Dual Stage Ranco ETC question

Hello all,

I just got a line on a free chest freezer, which I plan on using for a fermentation fridge. I am trying to decide if i should buy a single stage Ranco ETC, or a dual stage.

My fridge is going to be in my basement, which is hot in the summer, and darn cold in the winter. Im really not sure how the dual stage works, which may be the source of my questions. Can I buy a single stage ETC, and just plug it into the fridge in the summer to keep it cool, and then just turn the fridge off and plug the ETC to a light bulb in the winter to keep it warm? Is there any problem with doing this?

Wouldnt a dual stage ETC constantly be fighting between the heating and cooling elements to maintain the proper temperature?

Thanks!

I just mounted my Ranco on my freezer this weekend.

I used the Ranco ETC 111000. It does both heat and cold.

Do a search on "ranco" and you'll find my thread as well as others.

The dual stage allows heating and cooling to switch back and forth automatically which is needed when your ambient swings both above and below your desired temp frequently. Say you want 55F and ambient goes between 50 and 60 from day to night. You'd set it to 55 where it would kick the freezer on at 57 and the heating element would kick on at 54. These points are determined by the controller's swing (how far off of setpoint it will go before tripping.

A single stage, SPDT controller can work in a similar way but you can only do one stage per wiring configuration. You're either plugged in for heat or cooling. You could try both at the same time but then there's no OFF... it's either heating or cooling which would be wasteful if the two are fast enough.

My cheap solution to this problem is to use a very low wattage light bulb. You can have it on all the time or if you have a SPDT controller, have it come on when the cooling circuit is off. This works well if your desired setpoint is only a few degrees higher than ambient. Say your basement is usually about 65 and you want to ferment an ale at 69. Set your cooling to 69 and put a 5-10 watt bulb in there. The bulb will slowly eek the temp up. When it hits 69, the cooling circuit kicks in. It sounds like they'll be fighting back and forth all day but I doubt the compressor would kick on more than twice a day because the heating wattage is so low.

So, Bobby? If I remember correctly I'm supposed to set the freezer on its highest setting and let the TC take charge, also TC , of the compressor, right?

I hope so since that's where's it's been for a couple of days.

Even if you didn't set the freezer as cold as it would go, it's highest possible temp is likely 30F anyway. The TC is under full control no matter what. This is more important in refrigerators when you really want the temp to be 33 and the internal temp is set to 39 for example.

Just verifying the TC takes charge..takes control..