Top vent loose, stuck or rusted

The top vent is loose, stuck or rusted

• Stuck: soot, grease or rust. Brush it, work it, and oil it lightly (owners of other makers' cast-iron vents).
• Cap swings shut, or the disc spins: the cap pivot or disc centre screw has loosened (our reading).
• Loose or rocking on the chimney: lift it off and check the collar and the vent's bore for chips or rust.
• Broken or rusted through: a new vent, KJ-DFT13 (sold out in the US on 11 Oct 2026).