Refrigeration - A better controller

 This will PROBABLY be the last post on refrigeration. At least I hope so. The system is running perfectly. Here is what’s new:

First some back-story.  While we have been very happy with the refrigeration set up on BlueJ for the last seven years, there’s one aspect of performance that has always been less than I would want. And that’s the controller.

Speaking of back-story, if you want to read about BlueJ refrigeration from the beginning, start HERE.

The Isotherm ICEC controller that came with our system is marketed as an energy saver. It also slow-starts the compressor, and is reported to have a way to bank cold in the fridge when there is excess DC power available. Sadly with the exception of the slow-start, I’m not sure any of those claims are true, and it has difficulty maintaining correct temperature when the ambient air is very warm. So not perfectly happy.

Most of this fault comes in the design. It is essentially an analog device trying to do the job of a digital controller. To make matters worse, there’s no way to know what’s going on, and all the settings are done through a series of little DIP switches that leave you frustrated when nothing seems to change, and you don’t know if it’s not working, or you have the switch set wrong.

Salvation has come in the way of the Isotherm ITC. This is a (updated!) replacement controller and display for the DanFoss compressor, it is completely and fully digital. Not only does it let you set the temperature in degrees (Fahrenheit or Celsius), but it shows you the current temperature in degrees. Along with a fully functional eco-mode and compressor soft start, it also has an intelligent battery cut off that can be set to back off maximum cooling capability when the battery starts to run low, and then shut off completely completely when it hits a threshold. 

I installed it this spring and it only took a couple of hours. The biggest parts of the job were running the new thermostat into the icebox and replacing the old one, and then drilling the countersunk hole for the controller. You have the option to mount it flush, but then it protrudes in a rather on slightly way, and blocks access to the cabinets. Flush mount, it looks factory installed, and you don’t lose the capability of the cabinets. From this controller, you can access all the new functions (no DIP switches) and see the results on the display.

I could also remove the separate digital thermometer I had for the icebox, and also the separate low-power DC cut-off switch. A much cleaner installation now. 

We’ve been very very happy with it, it works exactly as advertised!


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