Water heater

A water heater, capable of using each of a plurality of types of gas as fuel, a first type of gas among the plurality of types of gas having a greater calorific value than a second type of gas, wherein the water heater comprises:

• a venturi, comprising an air intake port and a gas intake port, comprising a supply path of air and gas to a combustion chamber, and where the gas is drawn in response to negative pressure generated by passing air;
• an adjustment part, replaceably incorporated into a gas supply path, having an inner diameter according to a gas type;
• a fan, mixing air and gas and supplying the mixed air and gas to the combustion chamber;
• a burner, for combusting gas;
• an ignition part, igniting the burner;
• a sensor, detecting that combustion is being performed in the combustion chamber;
• and
• a control device, operating the water heater in a plurality of test operation modes,
• wherein the control device:
• in a first test operation mode among the plurality of test operation modes, causes the fan to rotate at a rotation speed preset to be lower than a rotation speed during normal ignition;
• causes the ignition part to ignite the burner;
• and,
• in response to combustion being detected before a predetermined first time elapses from the ignition of the burner, considering that the first type of gas is being supplied to the combustion chamber and an adjustment part for the second type of gas is incorporated into the water heater, determines a combination of the gas used as fuel and the adjustment part to be erroneous.