Chimney Safety Institute of America (CSIA) Certification Practice Test

How much of the actual flue temperature do magnetic thermometers display?

1. 30%

2. 50%

3. 70%

4. 100%

The correct answer is: 50%

Magnetic thermometers are designed to measure the temperature of a chimney flue indirectly by attaching to the exterior of the flue pipe. The reading they provide does not represent the full temperature of the flue gases inside but is a reflection of the heat on the surface of the flue. Typically, these thermometers display about 50% of the actual flue temperature. This is due to heat absorption and dissipation through the flue material and surrounding environment, which results in the external measurements being lower than the internal flue temperatures. Understanding this principle is crucial for chimney sweeps and professionals in assessing how effectively their heating appliance is operating and ensuring safe and efficient venting of combustion gases.