TETB kegerator build

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Great read altogether though the rear of the display on top of the tower maybe open to corrosion through condensation in the tower unless the room and tower are equal temps.Might be worthwhile spreading a thin layer of hot melt glue across the contacts and edges to seal it off.Cracker....
Thanks! That’s a good point about possible condensation - I’ll stick a disk of high density foam under the display to ward that off 👍🏻
 
Gas connections

So todays mission was to sort out the CO2 input to the fridge and subsequent distribution to the kegs.
I thought this was going to be pretty straightforward but it's taken a lot longer than expected... I'm very pleased with the results though.

The first question was where to bring the gas in. I had a few different ideas for this but eventually decided the safest way was to take it in across the top and then down through the 'roof' of the fridge as that route seems so far to have been clear of tubes and wires (touch wood).

To keep things simple I decided to route the CO2 pipework in 1/4" tubing because it's more flexible and offers negligable resistance to the gas flow.

First step was to make a mounting for a 1/4" push fit bulkhead for the back panel and bring in the tubing. Virtually identical to the what I did for the electrical connections but on the other side:

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Next, distributing the gas to the kegs.
I bought a two-way manifold from BKT. Quite a bit more expensive that just using JG tee-pieces but it keeps everything neat and tidy. What's more I hadn't realised that each port has not only an isolation valve but a check valve too.

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It did take a while to decide how to mount it though. It's got a slightly unusual shape and the flange with the mounting holes is a bit too narrow to fix it firmly to a slightly flexible surface like the plastic liner of the fridge. Finally the 'input' was at the wrong end for several of the more obvious ways to orient it.

After a fair bit of head scratching I decided to fix it to a mounting plate that I could bolt though the 'roof' to one of the metal cross-pieces. First some careful measuring and probing with the small screwdriver; then I carefully removed two 'cores' of insulation using (what else but) an apple corer :-). Then M4 bolts through from the inside, add a nice big washer to spread the load and tighten up wit a box spanner before pushing the cores back in to insulate the hole:
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I chose the location so as to be easy to reach the 1/4" input tube using a 90º elbow and a stem reducer, then realised I didn't have a spare reducer. Therefore a bit of an ugly temporary fix while I get one delivered (yuk!)

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Finally I could hook everything up, load the kegs and pour myself a pint... felt like I needed one after that lot :-)

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The input on the manifold should be swappable with the other side.
Yes I thought so too but when I tried to unscrew it wouldn’t budge under reasonable torque so I assumed it might have thread sealant on it.

What is the lead strapped to each keg?
Temperature sensors - the little digital stainless steel ones (DS18B20). There are three in total: one per keg and a separate one to measure the air temp at the back of the fridge. This is so the controller can chill the beer down to the required level without the air temp getting too cold in the process.
 
Yes I thought so too but when I tried to unscrew it wouldn’t budge under reasonable torque so I assumed it might have thread sealant on it.
That's correct. I spoke to Johnny at BrewKegTap who confirmed and said I'd invalidste the warranty if I tried to remove the plug to swap it to the other end. It's a bit of a pain in the neck to say the least.

I can't remember if they're cast or milled. If cast, I guess they produce one very long manifold and then cut it to length but can't see why, if milled, they can't produce 'left'and 'right', but it obviously boils down to cost.
 
That's correct. I spoke to Johnny at BrewKegTap who confirmed and said I'd invalidste the warranty if I tried to remove the plug to swap it to the other end. It's a bit of a pain in the neck to say the least.

I can't remember if they're cast or milled. If cast, I guess they produce one very long manifold and then cut it to length but can't see why, if milled, they can't produce 'left'and 'right', but it obviously boils down to cost.

The manifolds are tapped each end and the plug and input are fitted with an adhesive / sealant. They will unscrew if you hold the body firmly in a vice and apply a lot of torque with a ring spanner or socket. I swapped mine and then resealed them with some blue stuff I got from Toolstation (can't remember the name, but it is a plumbing sealant). Everything went back together fine and I have not had any leaks.
 
The manifolds are tapped each end and the plug and input are fitted with an adhesive / sealant. They will unscrew if you hold the body firmly in a vice and apply a lot of torque with a ring spanner or socket. I swapped mine and then resealed them with some blue stuff I got from Toolstation (can't remember the name, but it is a plumbing sealant). Everything went back together fine and I have not had any leaks.
Yes for sure. Often threads are sealed with an adhesive that is designed to weaken when heated, so you can bake the part in the oven for a bit or (briefly) apply a blowtorch. Definitely inadvisable here though because of the seals in the taps.
Manufacturers’ warranties are of virtually no use anyway - generally more effective to inform the retailer you’re returning the item under the Sale of Goods Act as being of un-merchantable quality / not as described etc.
 
