A draft gauge visually ensures positive pressure in the chimney to remove combustion products.

A draft gauge visually ensures positive pressure in the chimney to remove combustion products.

• A. True
• B. Not applicable
• C. False
• D. Depends on draft gauge type

Answer: (C)

A draft gauge is used to measure the actual draft, the pressure difference that drives combustion gases up the flue. It isn’t about visually confirming that the chimney is under positive pressure. The goal is to have adequate draft in the correct direction to move the combustion products out of the building, which is determined by reading the gauge and confirming the flow is upward and sufficient. A visual check cannot guarantee this; in fact, a positive pressure reading in the chimney isn’t the reliable or desired condition and could indicate abnormal or backdraft situations under certain conditions. So, you verify venting with actual draft readings rather than a visual notion of positive pressure.

A draft gauge is used to measure the actual draft, the pressure difference that drives combustion gases up the flue. It isn’t about visually confirming that the chimney is under positive pressure. The goal is to have adequate draft in the correct direction to move the combustion products out of the building, which is determined by reading the gauge and confirming the flow is upward and sufficient. A visual check cannot guarantee this; in fact, a positive pressure reading in the chimney isn’t the reliable or desired condition and could indicate abnormal or backdraft situations under certain conditions. So, you verify venting with actual draft readings rather than a visual notion of positive pressure.