A gas heater includes a premix burner, a supply channel for supplying a mixture of a gaseous fuel and air to the burner, and a check valve placed in the supply channel upstream of the burner. The check valve includes a moveable valve body having a first end position in which the check valve is opened and a second end position in which the check valve is closed. In a first pressure condition in which a pressure upstream is higher than a pressure downstream, the valve body is urged to the first end position. In a second pressure condition in which the pressure upstream is lower than the pressure downstream the valve body is urged to the second end position. After closure of the check valve the check valve remains closed for a delay time.

The present invention relates to a boiler having a gas sensing and an earthquake sensing function and a control method thereof, in which a gas leakage and an earthquake occurrence are automatically sensed and thus the boiler is forcibly stopped by causing fuel supply thereto to be cut off. The present invention is configured to cause fuel supply to the boiler to be cut off by comprehensively determining whether gas is leaking from the boiler and whether an earthquake has occurred at the present time, thereby minimizing loss of life due to the gas leakage and the earthquake occurrence.

The present invention provides a gas water heater, and a safety control method and system therefor. The system includes: an exhaust fan; a rotational speed detecting unit, configured to detect a rotational speed of the exhaust fan; a power obtaining unit, configured to obtain a set value for output power of the exhaust fan; a rotational speed difference obtaining unit, configured to obtain an actual value of the rotational speed and a reference value of the rotational speed according to the set value for the output power, and to calculate a difference between them; and an exhaust control unit, connected to the exhaust fan, the rotational speed detecting unit, the rotational speed difference obtaining unit and the power obtaining unit respectively, configured to correct a predetermined wind pressure curve graph at an air outlet of the exhaust fan according to the difference.

A gas heater includes a premix burner, a supply channel for supplying a mixture of a gaseous fuel and air to the burner, and a check valve placed in the supply channel upstream of the burner. The check valve includes a moveable valve body having a first end position in which the check valve is opened and a second end position in which the check valve is closed. In a first pressure condition in which a pressure upstream is higher than a pressure downstream, the valve body is urged to the first end position. In a second pressure condition in which the pressure upstream is lower than the pressure downstream the valve body is urged to the second end position. After closure of the check valve the check valve remains closed for a delay time.

A method of ensuring the safety of exhaust of a water heater includes the following steps: A. start the blower and detect a rotational speed of a motor thereof; B. determine a first range based on the detected rotational speed; C. start the blower and detect the rotational speed of the motor when the water heater is restarted again; D. keep supplying gas to the burner for combustion when the rotational speed detected in step C is within the first range. During operation, a second range is determined by detecting the rotational speed of the motor after an outlet water temperature reaches a corresponding constant temperature range; the rotational speed is continuously detected, and the gas supply is stopped if the detected rotational speed is out of the second range. Thereby, the result of the method would be more accurate regardless of the actual installed status of the exhaust pipe.

The present invention provides a gas water heater, and a safety control method and system therefor. The system includes: an exhaust fan; a rotational speed detecting unit, configured to detect a rotational speed of the exhaust fan; a power obtaining unit, configured to obtain a set value for output power of the exhaust fan; a rotational speed difference obtaining unit, configured to obtain an actual value of the rotational speed and a reference value of the rotational speed according to the set value for the output power, and to calculate a difference between them; and an exhaust control unit, connected to the exhaust fan, the rotational speed detecting unit, the rotational speed difference obtaining unit and the power obtaining unit respectively, configured to correct a predetermined wind pressure curve graph at an air outlet of the exhaust fan according to the difference.

The present invention relates to a boiler having a gas sensing and an earthquake sensing function and a control method thereof, in which a gas leakage and an earthquake occurrence are automatically sensed and thus the boiler is forcibly stopped by causing fuel supply thereto to be cut off. The present invention is configured to cause fuel supply to the boiler to be cut off by comprehensively determining whether gas is leaking from the boiler and whether an earthquake has occurred at the present time, thereby minimizing loss of life due to the gas leakage and the earthquake occurrence.

A method of ensuring the safety of exhaust of a water heater includes the following steps: A. start the blower and detect a rotational speed of a motor thereof; B. determine a first range based on the detected rotational speed; C. start the blower and detect the rotational speed of the motor when the water heater is restarted again; D. keep supplying gas to the burner for combustion when the rotational speed detected in step C is within the first range. During operation, a second range is determined by detecting the rotational speed of the motor after an outlet water temperature reaches a corresponding constant temperature range; the rotational speed is continuously detected, and the gas supply is stopped if the detected rotational speed is out of the second range. Thereby, the result of the method would be more accurate regardless of the actual installed status of the exhaust pipe.

A gas flow controller for use in a gas fired apparatus includes an actuator, a pilot valve operably connected to the actuator, a main burner valve, and a flow controller valve operably connected to the actuator. The pilot valve is moveable from a closed position to an open position by actuation of the actuator to provide selective fluid communication between a gas inlet and a first fluid chamber. The main burner valve provides selective fluid communication between the first fluid chamber and a main burner outlet. The flow controller valve is moveable from a closed position to an open position by actuation of the actuator to provide selective fluid communication between the gas inlet and a back side of the main burner valve to maintain the main burner valve in a closed position when the pilot valve is in the open position.

A controller for a water heater which has a power source configured to power up the components of the controller, wherein the power source is independent of a battery or mains electricity and uses a thermoelectric effect; and a gas sensor powered from the controller via the power source, wherein the gas sensor is configured to be positioned externally to the controller and connected to the controller, and wherein the controller is configured to trigger an alarm if a concentration of gas in the vicinity of the gas sensor is above a predetermined threshold.