Ranco Dual Stage Settings

[JR McKnight]

I just picked up one of these things and im not sure how I should set the set points and differentials. Does anybody know if there is an ideal setting for these?

[Mylo]

Well, like Whitey says.... it depends. The dual stage has obviously a heat setpoint and threshold, and a cool setpoint and threshold. You goal is to minimizing the deadband, prevent bouncing, and not kill your compressor. It's quite a balancing act. Assuming that you just have a fermwrap or reptile pad, carboy, and fridge/freezer of some style - here is what I would do - assuming I want to ferment my beer at 68.

1) Set your cool setpoint to 67
2) Set your cool diff to 2
3) Set your heat setpoint to 66
4) Set the heat diff to 1

So the heat will come on if it drops to 65 - and it will take it up to 66. 66 - 67 is the deadband - nothing is on. The beer will continue to rise (naturally, not with the heater) until it hits 69 - then the compressor will kick on and take it back to 67. You can use this formula for any temp - I just happened to pick 68 for illustrative purposes.

This all assumes that you have the probe in either a thermowell, or taped to the side and insulated from ambient.

Good luck.


Mylo

[boobookittyfuk]

a 2 degree differential is the smallest you would want. I usually keep mine set at 4 because i don't want my freezer/fridge turning on and off every 3 minutes.

[Mylo]

a 2 degree differential is the smallest you would want. I usually keep mine set at 4 because i don't want my freezer/fridge turning on and off every 3 minutes.

I should have emphasized that. Thanks, Mr. Fuk. However, if your probe is well insulated or in a thermowell, then even with a 2 degree diff, your compressor should not kick on that frequently. Beer has a pretty large thermal mass. I wouldn't recommend a 1 degree diff for your compressor, anyway.


Mylo

[JR McKnight]

Awesome Mylo, thanks. That is exactly the kind of information I was looking for.

[boobookittyfuk]

if you are using the ranco for controlling the temperature of your fridge, then you only needed to get the single stage controller since your fridge can't warm things, only cool. the two stage controllers are for when you have a cooling and heating combo like the temperature controlled conicals that morebeer has.

[Mylo]

if you are using the ranco for controlling the temperature of your fridge, then you only needed to get the single stage controller since your fridge can't warm things, only cool. the two stage controllers are for when you have a cooling and heating combo like the temperature controlled conicals that morebeer has.

Or if your fridge is in a cold place - like the garage in winter.


Mylo

[JR McKnight]

Or if your fridge is in a cold place - like the garage in winter.


Mylo

Yea, its a chest freezer in the garage.