TETB kegerator build

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Introduction

Does the world really need another kegerator build blog...?

Probably not. But the idea with this one is to make it specific: what model of fridge, where precisely to drill the holes, etc.

Here's what I aim to build:
  • a kegerator based on a brand new, cheapish, widely available (in the UK) under-counter fridge;
  • with room for a minimum of two new-style 19L AEB cornies;
  • and with a two-tap font (tower) mounted on the top.
I'll say upfront that the objective is not to be cheap and cheerful. That doesn't mean I'll be splurging money for the heck of it, but equally I won't be cutting corners at the expense of quality.

Also some of the design will be a bit geeky for many people (e.g. I'll be building a custom temperature controller) but I hope you'll be able to adapt what I do to meet your own preferences, like using an InkBird or similar. If you do that or use different components then please share via the comments so other people can benefit from what you've done athumb..

Hacking the fridge
I'm using a Curry's "Essentials" CUL55W20 larder fridge which I bought new online for £150 plus £10 delivery.
You can read more about it including the internal dimensions in my other thread.

First job was to remove the packing tape and all the internal shelves and door cubbies. They look useful though so I'll keep them for now.

Second job was to remove the thermostat/light module - otherwise there isn't room for two kegs.
It comes off pretty easily, but there's a couple of small winkles.
  • Before starting unplug the fridge from the mains and make sure you are wearing a hard hat, gloves, snow shoes and shark repellent.
  • The module is held in by two pozi drive screws. The first is directly accessible but to get at the second you have to remove the clear plastic cover over the light. To do that, get your thumb under the small grip on the lower part of the clear cover (arrowed), ease it down and hinge the cover open and off.
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  • Gently pull the module clear to reveal the wiring:
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  • Carefully pull off the spade connectors using long-nosed pliers, then slide the light out of the mounting grooves. Finally pull the thermostat sensor out of the clear plastic tube at the back of the cavity.
  • You should be left with something like this:
Screenshot 2021-09-18 at 16.34.29.png

The wires are as follows:
BROWN: 240v mains from the plug
RED: mains feed to the compressor
ORANGE: mains feed to the internal light
BLUE and YELLOW: connections to the light
GREEN/YELLOW: safety earth

Tuck the wires away, then you should be able to fit in two kegs like this:
IMG_6184.jpeg


To be continued...
 
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Chippy_Tea

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Does the world really need another kegerator build blog...?
Probably not. But the idea with this one is to make it specific: what model of fridge, where precisely to drill the holes, etc.

I never tire of reading these threads my D.I.Y skills are not good, SWMBO would go as far as to say i am the opposite of King Midas where everything i touch turns to s***e
 
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Next step is to make some access holes in the fridge. Initially just for the temperature sensor but later to feed out the amber nectar.
The key thing here is to avoid damaging any of the refrigerant pipes or wiring, so its advisable to proceed with caution.

The first step is to remove the top cover, which is held in place by two pozi drive screws at the back and two slide-in clips at the front.

With the fridge door closed, remove the two obvious screws at the back and put them somewhere safe.
Now lift the rear edge vertically up and then push it forwards to release the slide-in clips (arrowed in second photo)

Screenshot 2021-09-18 at 17.34.03.png


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The top cover should now be completely free, revealing the top of the hard expanding foam pumped into the fridge to provide insulation. There are doubtless pipes and/or wires buried in this.
Note that the top cover does not sit completely flush to the foam but leaves a gap due to a number of stand-offs. This is convenient for us as it allows space to run cables and/or pipes over the top of the foam.

Now mark a point 10cm in from the righthand side and 8cm from the back edge; and then carefully push a small screwdriver through the foam feeling for pipes.
As you can see in the photo I started 10cm from the back edge - but that was slightly too far forward as I narrowly missed a metal support strip (see second photo). EDIT: in the second fridge I converted this bar was about 1cm further back.

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Carefully remove a cylindrical area of the insulating foam to reveal the inner plastic lining of the fridge. I did that using the open end of a box spanner but you could equally well use an apple corer or similar. Take your time. Keep the bits of foam as you will shove them back in later to fill the hole.

