When is it allowed to connect a water heater using flexible connections?

The correct answer indicates that it is typically not allowed to connect a water heater using flexible connections. This restriction is usually in place because flexible connections can introduce potential hazards, such as leaks or failure under high pressure and temperature conditions. Rigid piping is generally preferred for water heater installations as it provides a more secure and stable connection, which is critical for both safety and compliance with plumbing codes.

Flexible connections may be suitable in certain specific scenarios, like when there is limited space or for certain maintenance activities, but these situations usually have defined guidelines in plumbing codes that must be followed. Since flexible connections do not provide the same durability and integrity as rigid connections, their usage is often limited in permanent installations to ensure long-lasting performance and safety.

In other scenarios mentioned, such as when replacing an existing heater or during initial installation, flexible connections are typically allowed under specific conditions, provided they comply with local codes and regulations. The overall emphasis in plumbing practices is on ensuring secure and reliable connections that minimize risks.