Water heater with a flame arrester

A water heater with a flame arrester comprising:

• a hot water storage chamber and a combustion chamber arranged upward and downward within a body, said combustion chamber is provided with an air supply inlet for supplying the air to the inside of said combustion chamber and an exhaust passage which passes through said hot water storage chamber and upper portion of said body to discharge the exhaust within said combustion chamber;
• said flame arrester is provided within said inlet or an air supply passage connected to said inlet;
• a main gas burner provided within said combustion chamber for keeping the temperature of hot water within said hot water storage chamber constant;
• a safety apparatus is provided capable of maintaining safety in a room nearby said body when an air supply shortage or oxygen deficiency occurs within said combustion chamber due to clogging of the said flame arrester;
• and
• said safety apparatus, comprises a sensor burner, means for detecting a changing state of flame of the sensor burner, means for shutting off fuel to said main gas burner in response to an abnormality detection result by said burner flame changing of state detecting means;
• said sensor burner being an all primary air burner which comprises:
• a porous plate having a plurality of flame ports formed therein;
• and
• a cylindrical guard, surrounding said porous plate, for preventing flame from contacting secondary air.