Abstract: A secondary safety circuit for a gas-fired device and method of operating the circuit. The secondary safety circuit includes a low-voltage direct current power source, a valve, and at least one sensor. The valve can be positioned in a pilot burner gas line. The secondary safety circuit ensures the valve is closed upon detecting an unsafe condition with the sensor.

Abstract: A water heater having primary and secondary heat exchanger and a pump to move water between the primary and secondary heat exchangers. The pump may also be used for the purpose of recirculating water within a building. The water heater may be manufactured with a method in which certain steps and components are added to a water heater of a first efficiency to arrive at a water heater having a second efficiency greater than the first efficiency. The additional steps and components may include attaching a condensing recuperator to a traditional power vent water heater.

Abstract: A storage-type water heater. The storage-type water heater comprising a water storage tank configured to retain tank water, means for heating the tank water in the water storage tank, and an anti-stacking pump assembly. The anti-stacking pump assembly includes a water tube configured to be positioned in the water storage tank, an impeller positioned within the water tube, a motor drivingly connected to the impeller, a water inlet formed in the water tube upstream of the impeller and configured to deliver tank water into the water tube from the water storage tank, and a water outlet formed in the water tube downstream of the impeller.

Abstract: A water heater. The water heater includes a water tank having a tank wall defining an interior space and adapted to contain water to be heated, a tank extension having an extension wall detachably mounted to the tank wall, the extension wall defining extension space communicating with the interior space, and defining an extension axis, an air inlet at least partially in the extension space extending through the extension wall at a radial angle to extension axis of tank extension, a combustor at least partially in the extension space and in fluid communication with the air inlet, and a plurality of heat exchange tubes configured to receive products of combustion from combustor and extending into interior space of the water tank. The extension space is configured to be flooded with water from the water tank.

Abstract: A water heater. The water heater includes a water circuit adapted to conduct water to be heated, a combustion system operable to produce products of combustion and operable to provide the products of combustion to heat water in the water circuit, and a fuel train assembly configured to provide fuel to the combustion system. The fuel train assembly includes a gas expansion chamber, a first gas shut-off valve positioned upstream of the expansion chamber, and a second gas shut-off valve positioned downstream of the expansion chamber.

Abstract: A storage-type water heater. The storage-type water heater comprising a water storage tank configured to retain tank water, means for heating the tank water in the water storage tank, and an anti-stacking pump assembly. The anti-stacking pump assembly includes a water tube configured to be positioned in the water storage tank, an impeller positioned within the water tube, a motor drivingly connected to the impeller, a water inlet formed in the water tube upstream of the impeller and configured to deliver tank water into the water tube from the water storage tank, and a water outlet formed in the water tube downstream of the impeller.

Abstract: A water heater. The water heater includes a water tank having a tank wall defining an interior space and adapted to contain water to be heated, a tank extension having an extension wall detachably mounted to the tank wall, the extension wall defining extension space communicating with the interior space, and defining an extension axis, an air inlet at least partially in the extension space extending through the extension wall at a radial angle to extension axis of tank extension, a combustor at least partially in the extension space and in fluid communication with the air inlet, and a plurality of heat exchange tubes configured to receive products of combustion from combustor and extending into interior space of the water tank. The extension space is configured to be flooded with water from the water tank.

Abstract: A thermal cut-off circuit for a gas-fired device and method of operating the circuit. The thermal cut-off circuit includes a thermal cut-off switch and an ambient thermal switch. The thermal cut-off switch is positioned in a combustion chamber and the ambient thermal switch is preferably positioned in a flow of air entering the combustion chamber. The thermal cut-off circuit ensures a gas valve is closed upon detecting a possible incomplete combustion in the combustion chamber.

Abstract: A blower for a water heater having a flue defining a flue axis. The blower includes a housing at least partially defining a first chamber and a second chamber and having an inlet opening into the first chamber and an outlet communicating between the second chamber and atmosphere, the inlet being alignable with the flue, a ramp extending through the second chamber and having a surface, the surface being oriented at an acute angle with respect to the flue axis, and an impeller positioned in the second chamber and being operable to draw exhaust from the flue into the first chamber through the inlet and being operable to direct the exhaust through the second chamber and across the surface of the ramp, the surface of the ramp directing the exhaust through the outlet in a direction substantially parallel to the flue axis.

Abstract: A thermal cut-off circuit for a gas-fired device and method of operating the circuit. The thermal cut-off circuit includes a thermal cut-off switch and an ambient thermal switch. The thermal cut-off switch is positioned in a combustion chamber and the ambient thermal switch is preferably positioned in a flow of air entering the combustion chamber. The thermal cut-off circuit ensures a gas valve is closed upon detecting a possible incomplete combustion in the combustion chamber.

Abstract: A secondary safety circuit for a gas-fired device and method of operating the circuit. The secondary safety circuit includes a low-voltage direct current power source, a valve, and at least one sensor. The valve can be positioned in a pilot burner gas line. The secondary safety circuit ensures the valve is closed upon detecting an unsafe condition with the sensor.

