What should not be interchanged between different sizes?

Regulators should not be interchanged between different sizes due to their critical role in controlling the pressure and flow of fuel oil in a system. Each regulator is specifically designed for a particular pressure range and flow capacity associated with a designated pipe size. Using a regulator meant for a different size could result in improper pressure regulation, which can lead to potential hazards, such as leaks, equipment failures, or even catastrophic failures within the fuel-oil piping system.

Other components, such as containers, filters, and hoses, may have varying degrees of compatibility or may be adaptable across different sizes, but regulators play a unique and essential role that demands precise specifications to maintain the safety and efficiency of the fuel-oil system. It is vital to match the regulator with the appropriate size and specifications to ensure optimal performance and compliance with safety standards.