When preparing to fill RV tanks, which components must be shut off to eliminate ignition sources?

• A. the vehicle's engine and heater
• B. the battery and headlights
• C. the air conditioning unit
• D. the service valve on the tank and appliance pilots and ignition system

Answer: (D)

When preparing to fill RV propane tanks, the priority is to remove any chance of propane reaching an ignition source. The best practice is to shut off the gas flow and any flames or sparks in the propane system itself: close the service valve on the tank to stop the supply, and shut off appliance pilots and the ignition system so there are no flames or sparks near the lines. This combination prevents a leaked propane vapors from being ignited. The other items listed could be ignition sources in other contexts, but they aren’t part of the immediate safety step for propane filling; focusing on the valve and the pilots/ignition components directly neutralizes the primary ignition risk.