Igloo Cooler RIMS Brewing System

Why I decided to build an Igloo Cooler RIMS Brewing System

When I visited Category 12 Brewing in Victoria, B.C, Canada, I had the opportunity to meet some impressive folk. The Head Brewer, Michael Kuzyk, was clearly a man dedicated to detail, and indeed the scientific method.

I finished my day at the brewery taking away one main thing – attention to detail is key; take notes whilst brewing, and use them to perfect your brewing technique. Unfortunately, if your brewing method is not consistent, then neither will your beers – no matter how good your notes are.

One example of inconsistency in my technique was mash temperatures. I could never hit them EXACTLY as intended. Moreover, I could never be sure of the temperature that my mash had rested at. In addition, ramping temperatures using hot water infusions was not as accurate as I wanted it to be.

Consistency and detail is something I believe will help me brew the best Kölsch that I can, and it is with this in mind that I decided to build a simple and effective Igloo Cooler RIMS brewing system. Now that it all finished, and most of the kinks have been worked out, I am going to tell you how I did it.

A Description of the Igloo Cooler RIMS Brewing System

This is what the system should look like when finished.
This is what the system should look like when finished.

The Igloo Cooler RIMS system is arranged so that the RIMS tube is mounted to the side of the Igloo cooler. The control panel sits on my counter top beside the system, and consists of a Sestos PID controller and 40A SSR. I wanted the system to stay basic, so I have omitted the use of any toggle switches / neon lights and so forth. The whole unit plugs into TWO SEPARATE electrical outlets in my kitchen, which are rated at 13A each on 240v.


Parts / Tools Required

For the control box:

  • 1 x Weathersafe Outdoor Power Connect-2 Mini Box (Maplin, £15.49)
  • 1 x Tube of heat transfer compound (Maplin, £5.99)
  • 1 x Sestos PID Temperature Controller D1S-VR-220 (Amazon, £19.60)
  • 1 x 40A Solid State Relay (store.brewpi.com, £7.28)
  • 1 x Dual Solid State Relay Heatsink (store.brewpi.com, £9.10)
  • 2 x 1.5mm appliance flex – this comes in rounds of 5 meters (Clas Ohlson, £5.49/e)
  • 2 x 13A fused plugs (Maplin, £2.19/e)
  • Assorted insulated spade terminals (Maplin – had this to hand, aprx. £5)
  • Assorted small nuts, screws, and washers kit (Maplin, £5,49)
  • 1 x strip of 30A connector blocks (Maplin, £8.99)
  • Crimping tool (Maplin – had this to hand, aprx. £7)

Total controller price: Aprx. £99.30

For the RIMS tube:

Total rims tube price: Aprx. £197.39

For the plumbing:

Total plumbing cost: Aprx. £83.11


Note: I am almost completely certain that some of the fittings / parts used in the assembly could have been found at alternative suppliers for cheaper. If you want to shop around for parts to make your own system, go ahead. The reason I got the parts from the suppliers above was because it was convenient for me to do so.

Note: I also used a Dremel tool, Dremel cut-off bit and Dremel drill bit big enough for the mounting screws supplied with the SSR. I also had basic screw drivers to hand.

How I put the Igloo Cooler RIMS Brewing System Together

1. Modification of the control box for the SSR

Picture 1: As you can see here, I have made a rectangular sized cut-out on the top end of the back of the control box. For illustration, you can see the heat sink behind it and you can also see the two holes in the heat sink where you attach the SSR.
  1. Use a Dremel tool and cutting bit to cut out a small rectangular cut-out in the top back of the outdoor power box. The hole should be just big enough for the Solid State Relay (SSR) to fit through (see picture 1).

2.  Mounting the heat sink to the control box

  1. Place the heat sink on a table, so that the control box rests on top (see picture 1)
  2. Because the heat sink is actually designed for two SSRs, there should be two more tapped holes on the heat sink ready for a second SSR. These are the holes that we are going to use to mount the heat sink to the control box. You need to drill two holes below the cut-out on the control panel to make way for two screws. These two screws will pass through the control box, and attach to the heat sink. note: it is hard to explain how to line it up, but making good use of a measuring tape you shouldn’t have much problem (see picture 2). 
  3. After the heat sink has been mounted, the control box should be able to stand up on an angle; the heat sink acts as a stand (see picture 3).
Picture 2: Here you can see where the two screws pass through the control box and into the heat sink. This acs to secure the heat sink to the control box.
Picture 2: Here you can see where the two screws pass through the control box and into the heat sink. This acTs to secure the heat sink to the control box.


