A method, system or computer usable program product for controlling an on-demand hot water heater including providing a plurality of nodes for receiving hot water from an on-demand hot water heater in a hot water delivery system, receiving a demand with a node identifier for hot water at a node, determining a hot water temperature for the node from a centralized database, the database including a set of node identifiers with a corresponding set of preset hot water temperatures, and controlling a temperature of hot water flowing from the water heater based on the determined hot water temperature.

The present invention becomes possible to employ a main microprocessor with a relatively lower number of input ports, whereby while maintaining the performance and function of a water heater, the cost of a control apparatus is cut down. Some of sensors, adapted for measurement of various parameters which are for use in operational control of the water heater and in need of immediate response, are connected to a main microprocessor 31. The other sensors that are not in need of an immediate response, such as an ambient temperature sensor 36, are connected only to a sub microprocessor 32 if the main microprocessor 31 does not have any extra analog signal input port. The sub microprocessor converts an analog signal from the sensor 36 which is connected only to the sub microprocessor into digital data. And the sub microprocessor transmits the digital data to the main microprocessor through communication therewith.

A method of controlling a gas furnace system includes determining a first pressure in a conduit coupled to a draft inducer from signals output by a pressure transducer positioned to sense a pressure within the conduit with a motor of the draft inducer in a stopped condition. A first status of the pressure transducer is determined based at least in part on the first pressure. The motor of the draft inducer is controlled to increase a speed of the motor from the stopped condition in response to a call for heat when the first status does not indicate that the pressure transducer is unreliable, and the motor is maintained in a stopped condition when the first status indicates that the pressure transducer is unreliable.

A method of controlling a gas furnace system includes controlling a motor of a draft inducer coupled to a conduit to increase a speed of the motor from a stopped condition in response to a call for heat, and receiving pressure signals output by a pressure transducer responsive to pressure in the conduit. Signals indicating whether a pressure switch responsive to pressure in the conduit is in a first state or a second state are received. A first status of the pressure transducer is determined based on the received pressure signals from the pressure transducer and the signals indicating whether the pressure switch is in the first state or the second state. The method includes continuing to operate the motor when the first status does not indicate that the pressure transducer is unreliable, and stopping the motor when the first status indicates that the pressure transducer is unreliable.

A device to store energy includes a phase change material (PCM), with a phase change temperature Tc, contained in a sealed container and constituting a storage core. A source to exchange heat with the PCM, at a temperature TA, to cause a phase change of the PCM. A recuperator to exchange heat with the PCM, at a temperature TB, to cause a phase change of the PCM in the opposite direction to the phase change produced by the source. A controller to control the heat flows between the PCM, the source and the recuperator. An apertured support in contact with the PCM in the sealed container and in thermal contact with the source and the recuperator.

A demand based control for a hydronic heating system varies the heat response based on an actual demand of the conditioned space, rather than an estimated thermal loss. Differences between supply and return of a heat transfer medium, such as forced hot water, are measured for the conditioned space, as well as the flow rate of the forced water to determine an actual thermal transfer to the conditioned space. A required heat generation is computed based on the measured transfer and resultant temperature change of the conditioned space, and heat generation parameters such as boiler firing rate and circulator pump speed varied to control the heat transfer to the conditioned space and avoid overshoot or excessive heat generation beyond that needed for the measured demand.

A method controls an air handler that generates heated air from hot water generated by a water heater. The method includes generating a signal in the presence or absence of an indicia of water flow associated with the water heater; initiating operation of a pump associated with the air handler when the signal indicates that water flow associated with the water heater is at least at a selected level to supply hot water to the air handler sufficient to generate heated air; and/or terminating operation of the pump and/or a blower/fan associated with the air handler when the presence or absence signal indicates that the water flow associated with the water heater is less than the selected level.

This invention provides an electronic control for combination (fuel-fired boiler and electric heat pump) building space and water heating systems that optimizes operation of such within the operating temperature limits and heat capability of both the heat pump and boiler unit in the combination system. In a diagnostic mode, the controller assesses the ability of existing heat radiation systems in thermostatically controlled zones to meet heating loads at different operating temperature limits of the heat pump and boiler. The system/controller provides information to guide most effective deployment of system heat-dissipation devices. In its normal operating mode, the controller is capable of receiving input signals from zone thermostats, the boiler and heat pump, along with current outdoor temperature and other data, processing and evaluating inputs over time, and outputting control signals. The controller facilitates use of a combined heat pump and boiler heating system with minimum equipment, installation, and operational cost.

A water heater system includes a water heater having a first water outlet and a second water outlet. The water heater system further includes a flow detection device coupled to the first water outlet to detect a water flow through the first water outlet. The water heater system also includes a flow control valve fluidly coupled to the second water outlet. The flow control valve is configured to control a flow of water through the second water outlet based on whether the water flow through the first water outlet is detected by the flow detection device.

The disclosed technology includes a controller for a cascade boiler system having both condensing and non-condensing boilers. The controller can receive supply water temperature data and return water temperature data to determine a current temperature differential in the system. The controller can determine a current load demand value using the current temperature differential and a set point temperature. If the current load demand value is less than or equal to a first load demand threshold, the controller can output a control signal for a condensing boiler to transition to a heating mode. If the current load demand value is greater than a second load demand threshold, the controller can output a control signal for a non-condensing boiler to transition to a heating mode.