Shine a torch through from inside, to make sure you are really looking at the inner lining.


To be continued...
 
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The next job is to make your first hole. In my case this will be for the temperature probe.

First of all I poked a small screwdriver through to make sure I was coming out in a good place inside.

Screenshot 2021-09-18 at 20.24.31.png



Feel free to just feed your sensor cable through directly, but I'm going to use a connector because it'll give me more flexibility later on.

I'm going to use the round 12mm metal 'GX12' aviation connectors as they are cheap, look good and are simple to mount.
They come in 2, 3, 4, 5 and 6 pin versions, handle up to 5A and have a screw-on ring that keeps the connections secure.

Screenshot 2021-09-18 at 20.14.36.png


The GX12 connectors need (surprise surprise) a 12mm mounting hole.

First wire the connector. The pins are quite close together so use a fine soldering iron, and it's best to put a bit of heatshrink insulation over each connection once you've done it. Make a careful note of the pin-numbers you choose - the numbers are moulded on the back of the connector but you'll have to look closely.

I used the following connections:
  1. Gnd (black)
  2. +5v (red)
  3. signal (yellow)
Push the connector through from the inside and if necessary hold in place with a bit of insulation tape.
From the outside thread the washer and nut over the cables and position them using a pair to tweezers or long-nosed pliers. Finally, tighten the nut with a box spanner and then back-fill the hole with the bits of insulation you dug out, held in place with a bit of PVA adhesive.

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My next step was to securely mount a matching connector on the outside of the fridge. Whilst not strictly necessary, this does enable you to disconnect the fridge from the controller without leaving a trailing cable.

I did this by making a small mounting bracket from aluminium sheet and sandwiching it under one of the top cover mounting screws on the back panel.
The connector is wired pin-for-pin to the one inside the fridge.

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to be continued in the next thrilling instalment ...
 
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If Carlsberg did Kegerator Build threads, they’d still be miles behind a TETB Kegerator Build thread

I can’t wait to see just how deep this rabbit hole ends up 😂
Some people have suggested that I might have a weeny bit too much time on my hands... athumb..
 
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This week I’ve been waiting for a couple of parts to arrive, so I thought I’d knock up a temperature controller for this build. Consequently a fair bit of designing and coding in the last couple of days.
I’m actually using two fridges - one primarily for fermenting and the other for conditioning and dispensing. So I thought I’d do a single controller for both of them:

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I won’t go into much detail on the design of the controller because it’s a bit off topic, but if anyone wants more info then message me.

The electronics is still on the prototype board at the moment. Today’s job is probably to transfer that to a PCB and put it in a box.
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Looking great TETB!

Mine is now complete, although I have not gone to the lengths that you have with yours.
Thought I'd post here rather than ANOTHER kegerator thread.

Used a donor SMEG fridge that cost me £50 on FB Marketplace, and 4 x CMB/CM Becker V10 taps.
Already had 2 kegs in my shed, gas, lines etc, so I just need another 2 of the narrow 19L kegs to fill her up.
They'll fit according to the tape measure.
Only other thing I bought was an STC-1000 as the thermostat was iffy and the fridge was icing up. That's why it was only £50...

Good luck finishing yours.


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OK the controller is finished so it's back to hacking the fridge:

Re-wiring the Compressor
This step is not at all compulsory: you can just follow the traditional route of hot-wiring the thermostat and plugging the whole fridge into your Inkbird or whatever. However that means that the light wouldn't always go on when I opened the door - and that would upset my obsession with detail... so instead I'm going to leave the mains permanently connected and just switch the compressor on and off with a relay.

That means we are going to have to remove the protective cover over the compressor terminals.

First of all disconnect the fridge from the power.

Tip the fridge up and rest it on something, then improve the access by removing the plastic drip tray from on top of the compressor - it just pulls out backwards like this:

IMG_6247.jpeg


Now we can remove the protective cover from the compressor power terminals.

First release the cable clamp. Remove these two screws and put them somewhere safe; then pull out and remove the clamping plate. Remember which way round it fits for when you put it back later.