Control box with heat sink acting as a stand
Picture 3: Igloo Cooler RIMS Brewing System Control box with heat sink acting as a stand

3. Attach the SSR to the heat sink

  1. Smear the heat transfer compound on the back of the SSR.
  2. Mount SSR to the heat sink, so that the SSR is protruding on the inside of the control box (see picture 6. NB – no wiring should be present at this point of the build.)

4. Modification of the control box for the Sestos PID and mounting the Sestos PID to the control box

Picture 3
Picture 4: Sestos PID mounted to the bottom right side of front of the panel.
  1. The Sestos PID instructions have the exact dimensions of the unit. Take note of these.
  2. Using a Dremel and a cutting bit, make a cut-out on the bottom, right hand side of the front of the control box to fit the PID.
  3. Insert the PID, and using the white, flush mount adapter (included with the PID), secure the unit to the front of the box (see picture 4)

5. SSR and element wiring (PART 1/2)

Sestos PID Wiring Diagram
Picture 5: Control box wiring diagram – to be read in conjunction with all wiring steps. The big rectangle is the Sestos PID and the small rectangle is the 40A SSR.
  1. Measure a length of flex, so that it is long enough to run from (a) the power outlet, into (b) the control box, and from the control box to (c) where the RIMS tube will be located.
  2. Cut the length in half. You should now have 4 exposed ends of wire (2 lengths, 4 ends)
  3. Wire a 13A fused plug to one end of one of the lengths.
  4. Strip 4″ of outer sheath from the three unused ends on the two pieces of flex.
  5. Take the length of flex with the plug installed on one end, and attach the brown wire to the terminal marked ~1 on the SSR using an insulated ring terminal.
  6. Take the other length of flex, and attach the brown wire to terminal marked ~2 on the SSR using an insulated ring terminal.
  7. Use 1 connector block to connect the blue wires from each length of flex.
  8. Use 1 connector block to connect the green / yellow wires from each length of flex.
SSR wiring
Picture 6: This is what the SSR wiring should look like after step 5. The flex on the bottom right runs to a 13a fused plug. The flex on the left will run to the element.

6. Wiring the electricity to the PID

  1. Cut a length of flex long enough to run from the outlet to your control box (mine is about 5 feet).
  2. Strip off 6″ of the outer-sheath of the flex cable.
  3. Crimp a insulated spade connector to the brown and blue wires.
  4. Insert the spade connectors into the connections marked 1 and 2 on the back of the PID. The order does not matter.
  5. On the other end of the flex cable, wire on a 13a fused plug.
  6. Check that the PID powers up by plugging THE PID in.

7. Wiring the PID to the SSR

  1. Using coloured wires from the inside of the flex cable, make the following connections:
    1. from terminal 6 on the PID to the terminal marked NEGATIVE (-) on the SSR
    2. from terminal 8 on the PID to the terminal marked POSITIVE (+) on the SSR

8. Wiring the PID to the temperature sensor

  1. The temperature sensor should have three wires. These three wires need to be attached to the PID at terminals 3, 4 and 5.
  2. The order DOES matter; however, because the wires do not come marked I used trial and error to determine the order that the wires needed to be in. The order can be determined using a ohm meter, but I didn’t have one to hand.
  3. It will not hurt the unit to take this approach. Each time you try a different combination, power up the PID. if the PID shows the temperature, your golden. If not, it will just flash and give you the code for an error and you will need to try again.

9. Mounting the RIMS tube to the side of the Igloo cooler


  1. Wrap PFTE tape around the element threads, and screw the element into the rims tube. Ensure that this is tight enough to create a water-tight seal.
  2. Take off one of the handles on the side of the cooler. Save the screws.
  3. Take off the cup holder mount on the side of the cooler.
  4. Mount the two pump clamps using to the side of the cooler. IMPORTANT: when mounting the pump clamps, make sure you do not screw through the inner wall of the cooler. Go slowly, and watch the inside of the cooler to ensure that you do not cause any leaks. It’s best to try and screw the screws on an angle to avoid the possibility of this occurring.
    1. the top clamp can be mounted where the handle was using the same holes.
    2. the bottom clamp needs to be positioned so that it mounts to the cooler alongside the bottom portion of the RIMS tube using the shortest self-tapping screws you have
  5. Use the excess cut-out piece of ABS plastic from step 1 and the cup-holder mounting bracket as supports for the clamps
    1. position them at an angle, and attach to the cooler using short self-tapping screws.
  6. Secure the tube to the cooler using the clamps.