Abstract: A water heater adapted to be positioned outside of a building and to interface with the plumbing system of the building. The water heater includes a water storage tank adapted to store water outside of the building, a means for heating the water in the tank, a base member supporting the tank outside of the building, and a plurality of water pipes communicating with the water tank. The water heater also includes a manifold that is mounted to the base member and includes a plurality of pipe unions adapted to interface between the plumbing system and the plurality of pipes to provide cold water to the tank and to remove heated water from the tank for use in the building.

Abstract: An apparatus for heating a medium includes a combustion chamber; a burner within the combustion chamber and operable to create products of combustion for heating the medium to be heated; a conduit for the exhaust of the products of combustion; and an airflow apparatus capable of creating airflow in the absence of any opposition to the airflow, the airflow having a pressure, the airflow apparatus communicating with the conduit and operable such that the pressure of the airflow resists standby convection flow of gases out of the conduit when the burner is not operating, and wherein the airflow apparatus is adjustable to vary the magnitude of the airflow to substantially equalize the airflow and the standby convection flow of gases to create a substantially stagnant state within the conduit when the burner is not operating.

Abstract: An apparatus for heating a medium includes a combustion chamber; a burner within the combustion chamber and operable to create products of combustion for heating the medium to be heated; a conduit for the exhaust of the products of combustion; and an airflow apparatus capable of creating airflow in the absence of any opposition to the airflow, the airflow having a pressure, the airflow apparatus communicating with the conduit and operable such that the pressure of the airflow resists standby convection flow of gases out of the conduit when the burner is not operating, and wherein the airflow apparatus is adjustable to vary the magnitude of the airflow to substantially equalize the airflow and the standby convection flow of gases to create a substantially stagnant state within the conduit when the burner is not operating.

Abstract: A water heater includes a water tank adapted to contain water; a flue extending through the water tank and having a first end communicating with the water heater's combustion chamber for the flow of products of combustion through the tank; a damper communicating with the flue; and an apparatus for creating a flow of air proximate the second end of the flue to resist the flow of warm air out of the second end of the flue due to standby convection.

Abstract: A method and apparatus for mounting a water heater on the roof of a building or at another location outside of the building. A roof curb surrounds a hole in the roof, and a base member is mounted to the roof curb. Alternatively, the base member is mounted on a concrete pad at ground level. A water tank is mounted to the base member with the longitudinal axis of the water tank extending horizontally. Support rails are mounted to the base member, and wedge-shaped supports are mounted to the support rails. The wedge-shaped supports are interconnected with tank mounted brackets that are mounted to the sides of the water tank. Thermally insulated spacers are interposed between the wedge-shaped supports and the tank mounting brackets.

Abstract: A water heater includes a water tank adapted to contain water; a flue extending through the water tank and having a first end communicating with the water heater's combustion chamber for the flow of products of combustion through the tank; a damper communicating with the flue; and an apparatus for creating a flow of air proximate the second end of the flue to resist the flow of warm air out of the second end of the flue due to standby convection.

Abstract: A water heater adapted to be mounted on the rooftop of a building includes a substantially cylindrical tank having a horizontally-oriented longitudinal axis. A U-shaped flue tube has a burner end and an exhaust end, both ends being mounted in a head portion of the tank. The legs of the flue tube define a flue plane that is preferably angled 30°-60° with respect to vertical. An inlet tube and an outlet tube also extend through the head of the tank. The inlet tube is positioned at the bottom of the tank and has holes that open downwardly only; the outlet tube is positioned at the top of the tank and has holes that open upwardly only. The tank is weather-tightly enclosed by a cabinet. A base member of the cabinet is supported by a roof curb and supports the water tank. The base member includes a drain opening for draining water from the inside the cabinet to the sewage system of the building, and a water pipe opening through which extend a plurality of pipes communicating with the tank.

Abstract: A water heater adapted to be positioned outside of a building and to interface with the plumbing system of the building. The water heater includes a water storage tank adapted to store water outside of the building, a means for heating the water in the tank, a base member supporting the tank outside of the building, and a plurality of water pipes communicating with the water tank. The water heater also includes a manifold that is mounted to the base member and includes a plurality of pipe unions adapted to interface between the plumbing system and the plurality of pipes to provide cold water to the tank and to remove heated water from the tank for use in the building.

Abstract: A water heater includes a water tank adapted to contain water; a flue extending through the water tank and having a first end communicating with the water heater's combustion chamber for the flow of products of combustion through the tank; a damper communicating with the flue; and an apparatus for creating a flow of air proximate the second end of the flue to resist the flow of warm air out of the second end of the flue due to standby convection. The apparatus for creating airflow may be a fan or an ionic wind generator. Additionally, the airflow may be directed into or across the end of the flue at the top of the water heater to either create a downdraft or an air curtain for containing warm air within the flue.