Call Allen's Air Conditioning, Inc. to schedule your  repair in  AL today!
Call Allen's Air Conditioning, Inc. to schedule your  repair in  AL today!

Understanding Basic Combustion

Understanding Basic Combustion

Useful Information on Combustion Efficient Fuel Use

A Definition:

Combustion is the rapid oxidation of a fuel resulting in the release of usable heat and the production of a visible flame

The Combustion Equation:

Natural Gas With Air:

Ch5 + 2O2 + 8N2 ----------->

CO2 + 2H2O + 8N2 + 1000 BTU Heat

Examples of Combustion

Perfect Combustion Provides:

The hottest flame
Minimum exhaust volume

Perfect Combustion

Characteristics:

  • All fuel combusted
  • Blue near burner tile
  • Forms a yellow conical flame shape
  • Produces the highest flame temperature
  • Provides the minimum exhaust volume

Lean Combustion

Characteristics:

  • Flue products oxidizing (Free O2)
  • Pale blue color
  • Forms a more conical flame
  • All fuel combusted
  • Flame temperature drops (Heating excess air)

Incomplete Combustion

Characteristics:

  • Air starved or fuel rich
  • Carbon Monoxide and H2 formed
  • Reducing atmosphere
  • Flame color is predominantly yellow color
  • The flame is less defined
  • Flame temperature drops

Optimum Energy Utilization Occurs when Perfect Combustion Ratios are Maintained

When a Furnace Tune-Up is Done Right the Technician will have taken time to:

  • Verify proper mix and directed air/fuel supply
  • Confirm that you have stable combustion
  • Check to make sure that the system is venting all the by-products of the exhaust flue gases

A Definition of Combustion Terms
Excess Air Definition:

Air remaining after the fuel has been combusted
-or-
Air supplied in addition to the quantity needed for stoichiometric combustion

Primary & Secondary Air:

Primary Air --

  • Air mixed with the fuel prior to ignition

Secondary Air --

  • Air supplied to the flame after it is ignited

Secondary Air Effects --

  • Imprecise air/fuel ratio control
  • Exhaust volume increases
  • Fuel rate rises
  • Less available heat