DIY Gadgets Sous Vide

DIY Sous Vide Heating Immersion Circulator for About $75


I’ve recently been fascinated by the idea of sous vide cooking – a method of slowly cooking vacu-sealed foods in a precisely controlled water bath to achieve the optimal doneness.  Last year, Sur La Table started carrying the world’s first “home” sous vide cooker, the SousVide Supreme.  This was fantastic, since commercial sous vide cooking machines cost north of $2000.  However, the home model (priced at $450) is still a steep investment for something that essentially just keeps water warm.  I was determined that I could build a better device on-the-cheap.

Behold, the $75 DIY sous vide heating immersion circulator!  By scrapping together parts that are readily available on eBay and Amazon, I was able to build a self-contained device that heats and circulates water while maintaining a temperature accurate to .1 degree Celsius (yes, point one degrees!).  And unlike the SousVide Supreme, my device can be mounted onto any container (up to a reasonable size, perhaps 15 gallons) allowing you more room to cook, if needed.

To build your own device, you’ll need some basic soldering skills, the list of stuff below, about 6 hours of free time (plus time for glue to dry) and the can-do attitude of a geek who doesn’t want to pay $450 for a water heater.  Click the “more” link for complete step-by-step instructions.

If these instructions have helped you build you own machine, I hope you’ll consider donating.  My goal is to mass-produce the world’s first sous vide heating immersion circulator for under $100, and every donation helps!

Update: Along with my business partners, I’ve finally commercialized a home sous vide machine!  It’s called the Sansaire, and it’s available for pre-order now!
Sansaire $199 Sous Vide Machine

DSC_0050 DSC_0046

Makes: 1 sous vide immersion heater
Total tinker time: about 6 hours

Shopping list:

Note: Make sure the controller you purchase has an SSR or Voltage output.  Controllers with a relay-only output will require an external relay and different wiring than what is listed in this project.

I’ve updated the parts list to specify an SSR – it adds a little to the cost of the project, but it is far more reliable, easier to connect, and works with any SSR/Voltage-output PID controller.

  • 1 piece of 1/4” acrylic, about 5cm x 20cm
  • 1/4” x 2” eye bolt and nut
  • About 2’ of 16-18 gauge wire
  • 3 wire nuts
  • Electrical tape
  • A means of cutting acrylic (see article)
  • Soldering iron and solder
  • Multimeter (tool that measures voltage, current, resistance)
  • Hobby knife (X-Acto or similar)
  • Tub and Tile Silicone Caulk
  • Hot glue gun
  • Krazy Glue

Step 1 – Making cutouts in your enclosure

This is the most difficult part of the whole project.  In order for the final assembly to be sturdy, water-resistant and decent looking, you’ll need to cut your mounting holes as precisely as possible.  I am very lucky to have access to a laser cutter at a lab at work, which makes this kind of precision cutting very easy and accurate.  However, in the absence of a $30K computerized laser cutting machine, with a steady hand, you can achieve the same results using a high-speed rotary tool like a Dremel.

I’ve included a cutting template that is matched to the heaters, PID controller and switch in the shopping list.  However, if you use different parts (different models, different manufacturers) you’ll need to adjust the template to ensure a tight fit of all parts.

image Click here for the 1:1 scale diagram (PDF)

  1. Pick a side of the storage container that you want to be the bottom.  Using the template as a guide, cut out the three holes for the immersion heaters.  Make sure that these holes are closest to the open end of the container (the end that has the lid) to ensure you’ll be able to reach inside later for wiring, etc.
  2. Next, cut the small oval-shaped hole for the water pump power cord.
  3. Turn the container over so the side with the holes is facing down.  Now, cut out the openings for the PID controller, the on-off switch, and the power cord.  Be sure that the hole for the PID controller is towards the top.  Otherwise, you’ll be cramped for space when trying to reach the back of the controller.
  4. Next, dry-fit all of the parts to ensure a good, snug fit.  The tighter the fit, the more sturdy the finished product will be. IMG_0441

Step 2 – Making the mounting bracket and pump holder

The mounting bracket is a J-shaped piece of acrylic that will let you attach the finished sous vide cooker to the side of a pot or basin.

