Abstract: A blowby gas treatment device includes a pressure control valve, a fresh air induction pipe, a first blowby gas pipe, a second blowby gas pipe, a shutoff valve, a one-way valve, and a PCV valve. A leak diagnosis includes a first-stage diagnosis to determine whether or not falling of a pressure in a crank case after closing of the shutoff valve under a non-supercharging condition is normal. A second-stage diagnosis is implemented by using an air fuel ratio feedback control, and determining whether or not a sensed intake air quantity obtained by an air flow meter is equal to an actual intake air quantity flowing into a cylinder set. When the sensed intake air quantity is equal to the actual intake air quantity, presence of an in-system leak is determined, and when the actual intake air quantity is larger, presence of an out-of-system leak is determined.

Abstract: A combustion apparatus. Combustion means (burner) generates flame by combustion. Air supply means (intake fan) supplies air to the combustion means. Flame current detecting means (FRB) is set at a certain detection position and detects a flame current value included in the flame which is generated by the combustion means. Determination means (control device) determines a distribution where the flame current value that is detected is included for the flame current detecting means. Control means (control device), when the flame current value is not included in a distribution, which is set as normal values, outputs a control command of increasing or decreasing at least one of the supply of the air by the air supply means and the supply of fuel based on a determination result by the determination means.

Abstract: A combustion apparatus (water heater) includes a combustion unit (burner) combusting fuel, at least two flame detector (flame rods) detecting whether there is a flame or not in the combustion unit, a determination unit (control device) determining whether or not there is a misfire, based on detected results of the flame detectors, and a control unit (control device) stopping supply of the fuel to the combustion unit in response to a determined result of the determination unit.

Abstract: A combustion apparatus. Combustion means (burner) generates flame by combustion. Air supply means (intake fan) supplies air to the combustion means. Flame current detecting means (FRB) is set at a certain detection position and detects a flame current value included in the flame which is generated by the combustion means. Determination means (control device) determines a distribution where the flame current value that is detected is included for the flame current detecting means. Control means (control device), when the flame current value is not included in a distribution, which is set as normal values, outputs a control command of increasing or decreasing at least one of the supply of the air by the air supply means and the supply of fuel based on a determination result by the determination means.

Abstract: A combustion apparatus (water heater) includes a combustion means (burner) combusting fuel, at least two flame detecting means (flame rods) detecting whether there is a flame or not in the combustion means, a determination unit (control device) determining whether or not to be a misfire based on detected results of the flame detecting means, and a control unit (control device) stopping supply of the fuel to the combustion means in response to a determined result of the determination unit.

Abstract: A hot-water supply apparatus is an apparatus which has a primary heat exchanger absorbing sensible heat of combustion exhaust and a secondary heat exchanger absorbing latent heat of the combustion exhaust, and improves a freezing prevention function of the hot-water supply apparatus at a cold period. Further, this apparatus has a temperature detection means (temperature sensors) which detects a freezing prevention temperature, a combustion means (a burner group) which supplies combustion exhaust generated by combustion to the primary and secondary heat exchangers, an air supply means which supplies air to the combustion means, and a control means (a control unit) which makes the combustion means burn and drives the air supply means based on a detected temperature of the temperature detection means.

Abstract: A hot-water supply apparatus is an apparatus which has a primary heat exchanger absorbing sensible heat of combustion exhaust and a secondary heat exchanger absorbing latent heat of the combustion exhaust, and improves a freezing prevention function of the hot-water supply apparatus at a cold period. Further, this apparatus has a temperature detection means (temperature sensors) which detects a freezing prevention temperature, a combustion means (a burner group) which supplies combustion exhaust generated by combustion to the primary and secondary heat exchangers, an air supply means which supplies air to the combustion means, and a control means (a control unit) which makes the combustion means burn and drives the air supply means based on a detected temperature of the temperature detection means.

Abstract: There is provided a water heater unit realizing antifreezing of a water tube and the like of a heat exchanger without providing a backwind stopper on an exhaust tube. The water heater unit comprises a heat exchanger for heating water by a combustion heat of combustion means, water temperature sensors for detecting the temperatures of the water tube connected to the heat exchanger and an air supply fan for supplying air to a combustion chamber in which the combustion means is installed. When temperatures detected by the temperature sensors reach a temperature at which freezing of the heat exchanger is expected, the air supply fan is driven to supply air to the combustion chamber and the air is exhausted toward an exhaust port, thereby effecting heat exchange and antifreezing of the water tube.

Abstract: There is provided a water heater unit realizing antifreezing of a water tube and the like of a heat exchanger without providing a backwind stopper on an exhaust tube. The water heater unit comprises a heat exchanger for heating water by a combustion heat of combustion means, water temperature sensors for detecting the temperatures of the water tube connected to the heat exchanger and an air supply fan for supplying air to a combustion chamber in which the combustion means is installed. When temperatures detected by the temperature sensors reach a temperature at which freezing of the heat exchanger is expected, the air supply fan is driven to supply air to the combustion chamber and the air is exhausted toward an exhaust port, thereby effecting heat exchange and antifreezing of the water tube.