FC FC Combustion & Fuel Systems

Question 1

What is the stoichiometric air-to-fuel ratio for natural gas combustion?

Accepted Answer

15.4:1

Answer

10:1

Answer

12:1

Answer

20:1

Question 2

Which color of a burner flame indicates incomplete combustion?

Accepted Answer

Yellow or orange

Answer

Blue

Answer

Blue with yellow tips

Answer

White

Question 3

What device on a gas furnace controls the flow of gas to the main burner?

Accepted Answer

Gas valve

Answer

Pressure regulator

Answer

Orifice spud

Answer

Manifold

Question 4

What is the purpose of a burner orifice in a gas furnace?

Accepted Answer

To meter the correct amount of gas into the burner

Answer

To ignite the gas

Answer

To mix air with gas

Answer

To sense flame presence

Question 5

When converting a furnace from natural gas to propane (LP), what must be replaced?

Accepted Answer

The orifice spud and pressure regulator spring

Answer

The heat exchanger

Answer

The blower motor

Answer

The thermocouple

Question 6

What is the typical manifold gas pressure for a natural gas furnace?

Accepted Answer

3.5 inches W.C.

Answer

0.5 inches W.C.

Answer

7 inches W.C.

Answer

11 inches W.C.