A/C Thermostat Wiring?

Hi,
I'm getting started on my fermentation cabinet and could use some help with the A/C wiring.

I have an old window unit that I was hoping had the screw type temp control that Jamil mentioned on one of the Brew Strong podcasts.

Sadly, that's not the case. I pulled it apart and found a Ranco PCB in there.

Does anyone know how to rewire this to run at colder temps?

Here is an image of the PCB.



Thanks,
Chris

Why not just get a Johnson controller and be done with it? I would think it would be a lot easier, and if you screw up your wiring, you might trash your whole AC unit.

I am eventually going to have it hooked up to a FermTroller.

That's not really my issue at the moment. I am trying to figure out how to get the unit to run colder than the 60 degree (or comething around there) lower temperature limit.

You could wrap the probe in enough insulation to fool it into thinking it's warmer then it is. Trial and error. Used to do that with my oven for pizza baking, which is a bit tricky but it worked.

Build this.http://suburb.semo.net/jet1024/Controller.htm I made this to control a glycol jacketed fermentation thingy

If there is enough wire slack cut the sensor wires long enough to wire nut/solder back together. Test the sensors to see what the resistance is between leads and if as I suspect ranco used 10K@70 Deg F thermistors, you can install 22K ohm resistors across the sensor leads to shift operaing point down to 30's. This will change the span on the slide control but it will be a set and leave alone situation probably as the old scale span will not be the same as altered scale span. If the reading is different PM me with reading and temperature and I can calculate a shunt resistor value for you.