As pressure on a gas decreases, the gas expands and cools; increasing pressure makes the temperature rise. You could also express these phase changes as evaporation and condensation, which is how evaporator coils and condenser coils get their names. Refrigerants, including Freon and Puron, may never need recharging throughout the life of your AC.
1 Make sure that the start of the ruler is directly below the center of one eyeâs pupil. 2  Hold the ruler (keeping it steady and parallel to the floor); mark the location on the ruler of the other eyeâs pupil. 3  Measure the distance in millimeters between the two marks. 4  That distance will be your PD.
Before you want to buy a pair of eyeglasses, you need to know the pupillary distance of you. If you have bought the eyeglasses from the store, you could have the data of your pupillary distance. Usually the adult female common pd is 56 mm to 62 mm. However different people owns different situation. You should go to the store to have a eye check to get this information.