For safety, how many means of water feed are required when exceeding 500 square feet of heating surface?

In systems where the heating surface exceeds 500 square feet, the requirement for two means of water feed is primarily a safety measure intended to ensure the reliability and efficiency of the heating system. This standard is designed to provide redundancy; if one feed method fails for any reason, the second can maintain the necessary water supply to the system. This is especially crucial in steam heating systems where adequate water levels are vital for safe operation and to prevent such hazards as overheating or system failure.

To clarify, having only one means of water feed could pose significant risks, especially in larger systems where the volume of water can affect performance and safety. With two feeds, operators can ensure that if one fails, the system is not put at risk, maintaining continuous operation and eliminating the possibility of dangerous steam accumulation.