A gas valve for a gas appliance of a gas burner system. The gas valve is connected to a gas source via a gas pipe. The gas valve is disposed with a check valve body, wherein the check valve body allows gas in the gas pipe to flow into the gas valve and prohibits the gas in the gas valve to flow into the gas pipe so the check valve body can thereby prevent the gas in the gas valve from flwoing back to the gas pipe. When gas in the gas pipe flows to to another gas appliance of the gas burner system, the gas flowing to another gas appliance does not mix with air in the gas appliance, thereby reducing the iginition time and enhancing the combustion efficiency.

A fluid heating system may be installed for residential and commercial use, and may deliver fluid at consistent high temperatures for cooking, sterilizing tools or utensils, hot beverages and the like, without a limit on the number of consecutive discharges of fluid. The fluid heating system is installed with a tankless fluid heating device that includes an inlet port, an outlet port, at least one heat source connected with the inlet port, and a valve connecting the at least one heat source to the outlet port. A temperature sensor is downstream of the at least one heat source and connected to the valve. Another temperature sensor is on the heat source to enable it to be kept at an elevated temperature. The valve is operated so that an entire volume of a fluid discharge from the fluid heating system is delivered at a user-specified temperature on demand, for every demand.

Provided is a method of disinfecting a hot water supply system having a plurality of controllable hot-water outlets and a water heating arrangement including an energy store comprising a phase change material that has a phase transition temperature of less than 60 Celsius, the method comprising: informing an operator of a future disinfection event; increasing a hot water supply temperature from a pre-event temperature of less than 60 Celsius to a disinfection temperature; providing a signal to the operator to cause the operator to open a first of the hot water outlets; providing a signal to the operator to close the first outlet after a disinfection period; providing a signal to the operator to open another hot water outlet; providing a signal to the operator to close the another hot water outlet after a disinfection period; and repeating the signalling to the operator to open and then, after a disinfection period, to close each of the plurality of controllable hot-water outlets; reducing the hot water supply temperature to the pre-event temperature of less than 60 Celsius from the disinfection temperature; and indicating to the operator the completion of the disinfection event. A corresponding hot water supply system is also provided, the system preferably including a heat pump.

A water heater with a housing having an internal chamber, an inlet port, and an outlet port; a heating element coupled to the housing; a water inlet line; a water outlet line; an inlet temperature sensor within the water inlet line; an outlet temperature sensor within the water outlet line; and a controller electrically connected to the inlet temperature sensor, the outlet temperature sensor, and the electrically power heating element. The controller is operable to detect a flow condition without using mechanical flow detection means and without supplying stand-by heating by adding an absolute value of the sensed change in temperature of water flowing upstream from the inlet port to the absolute value of the sensed change in temperature of the water flowing downstream from the outlet port to yield a sum and comparing the sum to a reference temperature.

A water heater (10) is suitable for point-of-use applications. The water heater includes a first temperature sensor, a second temperature sensor, and a controller connected to the first and second temperature sensors. The controller is configured to receive the signals generated by the first temperature sensor and the second temperature sensor and to detect a flow condition of water within the heat without using mechanical flow detection means and without supplying stand-by heating by adding an absolute value of the sensed change in temperature of water at the first temperature sensor to the absolute value of the sensed change in temperature of water at the second temperature sensor to yield a sum and then comparing the sum to a reference temperature.

A jacket for a hot water heater appliance includes a top, bottom, front, back, and a fastener. The top is configured to insulate an upper portion of a hot water tank. The bottom is configured to insulate a lower portion of the hot water tank. The front is configured to insulate a front portion of the hot water tank. The back is configured to insulate a back portion of the hot water tank. The fastener is configured to releaseably fasten the front to the back. The top, bottom, front and back include expanded polypropylene (EPP) configured to provide insulation to the hot water tank.

The disclosed technology includes an on-demand water heater which uses a heat pump to heat the fluid. The on-demand heat pump water heater can have a low fluid capacity heating chamber which has an inlet and an outlet, a heat pump for heating the fluid, and a controller to control the heat pump and maintain the temperature of the fluid at a predetermined temperature. The on-demand heat pump water heater can include one or more temperature sensors, flow sensors, fluid mixing valves, or supplemental heat sources.

A hydronic system, of the present disclosure, includes a control unit including a memory comprising stored instructions and a processor configured to execute the stored instructions to cause the control unit to perform at least monitoring, a volume of hot water in a hot storage tank via a first set of flowmeters, monitoring, a volume of chilled water in a cold storage tank via a second set of flowmeters, monitoring, a first outlet temperature of the hot water within the hot storage tank via a first temperature sensor and a second outlet temperature of the chilled water within the cold storage tank via a second temperature sensor, and operating, a heat pump unit for recharging the hot water and the chilled water within the hot storage tank and the cold storage tank respectively. The heat pump unit is operated when a respective predetermined limit reaches for anyone of identified parameters.

A hydronic system includes a control unit configured to monitor a volume of water and an outlet temperature using flowmeters and temperature sensors, respectively. The control unit is configured to operate a heat pump to recharge a storage tank when a respective predetermined limit is reached for the volume of water or the outlet temperature. The control unit is configured to determine a time period based on the volume, the outlet temperature, and an operation cycle that may be on-peak or off-peak. The operation cycle is determined using day-ahead hourly prices, a temperature forecast, or a greenhouse gas emissions forecast. During an on-peak operation cycles, the control unit is configured to operate the heat pump unit instantaneously within the determined time-period. In an off-peak operation cycle, the control unit is configured to operate the heat pump unit selectively based on a cost and a schedule of a power source.

A water heater system including a boiler having a heat exchanger and an indirect water heater having a heat exchanger, and a controller configured to activate a pump such that the water flows between the boiler heat exchanger and the indirect water heater heat exchanger, and to control a heat source to provide heat to the boiler at a firing rate. The water heater system measuring temperatures of the water at the boiler water inlet and at the boiler water outlet, calculating an amount of heat transfer from the boiler heat exchanger to the indirect water heater exchanger based on the measured temperatures, and adjusting the firing rate based on the calculated amount of heat transfer to determine a heat transfer capacity of the indirect water heater exchanger.