A boiler with both an induced and forced draft fan is referred to as what?

A boiler with both an induced and forced draft fan is referred to as what?

• A. A balanced draft boiler
• B. A double draft boiler
• C. A dual-phase boiler
• D. A mixed draft boiler

Answer: (A)

Having both a forced draft and an induced draft fan creates a balanced draft system. The forced draft pushes air into the furnace to support combustion, creating a controlled positive pressure inside the combustion chamber. The induced draft, on the other hand, draws flue gases through the boiler and up the stack, establishing a negative pressure that pulls air through the grate and combustion zone. When both are used together, their pressures are kept in balance, which minimizes leakage of combustion gases and ensures a stable, controllable flame. This balance improves combustion efficiency, combustion product control, and safety, which is why this configuration is called a balanced draft boiler. Other terms aren’t standard for this setup; they don’t specifically communicate the idea of balancing the draft with two opposing fans as clearly as the established term.

Having both a forced draft and an induced draft fan creates a balanced draft system. The forced draft pushes air into the furnace to support combustion, creating a controlled positive pressure inside the combustion chamber. The induced draft, on the other hand, draws flue gases through the boiler and up the stack, establishing a negative pressure that pulls air through the grate and combustion zone. When both are used together, their pressures are kept in balance, which minimizes leakage of combustion gases and ensures a stable, controllable flame. This balance improves combustion efficiency, combustion product control, and safety, which is why this configuration is called a balanced draft boiler.

Other terms aren’t standard for this setup; they don’t specifically communicate the idea of balancing the draft with two opposing fans as clearly as the established term.