Hercules® Cryo-Tek™ FG Antifreeze

Virgin propylene glycol has never been used previously.  Some boiler manufacturers state in their warranties that antifreeze made with virgin propylene glycol is required or the warranty is voided.   Recycled propylene glycol is captured and cleaned after use (mainly for de-icing aircraft). It is then considered a lower grade of propylene glycol and may still contain other ingredients even after cleaning.   Hercules Cryo-Tek antifreeze is made only with virgin propylene glycol.

Yes.  Use Cryo-Tek 100AL antifreeze for boilers with aluminum heat exchangers. Sludgehammer Universal Corrosion Inhibitor and Sludgehammer System Restorer & Noise Reducer is compatible with all metal heat exchangers, including aluminum.

The answer depends on which Cryo-Tek antifreeze is being used, and what level of freeze protection is required. For more information, see this chart. Freeze point:  The temperature at which crystals begin to form. Pumpable:  The temperature at which there are sufficient crystals to impede the flow of the product. Burst protection:  The temperature at which pipes burst.