with drill attachment) top, bottom holes and side hole for fuse. Mount fuse.
- The conical sander bit can be used to get a well circularly defined hole. Pick a sanding bit with same or similar size to the wire clamp
Wiring the TC-9102D-HV box
-The wiring is simple and shown with the box you get the TC-9102D-HV with. Only changes I made were to add a fuse directly (soldered) after power input and of course ground for the switched side. The extension power comes in from the top and the two x 14/2 cables and thermal sensor come out the bottom but clearance is very tight. Its very frustrating and remember you have to have enough empty space for the wires and wire nuts. You may want to unscrew the PCB from the mount when you are wiring to make it a little easier.
-Connect hot to fuse then from fuse use wire nuts to bring out 3 more wires. 1 for TC input and 2 more for relay inputs. Neutrals and grounds should all be simply tied together with wire nuts.
-Twist conductors together before very tightly screwing on wire nut. Secure with electrical tape to prevent twisting, but wire nut should be on tight and conductors should not be too short or too long for wire nut.
-Close down clamps tight enough to prevent slippage but not so tight as to cut into wires. Ensure cable sheathing is stripped just past where the cable comes all the way in
Cutting the Project Box
-Bought a dremmel for the sole purpose of cutting the outlet holes. Big mistake. That thing is weak. However one of the cutting attachments was perfect for using on a real power drill. Unfortunately my cutting disk broke and I couldnt get to hw store to replace in time but this is my recommendation. So in the end I finished by scoring along my cutting marks using a #11 exacto knife making about 150 strokes with each outlet side. Slow as heck but whatever. Youll get there much quicker with using the cutting attachment coming in at an angle large enough so the chuck doesnt damage the top of the box. You can always file down later.
-Hole on bottom of box for input of 2 x 14/2 cables, holes for outlets, outlet dual-plate screws, indicator lamps and switch. The latter can be affixed using the nuts that come with them.
Wiring the Project Box
-Wire each switched 14/2 to line side of respective GFCI the switched cables
-One of the hots will first be wired (and soldered) to switch before the GFCI. This will be the Heat side. Dont worry about which cables go where because it is fully configurable in the logic of the controller. Just make sure you know which is which after otherwise youll have an always on freezer or always on heater.
-Wire the temp controller lights to the load side of the respective GFCIs. They will turn on when the switched lines are turned on.
Preparing the Thermal Wrap & Why I have a switch
-The thermal wrap comes as a tube and you can mount the 120 VAC power cable to it via clamping down hard on the clamps that they have on end of power cord that theyve machined on there. This leaves exposed conductors which made me nervous so I covered this with epoxy.
-This is then hooked into a thermostat that sets max temp point of the thermal wrap to about 108F. Its recommended by the manufacturer and was cheap so I bought it. Its supposed to be safer and extend the life of the product. Not sure about that but I built it in
-In the case I did not cover a section of it condensation could get in there and leave a live wire out along with wetness which is a terrible combination. 120VAC plus dampness=death. Yes I have GFCIs but they could fail and their current trip point is also too high to prevent serious injury. For this reason I wired in a toggle switch in series in my project box to the outlet that goes to the therm wrap. I shut it off every time I reach in to prevent injury
-Secure the therm wrap to the inside walls using the thermal tape and connect the thermostat sensor to it with thermal tape. Order extra thermal tape as with the temp and humidity changes the thermal tape can come unstuck.
-Feed all the wires through the back of the unit using Clear spiral wrap plastic protectors to spiral around the conductors to protect them from opening and closing pressures.
-Since youve got the temp controller, project box and thermostat for the thermal wrap thats 3 big things. You might want to build some kind of shelf to keep them out of the way. In this case you may need to extend the thermal sensor length as its only about 3. You can do this according to manufacturer using 18 AWG wire for I believe up to 15 feet (maybe its much more).
-I also got the control diagram laminated and attached to top of door so I know how to adjust the settings. Its a flow chart.
-To keep temperature at 45F (just for chilling) I set the heat to 45F with 6 degrees differential and cold to 47F with 1 degree differential
-You may need to change the calibration settings on your thermal probe by comparing it with an accurate thermometer in the same place as your thermal probe
-Remember the temperature of your beer should move around slower than the ambient so it all depends on how you are mounting your thermal sensor. The closer it is to the actual beer temperature the lower you can set your differentials without burning out the compressor
-During operation its very important the compressor doesnt turn off and on too much. There is a default Auto Cycle delay that you can set but really you want this from your temperature and temperature differential settings. So ensure its not cycling too much for the manufacturer specs or the compressor will wear out quite quickly. Its tough to get this value from a manufacturer but with these settings my compressor turns on twice an hour. I dont know if thats good as Im not an expert but based on google searches it seems ok.
-REMEMBER FOR ENHANCED SAFETY TO ALWAYS SWITCH OFF THE HEAT SWITCH ON THE PROJECT BOX when opening freezer. That way if there is an exposed wire due to damage to thermal wrap, bad insulation via epoxy or whatever its not going to turn on and kill you. If it does the GFCI may or may not provide protection. I like to play it safe.