Possible fan for kegerator

[Mac_rancher]

I'm curious to hear some opinions regarding my diy kegerator. I converted an older sunbeam beverage fridge with a window door to a kegerator with tower. The cooling coils sit just behind the back wall and cool through the wall. I find that I'm getting quite a bit a moisture build up on the wall with humidity somewhere in the 70% range when it is not cooling. I live in a very dry climate. I've check the door seal with a dollar bill and it seems to have a great seal. With the moisture build up I think it is inhibiting my cooling ability and fridge after about 24hrs can't cool below 33 degrees (floor reading with bluetooth thermometer sensor). Once it reaches that temp the compressor stays on and the temp flatlines. I have a keg of water I'm testing out, and I can get it down to about 43 degrees at it's lowest.

To try to help solved this I've installed an eva-dry dehumidifier but it hasn't seemed to help. I'm thinking I might install a fan on the ceiling to keep air moving to help prevent condensation on the back wall. This is an option I'm thinking about using. I would mount it to the top of the fridge and aim the exhaust toward the back. I could wire it directly to the hot wire for the light and ground to the thermostat. I'm thinking it would move enough air and be low profile to prevent getting in the way. Any thoughts? Would this be a good fan option or should I do a muffin fan instead? Any other ideas other than ice on the back wall for why I can't cool enough?

 

[Erik the Anglophile]

I just use a dual fan for computer a computer. Works great, you just need enough to get some air circulation in there.
And why would you want your beer so extremely cold?

 

[Mac_rancher]

I just use a dual fan for computer a computer. Works great, you just need enough to get some air circulation in there.
And why would you want your beer so extremely cold?

I was debating about trying two as well. I have an analog thermostat, so I'm not sure what temp it thinks it is running at. I know the bottom will hit 32, but the top I'm sure is in the 50's. Because of this my keg equalizes around 43-44. I've heard optimal temp for your beer is 38-40, so I'm trying to hit that mark.

 

[AlexKay]

If you’ve got such serious temperature stratification, a fan will definitely help. Don’t get the one you linked; for safety, you want a 12 V (or less) fan. Computer fans can certainly work, plus they’re easy to hook up, and you can add speed control trivially. I bought this one which is on the pricey side but it’s waterproof.

 

[Mac_rancher]

I started thinking about it last night and was realizing what you said. Safer to mess with 12v than 120v. Thanks for the advice on that one. How do you recommend I orient the fans? I figured I'd mount them perpendicular to the top, with the fans blowing toward the back wall of the kegerator.

 

[Erik the Anglophile]

I have mine in the top, tilted downwards at a ~45° angle.
I think the fact there is a fan is more important than the minutia of how it is placed.

 

[AlexKay]

Agree that presence is probably more important the placement. In terms of placement, though, my vote would be spaced off the top (so that air can freely move into the fan), blowing warm air down.

 

[Mac_rancher]

Makes sense, thank you. I am wondering more now about the cooling capability of the unit. It’s a beverage fridge, about the size of a typical 150 can beverage fridge (4.6 cu ft). That’s 1,800 oz of liquid it would cool. It can only get 640oz of liquid down to 44-45 before it just runs forever. Accidentally ran it for 6hrs straight last night without realizing it wouldn’t reach temp and shut off.
I’m wondering if it might be low on refrigerant, but not low enough to trigger the compressor to shut off. Should the return pipe to the compressor be very cold? Mine is cool as it comes out of the fridge body, but it cold by any means.

 

[Mac_rancher]

Problem solved…switching to the tried and true Danby 4.4. Found it at a pawn shop locally. Going to test it today and make sure it’s good to go before I try a conversion…learned my lesson on that one.