Temperature controllers for kegerator

[Wiggum]

I have a Marvel kegerator. It has one of those dial type control units for the Temperature. It can be a pain to pin point the temps with different beers. It doesn't have a Temp setting just a dial with 1-9 or something on it.

Would one of the temperature control units digital or analog that go between the power of the unit and the probe maybe can hang down the center of the tower maybe? I hate to drill into the main part of the unit. I also saw a different controller that can be put into water so you can get liquid temps.

Or just grin and bear it with the dial and leave well enough alone?

 

[day_trippr]

Nobody ever got much fun out of leaving well enough alone

I only have first-hand experience with the Ranco ET series controllers, but they have a really long probe wire (8') which could be snaked down the tower column. You'd have to check the specs on the alternatives (Johnson, STC-1000, eBay aquarium controller, etc) on that, but otherwise any one of those would work fine and be an improvement over that mysterious knob.

Not sure how you'd get into the tower, but the probe is 1/4" diameter, so I suppose a discretely located hole just above the flange towards the rear would do the trick.

Cheers!

 

[billl]

The probe wires on most controllers are pretty thin and you can just smash them in the door.

You can get REALLY close to "liquid" temps with any type of probe by taping it to the side of the keg and then taping some cloth or bubble wrap over it.

 

[Wiggum]

Any potential problems with having the unit turn on and off via the outlet instead of it's automatic temp control?

I didn't even think about putting it through the door. I was thinking of a small hole in the tower and feeding it down into the kegerator.

 

[porcupine73]

If it doesn't have any fancy electronics to control defrost and stuff like that switching via the outlet doesn't cause any problems. For that application the Johnson Controls would work well, though the STC-1000 might be more economical. You definitely want something with the compressor protection timer or anti-short cycle timer.

 

[zentropy]

I just started using an A419 (Johnson) controller. I was curious if anyone has used this type of controller with a dormsize kegerator (mine is similar to the typical sanyo model, which has the chilling plate at the back of the fridge).

I left all the default factory settings the same except for the differential, which was set to 5. I bumped it down to 3, thinking I would get a smaller temp swing. I put the temperature sensor on the side of the fridge interior, midway from the bottom. It is NOT in a thermowell.

My initial experience with a fermentation temp set to 67F shows that this fridge is very often at 63 or 64F. Not so good. I was using the analog dial Johnson controller before with the temp sensor in the same location with better results.

Has anyone used different settings (e.g. cut-out vs. cut-in, etc.)?

 

[porcupine73]

If you have it set at 67 with a diff of 3 and whichever way the cut in/out is set, i.e. if it turns on at 67 and off at 64 then seeing a temp of 63 is not surprising. I think the only thing you can do there is reduce your differential (but making sure to keep the anti-short cycle time set high enough, like at least three minutes). The Johnson is simply an on/off control. So when it cuts out, the refrigerator turns off, but still has some cooling capacity as the liquid refrigerant enters the evaporator. So the temperature might continue to dip another degree or two after the cuts out. The Johnson can do nothing about this being just on/off control. This is where a PID controller could be tuned to have less overshoot.

 

[Wiggum]

What would be the best unit to look at? The Johnson?