What is the minimum size for a vertical drain pipe and blowoff valve in an automatic low water level fuel cut-off and water feeding device?

The minimum size for a vertical drain pipe and blowoff valve in an automatic low water level fuel cut-off and water feeding device is ¾ inch NPS (DN 20). This size is specified to ensure adequate flow capacity and to prevent blockages, which can occur in smaller pipes. When dealing with safety devices such as low water level cut-offs, it is critical that the drainage system is effective in allowing any excess water or condensation to safely exit the system to avoid damaging equipment or creating hazards.

A ¾ inch NPS size strikes a balance between providing sufficient drainage capabilities without being overly large, which could complicate installation or increase costs unnecessarily. Additionally, this size is typically conducive to the common dimensions used in many systems, making it a widely accepted standard. Thus, using a ¾ inch size helps in maintaining the reliability and efficiency of the safety device.