The Imperial Flue-Gas Thermometer is designed to measure the flue-gas temperatures of wood burning stoves. Every wood heating system behaves differently so it is impossible to give exact temperatures. Use the following flue-gas temperatures as a guide;

100 Degrees to 400 Degrees. Creosote range.

400 Degrees to 900 Degrees. Operating efficiently.

900 Degrees to 1700 Degrees. Overheating too hot.

For most accurate readings its recommended to place the thermometer on the stove pipe at least 18'' above the stove top.