Vapor resistant fuel burning appliance

A method of controlling a fuel-fired appliance, the appliance comprising a burner and a sensor that can detect flammable vapors exterior to the burner, the method comprising steps of:

• monitoring an output of the sensor;
• preventing the burner from operating for a fixed period of time if the output of the sensor is above an upper vapor limit;
• and
• restarting the burner if, at the end of the fixed period of time, the sensor output is below a lower vapor limit, wherein the lower vapor limit is below the upper vapor limit.

A fuel-fired water heater, comprising:

• a burner;
• a sensor adapted to detect flammable vapors exterior to the burner;
• and
• a controller that is configured to:
• monitor an output of the sensor;
• stop operation of the burner if the sensor output indicates a sufficient presence of flammable vapors, and after a fixed period of time of stopped operation, automatically restart the burner if the sensor output indicates an insufficient presence of flammable vapors;
• and
• lockout the burner if the sensor output indicates a sufficient presence of flammable vapors after the fixed period of time.

A method of controlling an appliance, the appliance comprising a burner, an ignition system, and a sensor that can detect flammable vapors exterior to the burner, the method comprising steps of:

• detecting flammable vapors;
• disabling the burner if flammable vapors are detected above a first predetermined level;
• if the disabling step disables the burner, waiting a time period;
• sometime after the time period, determining if flammable vapors are detected below a second predetermined level, wherein the second predetermined level is different from the first predetermined level;
• entering a run state if flammable vapors are detected below the second predetermined level, wherein in the run state, the burner is no longer disabled;
• and
• entering a lockout state if flammable vapors are detected above the second predetermined level, wherein in the lockout state, burner operation is prevented without some user intervention;
• and
• wherein during the entering a run state step, the ignition system enters a run state if flammable vapors are detected below the second predetermined level, and during the entering a lockout state, the ignition systems enters a lockout state if flammable vapors are detected above the second predetermined level.

A method of controlling an appliance, the appliance comprising a burner and a sensor that can detect flammable vapors exterior to the burner, the method comprising steps of:

• monitoring an output of the sensor;
• incrementing a counter having a counter value when the sensor output indicates a presence of flammable vapors above a first predetermined level;
• decrementing the counter when the sensor output indicates a level of flammable vapors that is below a second predetermined level, but not allowing the counter value to fall below a selected lower counter limit, wherein the second predetermined level is below the first predetermined level;
• and
• stopping burner operation if the counter value reaches a first predetermined value.