2 March 2010: DIY Immersion Circulator (SeattleFoodGeek Mk. II)

Aschultz wrote:

Sous Vide

Seattle Food Geek PID Controlled Immersion Circulator. Mk. II

This is a version of the Immersion Circulator described here. Per Scott’s thoughts, I have made the unit into a generic temperature control device. In addition to cooking Sous Vide, I will also try to use this to control  temp on my Alton Brown Terra Cotta Flower Pot Smoker.

Parts list

Immersion Circulator:

• Clear Storage Container – Medium [Amazon.com] $4.95
• (3) NORPRO 559 Immersion Heater for Warming Liquids [Amazon.com] $19.47
• 79 GPH Fountain, Hydroponics, or Aquarium pump- VA80 [Ebay.com] $9.99
• PT100 Thermocouple Probe [Ebay.com] $5.99 + $2.99 Shipping
• 1/4″ Gold Plated Stereo Phono Plug (for PT100) [Radio Shack] $3.99 PN274-0866
• Plexiglas (~5″x7″) [hardware store] $FREE from my local hardware store!
• 3/4″ x36 Flat Bar [hardware store] $3.99
• 1/4″ x20 (36″) Threaded Rod [hardware store] $1.79
• (16) 1/4″ x20 Nuts [hardware store] $1.12
• (4) 1/4″ Fender washers [hardware store]  $0.84
• 3 outlet wall plug adapter [hardware store] $4.99

PID Controller Module:

• Dual Digital F/C PID Temperature Control Controller [Ebay.com] $38.99
• 12VDC Toggle Switch with Safety Cover (I only used the cover from this switch) $4.99 PN275-0601
• SPDT Heavy-Duty Switch [Radio Shack] $2.39 PN275-0603
• GFCI Outlet [Home Depot] $11.97
• Mud Ring for Low Voltage [Home Depot] $1.28
• Decora Wall Plate [Home Depot] $0.59
• Female 1/4″ Stereo TRS connector [Radio Shack] CLEARANCE $0.97 PN274-142B
• About 2’ of 16-18 gauge wire
• 1 wire nuts [Hardware Store] $0.20
• Tub and Tile Silicone Caulk $3.89

Misc Tools/supplies:

• Hot glue gun
• JB Weld
• Rotozip or other means of cutting metal/acrylic/plexi
• Soldering iron and solder
• Electrical tape
• Wire Strippers
• Multimeter (tool that measures voltage, current, resistance)

You’ll also need a vessel to do your actual cooling in. I bought a 8″ plastic service container from my local restaurant supply store. Rather than buying the matching lid, I opted for a new plastic cutting board that fits over the entire container…it was a buck less and both can be used for other kitchen duties (no Uni-taskers!) This cost me $30.81, but you can also just use a large pot on top of a cooling rack. (which I have used for eggs, etc since it is a smaller body of water to heat and hold at temp.

Assembly

Immersion Circulator:

1) Making the frame.

Cut metal strip into four pieces to create base the same size as your piece of plexi-glass. Mark the metal strips and drill holes for assembly. Cut the threaded rod into four 9″ pieces, and assemble the immersion circulator base using the threaded rod as vertical posts.

Place the frame upside down on the piece of plexiglass to mark for the holes that will mount the plexiglass to the bottom metal assembly. After drilling the holes, test for fit. The plexi will sit on top of a nut and fender washer on each post. This will allow you to adjust the height of the immersion heaters and temperature probe to heat more or less liquid as necessary.

2) Mounting the heaters.

After confirming that the plexiglass will move up and down the posts with relative ease, remove it and cut holes for the heaters. With this design, the heater holes need to be large enough for the power cords to fit through. Disregard the long rectangle at the other side of the plexiglass, learn from my mistakes…measure twice and cut once.

Because the holes will be larger than the white part of the heaters, you’ll need to secure them to the plexiglass. I used JB Weld, after your adhesive dries, fill in the gaps with silicone. I used a marker to align the coils of the heaters.

After the JB Weld dries (over night) I filled in the gaps with silicone.

