Ranco 2 stage controller (chest freezer + ceramic space heater) cycling too often??

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julian81

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Hey guys,

Just got my fermentation chamber mostly complete today. Drilled a hole in the side (no issues, straight through the foam/insulation) and re-spliced wires for both my stir plate and ceramic space heater (http://www.amazon.com/dp/B000TKDQ5C/?tag=skimlinks_replacement-20). I'm using a Ranco 2 stage wired controller from MoreBeer (awesome product).

I have everything plugged in and powered, and to test I set did the following

68/2 for cooling and 68/2 for heating. My idea here is that it could swing between 66 and 70 but remain at 68 for the most part for ale fermentation.

The only issue is it was switching both heating/cooling off/on quite often. Every few minutes (maybe 5-10minutes). It would heat up really quickly and then cool down quickly and just keep cycling back and forth. I will note that there is nothing in there at the moment. No carboys, nothing to ferment right now, and the probe is just dangling in the corner where it's slotted through the hole.

Is this normal? I'm feeling like it shouldn't be cycling the compressor/heat as much. I've unplugged it all for now, but is this normal and OK? I don't want to damage my equipment (compressor mostly). If not, what am I doing wrong?

Thanks guys!
 
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devilishprune

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Maybe I don't understand, but I don't understand having both a heater and the freezer on at the same time. I don't think that it should cycle that much. I think that my keezer cycles like 15 mins/hour and that's too much. BUT, it's about 43 degrees compared to your 68 so...

If your house is greater than 68 degrees then I would use only the cooling side, and vice versa for the heating side. That might help you out. Also, you're probably going to want a lower temp than that for fermenting, since fermentation is exothermic and will be warmer than the environment in your freezer.
 

Catt22

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I think you have the set points too close together. Try 69 w/+2 deg differential for cooling and 67 w/-2 deg differential for heating. This should kick on the compressor at 71 and off at 69. The heating element won't turn on unless the temp drops to 67 and it will turn off at 69.

What you are trying to avoid is cooling so much that you reach the turn on set point for the heater and the same in the other direction where you are heating to the point that it turns the compressor on to begin cooling. If 69 & 67 are still too tight, you can try widening the dead zone even more using 70 & 66, 71 & 65 and so on. The fermenter should settle near the average of the cooling and heating set points and remain quite stable once everything is give the time to stabilize which may take 24 hours or even longer. When changing settings be sure to allow plenty of time for the system to stabilize. Widening the dead zone is necessary when the cooling/heating equipment overshoots the target set points excessively. How and where you mount the controller probe can affect the overshoots.
 

Junkster

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You may want to try putting in a deadband in the area of your desired temperature. If you want 68, then set your cooling to 69/2 and your heating to 67/2. The temperatures can swing very quickly in an empty chamber - try adding some thermal mass like jugs of water to simulate real world conditions.
 
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julian81

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Thank you guys. I appreciate all the feedback. I definitely think I need to widen the deadzone as a few of you have mentioned.

Also, I dig devilishprune's comment about fermenting being exothermic. I think i need to tone each of the setting down to account for that. Good call man!

I'll fill a better bottle with water and tape the probe to it and put some bubble wrap over it to simulate some thermal mass. I was thinking that might be it, so thanks for the confirmation.

I'll report back with results.

One last question? If you guys aren't fermenting, I'm assuming you just keep everything unplugged/powered off? No need to keep things running for no reason, right?
 

Catt22

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TOne last question? If you guys aren't fermenting, I'm assuming you just keep everything unplugged/powered off? No need to keep things running for no reason, right?
That's correct, but you can also use it for conditioning, lagering or storing beer. Obviously no need to run it if it is empty.
 
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julian81

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That's correct, but you can also use it for conditioning, lagering or storing beer. Obviously no need to run it if it is empty.
Yeah, that makes sense. Thanks.

So, I filled a 6gal better bottle with about 5 gallons of warm tap water (I think it was around 70) and taped the Ranco probe to the carboy about half way down with medical grade adhesive tape. Then I put a layer of small bubble wrap over it and taped that down at all corners so it's sealed. I then set the Ranco per MoreBeer's video recommendation.

