One stage vs two stage temp controller? Huh?

[krisagon]

1) Can anyone explain (in noobish terms) what the difference is between a one stage and a two stage temp controller?

2) My basic plan is to hook a heating pad type thing to my carboy and have it shut off when it reaches a certain set temp. Which one would be better for me?

I searched on this topic, and got results that are way over my head.
Thanks!

 

[passedpawn]

You only need a single-stage controller if you are only heating. Same if you are only cooling.

One stage turns something on, when the temp crosses a threshold. Two stage turns Thing 1 on when temp is above the threshold, or Thing 2 when the temp goes below the threshold.

I.e., here in florida now it gets up to 80 during the day and below 60 at night. If I want my fermentation chamber to stay at 65, I need to have both cooling and heating. So, a 2-stage is perfect: Both my freezer power and a heater are connected to it. It's set to 65 (that's the threshold).

One thing to point out. A poorly designed 2-stage controller might switch a lot at that threshold. You can imagine the temp getting to 65.001 F, the freezer turns on, then 1 minute later it's at 64.999 and the freezer turns off and the heater turns on, and this cycle repeats for ever. My freezer would die pretty fast. That is where hysteresis comes into play. Hysteresis is the range (i.e., 3 degrees, from 62-65) where nothing happens. Essentially there are 2 thresholds, 62 and 65. Heater turns on when below 62, freezer turns on when above 65.

I should note that I only have a single stage device now. I need a 2-stage.

 

[krisagon]

Great thanks man!
This is exactly the kind of answer I was going for.

 

[Mayotruck]

I should note that I only have a single stage device now. I need a 2-stage.

Couldn't you just set the single stage to 65 on your your freezer if it drops below the set theshold (example: 3 degrees)freezer will kick on and if it goes above it should auto shut off?

Or am i missing something here?

 

[AnOldUR]

Or am i missing something here?

That along with wanting the tempature control to chill above a set temperature, you may want heat to go on if the temperature drops too low.
For example a fridge in a garage that may freeze your beer on a cold night.

 

[Mayotruck]

ah ok cheers never thought about that! My freezer is inside so i never thought about it dropping to a temperature that's to cold.

 

[gr84x4]

I am interested in a dual stage. What model should I look at and where is the best place to look? I think I want it all wired up. I do not think I want to DIY.

 

[cyclogenesis]

hey folks. dragging up an old thread to ask a question.. So I, thanks to the HD sale, have my new freezer for fermentation.. (woop!) I am debating whether to go single or dual stage.. the only real reason I can think of to go dual is diactyl resting.. My unit sits in my basement with a summer ambient of ~60F (ie ales with no control.. ) Having a larger in the ferm chamber with no cooling should I be able to get it to rest temps with no active heating? ie from remaining yeast activity alone?

Thanks!

 

[AmandaK]

I have both a single and dual stage. I use the dual for Belgians (since everything is inside). But, I could see using a dual for diacetyl resting, that would make a lot of sense.

Here's what I use, prewired: Ranco Dual Stage - Prewired

 

[worxman02]

I bought the Control Products Dual Stage High Voltage (120v) temp controller from amazon and I love it. It was a bit of a pain to wire up but most of that was because I didn't buy a large enough junction box to allow for the weird wiring. I've only used it in single stage mode so far as I just got a fridge for fermentation. I did use it when I brewed over the winter with my brew belt and it worked great. Its really easy to setup and I like that it has non-volatile memory so it remembers all your settings even when there is no power to it. I also think it looks pretty cool. Im going to use it for the first time in dual stage mode after I brew my batch of chocolate oatmeal stout tomorrow. I'm sure it will work great. I like having a digital one as opposed to a analog controller as all the settings are very obvious and you have lots of options for a pretty low price point. I recommend you buy it if your looking for a affordable dual stage controller.

 

[passedpawn]

I bought the Control Products Dual Stage High Voltage (120v) temp controller from amazon and I love it.

I like that controller. Must get one.

 

[cyclogenesis]

Thanks folks!

 

[billl]

Just to state the obvious, but if you are only going to do either heating OR cooling at a given time, you can just plug in the device you need. eg use the fridge on the control for fermentation and then the heater for a couple day rest.

The 2 stage is a life saver when you have temp swings though - eg hot in the day and cool at night. Just set it and forget about it for a couple weeks.

 

[LandoLincoln]

Just to state the obvious, but if you are only going to do either heating OR cooling at a given time, you can just plug in the device you need. eg use the fridge on the control for fermentation and then the heater for a couple day rest.

The 2 stage is a life saver when you have temp swings though - eg hot in the day and cool at night. Just set it and forget about it for a couple weeks.

Some single-stage controllers aren't that easy to switch from heating mode to cooling mode. For my analog Johnson controller, you have to remove the metal cover and flip a dip switch or two, I believe.

 

[passedpawn]

Some single-stage controllers aren't that easy to switch from heating mode to cooling mode. For my analog Johnson controller, you have to remove the metal cover and flip a dip switch or two, I believe.

Or rig up a gizmo like this:

https://www.homebrewtalk.com/f51/chiller-heater-johnson-controller-w-pic-159995/

 

[NHAFER]

Looks great!

 

[Majd]

Hi guys, I know it is an old thread, but I have this question about digital temperature controllers. If I want to design my propane burners to turn on and off for the HLT at my brewing stand to control temperature at a specific range. Would that require a two stage digital controller or can I get by with a one stage? Any advise about how to build such a control?

Thanks