  1. Cut out the rectangle on the 2nd page of the parts diagram and drill the hole as indicated.
  2. Find a rectangular surface that will allow you to make the 2 90-degree bends necessary to shape the acrylic into a “J”.  I used a small, glass olive oil bottle with flat sides and rounded corners.
  3. Turn on your stove.  Holding the long end of the acrylic with an oven mitt, warm it a few inches above your stovetop, turning to heat both sides.  It may take a few minutes for the acrylic to be warm enough to bend- you’ll know you’re getting close when the acrylic starts to curl away from the heat.
  4. Bend the acrylic along (approximately) the lines indicated in the diagram to form a “J”.  Press the bottom part of the J (not the side with the hole, and not the long side) against a flat surface such as your counter top.  Immediately cool the acrylic with cool water to hold its form.

Step 3 – Mounting the immersion heaters

The immersion heaters are the primary working element of the sous vide machine.  We’ll mount them hanging down from the bottom of the enclosure, and arranged so that the opening in the middle of the coil is lined up between all three heaters.

  1. Cut the power cord off of each heater, leaving about a 4” tail of wires from the heating end.  Keep one of the long lengths of power cord (including the plug) to use later as the main power cord.
  2. Using your hobby knife, scrape down the flat sides of the heater handles to remove lettering and to flatten out the circular rim at the top of the handle.  This will allow for a deeper and tighter fit in the heater openings.
  3. Arrange all three heaters in their respective openings.  Note that the heaters should be oriented such that the coils are facing towards the center-line of the enclosure.  You should be able to fit your finger down the middle of all three coils.  Make sure the heaters are snug in their openings. IMG_0449
  4. Apply a small bead of tub and tile caulk around the heaters on the outside of the enclosure.  Allow to dry overnight before proceeding.

Step 4 – Wiring

CAUTION: Don’t ever power on the heater coils unless they are submerged in water!  Also, don’t electrocute yourself.

If you have experience with basic circuitry and wiring, this will be pretty easy.  However, if you’ve never worked with a soldering iron or circuit diagrams, these steps will take you a while.  Refer to the wiring diagram below for the “big picture.”

Wiring diagram for JLD612 PID Controller with SSR

sous vide electrical diagram for LJD612 PID

Wiring Diagram for CD101 PID Controller with physical relay

Update: I’ve updated the wiring diagram to make it clear that the view of the relay posts is from below.  In other words, if you set the relay down on your table with the pins facing up, that will match the alignment in the wiring diagram.

circuit diagram


  1. Strip off about 1/4” of shielding from your power cord (remember, the cord that you saved from one of the immersion heaters?).  Run the power cord in through the power cord opening on the front of the enclosure.  Separate the 2 wires about 6”.  One of these wires will go through the power switch, and the other will go directly to the PID controller, heaters and pump.
  2. Use your multimeter to find the two posts on the back of the power switch that are normally open, but closed when the switch is on.  On my power switch, these were the far and middle posts (not the two posts closest to the “ON” side of the switch, you know, with the dot).  IMG_0457
  3. Pass the switch mounting nut (the thing that screws on the back) over one lead from the power cable, inside the enclosure.  Run the lead out through the power switch hole.  Solder that lead to one of the posts you identified in step 2.  Cut an 8” length of wire and solder one end to the 2nd lead on the switch.  Tuck the wires inside the enclosure, place the switch in its hole, and tighten the mounding nut to secure it in place.  You’re now done with the power switch.
  4. Next, wire together the heater leads.  Separate the leads from the heating coils.  Gather together one lead from each coil to make two bundles of three.  Cut two 6” lengths of wire and add one to each bundle.  You should now have two bundles, each with four wires – 3 of which go to the heaters, and one left dangling.  Solder the wires in each bundle together, then cap with a wire nut and some electrical tape.
  5. Of the leads you have coming out of the heater bundles, one will go straight to the incoming power, and the other will go to the relay that turns on and off the heaters.
  6. At this point, it gets too difficult to describe the rest of the wiring in words, so refer to the wiring diagram.  Just make sure to be aware of how everything will mount in the enclosure when you’re all done.  Pass the wires through the mounting ring on of the PID controller before attaching them to the terminals, etc.
  7. After wiring the connections to the relay (or SSR), coat the bottom with hot glue to surround the connection points.  This will act as an insulator and prevent the relay from shorting out against any metal inside the case.  Or, if your SSR came with a plastic cover, secure it in place to prevent the connections from shorting.
  8. If you are using the PT100 thermocouple (which I recommend), make sure you connect the leads exactly as shown in the wiring diagram or you will have an inaccurate temperature reading.  (There’s no instruction manual with these probes, so it took 30 minutes of trying different combinations before I found the right one).

