Furnaces

The stack damper in a furnace is set to give from?

0.05 to 0.15 inches of water

Section of the furnace that contains the burners and open flames is called ____.

Firebox

When a burner flame goes out during operation it is referred to as:

Flame out

_____furnaces use a fan to push fresh air to the burners for combustion.

Forced Draft Furnaces

_____ is located on the natural gas fuel line to the furnace that is designed to maintain constant pressure to the surface burner.

Fuel pressure control loop

A device used to heat up chemicals or chemical mixtures is _____.

Furnace

_____ are designed to be operated with lower amounts of excess air than typical burners.

Low NOx Burners

Fire Triangle

fuel, oxygen, heat

When a furnace tube or section of refractory gets too hot.

hot spot

Decreasing excess air in the furnace ____ radiant heat transfer

maximizes

Most fired furnaces use

natural gas.

Temperatures in furnaces range between

1600F to 2000F

Hydrogen as fuel has a fuel heat value of:

274 BTU/Cu.ft

Convective heat transfer accounts for ____.

30 to 40%

Gas flow out of a furnace is typically set at:

350,000 pounds per hour

Radiant heat transfer accounts for?

60% to 70%

_____ heats air before it enters a furnace at the burners.

Air preheater

_____ furnace requires 2 fans one inducing flow out the stack and one providing positive pressure to the burners.

Balanced Draft Furnaces

Four draft types utilized on furnace designs are:

Balanced, Induced, Forced, and Natural

_____ are located on each burner and will immediately alert a technician when a burner goes out or is functioning outside normal parameters.

Burner Alarms

CH4+2O2 combustion yields what?

CO2+2H2O

____ is formation of carbon deposits in the tubes of a furnace.

Coking

_____ shows 10 tube color variations associated with temperature.

Color chart of steel tubes

____ are located on the roof of the furnace and are not in direct contact with the burner flames.

Convection Tubes

Tubes located above the shock bank is called ___.

Convection tubes

Negative pressure of air and gas at different elevations in a furnace is called _____.

Draft

_____ airflow will decrease furnace temperatures around the burners and force the automatic controls to increase natural gas flow rates to the burner, wasting money.

Excess air

____ furnace has a fan located below the stack pulls air up through the firebox and out the stack.

Induced-draft furnace

____ furnaces are not equipped with fans. Hot combustion gases flow through the furnace using natural bouncy forces.

Natural Draft Furnaces

____ allows for visual inspection using a welders shield.

Peepholes

Amount of combustibles in the flue gas?

Percent combustibles

Tubes located along the walls of the firebox are called _____.

Radiant Tubes