68 / 2 for cooling
64 / 2 for heating

This leaves a 68-64 "dead zone".

So far the freezer kicks on as soon as it hits 70 and cools till it reaches 68, then shuts off. I saw it go down to 66 and then start to go back up. So no heating is being used currently and it seems as though the cooling is operating within a 4 degree range (getting to low of 66 and kicking on again at 70).

Those 4 degrees seem to be taking MUCH longer before the freezer compressor kicks on again so the added thermal mass DEFINITELY makes a difference.

I will probably tweak this as I go, but I definitely think the compressor kicking on every 20-30mins is better than every 5 minutes. Does that sound right about right?

And yeah, this will be turned off when not in use.
 

triangulum33

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Very good info. I'm building the same setup except I'm using a reptile heater.



Please continue to report your findings!

FWIW, an engineer at Dwyer said that their TS-6 probe for Love controllers can be submerged in water. That could help prevent cycling too.
 
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julian81

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I thought about getting a Love controller and actually had an order in with Dwyer, but decided to cancel it when I found the Ranco. It's pre-wired, simple easy interface and provides the same functionality right out of the box. I'm not very good with wiring and given the chance of screwing something up, and having to build a box to house it in, the Ranco was clearly the better choice. I will report back more findings when I start timing how long it takes to cycle with this new setup....as well as when I brew something new to put in there, which will be soon :)

EDIT: also I thought about getting a reptile heater, but I read a lot of threads here, I decided to go with the ceramic heater since it PUSHES the air around, circulating it within the confined space, which I feel more accurately distributes the heat. I know a lot of people use light bulbs, or ceramic bulbs, or ceramic space heaters so they probably all WORK, it's more preference than anything I guess.
 

ryan0914

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I just got mine up and going last week. I have a old heating pad, from back when the didn't have the auto off. and a small desk oscillating to move the air. i have it plugged into a plug spliced before the controller, and plugged into a timer. Right now i have about 8 gal of wart at about 37 waiting for their yeast to be ready.
While I'm here I was wondering if their was a way that it can be wired into the controller so it will turn on whenever either of the circuits are turned on. I'm thinking that it wont be able to, because if one comes on it'll complete the circuit through the fan to the other line.
Is this correct or does anyone know of a way?
 

jafo28

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Very good info. I'm building the same setup except I'm using a reptile heater.



Please continue to report your findings!

FWIW, an engineer at Dwyer said that their TS-6 probe for Love controllers can be submerged in water. That could help prevent cycling too.
These things work great. I've been using the same thing for heating my chamber, and have had zero problems. I am using a johnson controller though.
 
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julian81

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So it looks like it's staying constant at 69F in the freezer. The ambient temp in my garage where the freezer is, is 54F. It' s been at 69F for the past almost hour and hasn't jumped up. If it does, it will turn on the freezer for a few minutes until it hits 68F and then shut off at which point it will probably drop a degree or 2 more to stabilize (as stated, around 66F) and then take several hours before it turns back on, if at all given the ambient temp.

So as it stands, it looks like I do not require the heating, but may in the future if the ambient temp of my garage drops significantly.

This is working perfectly :) I'll tweak it as I see fit when I've got fermenting wort in there.
 

triangulum33

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These things work great. I've been using the same thing for heating my chamber, and have had zero problems. I am using a johnson controller though.
One concern I've had is how to know if and when the thing burns out. I dont want to go out to the garage after a 25* night and find it burned out and all my yeast dead.
Maybe just try to change it out periodically?
 
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julian81

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One concern I've had is how to know if and when the thing burns out. I dont want to go out to the garage after a 25* night and find it burned out and all my yeast dead.
Maybe just try to change it out periodically?
You could setup a remote thermometer sensor with network capabilities and configure it to email/sms you if it dips below a certain defined threshold. These devices are pretty expensive though, and you'll need access to a wired ethernet network nearby (I personally don't have any network capabilities, other than wireless, in my garage). I just googled for a few products and found the following:

http://www.hw-group.com/products/poseidon/poseidon_3265_en.html
http://www.itwatchdogs.com/product-detail-microgoose-9.html

And here's a broader list of various SNMP enabled devices.

http://www.snmplink.org/snmpappliance/hardware/
 
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