Step 5 – Final Assembly

  1. Using Krazy Glue, glue the J clamp to the bottom-front of the enclosure.  Wait until dry before proceeding.
    Note: This glue joint is a popular point of failure.  If you’d like, strengthen the connection between the J clamp and the body by using two screws and nuts.
  2. Glue the nut for the eye bolt to the inside of the hole in the J clamp.  Ensure that the nut lines up with the hole so the eye bolt can pass through.
    eye bolt
  3. Seal the openings for the power cord and pump cord using tub and tile caulk.
  4. Put the back cover on the enclosure and wrap the seam with electrical tape.
  5. Stick the suction cup feet of the immersion pump to the flat end of the J clamp and position the water outlet to pump through the middle of the heating coils.DSC_0039

Step 6 – Testing

Now that everything is wired up and assembled, you probably want to see if it works.  WAIT!  Don’t turn the machine on (ever!) unless the coils are submerged in water or, they will burn out in about 5 seconds (I learned this the hard way).  DSC_0038
To test the machine out, fill a basin with water so that it covers at least the coil part of the heaters.   Mount the machine on the edge, so that the J clamp hangs over the lip.  Tighten the eye bolt to secure the machine.  Plug in the cord and flip the power switch!  If the PID controller turns on and the pump starts pumping, that’s a good sign!  Note that the heaters may not warm up just yet, depending on what the target temperature is by default.

Step 7 – Programming the PID Controller

For users of the JLD612 PID Controller

For programming instructions such as running Auto-tune and changing alarm values, refer to the JLD612 manual.  Here are the steps you should take when programming your controller for the first time.

  1. Press SET and enter code 0089, then press SET.
  2. Set the value of Inty to Pt10.0 to get the temperature to display with one decimal place.  (I had to set it to Pt100, then back to Pt10.0 to get this to work the first time.
  3. Select End to exit the programming menu.


For users of the CD101 PID Controller

Out-of-the-box, the PID controller is designed to work with a different type of thermocouple, so the readings that you get using a PT100 will be strange.  Follow the instructions in this manual (that doesn’t ship with the PID controller) to set it for the PT100 probe.  You can also follow the instructions there to set the number of decimal points of precision.

Next, set a target temperature by tapping the SET button, then using the up and down arrows to pick a number and pressing SET again to confirm.  50C is a good target temp.  The OUT1 light will light up, indicating that the PID controller is turning on the heater.  You should hear a soft clicking noise – this is the relay kicking in.  At this point, the heating coils are on and warming up.  As the temperature measured by the probe (green, top line) approaches the target value (orange, 2nd line), the relay will click on and off more frequently to sustain the temperature.. DSC_0040

Ideas, Improvements, Thoughts

After burning out my first set of heating coils, I realized that there must be a better method of heating the water.  The coils are very effective and heat the water very quickly.  However, I’m pretty paranoid about burning them out again, and they’re a pain to replace.  I’ve found some commercial immersion heating elements, but they’re about $100, which inflates the budget for this project by quite a bit.  I may try using the heating element and pump system from an old espresso machine, the kind that makes steam.  Since it already has a self-contained heater and an pump, it might even be cheaper than the heating coils and aquarium pump.

I’ve also thought about turning this machine into a general-purpose temperature control unit.   Instead of wiring the heaters directly to the relay, I would install a power outlet on the back of the enclosure and add a jack to plug in an external temperature probe.  If I wanted to use the immersion heaters, I’d just plug them in to the power outlet.  If one got fried, I’m only out $6 instead of an hour of removing glue and solder.  Also, a general-purpose temperature controller is great for making your own smoker box.  A-la Alton Brown, you can plug in a hotplate filled with wood chips and have a precisely temperature-controlled smoker for just a few bucks.

I’m thrilled to start playing with sous vide cooking, and I’m happy that I was able to build an accurate, reliable machine for $75.  Even the PID Controller + Crockpot method costs $185 (not including the Crockpot!).


