When is it permitted to replace the antifreeze in an existing system with factory premixed antifreeze solution?

When is it permitted to replace the antifreeze in an existing system with factory premixed antifreeze solution?

• A. The antifreeze solution contains more than 60% propylene glycol
• B. The antifreeze solution contains less than 40% propylene glycol
• C. Only during system shutdown
• D. Never

Answer: (B)

Antifreeze in sprinkler systems must stay within a specific glycol concentration to protect against freezing while keeping corrosion inhibitors effective. Factory premixed antifreeze solutions are formulated for a defined concentration range, so you should replace with premixed only if the current antifreeze concentration is below that range. If the system already contains a high glycol content (around 60% or more), adding a premixed solution would push the mix out of the intended range and could reduce protection or cause other issues. In that case, flushing and refilling with the correct mixture is the safer approach. So, replacement with factory premixed antifreeze is permissible when the existing solution has less than about 40% propylene glycol.

Antifreeze in sprinkler systems must stay within a specific glycol concentration to protect against freezing while keeping corrosion inhibitors effective. Factory premixed antifreeze solutions are formulated for a defined concentration range, so you should replace with premixed only if the current antifreeze concentration is below that range. If the system already contains a high glycol content (around 60% or more), adding a premixed solution would push the mix out of the intended range and could reduce protection or cause other issues. In that case, flushing and refilling with the correct mixture is the safer approach. So, replacement with factory premixed antifreeze is permissible when the existing solution has less than about 40% propylene glycol.