What temperature should be maintained or less for the potable hot water distribution system in a combined heating system?

In a combined heating system, maintaining the temperature of the potable hot water distribution system at or below 140°F is significant for several reasons. First and foremost, temperatures above this level can pose a serious risk of scalding, especially for vulnerable populations such as children and the elderly. Setting the maximum temperature at 140°F helps mitigate this risk while still providing hot water sufficient for household uses like bathing, dishwashing, and laundry.

Additionally, 140°F helps to minimize the growth of bacteria, particularly Legionella, which can thrive in water temperatures below this threshold. This temperature not only supports effective sanitation in hot water systems but also ensures that the water retains its clarity and quality for consumption.

Keeping the heated potable water below this temperature aligns with safety regulations and best practices outlined in plumbing codes and health guidelines, promoting safe and functional hot water distribution in residential and commercial settings.