What action should be avoided with regulators between different sizes?

Interchanging regulators between different sizes should be avoided because it can lead to unsafe operating conditions and equipment failure. Regulators are designed and calibrated to function within specific pressure ranges and flow rates that correspond to the fuel system's requirements. When regulators of different sizes are interchanged, it can cause improper pressure regulation, potentially resulting in either over-pressurization or inadequate fuel delivery.

This action undermines the safety systems in place, increasing the risk of leaks, fires, and explosions. Proper functioning of a fuel-oil piping and storage system hinges on using components that are correctly matched in size and specification to ensure safety, efficiency, and compliance with regulatory standards. Therefore, it is crucial to only use the appropriately sized regulators as designated by the system requirements.