STC-1000 Delay Confusion

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Jay-Brew

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I am kind of confused about how the delay works on STC-1000. I know it delays cycling the freezer/fridge. When I plug it in it does its delay, which I expect. Once it gets down to the set temperature then my freezer stops and then the temperature slowly is rising back up one degree (which is the temperature differential I set) and the freezer kicks on without flashing and having a delay. It probably took longer than the set delay time for the temperature to rise back up to when it needed to start cooling again.

For some reason I expected that whenever it needs to begin cooling it will start the delay at that point, however, does the delay begin as soon as the cooling cut out? This is what I suspect, but not quite sure. Hope that makes sense.
 
The delay timer begins counting down when the cool set temperature is reached and the cool relay opens, removing voltage from the compressor.
 
Mine flashes the led for "cool" during the delay period. It will be a solid led when the relay is on.
 
I am kind of confused about how the delay works on STC-1000. I know it delays cycling the freezer/fridge. When I plug it in it does its delay, which I expect. Once it gets down to the set temperature then my freezer stops and then the temperature slowly is rising back up one degree (which is the temperature differential I set) and the freezer kicks on without flashing and having a delay. It probably took longer than the set delay time for the temperature to rise back up to when it needed to start cooling again.

For some reason I expected that whenever it needs to begin cooling it will start the delay at that point, however, does the delay begin as soon as the cooling cut out? This is what I suspect, but not quite sure. Hope that makes sense.

The delay timer starts a soon the compressor turns off.
If your delay is set to 3 minutes and the temp rise exceeds the set point after 2 minutes the compressor won't start for an additional minute.
 
[...]does the delay begin as soon as the cooling cut out?[...]

Yes, exactly right. The whole purpose of the anti-short-cycle delay is to prevent the compressor from turning on too quickly after shutting off. Hence, as soon as the compressor stops, "the clock is running" on the ASD, and if that timer expires before the temperature reaches Setpoint + Differential, the compressor will be free to start without delay...

Cheers!
 
Thanks everyone. That is what I thought, but at first figured once a cooling cycle needed to start it would always do the delay and didn't think the delay actually started once the compressor cut out the last time which could be a long time ago thereby not having an obvious delay once cooling was required again. Anyway, glad to know it is working fine.

Finished my STC 1000 build yesterday and have been testing it and it seems to be working well so far. Pretty happy to be able to start controlling fermentation temperatures more accurately now and hopefully come up with better beer.
 
I'm having a problem with my freezer and stc controller when it hits the set temp it keeps going down like 2 degrees colder. I only have cool hooked up at the moment no heat. Is there a way to prevent this?


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I'm having a problem with my freezer and stc controller when it hits the set temp it keeps going down like 2 degrees colder. I only have cool hooked up at the moment no heat. Is there a way to prevent this?
Where is the probe being placed? Is the compressor turning off when the set temperature is reached?
 
Where is the probe being placed? Is the compressor turning off when the set temperature is reached?


The compressor is turning off. The probe is just placed in the freezer. Should it be attached to the fermenter somehow?


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The compressor is turning off. The probe is just placed in the freezer. Should it be attached to the fermenter somehow?


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Yes, the air will cool faster than the liquid. You want to at least tape it to the side of the fermenter though a thermowell bung is your best bet.
 
I'm having a problem with my freezer and stc controller when it hits the set temp it keeps going down like 2 degrees colder. I only have cool hooked up at the moment no heat. Is there a way to prevent this?


Sent from my iPhone using Home Brew

I just built my STC 1000 last weekend and have been seeing how it works for the last few days. Think mine is doing what yours is, but I don't see it as being an issue to worry about. I have a carboy filled about 3/4 full in a 7 cubic foot freezer with the sensor under bubble wrap taped to the side of the carboy.

Temperature is set to 19.5 with 0.5 differential and 10 minute delay. My basement is cool right now so only the heater is working. Once it drops to 19 the heater will kick in for several minutes until it reaches 19.5 and then stop. However, then the temperature keeps rising to about 19.7 at which point it very slowly drops until getting back to 19.

Anyway, think it's working fine, at least in my view.
 
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