I gotten a lot of emails and comments asking for troubleshooting help, and rightfully so – there’s a lot going on in this project, especially if you’re pretty new to DIY electronics.  I’ve decided to add my basic troubleshooting routine, which should hopefully get you sorted out.  If you still have problems, please post a comment below, or send me an email at

If your heaters don’t get hot when they should (i.e., your machine isn’t working), do the following:

  1. Ensure that your OUT1 light goes on and off when it should.  It should be on when the unit is heating, and off when you’re at or above the set value.  If not, double check that you’ve set your temperature probe type correctly, and that OUT1 is set to heating mode in the PID settings menu.  If this looks correct, proceed to step 2.
  2. Verify that your PID controller has an SSR/Voltage output.  This should be specified on the sticker on the side of your PID controller.  The controller in the photo below only has a relay output (this is not what you want).
    relay only controller
    PID controllers generally have two types of outputs: relay and voltage.  Contrary to how it sounds, a relay output is not used for controlling a relay.  Rather, a PID controller with a relay output actually has an internal relay.  Unfortunately, the internal relay is typically not rated for the kind of load that the heating coils pull, so you cannot connect them directly to the internal relay.  A PID controller with an SSR/voltage output produces a DC voltage (8-12V DC) that we can use to control an external mechanical relay or a solid state relay (SSR).  That’s what we want.
    Telltale signs that your PID controller has a relay-only output: a) there’s no voltage across pins 5&6 (or the corresponding pins on your controller) when the OUT1 light is on, b) you hear a clicking sound when OUT1 turns on and off, even when your external (blue) relay is disconnected, and c) you measure continuity across the pins that correspond to OUT1 when OUT1 is on.
    If you have a PID controller with a relay output, not all is lost.  You’ve got two options:
    1)  Return it for a PID controller with an SSR/voltage output, or
    2)  Use the internal relay to control an external 120VAC relay that is rated for 8+ Amps @ 120VAC.  The wiring for this configuration is a little messier, and you’ll need to buy a different relay than the one specified in the parts list.  The wiring diagram for this configuration is below.  Note that I haven’t attempted to show the actual pin configuration of the external relay – rather this is the logical way you’ll need to wire it in.
    circuit diagram for relay-out
    If you’re sure that your PID controller has an SSR/voltage output, proceed to step 3.
  3. Verify that you are using the right kind of relay for your PID controller. The CD101 will work with either an SSR (solid state relay) or a physical relay. However, the JLD612 and many other PID controllers will only work with an SSR.
  4. If you’re using a CD101 and a physical relay, ensure that your external (blue) relay is wired correctly.  You should hear a clicking noise coming from that relay when OUT1 lights up or turns off.  If not, you may have connected the leads from pins 5 & 6 backwards, or your external relay may require a higher activation voltage than what your PID controller outputs.  Measure the voltage from pins 5 & 6 and compare to the coil voltage specified by your relay.  In practice, there is some wiggle room (ex., a relay with a 9V coil will often be activated by less than 9V).  If the PID doesn’t produce enough voltage, buy an SSR.  If your relay is clicking, proceed to step 5.
  5. Check for 120VAC going to the heater leads when OUT1 is on.  If you’re not seeing a voltage, check the connections across your relay and between pin 1 and your heaters.  If you’re getting 120VAC to your heater bundles, proceed to step 6.
  6. Your heaters are likely burnt out.  This can happen in a flash if you accidentally supply power to the heaters when they are out of water.  Double check by submerging your heaters and connecting an 120VAC power source directly to the leads (exercising great caution not to electrocute yourself).  If they heat up, you’ve got a loose wire somewhere in your connections.  If they don’t heat up, they’re burnt out and you’ll need to replace them.

If these instructions have helped you build you own machine, I hope you’ll consider donating.  My goal is to mass-produce the world’s first sous vide heating immersion circulator for under $100, and every donation helps!

998 comments on “DIY Sous Vide Heating Immersion Circulator for About $75”

@Jack Think of that relay as a switch. All it does is open and close. In order to get 120V out, you’ll need to pass 120V in. To do this, (referring to my wiring diagram above) jumper pin 2 to pin 3 and move the heater lead from the relay pin to pin 4.

Just got all my parts and, of course, I’m leaving for the beach for a week.

Scott, What is your PID model code? The one I got through your link is FK02-M * AN-NN

I’m asking because of all the comments about relay vs no relay. Fairly certain I need the Radio Shack relay.