10. Arrange the wiring in the control box

Ultimately, what you want is the following: (a) one length of flex with a 13A fused plug on the end to power the PID, (b) one length of flex with a 13A fused plug on the end to one side of the SSR and (c) one length of flex coming from the other side of the SSR leading out of the control box for the element. You should also have a wire for the temperature sensor, which also needs to lead out of the box to the RIMS tube. The wires from a, b, and c need to be arranged inside the control box such that they can come in and out using the pre-fitted ‘outlets’ on the bottom of the control box. The wire to the temperature sensor is quite small and can fit alongside one of these wires.

double, and triple check your connections before sealing up the box.

11. SSR and element wiring (PART 2/2)

  1. After step 10, the box should be sealed and you should have one wire ready to be connected to the element.
  2. Attach the cable gland to the element shroud.
  3. Thread the wire through the cable gland
  4. Wire the element using insulated ring terminals. MAKE SURE YOU PROPERLY GROUND THE ELEMENT USING THE GROUNDING LUG PRE-FITTED TO THE ELEMENT. The other two terminals (which should have little porcelain insulators pre-fitted on them) are for LIVE and NEUTRAL. The order does not matter.
  5. Wrap the connections with electrical tape so that a short does not occur.
  6. Screw the shroud on the element.

Where you should be after steps 1- 11

The control box should be completed and sealed, and all wiring completed. The RIMS tube should be mounted to the side of the Igloo cooler and the element connected to the control box.

12. Plumbing the system

  • I have used cam lock fittings for all moveable connections. These are not strictly necessary, but highly recommended. It is assumed that you have a 1/2″ ball valve on the drain to your cooler. It is also assumed that you have a suitable false bottom pre-installed in your cooler.
  • Fix a length of 1/2″ silicone tubing from the ball valve on the cooler. This needs to run to the INLET of the mag pump.
  • Fix the silicone tubing to the inlet of the mag pump.
  • Using PFTE tape, fix a 1/2″ ball valve to the OUTLET of the mag pump.
  • Attach another length of silicone tubing to the outlet of the 1/2″ ball valve. This runs to the inlet on the rims tube (on the bottom side of the RIMS tube).
  • Fix the tube to the inlet of the RIMS tube.
  • Plug the ‘outlet’ of the RIMS tube (top side of the RIMS tube). I had something to hand to do this, but you should be able to pick up a 1/2″ plug from a plumbing supplier to serve the purpose. If you do not plug this hole, and run the wort out through the top side of the RIMS tube (as most systems do), you will get an air pocket and not be able to read the temperature correctly.
  • Attach a 1/2″ tee to the VERY TOP of the RIMS tube. This allows you to mount the temperature sensor to the side of the tee. the wort flows up through the tee and passes over the sensor as it returns to the tun.
  • Wrap PFTE tape around the threads of the temperature sensor, and screw into the side entrance of the 1/2″ tee.
  • Attach a length of 1/2″ silicone tubing to the top of the tee. This length serves as the return line to the mash tun.

There it is, Grizzly Bear’s Igloo Cooler RIMS Brewing System. The next step is to test for leaks, and tune the PID. Please see this post on how to set up your Sestos D1S PID for RIMS brewing. As always, if anything above needs clarification or you have any questions, please post a reply below!

NB – The process may seem more difficult than it really was. If you want to make your own system, take it one step at a time and it will all come together in due course.

Home brew beer fanatic and lover of all things Kölsch. Follow me on Twitter!

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  1. s see says

    Why do you have two power inputs via external plug, one to the pid and one to the SSR, why not split inside the box?

    • says

      I wanted to have a dedicated power cable strictly for the element. That way the power to the PID can be on without any risk of dry-firing the unit. I suppose it could be split, but I never considered it as an option.


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