I've been monitoring my fermentation chamber for the last hour. Latest cycle was 5 minutes on and 22 mins off. Is this good, or do I have a serious problem? I know it depends on the ambient temperature, which was about 82-84 degrees F. during monitoring. I'm using a Johnson analog controller. Does the differential work both ways? In other words, I know that setting the differential higher will cause the controller to "wait" until it kicks on the power. But does that work the other way? Does the differential adjustment cause to controller to keep power to the compressor to cool down past what your set-point should be?
Acceptable cycling times for a mini-fridge fermentation chamber
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Bubba_Mustafa
Well-Known Member
Its the off time that matters. You want the pressure to be equal (or close to it) on both sides of the compressor. Other wise you are putting a lot of stress starting up the compressor.
The differential is the dead band. How big a swing it does before kicking on again. So no, it should just offer the single ended dead band.
I'm finishing up my own temp controler and using both temp and time for the off period
The differential is the dead band. How big a swing it does before kicking on again. So no, it should just offer the single ended dead band.
I'm finishing up my own temp controler and using both temp and time for the off period
So, if I adjust the sliding differential switch (it has 4 marks, starting at "Min" and ending at "Max") more towards maximum, that will make the compressor not cycle as much and give me a larger temperature swing? And by doing that, it won't have to cool down past the set point, just run enough to counter the swing from the adjustment?
Bubba_Mustafa
Well-Known Member
You will probably have to test it. The dead band can be above the set or below the set temp. (I'm thinking above)
So lets say its above and its a 5^ dead band.
You want to ferm @ 65.
If you set it to 65, it will cool down to 65 then be off until the temp reaches 70, then turn on and cool to 65.
So you might want to set the set temp 62, then the high will be 67 and the low 63 (basically splitting the swing range) You will also need to decide if too warm or too cold is the prob, and adjust accordingly.
So lets say its above and its a 5^ dead band.
You want to ferm @ 65.
If you set it to 65, it will cool down to 65 then be off until the temp reaches 70, then turn on and cool to 65.
So you might want to set the set temp 62, then the high will be 67 and the low 63 (basically splitting the swing range) You will also need to decide if too warm or too cold is the prob, and adjust accordingly.
I'm using a Johnson Analog, and I think the differential is above, and at the minimum setting it is supposed to be 5 degrees. I moved it up last night a little and got the cycle time to 29 minutes off, and 5-6 minutes on. I guess I can live with that. Thanks for your help.
strat_thru_marshall
Well-Known Member
where is your temperature probe located? It's placement could affect the cycle.
It's mounted on the top of the chamber, on the far end from the refrigerator.
maida7
Well-Known Member
It was my understanding that the dead zone on those controllers swing both ways. Perhaps you can call the manufacture to check it out.
I recommend taping the probe to the fermenter. This way you control the temp of the ferment and not the air. You can insulate the probe against the fermenter with some styrofoam or bubble wrap. This way it won't cycle nearly as much.
I recommend taping the probe to the fermenter. This way you control the temp of the ferment and not the air. You can insulate the probe against the fermenter with some styrofoam or bubble wrap. This way it won't cycle nearly as much.
strat_thru_marshall
Well-Known Member
This.
You want to use the fridge to control the temp of the fermenting wort, not the air in the chamber. My ferm chamber is in my garage (summer in Oklahoma = hot in garage) and it only cycles on for about 3 minutes ever two hours or so. I tape the temp probe to the side of the carboy and insulate it with either foam or a folded up dish towel.
That makes sense, since it would take longer for the fermenter to change temperature due to thermal mass. But doing that would necessitate setting the differential at the very minimum wouldn't it? I don't think you want even a 5 degree change in the wort.
maida7
Well-Known Member
I have a digital controller so that may make it different. But I set my differential to 1 degree and tape the probe to the fermenter. The ferment temp is always exactly where I want +/- 1 degree. works perfectly!
My controller also has a heating side so I can nail my temps in all 4 seasons.
strat_thru_marshall
Well-Known Member
I set my diff at 1 degree on my digital controller, keeps my wort +/- 1 degree of target pretty much all the time. I can live with that temp swing, +/- 5 would be a little much.
Yes, I'm thinking that the digital controllers have the ability for tighter differentials. I believe my minimum differentiaal is 5 degrees. So, I don't think that taping the probe to the fermenter would work too good in my situation. I need a digital controller.
maida7
Well-Known Member
Yes, I'm thinking that the digital controllers have the ability for tighter differentials. I believe my minimum differentiaal is 5 degrees. So, I don't think that taping the probe to the fermenter would work too good in my situation. I need a digital controller.
If you make the leap, get the ranco with the dual outputs. Then you can control heat and cooling simultaneously. It's the ultimate
samc
Well-Known Member
I think the Johnson analog is 3 degrees diff. When I used mine (pre digi days) I bungee corded it to the keg with foam on top. Worked very well. Finally switched to Love controller and I keep it within 1 degree now.
Is that the ETC-111000?
Just looked it up, it's 3 1/2 degrees diff. Still seems like a pretty big shift for fermenting.
maida7
Well-Known Member
No that is the single model. The dual output is the 211000 and it costs more.
here is a where I bought mine
These come un-wired so you will need some electrical skills to make it work. Morebeer sells a fully wired version but you pay extra for that. If you handy you can wire your own and save a few bucks. Basically I added an electrical box and outlet to the bottom of the controller and wired the outlet and a cord with plug. There is a 1/2" knockout on the controller that makes adding the box a snap.
mine looks kinda like the one morebeer sells.
Doesn't the 111000 have the capability to switch between heating and cooling? I know the 211000 does it automatically, but I really wouldn't need to do that. I would only be cooling periodically and heating periodically. I wouldn't need to do both simultaneously.
maida7
Well-Known Member
yes it does so if you pay careful attention you could manage it with the single output model.
The advantage of the dual is that you can set the cool side to the peak of your ferment and the heat side to a temp you want to stay above. Then walk away and not worry. Like if you pitched at 64 and want the temp to rise naturally to 68. Set the heat to 64 and the cool to 68. Like I said, it's the ultimate.
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