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Now to remove the protective cover itself.

First remove the indicated screw and put it somewhere safe. Then put a flat-bladed screwdriver into the recess on top of the cover. Lever the recess carefully upwards to release the internal catch, while hingeing the cover downwards and to the left. Finally disengage the bottom edge of the cover then completely remove it to expose the power terminals.


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Next post: adapting the wiring....
 
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Looking great TETB!

Mine is now complete, although I have not gone to the lengths that you have with yours.
Thought I'd post here rather than ANOTHER kegerator thread.

Used a donor SMEG fridge that cost me £50 on FB Marketplace, and 4 x CMB/CM Becker V10 taps.
Already had 2 kegs in my shed, gas, lines etc, so I just need another 2 of the narrow 19L kegs to fill her up.
They'll fit according to the tape measure.
Only other thing I bought was an STC-1000 as the thermostat was iffy and the fridge was icing up. That's why it was only £50...

Good luck finishing yours.


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That's looking phenomenal @chopps !!
 
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Adapting the compressor wiring

Having removed the protective cover we can now see the compressor power cables. The Green/Yellow one is the safety earth connection, Blue is permanently connected to mains Neutral; and White goes to the RED wire that we removed from the thermostat inside the fridge. Your wiring may differ though, so check with a continuity tester to make sure.

The way you proceed will depend on your controller design: if you're using an Inkbird or similar then you might want to just wire a simple mains cable to the compressor and plug that into your controller.
Whatever you do, be careful to insulate and protect all the wiring and use cable of an appropriate rating and colour.

In my design I am controlling the compressor with a 12V / 10A mains relay:

Screenshot 2021-09-29 at 21.45.55.png


This is probably a bit meaty for the light current involved as the fridge mains label only states half an Amp - but I want it to last a good long time.

To use the relay I cut the white (switched live) cable, removed the spade connector and spliced in a couple of brown 5A wires leading across to where I am going to site the relay.
I insulated the joints, zip-tied the new wires to the existing cable loom and then replaced the protective cover and clamp. Finally I fed the wires through a bit of PVC tubing to provide some extra protection:

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Remember to refit the white plastic drip-tray otherwise any condensation from inside the fridge will end up dripping onto your mains wiring.

Next post: wiring and mounting the relay...
 
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Wiring and mounting the compressor relay

The relay I'm using comes with a standard 8-pin socket. This makes things a lot easier to wire up and also provides a couple of mounting holes.
Very fortunately, the mounting holes align with these two holes on the righthand side of the chassis. One of these is threaded (M4) and the other is plain.
A couple of M4 x 20mm stainless steel bolts through these holes work perfectly to mount the relay (with a shake-proof nut on the righthand one).

IMG_6235.jpeg


I wired the relay using crimped spade connectors, protecting the mains wires with thinner bits of PVC tubing and insulating the relay terminals using several turns of tape before bolting the socket down.

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Finally I ran some DC twin cable to the coil connections and routed it up the side of the fridge to a barrel connector mounted on the panel I made in an earlier step.
I zip-tied the DC cable to the wiring loom at the base and then stuck it to the back panel using dabs of hot glue:

IMG_6260.jpeg


Next post: hot-wiring the thermostat...
 
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Stop press - Snubber circuit

I forgot to say that after I'd fitted the control relay I went back and fitted an RC snubber across the switch contacts.

Snubber... what's he on about now? Well, to quote Wikipedia:

A snubber is a device used to suppress ("snub") a phenomenon such as voltage transients in electrical systems, pressure transients in fluid systems (caused by for example water hammer) or excess force or rapid movement in mechanicalsystems.

The key factor here is that a fridge compressor is a highly inductive load. This means that without a snubber circuit it creates sparking across the switch when you turn it on or off - which erodes the contacts and can even make them stick together. It's not good for an SSR either.

Fortunately for relatively small loads like a fridge a simple off-the-shelf component like this connected across the switch contacts will do the trick:

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Screenshot 2021-10-02 at 11.45.53.png


I my case I just wired this across the relay contacts and wrapped it up in insulating tape.
 
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