Glycol / water mixtures are required in all systems where the exposes exterior piping inside and outside the unit experience outdoor design temperatures below the freezing point of water. Glycol must have a minimum percentage of 20% glycol mixture to avoid the possibility of algae formation inside the piping system. the operating mixture percentage of the glycol / water mixture is dependent on the outdoor temperature to be experienced in the area of installation. See the glycol’s manufactures instructions for the correct mixture levels.