I got mine working! I had to get a replacement PID, since mine was not activating the relay and the internal was most likely fried. I went with the PID from, and the SSR, same as commenter “SJW” above, so I blew the $75 budjet. I’ve made “sous vide” steaks before using the cooler method at, the ones made with this setup are by far one of the best steaks I’ve ever had. Next up, eggs!

Thanks Scott, without your article I would have never had the inspiration to attempt this.

It works! It finally works. Thank you for your advice and directions. My problem turned out to be the common pin on my relay was broken at the base but the solder held it in place and was still giving me a 120v reading when I tested it instead of the wire

i would love to make this but i have never did anything like this before on a scale how hard is it to make. thanks Steve

@Steve Its not hard to make. Once you understand the concept behind it, it gets a lot easier. Some takeaways from my experience are as follows.
1. Consider using a different heating element.
2. Make a modular design so that replacing parts is easier.
3. Use an SSR instead of the mechanical relay.
4. Ask lots of questions!
Here is a link to my design, taking from the best of all the posts plus a few ideas of my own.

Following the charts on cooking times ( I had great success this weekend.
Using Lobster tails I removed most of the shell (apart from the piece at the end – for appearance). I placed each lobster tail in a vacuum bag added about 4 ounces of butter about 1 ounce of sweet white wine and about a tablespoon of vanilla extract (didn’t have any pods or I would have used that).

So essentially poaching in a beurre blanc sauce 61 C for approximately 45 minutes.
Wonderful !!!
Lobster was poached just perfectly the cooking sauce poured over it

Hey guys I’m about to try to build one of these beasts. I’m going to start off building a modular PID controller with plugs in the back to attach different heat sources.

For my PID controller I ordered the D1S-2R-220. Here are the specs.

I’m not very experienced with electrical and the schematics and broken english confuse me. I am wondering if you can wire a SSR to the D1S-2R-220 model or if it has something internal? I bought this without thinking and just assumed all PID’s were similar.

OK – got this thing wired, heater coils are operating and have Temp controller set up according to instructions. Set the temp for a test run and when the set value temp was reached the Out1 light went out but the heaters remained on. Any ideas?

@Benwa If the Out1 light is dark, then 5 & 6 should no longer be sending a signal to the relay. Verify:
1) There is no DC output from 5 & 6 when Out1 is off.
2) The relay is wired correctly.
My guess is that the wiring is incorrect and the heater coils are simply on all the time and the PID isn’t really “controlling” them. Just a guess.

When I had the 10A spdt relay wired originally with the rocker switch power attached to the N.O. post there was no power to the coils regardless of whether or not the Out1 light was on or off. I connected the rocker switch power to the N.C post and the coils came on. I thought perhaps I needed a Solid State Relay due to low voltage output. Now with the SSR connected I have power to the coils but they won’t turn off. I think the relay in the PID is burned up and i guess i’ll have to replace it.

@Benwa Did you check for both AC & DC off posts 5 & 6 of the PID? Some come with internal relays and some do not. I’ve seen people mention in the past where thought their hardware was faulty only to find a wiring issue. Specifically, some of the CD101’s come with an internal relay (from what I hear) and, therefore, there is no need for an external mechanical relay or SSR.

While it is true that some PID’s come with relays rather than output for SSR. My understanding is the relays are only for about 3 amps controlling power. Most heaters are require much more. (Watts=volts*amps thus amps=watts/volts 1100w/110v=10 amps) so your 3 amp rated contacts will burn out really quickly.
My PID had a relay output so I extended the circuit by using a 25 am rated SSR. I used the relay control to energise the SSR using power from a 9 volt wall “wart” transformer.

This means I can now control bigger & better heaters without concerns of burning out my PID.

Re agitation: haven’t yet built anything, but it strikes me that the very cheap “milk frother” or “cappuccino frother” devices you can get for next to nothing might be OK. They’re powered by 2 AA batteries, and are essentially a DC motor turning what I would describe as a tiny whisk head very fast. Replace the batteries by a 3V supply, extend the metal shaft, and you have a low-power agitator which will work at any temperature. Maybe it could be moved to a different position from time to time. Maybe replace the whisk head by a propellor to move the water further (like an electric paint stirrer on a small scale). Picture here:
Scale: 2 AA batteries fit in the handle.

Re sparks, mentioned as sometimes happening: any mechanical switch circuit (including electromechanical relay) can be suppressed by connecting a small capacitor rated for an appropriate AC voltage (typically 0.1 microfarad, 630VAC) in series with a small resistor (typically 100 ohms) across the switched contacts. Instead of worrying about getting the right values, you can buy inexpensive ready-made snubbers or interference suppressors. Theoretically values should be matched to the application, but I have used those given with total success to silence switches that produced interference due to sparking.

