Fuel-fired heating appliance with combustion chamber temperature-sensing combustion air shutoff system

Fuel-fired heating apparatus comprising:

• a combustion chamber thermally communicatable with a fluid to be heated, said combustion chamber having an outer wall defined by an arrestor plate having a perforated portion defined by flame quenching openings formed in said arrestor plate;
• a burner structure disposed in said combustion chamber and operative to receive fuel from a source thereof;
• a wall structure defining a flow path external to said combustion chamber and through which combustion air may flow into said combustion chamber for mixture and combustion with fuel received by said burner structure to create hot combustion products within said combustion chamber;
• a damper structure disposed externally of said combustion chamber and being resiliently biased toward a closed position in which it terminates air flow through said flow path;
• and
• a temperature sensing structure projecting into said combustion chamber, releasably blocking said damper structure in an open position in which it permits combustion air to flow through said flow path into said combustion chamber, and being operative to unblock said damper structure, and permit it to be driven to its closed position, in response to the presence of a predetermined, undesirably high temperature in said combustion chamber during firing of said burner structure.