PID Controller Module:

1) Assembly of the “Face” of the controller.

Mark and cut holes for the PID controller and toggle switch. To allow for the most room for the outlet I put my controller in the northwest corner of the bottom of the acrylic container. The lid will be used as an access hole for wiring and sealed later. At each stage, I dry fitted the components to ensure that there was adequate room for the next component.

2. Cutting holes for the GFCI and Thermal TRS Jack.

Next, Mark and cut holes for the GFCI outlet and 1/4″ Female stereo phono plug (that will eventually accept the temperature probe. You will need to notch the east and west sides of the rectangle for the GFCI to allow for mounting screws.

Now you’ll have to modify the orange mud ring to enable the dog ears to grab the acrylic container. without modification, the mud ring will not go thin enough to hold securely against the sides of the container (it’s made for dry wall:) I just used a rotozip with a conical grinding bit to take a notch out of the screw holes that hold the dog ears.

3. The PID module dry fit:

4. Convert the PT100 Probe to a 1/4″ Stereo Phono Plug.

Cut the ends of the thermal probe off. There are two blue wires, these are both the same signal (ground) I was very careful to keep them organized, but I later discovered that it is unimportant. Slide the strain relief parts of the 1/4″ Jack down the wire in the order shown…make sure you do this before you start to solder the connections. AFTER you slide on the strain relief, solder the connections to the terminals on the phono plug.

Wrap some electrical tape around the metal jacket on the PT100. Re-assemble the strain relief, when you’re done it will look like this:

5) Making the female side of the 1/4″ jack.

Repeat these steps for the female side of the 1/4″ Jack. This will get mounted inside the box when it’s complete.

My wiring diagram for the 1/4″ Jack(s).

6) Drill a hole for the power cord to enter the enclosure.

After you drill the hole, pass the power cord through so that the plug comes out of the lid.

7) The rest of the wiring…

Here’s where I ran into some trouble (hence the fewer pictures). I guess there are so many types of PID controllers on the market and many variants of even the same models. Thanks to another commenter on SeattleFoodGeek.com, I figured out that my PID had a build in relay…so my wiring looks like this:

Set Up

Immersion heaters go into water (be sure coils are covered by water), place PT100 (also plug in PT100 into the controller module) and Pump in water. Keep the PT100 a reasonable distance away from the heaters to prevent a false reading. The second thermometer in the pictures was only used for testing.

PID Settings:

MAKE SURE YOUR HEATERS ARE SUBMERSED (TRYING THIS “DRY” WILL BURN OUT YOUR HEATERS) AND THAT EVERYTHING IS PLUGED IN SAFELY BEFORE YOU CONTINUE.

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(at this point, pressing “Set” will cycle through the following settings. I think that the auto-tune function will set the first group of settings for you.)

ARU: 0000 This is the “Auto-tune” setting. Set it to 0001 the first time you test the unit.

P: 001.0

I: 0049

D: 0012

Ar: 0025

R: 0010

Pb: 000.0

LCK: 1000

<<Press and hold “Set” and “>

COD: 0000

(at this point, pressing “Set” will cycle through the following settings. I think that the auto-tune function will set the first group of settings for you.)

SL 1: 1100. This is for the PT100 probe.

SL 2: 0000

SL 3: 0000

SL 4: 0000

SL 5: 0000

SL 6: 0001

SL7: 0000

SL 8: 0000

SL 9: 0000

SL 10: 0000

SL 11:0000

(Now it will bring you back to the “COD: 0000” Screen. Changing this to 0001 will offer the following settings)

COD: 0001

(at this point, pressing “Set” will cycle through the following settings. I think that the auto-tune function will set the first group of settings for you.)

SLH: 250.0

SLL: 000.0

oH: 000.1

dF: 0001

(Now just let the unit time out until it brings you back to the normal screen)

Press “Set” to set the desired temperature, use the “<R/S” button to move the cursor and the up/down arrows to change the values.

Sous Vide Away!

Helpful Links.

Seattle food geek Sous Vide Build.

PID Controller Manual.

A Practical Guide to Sous Vide Cooking.