@Greg H: I see you used the Marshalltown bucket heater; is it completely submersible? I.e. could you lay it down in the pan of water?

Thanks to Scott for putting the original idea together and everybody else for adding their tweaks. There’s a good chance I’ll be making one of these.

@ GregH,

Checked for conductivity on 5&6 – no power. Sent back and replace dwith a new controller and unit is working fine now. As I suspected I just got a bad controller.

Hi there!

I am currently making my mind about building my own DIY sous-vide cooking station.
I am thinking about an ‘all-in-one’ appliance, or at least something that could be self-containing all the parts for easier storage in my tight kitchen.
I am thinking about turning a compact beer cooler into a 2 uses bucket : first as a vacuum chamber, and then as the bucket for hot water cooking. After usage, all the parts should fit inside the cooler: vacuum pump, hot sealer, PID and water heater/circulator.
Has any body ever tried that? I am thinking especially about using the beer cooler as a vacuum chamber: would it suppport the pressure?

Based on Alvin’s solution – can we replace the heating elements with a grounded socket outlet (same wiring diagram, with neutral connected to the outlet as well)?

Hi Scott, thanks for publishing these plans, great work. I have built the unit as above, and I am using the Marshalltown bucket heater, but seem to be having some problems. When the heater gets current to it the temp reading on the PID starts to go crazy, when the current is off it starts to read normally again. When I stick one probe of my multimeter into the wall and the other in the water I get 120 V potential and 3-4 amps (AC). It seems that the heater is causing a current in the water, which would obviously mess with the thermocouple. My wiring is per the plans, except that I am using a SSR. Any ideas on what is causing this? A faulty bucket heater? Thanks.

@SimonR I’ve heard a few reports of similar behavior before. As an experiment, please try this: switch the two power leads coming in to the machine. That is, swap the wire connected to the switch with the wire that connects directly to the controller. Then test the unit again. I’ve heard reports that the polarity of the wiring can actually cause this type of behavior, though (given my limited knowledge of wiring) I didn’t think polarity was such a concern for AC power.

Also, with that kind of current, be sure to test the water again with your multimeter before sticking a finger in.

All that said, the bucket heater _shouldn’t_ be leaking electricity into the water. It is possible that it is faulty.

Thanks for the reply. I switched the wiring, same thing. I am using the JLD612 for the PID with a SSR. I think the thermocouple wiring is correct as it displays the right temp when out of the water. I also installed outlets for the pump (always on) and the heater (relay activated). Whether I plug the bucket heater into either of these outlets, or a completely separate wall outlet the same thing happens. I replaced the bucket heater and still get the same results with the temp reading going wild. It must be the thermocouple I guess. I’ll order a new one and wait and see. Thanks again.

Hello… Thanks for posting the information and hosting this forum!

I’ve almost got mine working. My OUT1 light turns on and off when going above or below the set temp, but my output is always 120v. I am not sure why it is not cutting the power when reaching temp? Bad relay perhaps?

wow… very cool. I think this is my next project. So far I’ve bodged together an old Haake circulator w/o thermostat with an old watco pid, and just yesterday ripped the guts out of a broken Lauda MT and replaced with the same PID kit you have up there. Any more news about the long term survivability of that pump? That’s the only part I see as a possible weakness.

Tested my relay and it is working. When I use a 9v battery the relay switch clicks and 120v is sent to the heater. My 5 and 6 pins are not producing the 12v needed to click the relay switch… any thoughts?

@Mattch You might want to try a Solid State Relay, if that is indeed the issue. SSRs don’t have the voltage requirements of mechanical relays. If you search this page you find links to ones that will work at decent prices. Hope that helps!

Thanks for the feedback… got my issue resolved. This PID also has the internal relay. I wired hot from the rocker switch to the #4 pin and out from the #5 pin to my outlet where the heater connects. Same as Alvin mentioned above.

Great stuff… looking forward to trying out my improvised version of this on my electric smoker!

I have a question for the group. I constantly have to re-calibrate my PID (cd101 & pt100 thermocouple). I auto-tune every time but it marginally helps. Also, I have to offset the temp about 30F degrees. Anyone else having this issue?

