Setting Thermostats
The location of the thermostat sensing probes and the availability of power to drive the compressor during the 24 hour day will determine the thermostat settings on boat refrigerators. Thermostat settings or even thermometers can only react to the temperature in the box where their probe is mounted this is why refrigeration thermostats are normally marked with numbers instead of temperatures. Refrigeration systems incorporating holding plates are designed into boat refrigeration systems to store energy the same as a battery. Standard evaporators are not designed to store energy but will transfer heat more rapidly than holding plates. Thermostats used with standard evaporators generally have their probes connected to the evaporator this then results in a much better control over box temperatures than boxes having holding plates. To answer your question, if you have a cycling system which means power is available 24 hours per day adjust the thermostats the same way as you do your home refrigerator the holding plates will take care of themselves. If your power to drive the compressor is only available a few hours a day, set the freezer to a very low setting you can not get the the holding plates too cold, and set the refrigerator thermostat to provide thirty three degrees F. in the coldest corner of that box. I have included over one hundred questions and answers in my new 12 Volt Refrigeration Manual due to be available the end of July. Richard@kollmann-marine.com
