CCP Chimney Draft & Combustion Principles Flashcards
6 cards from real CCP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CCP Chimney Draft & Combustion Principles flashcards as text
What is the primary driving force behind chimney draft?
Answer: Temperature differential between flue gases and outside air
Chimney draft is primarily driven by the temperature differential between hot flue gases and cooler outside air, creating a buoyancy-based pressure difference.
What unit is typically used to measure chimney draft pressure?
Answer: Pascals or inches of water column
Chimney draft pressure is measured in Pascals or inches of water column (in. WC) because draft is a very small pressure difference requiring sensitive units.
Which condition is most likely to cause a chimney to backdraft?
Answer: Negative indoor air pressure relative to outside
Backdrafting occurs when the home has negative indoor pressure — often from exhaust fans or tight construction — pulling flue gases back into the living space.
What is the minimum natural draft typically required for proper residential appliance operation?
Answer: 0.01 to 0.05 inches of water column
Most residential appliances require a minimum natural draft of 0.01 to 0.05 inches of water column for proper combustion and safe venting.
How does chimney height affect draft performance?
Answer: Taller chimneys generally produce stronger draft
Taller chimneys create a greater column of buoyant hot gases, increasing the pressure difference and strengthening natural draft.
What effect does a cold chimney flue have on initial draft when an appliance is first lit?
Answer: It reduces draft until the flue warms up
A cold flue creates poor initial draft because the temperature differential between flue gases and the flue walls is insufficient to drive airflow upward.