When connecting a pressure gauge or pressure control to a steam boiler, you should use an ______ siphon device.

• A. Anti
• B. Isolation
• C. Check
• D. Needle

Answer: (A)

Prevent backflow into the gauge line. When a steam boiler system experiences pressure or level changes, a siphon can form in the connection to the pressure gauge or control, pulling boiler water into the instrument line. An anti-siphon device interrupts that siphon, typically by providing an air break or vent, so the gauge line cannot be drawn back into the boiler. This protects the instrument from contamination or damage and keeps readings accurate. Other options don’t specifically prevent siphoning in the gauge connection, so they don’t address this safety and accuracy issue as effectively.