Corny Scales

Next step in this seemingly-unending build is to fit load cells in the bottom of the fridge in order to measure how much beer is left in each keg.

Spent a while this afternoon cutting and shaping a plywood base for the floor and the two weighing pads. These all have to be quite accurately made as the kegs are quite a tight fit and obviously each keg needs to rest on just one of the pads - which became made more tricky when I realised that (a) the width of the interior tapers slightly towards the back; (b) there's a 5mm radius on the internal corners; and (c) the door mouldings intrude a bit at the corners.

However after a bit of work with the plane and sandpaper the base and pads are looking about right (1mm clearance all round)

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Next job is to fit the load cells...
 
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Excellent thread! I got the same fridge off Gumtree for fermenting but have decided to build a kegerator with it after I looked up the dims for corny kegs. I'll definitely be referring to this during my build (won't be going all in like yourself unfortunately) but was wondering if you know the locations of the coolant lines? I'm guessing they're just on the back? I'll be keeping my gas internal and want to fit some sort of strapping to hold the gas as I'm a bit worried about the dual output regulator tipping the tank over.
Did you give any thought to swapping out the plastic lid for a nice timber top?
 
excellent thread! I love a bit of brew engineering thumb.
what's your background?
Heh - I've got a couple of engineering degrees and I qualified as a Chartered electronic engineer - but I turned to the dark side (management & corporate finance) after about 10yrs.
I've always kept my hand in with any geeky engineering stuff in my spare time - embedded controllers, software engineering, recreational maths etc. Variety is the spice of life eh?
 
Excellent thread! I got the same fridge off Gumtree for fermenting but have decided to build a kegerator with it after I looked up the dims for corny kegs. I'll definitely be referring to this during my build (won't be going all in like yourself unfortunately) but was wondering if you know the locations of the coolant lines? I'm guessing they're just on the back? I'll be keeping my gas internal and want to fit some sort of strapping to hold the gas as I'm a bit worried about the dual output regulator tipping the tank over.
Did you give any thought to swapping out the plastic lid for a nice timber top?
Great stuff - glad the thread is proving useful.

I think the coolant lines are almost certainly in the sides and the back - which is why I went in through the top.
The absence of a radiator on the back makes me think the condenser (hot side) pipes are probably in the back, just below the surface; and the evaporator (cold side) ones might be in the sides, beneath the insulation.

I didn't see any evidence of any coolant lines in the top during any of my work, and I wasn't really expecting to find any there. Even so I was quite careful and prodded around carefully with a screwdriver as I was making the holes to make sure there were no unexpected surprises lurking buried in the insulation.

Incidentally after nearly 12 months continuous operation neither of my fridges have missed a beat (touch wood), despite regularly taking one of them down to around 0ºc; so they see to be a pretty reliable platform.

As for the plastic top, the kegerator one lives in the garage so aesthetics aren't a high priority - and I quite like the wipe-clean aspect of it for when the odd splash misses the drip tray.
 
Adding Heaters

When I designed these fridges back in 2021 I only really thought about cooling - and to be honest I managed to make that complicated enough as it was.
But after I did my first proper 'fast' lager fermentation this April it became clear that some sort of controlled heating capability would be really handy.

First step was to decide what type of heaters to use. I already had one of these short 'tubular' heaters but I've never found it terribly satisfactory as a brew heater.

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On the plus side it gives a good gentle all-round warm air effect, but on the other hand warm air can take a very long time to appreciably shift the temperature of a 25L fermentation. In any case it wasn't a very good fit to the dimensions of the fridge.

A heater in direct contact with the FV seemed like a better idea so I got a couple of these 30W 'belt' type heaters from MaltMiller:
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The next question was how to control them. For speed and simplicity I'd built the fridge controller to only have 12V outputs; but to manage these I needed to add mains inputs and outputs.
Fortunately I'd used a decent size enclosure so there was room for the necessary connectors:
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As the heaters would be turning on and off very frequently mechanical relays were out of the question, but I didn't have room for the 'hockey puck' type solid state relays that I use to control my Burco.
Fortunately the current required by the heater belts is very low (much less than an amp) so I could use very compact low power pcb mounted SSRs (actually these ones supplied by Digikey). I mounted these on a small daughter board so as to keep the high voltage stuff well away from the rest of the electronics. I also took a number of safety steps including removing alternate tracks from the PCB, so don't try this at home unless you know what you're doing folks.

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Next instalment: it all seemed to be going so smoothly...
 
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