Doh! Digital temp controller for chest fridge not compatible with inverter search mode

Dan_

I didn't fully think through my plan when I purchased a digital temperature controller to modify a chest freezer. It works great but being digital, it needs power and when the inverter is in search mode, the inverters search pulses are not long enough for the temperature controller to start up and trigger (needs 1.5 seconds to initialize).


Any ideas? Could a capacitor somehow be added to provide enough power? Suggestions for a mechanical thermostat?

waynefromnscanada

Re: Doh! Digital temp controller for chest fridge not compatible with inverter search mo

Doubt a cap will do the job, but I'd have to try it and where in the controller it would be placed. With that in mind, if you could figure where within the controller to connect the capacitor, you could check the operating voltage and perhaps use a battery as "backup" to power the timer between inverter pulses. Some inverters put out several cycles each pulse, while others only one single cycle. Tricky business indeed.

vtmaps

Re: Doh! Digital temp controller for chest fridge not compatible with inverter search mo

Dan_ wrote: »

Suggestions for a mechanical thermostat?

Johnson Controls makes well regarded digital and mechanical thermostats. (I have the digital version and I do not use search mode on my inverter).

btw, the digital version has a feature that prevents short cycling. If the power to the thermostat is interrupted, when the power resumes the thermostat waits 5 minutes before allowing power to the freezer. You would defeat this feature if you power the thermostat separately from the freezer.

--vtMaps

Dan_

Re: Doh! Digital temp controller for chest fridge not compatible with inverter search mo

Well, good news! I found a solution and didn't have to spend a cent. On most freezer thermostats you can take off the dial and adjust abscrew that changes the temp range. Most you turn the screw clockwise (mine, an old sears galaxy, you have to turn it nearly all the way clockwise to get 1-5c.
Here's the guide http://www.homebrewtalk.com/f51/guide-set-internal-chest-freezer-thermostat-32f-eliminate-external-control-249612/

Dan_

Re: Doh! Digital temp controller for chest fridge not compatible with inverter search mo

Well, good news! I found a solution and didn't have to spend a cent. On most freezer thermostats you can take off the dial and adjust a screw that changes the temp range. Most you turn the screw clockwise (mine, an old sears galaxy, you have to turn it nearly all the way clockwise to get 1-5c.
Here's the guide http://www.homebrewtalk.com/f51/guide-set-internal-chest-freezer-thermostat-32f-eliminate-external-control-249612/

waynefromnscanada

Re: Doh! Digital temp controller for chest fridge not compatible with inverter search mo

That's indeed great news. I've heard of some folks being able to do this, although I wasn't able to with mine. Hope it works out well for you.