It won't stay low

It will not hold a low temperature

• Overshoot. Ceramic holds heat, so start closing the vents 10 °C (50 °F) short and creep up (the manual).
• Too much lit charcoal. Light less for a low cook.
• An air leak at a worn felt gasket or the draft door. Owners close the dome on a banknote all round the rim: where it pulls out easily, the seal is weak.
• A top vent that will not close: the cap swings open on a loose pivot screw, or the disc has rusted open (our reading).