Method of ensuring safety of exhaust of water heater

A method of ensuring safety of exhaust of a water heater, wherein the water heater includes a blower, a controller having a memory, a gas control valve, and a burner;

• comprising the steps of:
• A. after receiving a correction command with the controller, starting the blower under a state that the gas control valve does not turn on, and detecting a rotational speed of a motor of the blower with the controller after the blower is operating for a while;
• wherein the rotational speed is saved in the memory of the controller;
• B. calculating a first acceptable rotational speed range by expanding the rotational speed saved in the memory with a predetermined range, and stopping the blower, so that the water heater stops operating, thereby to complete a process of initialization;
• C. starting the blower when the water heater is stopped and whenever the water heater is restarted again, and detecting the rotational speed of the motor of the blower after the blower is operating for a while;
• and
• D. keeping supplying gas to the burner for combustion when the rotational speed detected in step C is within the first acceptable rotational speed range;
• wherein before step A, the method further comprises a step of inputting the correction command to make the water heater execute the process of initialization;
• the process of initialization includes step A and step B, and wherein step A and step B are taken after receiving the correction command.