@GregH No, I’ve never had to recalibrate my unit. Is it possible that you’ve got a bad thermocouple?
However, I noticed that you’re not using Celsius. I found that my PID controller is ONLY accurate when set to Celsius. I have no idea why, it should just be a mathematical coversion to F. But perhaps this is part of the problem?

Is anyone using the CD101 with internal relay? I’m pretty sure that I need to run an external relay to control the heater. How are you powering your relay? I’ve been stumped for a few weeks, as this is the first time I’ve ever messed with creating something like this. Any help would be really appreciated. Thanks.

@Anthony Are you sure you have an internal relay? If so, you shouldn’t need an external one. Remember, all the relay does is complete the circuit to your heating element when it needs to and breaks it when it doesn’t. If you have an internal relay, then do a continuity check with a multimeter. When the Out1 light comes on, then circuit should complete.

@Greg H. I’m 95% sure I have one with the internal relay. I’ve done a continuity check with my multimeter. However, it says the internal relay is only rated for 3A, and I’m using the Marshalltown bucket heater. So I was trying to run an external relay because I’m afraid the current from the heater would be too much for the relay built into the controller.

@Anthony Ah ha, I see your issue. If you search this site for *facebook* you’ll find a post by Alvin. He talks about internal relays a bit and his info might point you in the right direction. Sorry I couldn’t be of more assistance.

If you have a low amperage relay in your PID unit you might want to take the path I took.
Use the internal relay to control power to a higher rated SSR. There might be an infintissemal delay in control But you can get a SSR that will happily switch 25 amps.

I used a wall wart power brick for an old cordless phone.

@Greg and John. Thanks for your help. I was wondering if I could run hot from the switch to the common in the relay and control an AC relay. Do you think that would work?

I have the JLD612 PID controller. It’s supposed to be able to use the internal relay to control one heater (ie < 3A), but I can't get this to work. I can see approx 8V DC switching on and off on the internal relay.

Does anyone have instructions on how to make that work?

Thanks, M.

@Anthony and @m I strongly advise you NOT to use the internal relay in your PID controller. Those relays are only rated for 3A. However, your heaters will pull over 7A. I’ve personally burnt out the internal relays on my PID controllers testing this method – they’ll work for a few hours, give or take, but invariably the extra load on the internal relay burns it out.

Either use the DC output to control a relay (as described in the instructions) or use the internal relay to control a 120V relay that is rated for at least 9A.

I don’t mean to be a downer about this, but as enticing as it sounds to use the internal relay, I promise it’s not going to last very long.

@Scott Thanks a lot for the confirmation. I knew I should avoid using the internal relay. I just wasn’t sure how I was supposed to provide power to an external one. Seems like I have two options.

Hey guys,

I’ve been having a few problems. First, my heaters weren’t working and then I realized i wired the relay looking at it from the bottom per Pete W on 3/15. Then my heaters were always on (left top post when looking at it from the top) and I saw somebody said that I had the wire going to the pump/PID #2 on the wrong post. So, now when I put it on the other post (the right side when looking at it from the top), I don’t get any heat at all. Please help. I do have a multimeter, but I have no idea how to use it. Everything is using the exact parts/wiring as the original diagram other than my expirement with changin the wiring to the on the top 2 posts of the relay.


Hey guys,

I’ve been having a few problems. First, my heaters weren’t working and then I realized i wired the relay incorrectly where I had it wired looking at it from the bottom per Pete W on 3/15. Then my heaters were always on with the wire from the pump/PID #2 connected to the left top post when looking at it from the top and I saw somebody said that I had the wire going to the wrong post. So, now when I put it on the other post (the right side when looking at it from the top), I don’t get any heat at all. Please help. I do have a multimeter, but I have no idea how to use it. Everything is using the exact parts/wiring as the original diagram other than my expirement with changing the wiring on the top 2 posts of the relay.

Thanks for the instructions. Found this after developing an interest in sous vide, but no interest in the cost.
Just to let you know, I done this over in the UK but have made a device with a plug socket outlet to control a crock cooker.
After a bit of fiddling, and confusion trying to interpret the pid calibration settings from Hong Kong, I managed to get it working.
The only thing I dont have is the three terminal thermocouple, but it seems to be accurate enough using the two terminal on the autotune function.
It cost me around £40 (inflated by having components shipped from the Far East).

Good work

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