A room heater is operated on receiving an on-command from a thermostat when a detected temperature detected by a second room-temperature detector falls below a first reference temperature, and is stopped on receiving an off-command when the temperature detected by the second room-temperature detector is above a second reference temperature that is set higher than the first reference temperature or when the thermostat is manually operated to be switched off. A setting temperature for temperature control to be carried out when the on-command is received again is updated according to a difference between the set temperature and the temperature detected by the first room-temperature detector on receiving the off-command. When the off-command is received before passing a predetermined period of time after receiving the on-command, the updating of the set temperature is prohibited if the temperature detected by the first room-temperature detector is below a predetermined minimum lower reference temperature.

A water heater includes a first heater, a second heater, and a controller. The controller can enable different operational modes of the water heater, wherein only the first heater operates, only the second heater operates, or both the first and the second heaters operate. The controller can also be configured to enable a hybrid operational mode and a bypass operational mode. Further, in the different operational modes, the controller can direct water flow to at least one of a first conduit coupled to the first heater, a second conduit coupled to the second heater, and a bypass conduit. The controller can be configured to receive input signals relating to environmental conditions around the water heater and/or an aquatic system in which the water heater is installed.

One or more techniques and/or systems are disclosed for a portable heater that may be used in an area used for human occupancy, to provide heat to that area. Such a heater can be portable, and comprise an environmental detector that senses ambient air conditions, and may provide data used to shut down the heater in threshold conditions. In one implementation, a portable heater for use in high altitudes can comprise a housing configured for portability, in which a combustion region and a fuel supply component are disposed. The heater can comprise an environmental detector with a flameless sensor configured to detect an ambient level of a constituent of the atmosphere, and generate a signal indicative of the constituent level; and a sensor interface that can control flow of fuel from the fuel supply, based at least upon a signal received from the sensor.

One or more techniques and/or systems are disclosed for a vent-free heater that may be installed in an area used for human occupancy, to provide heat to that area. Such a heater can comprise an environmental detector that senses ambient air conditions, and may provide data used to shut down the heater in predetermined threshold condition. In one implementation, a vent-free heater for installation in high altitudes can comprise a combustion region and a fuel supply component. The heater can comprise an environmental detector with a flameless sensor configured to detect an ambient level of a constituent of the atmosphere and generate a signal indicative of the constituent level; and a sensor interface that can control flow of fuel from the fuel supply, based at least upon a signal received from the sensor.

This disclosure is related to devices, systems, and techniques for outputting an alarm signal in response to detecting a leak in a water heater device. For example, a water heater device includes a leak sensor, an intermittent pilot light, and a circuit. The circuit includes processing circuitry configured to receive, from the leak sensor, an electrical signal including information indicative of a leak in the water heater device, activate, based on the electrical signal including information indicative of the leak, an alarm device, where the alarm device is powered for at least a period of time by a power source, where the power source is configured to receive energy from a thermoelectric device, and maintain an amount of energy stored by the power source so that the amount of energy is sufficient for the power source to supply energy to the alarm device.

A blower assembly is configured for use with a gas-operated heater having a burner and an exhaust port. The blower assembly has a blower and a sensor. The blower is configured to operate at two or more speeds and is configured to operatively connect to the burner in a manner to facilitate flow of combustion air into the burner and to facilitate flow of exhaust through the exhaust port. The sensor is configured to be sensitive to pressure of exhaust downstream of the blower. The sensor is operatively connected to the blower in a manner such that the blower will change speeds if said pressure exceeds a threshold pressure.

A hot water supply apparatus has: a thermo-sensitive valve which is connected in parallel to a cold water delivery pipe and a hot water delivery pipe and which is closed when the hot water temperature to flow inside the valve is above a predetermined temperature to thereby shut off communication between the cold water delivery pipe and the hot water delivery pipe; and a circulation pump. By operation of the circulation pump, water circulation takes place from a heat exchanger through the hot water delivery pipe, a return pipe, the circulation pump, and a cold water supply pipe back to the heat exchanger. When the thermo-sensitive valve is open, water circulation takes place also through the thermo-sensitive valve. Instantaneous hot water supply operation is finished when an amount detected by a flow sensor falls below a predetermined amount during the instantaneous hot water supply operation.

A water heater system includes a controller configured to integrate control of both recovery and recirculation operations of a recovery pump and a recirculation pump. As such, a separate device, installation location, and power source (e.g., available outlet) is not needed with the controller. Because a single controller is configured to control both recovery and recirculation operations, additional control functions are available. The controller may be in communication with an internal controller of the water heater and configured to receive an error notification upon abnormal operation of the water heater. The controller can stop recovery and recirculation operations in response to an error notification, unlike with traditional water heating systems which may otherwise continue to function. The recovery and recirculation operations are based on a setpoint temperature of the water heater such that changes made to the setpoint temperature will automatically adjust in the recovery and recirculation operations.

A water heater monitoring and notification method includes determining, by a controller of a water heater system, a deviation of a duration of a pre-purge operation from a pre-purge duration average value. The method further includes determining, by the controller of the water heater system, a deviation of a flame current from a flame current average value and determining, by the controller of the water heater system, a deviation of a pulse-width-modulation (PWM) parameter from a PWM parameter average value. The method also includes providing a notification related to a combustion system of the water heater system based on at least the deviation of the duration of the pre-purge operation from the pre-purge duration average value, the deviation of the flame current from the flame current average value, and the deviation of the PWM parameter from the PWM parameter average value.

Some aspects of the present disclosure relate to a sensor probe kit that has an electrical connection that ensures a sensor probe has been properly positioned in a boiler well. In some embodiments, the sensor probe kit has a seating mechanism that positively positions a sensor probe at a predetermined position within a boiler well. In many instances, the seating mechanism provides tactile feedback to an installer when the sensor probe is properly positioned within the boiler well. These features can help ensure the sensor probe is properly installed, and helps keep the sensor probe electrically connected to the well at all times after installation.