A simple fridge freezer with a single cooling system and a single thermostat runs the freezer compartment by default. The thermostat controls the temperature of the fridge compartment. The cooling circuit runs in the freezer compartment first, the fridge evaporator being tacked onto the end of it.
The fridge compartment thermostat usually cuts out at an air temperature of 3 or 4 degrees C. It may sense the evaporator temperature to do this. The thermostat will not then cut in to start the compressor until the air temperature has risen to about 7 or 8 degrees: this is to allow the fridge compartment evaporator to defrost. If the thermostat is sensing evaporator temperature then it will turn it on when the evaporator reaches 3 or 4 degrees.
If the fridge/freezer is in a “cold” environment, such as a garage where the temperature is only about 10 degrees then it takes a long time for the thermostat to reach its cut in point, therefore no cooling. If the freezer compartment is at about –20 degrees then it has a larger temperature differential to the garage temperature and will warm up to well above the required level in this time. If the garage is at or below the cut in temperature of the thermostat then the cooling system just won’t start. The result is total defrost of the freezer.
A freezer, i.e. no fridge compartment should be fine because its thermostat will be chosen to run it at freezer temperatures. We have a small freezer in the unheated garage and it works fine.
To answer Iffy's post
Yes Iffy, about -18 to -20 degrees C. (Dont freeze your new hip joint trying to prove it) (:
Last edited by: MJM on Sat 12 Nov 11 at 14:50
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