🔍 Key Concepts

• 46 CFR requirements for automatic boilers used for heating • Difference between low pressure hot water heating boilers and high temperature water boilers in 46 CFR • Boiling point of water and typical safe operating ranges for shipboard heating systems

💭 Think About

• Think about why the Coast Guard limits the outlet water temperature on a low pressure, cast iron, hot water heating boiler. What risk increases as the temperature approaches the boiling point? • Consider the normal operating temperatures of building or ship comfort heating systems. Do they usually run close to boiling, or somewhat below it for safety and equipment life? • Look in 46 CFR Part 52 and related sections: which temperature is repeatedly used as the upper limit for low pressure hot water heating service?

✅ Before You Answer

• Verify the exact definition of a low pressure hot water heating boiler in 46 CFR and note the stated maximum water temperature. • Check which of the listed temperatures is commonly associated with safe circulation and avoidance of flashing to steam in low pressure systems. • Confirm that the temperature you choose is specifically tied to cast iron, low pressure, hot water heating boilers and not to power boilers or high temperature water boilers.