The refrigerant flows through the coils on the back or under the freezer and through an expansion valve to the inside of the freezer. As the refrigerant passes through the expansion valve the pressure drops and hence the temperature also drops.
The noun MM has 1 sense: 1  1. a metric unit of length equal to one thousandth of a meter. 2  Meaning: 3  A metric unit of length equal to one thousandth of a meter. 4  Classified under: 5  Nouns denoting quantities and units of measure. 6  Synonyms: 7  millimeter; millimetre; mm. 8  Hypernyms (mm is a kind of...):
Millimeters, water gauge. Millimeters, water gauge, also known as millimetres water or millimetres water column and abbreviated to mm wg, mm H2O or mm wc respectively, is a unit of pressure. It is the pressure required to support a water column of the specified height (sometimes called 'head' of water). It is equivalent to 9.80665 Pa.