When using a flue gas analyzer that measures CO2, how would you verify the accuracy of the reading?

Verifying the accuracy of a flue gas analyzer reading for CO2 is best done by comparing the reading to a known sample. This method involves using a calibration gas that has a precisely defined concentration of CO2. By exposing the analyzer to this known concentration, you can determine whether the analyzer is functioning properly and providing accurate readings. This process, known as calibration, ensures that any adjustments needed for accuracy can be made, leading to reliable measurements when assessing the performance of heating appliances or systems.

Using a second sample could provide some insight, but without a reference value of what that second sample should be, it's not a definitive method for verification. Checking against a gas meter test dial or an appliance manufacturer's specifications does not relate directly to the accurate measurement of CO2 levels; those methods address different performance metrics and may not reflect the analyzer's precision in reading flue gas composition. Hence, relying on a known sample is the most effective way to ensure the accuracy of the analyzer.