Water heater with normally closed air inlet damper

A method of operating a fuel-fired heating apparatus having a combustion chamber, said method comprising the steps of:

• forming flame quenching inlet openings in an outer wall portion of said combustion chamber;
• causing combustion air to flow into said combustion chamber through said flame quenching inlet openings in response to the initiation of firing of said heating apparatus;
• and
• precluding fluid flow into said combustion chamber through said flame quenching inlet openings in response to termination of firing of said heating apparatus.

A fuel-fired water heater comprising:

• a tank adapted to hold a quantity of water to be heated;
• a combustion chamber disposed at a bottom portion of said tank and having an outer wall with flame quenching openings disposed therein;
• a flue communicating with said combustion chamber and extending therefrom upwardly through said tank;
• a burner disposed in said combustion chamber and operative to receive fuel from a source thereof and combust the received fuel with combustion air entering said combustion chamber via said flame quenching openings;
• and
• air flow control apparatus for controlling combustion air inflow to said combustion chamber, said air flow control apparatus including:
• an air inlet plenum extending outwardly from said outer wall and around said flame quenching openings in a manner such that all combustion air entering said combustion chamber flows through said air inlet plenum structure and said flame quenching openings, and
• a normally closed damper structure operatively connected to said air inlet plenum and (1) being movable to an open position, in which it permits air flow through said air inlet plenum, in response to firing of said water heater, and (2) being movable to an open position, in which it precludes air flow through said air inlet plenum, in response to cessation of firing of said water heater.