What is a common cause for a cad cell to become dirty?

A common cause for a cad cell to become dirty is soot. Soot is produced during the combustion process when oil is not burned completely, which is often a result of improper air-to-fuel mixture, oil quality, or burner operation. When soot accumulates on the cad cell, it can interfere with its ability to detect the light produced by the flame in the burner. This interference can cause the burner to either not operate properly or shut down due to a perceived lack of flame, which can lead to system inefficiencies and potential safety issues.

While other factors can contribute to contamination, such as dust accumulation, oil residue, and humidity, soot is particularly damaging because it is specifically a byproduct of combustion that directly affects the operation of the cad cell and the overall efficiency of the heating system. Proper maintenance and monitoring of combustion efficiency can help minimize soot production and ensure the cad cell remains clean and functional.